EP4294814A1

EP4294814A1 - Metal complexes having 4-h, 6-h or 8-h dihydroazulenyl ligands and use thereof

Info

Publication number: EP4294814A1
Application number: EP22704360.1A
Authority: EP
Inventors: Tobias Vollgraff; Joerg Sundermeyer; Angelino Doppiu
Original assignee: Umicore AG and Co KG
Current assignee: Umicore AG and Co KG
Priority date: 2021-02-18
Filing date: 2022-02-04
Publication date: 2023-12-27
Also published as: EP4047003A1; CN116917295A; WO2022175111A1; JP2024507790A; US20240317779A1

Abstract

The invention relates to a process for preparing compounds of the general formula M^AY_n(AzuH) (I), where M^A = alkali metal, Y = neutral ligand, n = 0, 1, 2, 3 or 4. AzuH is azulene (bicyclo[5.3.0]decapentaene) or an azulene derivative that bears a hydride anion H- in the 4, 6 or 8 position in addition to a hydrogen atom. The invention additionally provides compounds obtainable by this process, and a process using such compounds for preparation of complexes of metals of groups 6 to 12. The invention further relates to complexes of middle and later transition metals (groups 6 to 12) which each have at least one H-dihydroazulenyl anion (AzuH)¹-, and to the use of all the aforementioned transition metal complexes as precatalysts or catalysts or electron transfer reagents in a chemical reaction or as precursor compounds for production of a layer containing a metal M, or of a metal layer consisting of the metal M, especially on at least one surface of a substrate. The invention also provides a substrate obtainable by such a process.

Description

___________________________________________________________________ Metal complexes with 4-H-, 6-H- or 8-H-dihydroazulenyl ligands and their use ___________________________________________________________________ Homoleptic and heteroleptic metal complexes with anionic ligands which are derived from bicyclo[5.3.0]decapentaene (azulene) or mono- or polysubstituted azulene , i.e. H. Azulene derivatives derived, as well as processes for their preparation are known. Azulene and azulene derivatives, which z. B. in the 4-position have an alkyl or aryl substituent instead of an H atom, belong to the ortho-fused aromatic ring systems. They exist as neutral zwitterions. Anionic ligands derived from azulene or azulene derivatives can be obtained, for example, by addition of an alkali metal organyl, e.g. B. methyllithium or phenyllithium, in the 4-position, in the 6-position or in the 8-position of an azulene molecule or an azulene derivative. The product in question is an alkali metal dihydroazulenide which, in addition to an H atom, carries an organyl group in the 4-position, 6-position or 8-position, e.g. B. a methyl group or a phenyl group. Consequently, an RCH group is present in the C4 position or in the C6 position or in the C8 position of the azulene skeleton, where R is an organyl group. It should be noted that azulene has comparable electrophilicity in the 4-position, 6-position and 8-position. Therefore, the formation of regioisomers can occur. Because azulene also has a C_2v- symmetry, the products of the addition reaction are an alkali metal 4-organo-dihydroazulenide and/or an alkali metal 6-organo-dihydroazulenide. The respective anion can be referred to as a 4-organo-dihydroazulenyl anion or as a 6-organo-dihydroazulenyl anion. More specifically, it is a 3α,4-organo-dihydroazulenyl anion or a 3α,6-organo-dihydroazulenyl anion. If, instead of an alkali metal organyl, an alkali metal hydride, e.g. B. lithium hydride, in the 4-position, in the 6-position or in the 8-position of an azulene molecule or an azulene derivative, the result of the addition reaction is in each case an alkali metal dihydroazulenide which is in the 4-position, 6-position or 8 position carries an H atom and a hydride anion H-. Consequently, there is a CH in the C4 position or in the C6 position or in the C8 position of the azulene skeleton₂-group before. In the case of azulene, the respective anion can be referred to as a 4-H-dihydroazulenyl anion or as a 6-H-dihydroazulenyl anion. More specifically, it is the 3α,4-H-dihydroazulenyl anion or the 3α,6-H-dihydroazulenyl anion. Irrespective of the substitution pattern, the conjugated pi system is restricted to the five-membered ring by hydride addition. As a rule, the blue color typical of azulene is lost. With dihydroazulenyl anions, i. H. Organo-dihydroazulenyl anions and H-dihydroazulenyl anions are cyclopentadienyl-like monoanions or derivatives of the cyclopentadienyl anion. Therefore, like the cyclopentadienyl anion (Cp-), they are suitable, among other things, as ligands for the preparation of sandwich complexes of the metallocene type. With regard to production and storage, lithium dihydroazulenides have a number of advantages, especially compared to lithium cyclopentadienide (LiCp). A disadvantage of the chemistry of the cyclopentadienyl ligand, one of the most important ligands in organometallic chemistry, is that it is based on petroleum. The provision of LiCp first involves the thermal cracking of dicyclopentadiene into its monomer cyclopentadiene in the presence of a catalyst, e.g. B. Iron powder. After this first step, cyclopentadiene must be consumed quickly or stored in the freezer. Otherwise it quickly dimerizes back to dicyclopentadiene. In a second step, cyclopentadiene is reacted with a strong base, e.g. B. a lithium alkyl, usually the relatively expensive n-butyllithium. Examples of transition metal complexes containing dihydroazulenyl anions, i. H. Cyclopentadienyl-like monoanions or cyclopentadienyl derivatives as ligands are described, inter alia, in a review article by M. R. Churchill. (Prog. Inorg. Chem.1970, 54 – 98, Chapter IV., Section C.) Knox and Pauson (J. Chem. Soc.1961, 4610 – 4615) succeeded in the in situ production of lithium-3α,4- dihydroazulenide in the synthesis of the complex bis(3α,4-dihydroazulenyl)iron(II), which was obtained as a mixture of three isomers. The lithium azulenide was obtained by addition of a hydride anion to azulene using LiAlH₄ (Equimolar) shown as the hydriding reagent. This is based on a specification by Hafner and Weldes (Liebigs Ann. Chem.1957, 606, 90-99) for the synthesis of lithium-4-methyl-dihydroazulenide. Disadvantages of the synthesis described by Knox and Pauson are the long reaction time of 60 days and, in particular, the formation of aluminum trihydride (AlH₃) as a by-product. The strong Lewis acid AlH₃ can due to their - in comparison to the originally used LiAlH₄ - enter into further reactions with high reactivity, for example towards metal precursor compounds such as iron(II) chloride. It is also possible to form adducts with lithium 3α,4-dihydroazulenide and/or the ethereal solvent, such as e.g. B.H₃Al x OEt₂. Etherates of general formula H₃Al x ether, lying after a certain time usually as a highly polymeric, insoluble (AlH₃)_x before. Consequently, the reaction of the in situ generated lithium 3α,4-dihydroazulenide reported by Knox and Pauson is relevant in terms of purity and yield of the desired secondary products, e.g. B. complexes of the metallocene type, unfavorable. Because inevitably with H₃Al x ether or (AlH₃)_x contaminated products, in particular metal complexes, which cannot be purified at all or can only be purified with difficulty. In addition, from (AlH₃)_x basically there is a risk potential. It breaks down into its components above 100 °C, is extremely sensitive to moisture and oxidation and burns explosively in air. As a result, there is an increased preparative effort, in particular with regard to the safety measures to be taken. Edelmann's group (J. Richter, P. Liebing, FT Edelmann, Inorg. Chim. Acta 2018, 475,18-27) recently published their results regarding the synthesis of metallocene complexes of the early transition metals titanium and zirconium and the lanthanide neodymium, which have dihydroazulenyl ligands. The lithium dihydroazulenides used in the synthesis of metal complexes, namely lithium 4-methyldihydroazulenide, lithium 7-isopropyl-1,4,8-trimethyldihydroazulenide and lithium 7-isopropyl-1,4-dimethyl -8-phenyldihydroazulenide, were prepared analogously to the method of Hafner and Weldes (Liebigs Ann. Chem.1957, 606, 90-99), i. H. starting from azulene or 7-isopropyl-1,4-dimethylazulene (guajazulene) and methyl or phenyllithium. However, to obtain solvent-free products, the isolated lithium dihydroazulenides were washed with n-pentane instead of diethyl ether. Furthermore, lithium 7-iso-propyl-1,4-dimethyldihydroazulenide was generated in situ by addition of a hydride anion at the 8-position of guaiazulene. The hydrogenation reagent LiAlH₄ - In contrast to the instructions of Knox and Pauson (J. Chem. Soc.1961, 4610 - 4615) not in a stoichiometric amount, but used in excess. According to Edelmann and co-workers, only two heteroleptic sandwich complexes of zirconium(IV) could be isomerically prepared in low yields of 19% and 30%. In summary, the authors state that dihydroazulenyl anions and similar azulene-derived anions initially seemed promising as ligands for the preparation of early transition metal metallocenes and the lanthanides. However, according to the synthesis protocols they describe, the metallocene complexes are in most cases only available as isomer mixtures. Consequently, the synthetic value of dihydroazulenyl ligands for organometallic chemistry and mono- and bis-dihydroazulenyl complexes derived from them is significantly reduced. In summary, it can be stated that the chemistry of the dihydroazulenyl ligands described so far, that is, of organo-dihydroazulenyl ligands and H-dihydroazulenyl ligands, applies almost entirely to the d-electron-poor early transition metals of Group 4, i. H. titanium(IV) and zirconium(IV), as well as the lanthanides, i. H. Neodymium(III), with the d electron configuration d⁰ limited. Complexes of dihydroazulenyl ligands with transition metals having a d-electron configuration greater than d⁰ have, i.e. d^a with a = 1 to 10, very few are known. The only known example of a homoleptic bis-dihydroazulenyl transition metal complex, i.e. without additional chloro-ligands or the like, is the d⁶- Metal complex bis(3α,4-dihydroazulenyl)iron(II), i.e. Fe(AzulenH)₂, with two H-dihydroazulenyl ligands (AzulenH)^1-. The d⁶-Cr(0) complex Cr(AzulenH)₂ has an azulenium chromium(0) azuleniate unit, i.e. only one H-dihydroazulenyl ligand (AzulenH)^1-. A disadvantage of the above-described process procedures is - especially with a view to further use of the metal complexes obtainable therewith having at least one dihydroazulenyl ligand - that the metal complexes obtained in many Cases present as mixtures of three or even six isomers that cannot be separated from one another. In the few cases in which an isomerically pure preparation is possible, it is, for example, mixed zirconocenes, namely zirconocene dichlorides (J. Richter, P. Liebing, F. T. Edelmann Inorg. Chim. Acta 2018, 475,18 - 27) . Due to the presence of chloride ligands, the possibilities of further use of these metal complexes can be limited. Another disadvantage of the aforementioned synthesis routes is the use of lithium organyls in the preparation of the lithium dihydroazulenides. Disadvantages of organolithium compounds are in particular their high reducing power, which they have because of their high electropositive character and their nucleophilicity, the associated loss of selectivity and the strong exothermicity of the reactions in which they are involved. In the case of the synthesis of lithium dihydroazulenides using LiAlH₄ AlH disadvantageously falls as the hydride transfer agent₃ as a by-product. As described above, its quantitative separation represents a challenge that can hardly be overcome. This applies in particular to the production of such lithium dihydroazulenides on an industrial scale. Overall, the synthetic routes known from the literature for the preparation of metal complexes with H-dihydroazulenyl ligands can be classified as unsatisfactory from a technological, ecological and (atom) economic point of view. In addition, the selection of metal complexes, in particular the middle transition metals (groups 6, 7 and 8) and the late transition metals (groups 9, 10, 11 and 12), which have at least one H-dihydroazulenyl ligand and in high (isomer) Purity and good yield are extremely limited. The object of the invention is therefore to overcome these and other disadvantages of the prior art and to provide a method with which alkali metal H-dihydroazulenides, ie alkali metal 4-H-dihydroazulenides and/or alkali metal 6-H-dihydroazulenides and/or alkali metal 8-H-dihydroazulenides, can be prepared in high purity and good yields simply, reproducibly and comparatively inexpensively. In particular, the purity of these compounds should meet the requirements for precursor compounds for the preparation of transition metal complexes in high purity and good yield. The process should also be characterized in that it can also be carried out on an industrial scale with a comparable yield and purity of the target compounds and the formation of by-products that are difficult to separate and/or dangerous is avoided or the ability to separate such by-products easily and safely is made possible. In addition, a process for the preparation of metal complexes of middle and late transition metals using the aforementioned alkali metal H-dihydroazulenides is to be provided. By means of this method, metal complexes which have at least one 4-H-, 6-H- or 8-H-dihydroazulenyl ligand should be able to be prepared simply, reproducibly and comparatively inexpensively with high (isomeric) purity and good yield. The present invention also relates to metal complexes of middle and later transition metals which have at least one 4-H-, 6-H- or 8-H-dihydroazulenyl ligand, and their use. The main features of the invention emerge from the patent claims. The object is achieved by a process for preparing compounds of the general formula M^AY_n(AzuH)(I), where - M^A is an alkali metal, - Y is a neutral ligand which can be attached via at least one donor atom to M^A is bonded or coordinated where H₂O is excluded, - n = 0, 1, 2, 3 or 4 and - AzuH = azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom, where Azu = azulene according to the formula or Azu = an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6, C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, comprising the following steps: A. Providing i. Azulene or an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, wherein - at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6, C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and - at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, and ii. at least one hydridic reducing agent Z, B. Reaction of the azulene or the azulene derivative with the at least one hydridic reducing agent Z in a, in particular aprotic-polar, solvent S_P, and - when using at least one alkali metal aluminum tetrahydride M^AAlH₄ as a first hydridic reducing agent Z₁ - C. Provision i. at least one second hydridic reducing agent Z₂ selected from the group consisting of alkali metal hydrides M^AH and/or ii. at least one electron pair donor E, where the electron pair donor E has at least one donor atom, where H₂O is excluded, and D. optionally adding a neutral ligand Y if Y is not equal to S_P and Y is not equal to E. Compounds according to the general formula M^AY_n(AzuH)(I) are referred to herein generically as alkali metal H-dihydroazulenides unless a particular regioisomer is meant, e.g. B. Alkali metal 3α,4-H-dihydroazulenide. The compounds of the general formula I each have an H-dihydroazulenyl anion (AzuH)^1- which is a simply hydrogenated azulene or azulene derivative in the 4-position, in the 6-position or in the 8-position. The respective H-dihydroazulenyl anion (AzuH)^1- has a hydride anion H- in the 4-position or in the 6-position or in the 8-position in addition to an H atom. Consequently, there is a CH in the C4 position or in the C6 position or in the C8 position of the azulene skeleton₂-group before. The H-dihydroazulenyl anion is a derivative of the cyclopentadienyl anion or a cyclopentadienyl-like monoanion. The H-dihydroazulenyl anion can be a 3α,4-H-dihydroazulenyl, an 8,8α-H- dihydroazulenyl, a 3α,6-H-dihydroazulenyl or a 6,8α-H-dihydroazulenyl anion, or a mixture of two or more regioisomers. The leftovers R^f may independently be partially or fully substituted. One or more hydrogen atoms of the respective alkyl, alkenyl, alkynyl or benzyl radical, arene or heteroarene can be replaced, for example, by a halogen atom, d. H. fluorine, chlorine, bromine or iodine. The solvent S_P can also be a mixed solvent containing two or more solvents. One embodiment of the method provides that the solvent S_P comprises or is at least one aprotic-polar solvent. In another embodiment of the process, the solvent is S_P an aprotic polar solvent or a mixture of at least two aprotic polar solvents. According to another embodiment variant, in a solvent mixture S_P contained solvents miscible with each other. In connection with the present invention, two solvents are referred to as miscible if they are miscible at least during the respective reaction, ie are not present as two phases. The order in which a reaction vessel is charged with the starting materials, in particular the azulene or the azulene derivative and the at least one hydridic reducing agent Z, can be freely selected. This also includes the possibility of carrying out steps A. and B. and the optional steps C. and D., i.e. all steps relating to the preparation of the respective target compound, in a single step, i.e. all starting materials and solvents at the same time or almost at the same time to be placed in the reaction vessel. The terms reaction container and reaction vessel are used synonymously in connection with the present invention and are not limited to a volume, a material composition, an equipment or a shape. Suitable reaction vessels are e.g. B. glass flasks, glass-lined reactors, stirred tank reactors, pressure vessels, tubular reactors, microreactors and flow reactors. According to the present invention, the term "hydridic reducing agent" means a reducing agent which has at least one hydridic functionality M^R-H and can thus function as a hydride donor. Here is M^R in particular selected from the group consisting of alkali metals, aluminum and boron. The process described herein for the preparation of a compound according to the general formula M^AY_n(AzuH) (I) can be carried out as a batch process or as a continuous process. M-type compounds^AY_n(AzuH) (I) are by means of the method described here - depending on the in step A. i. provided starting material, which is either unsubstituted azulene or an azulene derivative, d. H. mono- or polysubstituted azulene, is available in pure isomer form or as a mixture of two or three isomers. In the case of the isomers obtainable by means of this process according to the general formula M^AY_nSpecifically, (AzuH) (I) is an alkali metal 3α,4- H-dihydroazulenide and/or an alkali metal 8,8α-H-dihydroazulenide and/or an alkali metal 3α,6-H-dihydroazulenide and/or an alkali metal 6,8α-H-dihydroazulenide. These can be adduct-free or solvent-free, namely when n = 0, or as adducts or solvates with one (n = 1), two (n = 2), three (n = 3) or four (n = 4) neutral ligands Y In solution, the alkali metal ions M regularly solvate^A+, especially when the solvent S_P is an ether or comprises at least one ether. Then, in particular, solvated lithium ions are present in solution, where Y=an ether and n=4, e.g. B.Li(OC₂H₅)₄ or Li(thf)₄. In addition, isolated compounds of the type M^AY_n(AzuH) (I) exist as adducts, where the respective metal cation M^A+ is complexed. Either the solvent S used in the process described here, which in particular contains an ether or consists of one or more ethereal solvents, acts here_P or the electron pair donor E as a neutral ligand Y. Alternatively or in addition to a, in particular ethereal, solvent S_P or an electron pair donor E, the addition of a neutral ligand Y in step D. can be provided. This can be particularly advantageous if the desired compound of type M^AY_n(AzuH) (I) is obtained as a viscous oil which is difficult to handle with a view to further reactions. In such a case, the addition of a neutral ligand Y, in particular an aprotic-polar solvent, can be provided in step D. The neutral ligand Y is advantageously selected from the group consisting of ethers (=alkoxyalkanes), thioethers and tertiary amines, in particular from the group consisting of ethers (=alkoxyalkanes) and thioethers. This is because in this way crystallization of the respective product can be brought about and/or accelerated. In the case of a crown ether, care must be taken to ensure that an inner diameter of the selected crown ether and an ionic radius of the respective metal cation M^A+ correspond with each other. In the present case, the term “alkoxyalkane” means any oxygen-containing ether, for example also glycol dialkyl ether and crown ether. The term "thioether" includes both non-cyclic and cyclic thioethers. Terminally dialkylated mono-, di- or trialkylene glycol dialkyl ethers are also understood as glycol dialkyl ethers. The glycol dialkyl ether provided as the neutral ligand Y is selected in one variant of the method from the group consisting of a monoethylene glycol dialkyl ether, a diethylene glycol dialkyl ether, a triethylene glycol dialkyl ether, a monopropylene glycol dialkyl ether, a dipropylene glycol dialkyl ether, a tripropylene glycol dialkyl ether, a monooxomethylene dialkyl ether, a dioxomethylene dialkyl ether and a trioxomethylene dialkyl ether, their isomer mixtures, and mixtures thereof. In a further embodiment of the process, the glycol dialkyl ether provided as neutral ligand Y is selected from the group consisting of ethylene glycol dimethyl ether CH₃-O-CH₂CH₂-O-CH₃, ethylene glycol diethyl ether CH₃CH₂-O-CH₂CH₂-O-CH₂CH₃, ethylene glycol di-n-propyl ether CH₃CH₂CH₂-O-CH₂CH₂-O-CH₂CH₂CH₃, ethylene glycol diisopropyl ether (CH₃)₂CH-O-CH₂CH₂-O-CH(CH₃)₂, ethylene glycol di-n-butyl ether CH₃CH₂CH₂CH₂-O-CH₂CH₂-O-CH₂CH₂CH₂CH₃, ethylene glycol di-n-pentyl ether CH₃CH₂CH₂CH₂CH₂-O-CH₂CH₂-O-CH₂CH₂CH₂CH₂CH₃, ethylene glycol di-n-hexyl ether CH₃CH₂CH₂CH₂CH₂CH₂-O-CH₂CH₂-O-CH₂CH₂CH₂CH₂CH₂CH₃, ethylene glycol diphenyl ether C₆H₅-O-CH₂CH₂-O-C₆H₅, ethylene glycol dibenzyl ether C₆H₅CH₂-O-CH₂CH₂-O-CH₂C₆H₅, diethylene glycol dimethyl ether CH₃-O-CH₂CH₂-O-CH₂CH₂-O-CH₃, diethylene glycol diethyl ether CH₃CH₂-O-CH₂CH₂-O-CH₂CH₂-O-CH₂CH₃, diethylene glycol di-n-propyl ether CH₃CH₂CH₂-O-CH₂CH₂-O-CH₂CH₂-O-CH₂CH₂CH₃, diethylene glycol di-iso-propyl ether (CH₃)₂CH-O-CH₂CH₂-O-CH₂CH₂-O-CH(CH₃)₂, diethylene glycol di-n-butyl ether CH₃CH₂CH₂CH₂-O-CH₂CH₂-O-CH₂CH₂-O- CH₂CH₂CH₂CH₃, diethylene glycol di-n-pentyl ether CH₃CH₂CH₂CH₂CH₂-O-CH₂CH₂-O-CH₂CH₂-O-CH₂CH₂CH₂CH₂CH₃, diethylene glycol di-n-hexyl ether CH₃CH₂CH₂CH₂CH₂CH₂- O-CH₂CH₂-O-CH₂CH₂-O-CH₂CH₂CH₂CH₂CH₂CH₃, diethylene glycol diphenyl ether C₆H₅- O-CH₂CH₂-O-CH₂CH₂-O-C₆H₅, diethylene glycol dibenzyl ether C₆H₅CH₂-O-CH₂CH₂-O-CH₂CH₂-O-CH₂C₆H₅, propylene glycol dimethyl ether CH₃-O-CH₂CH₂CH₂-O-CH₃, propylene glycol diethyl ether CH₃CH₂-O-CH₂CH₂CH₂-O-CH₂CH₃, propylene glycol di-n- propyl ether CH₃CH₂CH₂-O-CH₂CH₂CH₂-O-CH₂CH₂CH₃, propylene glycol di-n-butyl ether CH₃CH₂CH₂CH₂-O-CH₂CH₂CH₂-O-CH₂CH₂CH₂CH₃, propylene glycol di-n-pentyl ether CH₃CH₂CH₂CH₂CH₂-O-CH₂CH₂CH₂-O-CH₂CH₂CH₂CH₂CH₃, propylene glycol di-n-hexyl ether CH₃CH₂CH₂CH₂CH₂CH₂-O-CH₂CH₂CH₂-O-CH₂CH₂CH₂CH₂CH₂CH₃, propylene glycol diphenyl ether C₆H₅-O-CH₂CH₂CH₂-O-C₆H₅, propylene glycol dibenzyl ether C₆H₅CH₂-O-CH₂CH₂CH₂-O-CH₂C₆H₅, iso-propylene glycol dimethyl ether CH₃-O-CH₂-CH(CH₃)-O-CH₃, iso-propylene glycol diethyl ether CH₃CH₂-O-CH₂-CH(CH₃)-O-CH₂CH₃, iso-propylene glycol di-n-propyl ether CH₃CH₂CH₂-O-CH₂-CH(CH₃)-O-CH₂CH₂CH₃, iso-propylene glycol diisopropyl ether (CH₃)₂CH-O-CH₂-CH(CH₃)-O-CH(CH₃)₂, iso-propylene glycol di-n-butyl ether CH₃CH₂CH₂CH₂-O-CH₂-CH(CH₃)-O-CH₂CH₂CH₂CH₃, iso-propylene glycol di-n-pentyl ether CH₃CH₂CH₂CH₂CH₂-O-CH₂-CH(CH₃)-O-CH₂CH₂CH₂CH₂CH₃, iso-propylene glycol di-n-hexyl ether CH₃CH₂CH₂CH₂CH₂CH₂-O-CH₂-CH(CH₃)-O-CH₂CH₂CH₂CH₂CH₂CH₃, iso-propylene glycol diphenyl ether C₆H₅-O-CH₂-CH(CH₃)-O-C₆H₅, iso-propylene glycol dibenzyl ether C₆H₅CH₂-O-CH₂-CH(CH₃)-O-CH₂C₆H₅, dipropylene glycol dimethyl ether CH₃OH₂CH₂CH₂OH₂CH₂CH₂OH₃, Di-iso-propylene glycol di-n-propyl ether CH₃CH₂CH₂-O-CH₂CH(CH₃)-OCH₂CH(CH₃)-O-CH₂CH₂CH₃, tripropylene glycol dimethyl ether CH₃OH₂CH₂CH₂OH₂CH₂CH₂OH₂CH₂CH₂OH₃, dipropylene glycol dibutyl ether CH₃CH₂CH₂CH₂OH₂CH₂CH₂OH₂CH₂CH₂OH₂CH₂CH₂CH₃, tripropylene glycol dibutyl ether CH₃CH₂CH₂CH₂OH₂CH₂CH₂OH₂CH₂CH₂OH₂CH₂CH₂OH₂CH₂CH₂CH₃, as well as their mixtures. The glycol ethers specified can also be used as isomer mixtures. Diisopropylethylamine (DIPEA) or N,N,N',N'-tetramethylethylenediamine (TMEDA), for example, can be provided as the tertiary amine. Crown ethers are macrocyclic polyethers whose ring consists of several ethyloxy units (-CH₂-CH₂-O-) exists. They possess the ability to complex cations under formation of coronates. When the inner diameter of a crown ether and the ionic radius of a metal cation match, extremely stable complexes are formed. For example, the crown ether [18]-crown-6 is a very good ligand for a potassium ion, while z. B. the crown ether [15]-crown-5 is particularly well suited for the complexation of a sodium ion. A lithium ion can e.g. B. be very well complexed by the crown ether [12]-crown-4. By exchanging the oxygen atoms for other heteroatoms, e.g. As nitrogen, phosphorus or sulfur, aza, phospha or thia derivatives of the crown ether are accessible. In another variant of the method, the neutral ligand Y is a crown ether selected from the group consisting of macrocyclic polyethers and their aza, phospha and thia derivatives, with an inner diameter of the crown ether and an ionic radius of M^A correspond with each other. A further embodiment of the method provides that - the solvent S_P and the neutral ligand Y and/or - the neutral ligand Y and the electron pair donor E and/or - the solvent S_P and the electron pair donor E are miscible or identical. According to yet another embodiment of the method, the solvent is S_P and/or the neutral ligand Y is an ether. For example, the ether can be a non-cyclic or a cyclic ether selected from the group consisting of dialkyl ethers, cyclopentylmethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, tetrahydropyran, 1,4-dioxane, and their isomers, and mixtures thereof, in particular from the group consisting of diethyl ether, methyl tert-butyl ether, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, diisobutyl ether, di-tert- butyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, tetrahydropyran, 1,4-dioxane, and their isomers, and mixtures thereof. Advantageous to the process claimed here for the preparation of compounds according to the general formula M^AY_n(AzuH) (I) is that it is simple and reproducible and—depending on the choice of starting materials—sustainable and relatively inexpensive to carry out. The target compounds are also obtained in a high purity of at least 97%, advantageously more than 97%, in particular more than 98% or 99%, and in good yields, including space-time yields, of ≧60%. In general, the end product can still contain residues of solvents or, for example, impurities from the starting materials. It is known to those skilled in the art that the level of impurities, such as e.g. B. of solvents, using gas chromatographic methods (GC), if necessary with mass spectrometry coupling (GC-MS), can be determined. “Space-time yield” is understood here to mean an amount of product formed per space and time within a reaction container or reaction vessel. In particular, the preparation of compounds according to the general formula M^AY_n(AzuH) (I), where AzuH = GuaH = 7-iso-propyl-1,4-dimethyl-8-H-dihydroazulene, is advantageously rated as sustainable. Because in this case the target compounds, which include cyclopentadienyl-like ligands, can be produced starting from inexpensive renewable raw materials. The target price of starting from the natural substance guajol and other azulene formers by simple dehydration and dehydration (T. Shono, N. Kise, T. Fujimoto, N. Tominaga, H. Morita, J. Org. Chem.1992, 57, 26, 7175 – 7187; CH 314487 A (B. Joos) 01/29/1953) accessible partially synthetic guaiazulens is €74.70 per 25g (Sigma Aldrich, 12/2020). It is particularly advantageous that during the reaction of the azulene or azulene derivative with the at least one hydridic reducing agent Z such as Lithium triethylborohydride, in most cases - except e.g. B. when using at least one alkali metal aluminum tetrahydride M^AAlH₄ – only by-products, such as e.g. B. triethylborane, which in the used, in particular aprotic-polar, solvent S_P, show very good solubility and are therefore easily separated from the respective target compound M^AY_n(AzuH) (I) are separable. The very good solubility of by-products such. B. triethylborane, is in particular in cyclic and non-cyclic ethers, such as. B.Et₂O, dimethyl ether, diethyl ether, methyl tert-butyl ether, di-n-propyl ether, diisopropyl ether, their isomers, and mixtures thereof. In contrast, the alkali metal H-dihydroazulenides of the M type obtainable by the process described here^AY_n(AzuH) (I) in the, in particular aprotic-polar, solvent S_P, especially in non-cyclic ethers such as. B.Et₂O, dimethyl ether, diethyl ether, methyl tert-butyl ether, di-n-propyl ether, diisopropyl ether, their isomers, and mixtures, insoluble or nearly insoluble. Thus, the product can be quantitatively separated by means of a simple filtration step and/or by centrifugation and/or decantation. The compound of general formula M obtained in the form of a solid, liquid or oil^AY_n(AzuH) (I) may be stored and/or or directly combined with one or more other compounds, e.g. B. a metal complex with anionic leaving groups, z. a metal salt, e.g. B. FeCl₂, RuCl₂, CoCl₂ or Pd(OAc)₂, or an organometallic precursor with anionic leaving groups such as B. [Rh(cod)Cl]₂ (cod = 1,5-cyclooctadiene), [PtMe₃I]₄, [(p-cymene)RuCl₂]₂, [CpCrCl₂] or [Ir(nbd)Cl]₂ (nbd = norbornadiene) are reacted. Alternatively or additionally, the respective product of type M^AY_n(AzuH) (I) are subjected to isomer separation and/or one or more purification steps, e.g. B. at least one washing step with a particularly aprotic-polar solvent. The latter can be an ethereal or non-ethereal solvent. Used as solvent S_P e.g. B.Et₂O is chosen and the product is to be named Et₂O adduct, e.g. B.M^A(Et₂O)₂(AzuH) (I), are present, it is advisable to also use Et₂to choose. If, on the other hand, a solvent-free, in particular ether-free, product M^AY_n(AzuH) (I), where n = 0, desired, the solvent for the washing step should advantageously be an aprotic non-polar one, for example selected from the group consisting of n-pentane, n-hexane, n-heptane, n-octane, n-nonane, n-decane, n-undecane, n-dodecane, n-tridecane, n-tetradecane, cyclopentane, cyclohexane, cycloheptane, 1-octene, 1-nonene, 1-decene, 1-undecene, 1-dodecene, benzene, toluene or xylene, their isomers, and mixtures thereof. After washing with one of the aforementioned solvents, in particular a relatively low-boiling, such as. B. n-pentane and / or n-hexane, the respective compound is according to the general formula M^AY_n(AzuH) (I) in high purity of at least 97%, advantageously more than 97%, in particular more than 98% or 99%, and good yield, including space-time yields, of ≧60%. This can be a solvent-free compound of the type M^AY_n(AzuH) (I), where n = 0, or for example an adduct, where Y = a crown ether and n = 1. If the product precipitates according to the general formula M^AY_n(AzuH) (I) as a solid, this is usually already present in the pure form, in particular as an adduct, according to NMR spectroscopic analysis. Purification of the solid before further use is therefore usually not necessary, provided that the adduct can be used as starting material for the planned reaction without any problems. According to one embodiment of the method, the alkali metal is M^A selected from the group consisting of Li, Na and K. According to a further variant of the method, at least one hydridic reducing agent Z is selected from the group consisting of alkali metal hydrides M^AH, alkali metal boron tetrahydrides M^Abra₄, alkali metal trialkylborohydrides M^A[(R^C)₃BH], alkali metal aluminum tetrahydrides M^AAlH₄, alkali metal trialkylaluminum hydrides M^A[(R^D)₃AlH], alkali metal dihydrido bis(dialkoxy) aluminates M^A[AlH₂(OR^E)₂], and mixtures thereof, where i. the remainders R^C and R^D are each independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having from 1 to 10 carbon atoms, wherein any two substituents R^C or two substituents R^D can optionally form a ring, and ii. the remainders OR^E each independently a corresponding base of a glycol ether R^Eoh are Another variant of the method provides that at least one hydridic reducing agent Z is selected from the group consisting of lithium hydride LiH, sodium hydride NaH, potassium hydride KH, and lithium boron tetrahydride LiBH₄, sodium boron tetrahydride NaBH₄, potassium boron tetrahydride KBH₄, lithium trialkylborohydrides Li[(R^C)₃BH], sodium trialkylborohydrides Na[(R^C)₃BH], potassium trialkylborohydrides K[(R^C)₃BH], lithium aluminum tetrahydride LiAlH₄, sodium aluminum tetrahydride NaAlH₄, potassium aluminum tetrahydride KAlH₄, lithium trialkylaluminum hydride Li[(R^D)₃AlH], sodium trialkylaluminum hydride Na[(R^D)₃AlH], potassium trialkylaluminum hydride K[(R^D)₃AlH], lithium dihydrido bis(dialkoxy) aluminates Li[AlH₂(OR^E)₂], sodium dihydridobis(dialkoxy)aluminates Na[AlH₂(OR^E)₂], potassium dihydrido bis(dialkoxy) aluminates K[AlH₂(OR^E)₂], as well as their mixtures. Examples of lithium trialkylborohydrides Li[(R^C)₃BH] are lithium triethylborohydride, which z. B. as a solution in tetrahydrofuran (1.0 M or 1.7 M) can be used, and lithium tri-sec-butylborohydride solution, which is commercially available under the name L-Selectride^® is available as a solution in tetrahydrofuran (1.0 M). Commercially available sodium trialkylborohydrides Na[(R^C)₃BH] are e.g. B. Sodium triethylborohydride (1.0M in THF) and sodium tri-sec-butylborohydride solution (N-Selectride^®solution, 1.0 M in THF). Examples of commercially available potassium trialkylborohydrides K[(R^C)₃BH] are the potassium triethylborohydride (1.0 M in THF) and potassium tri-sec-butylborohydride (K-Selectride^®- solution, 1.0 M in THF). Examples of alkali metal trialkylaluminum hydrides are compounds according to the general formula M^A[(R^D)₃AlH], where M^A = Li, Na or K and the radicals R^D are independently selected from the group consisting of methyl, ethyl, propyl, butyl, Pentyl, hexyl and their isomers. For example, the use of Li[Et₃AlH], Na[iPr₃AlH] or K[MeEt₂AlH] may be provided. The two residues OR^E an alkali metal dihydrido bis(dialkoxy) aluminate of the general formula M^A[AlH₂(OR^E)₂] can be the same or different. In a variant of the method, it is provided that the glycol ethers R^EOH are independently selected from the group consisting of monooxomethylene monoethers, monoethylene glycol monoethers, monopropylene glycol monoethers, and mixtures of their isomers, and mixtures thereof. According to another variant, the use of at least one alkali metal dihydrido-bis (dialkoxy) aluminate according to the general formula M^A[AlH₂(OR^E)₂] provided, where M^A = Li, Na or K and the radicals OR^E are each independently selected from the group consisting of O-CH₂CH₂-O-CH₃, O-CH₂CH₂-O-CH₂CH₃, O-CH₂CH₂-O-CH₂CH₂CH₃, O-CH₂CH₂-O-CH(CH₃)₂, O-CH₂CH₂-O-CH₂CH₂CH₂CH₃, O-CH₂CH₂-O-CH₂CH₂CH₂CH₂CH₃, O-CH₂CH₂-O-CH₂CH₂CH₂CH₂CH₂CH₃, O-CH₂CH₂-O-C₆H₅, O-CH₂CH₂-O-CH₂C₆H₅, O-CH₂CH₂CH₂-O-CH₃, O-CH₂CH₂CH₂-O-CH₂CH₃, O-CH₂CH₂CH₂-O-CH₂CH₂CH₃, O-CH₂CH₂CH₂-O-CH(CH₃)₂, O-CH₂CH₂CH₂-O-CH₂CH₂CH₂CH₃, O-CH₂CH₂CH₂-O-CH₂CH₂CH₂CH₂CH₃, O-CH₂CH₂CH₂-O-CH₂CH₂CH₂CH₂CH₂CH₃, O-CH₂CH₂CH₂-O-C₆H₅, O-CH₂CH₂CH₂-O-CH₂C₆H₅, O-CH(CH₃)-CH₂-O-CH₃, O-CH(CH₃)-CH₂-O-CH₂CH₃, O-CH(CH₃)-CH₂-O-CH₂CH₂CH₃, O-CH(CH₃)-CH₂-O-CH(CH₃)₂, O-CH(CH₃)-CH₂-O-CH₂CH₂CH₂CH₃, O-CH(CH₃)-CH₂-O-CH₂CH₂CH₂CH₂CH₃, O-CH(CH₃)-CH₂-O-CH₂CH₂CH₂CH₂CH₂CH₃, O-CH(CH₃)-CH₂-O-C₆H₅, O-CH(CH₃)-CH₂-O-CH₂ C₆H₅, O-CH(CH₃)-CH₂-O-C₄H₉, and O-CH(CH₃)-CH₂-O-C₃H₇, and their isomers, and mixtures thereof. An example of hydridic reducing agents of this type is commercially available sodium bis(2-methoxy-ethoxy)aluminum dihydride (Na[AlH₂(O.C₂H₄OH₃)₂), which is also known as synhydride, Red-Al^® and Vitrid^®. This reducing agent is commercially available in the form of a viscous, toluene solution, with an approximate weight percentage of >60% by weight being stated. Another representative of this group of hydridic reducing agents is Na[AlH₂(O.C₂H₄O.C₄H₉)₂]. An embodiment variant of the method provides that a molar ratio A:Z is at least 1.00:2.00. It can also be 1.00 : 1.00, for example. In another embodiment of the process, the molar ratio A:Z is between 1.00:2.00 and 2.00:1.00, advantageously between 1.00:1.75 and 1.75:1.00, in particular between 1.00:1.50 and 1.50:1.00, for example 1.00:1.95 or 1.95:1.00 or 1.00:1.90 or 1.90:1.00 or 1 .00 : 1.85 or 1.85 : 1.00 or 1.00 : 1.80 or 1.80 : 1.00 or 1.00 : 1.70 or 1.70 : 1.00 or 1.00 : 1.65 or 1.65 : 1.00 or 1.00 : 1.60 or 1.60 : 1.00 or 1.00 : 1.55 or 1.55 : 1.00 or 1.00 : 1 .45 or 1.45 : 1.00 or 1.00 : 1.40 or 1.40 : 1.00 or 1.00 : 1.35 or 1.35 : 1.00 or 1.00 : 1.30 or 1.30 : 1.00 or 1.00 : 1.25 or 1.25 : 1.00 or 1.00 : 1.20 or 1.20 : 1.00 or 1.00 : 1.15 or 1 .15 : 1.00 or 1.00 : 1.10 or 1.10 : 1.00 or 1.00 : 1.05 or 1.05 : 1.00. In yet another embodiment, the A:Z molar ratio is 1.00:1.00. According to a further embodiment of the method, the electron pair donor E has at least one donor atom selected from the group consisting of a nitrogen atom, a phosphorus atom, an oxygen atom and a sulfur atom. At least one donor atom of the respective electron pair donor E is required to form a bond, in particular a coordinative bond, with an electron pair acceptor, in particular AlH₃, suitable. In another embodiment variant of the method, it is provided that the electron pair donor E has one, two, three, four or five donor atoms. At least one donor atom of the respective electron pair donor E is required to form a bond, in particular a coordinative bond, with an electron pair acceptor such as AlH₃ suitable. According to a further embodiment of the method, a molar ratio Z:E is at least 1.00:5.00. It can also be 1.00 : 1.00, for example. In another embodiment of the process, the Z:E molar ratio is between 1.00:5.00 and 5.00:1.00, advantageously between 1.00:4.50 and 4.50:1.00, in particular between 1.00 : 4.00 and 4.00 : 1.00, for example 1.00 : 3.75 or 3.75 : 1.00 or 1.00 : 3.50 or 3.50 : 1.00 or 1 .00 : 3.25 or 3.25 : 1.00 or 1.00 : 3.00 or 3.00 : 1.00 or 1.00 : 2.75 or 2.75 : 1.00 or 1.00 : 2.50 or 2.50 : 1.00 or 1.00 : 2.25 or 2.25 : 1.00 or 1.00 : 2.00 or 2.00 : 1.00 or 1.00 : 1 .75 or 1.75 : 1.00 or 1.00 : 1.50 or 1.50 : 1.00 or 1.00 : 1.25 or 1.25 : 1.00. In yet another embodiment, the Z:E molar ratio is 1.00:1.00. According to a further variant of the method, it is provided that the hydridic reducing agent Z comprises at least two hydridic reducing agents Zr, where r is an integer ≧1 in each case. This means that the hydridic reducing agent Z is, for example, a first hydridic reducing agent Z₁ and a second hydridic reducing agent Z₂ includes and optionally also a third hydridic reducing agent Z3 etc. may contain. The two or more hydridic reducing agents Zr can be provided separately from one another or as a mixture of two or more hydridic reducing agents Zr. In addition, the two or more hydridic reducing agents Zr can be provided with identical or different mass fractions. Another embodiment of the method provides that the hydridic reducing agent Z consists of exactly one or exactly two hydridic reducing agents. For example, a mixture consisting of a first hydridic reducing agent Z₁ and a second hydridic reducing agent Z₂ be provided. This can be a mixture of lithium hydride and diisobutylaluminum hydride (DIBAL). In a mixture of two different hydridic reducing agents Z₁ and Z₂ can have a molar ratio Z₁ : Z₂ of the two hydridic reducing agents is between 1:10 and 10:1, i.e. between 0.1 and 10.0, advantageously between 1:8 and 8:1, particularly advantageously between 1:6 and 6:1, in particular between 1: 5 and 5:1. The molar ratio Z₁ : Z₂ can also be between 1:9 and 9:1 or between 1:7 and 7:1 or between 1:4 and 4:1 or between 1:3 and 3:1 or between 1:2 and 2:1. According to another embodiment, a molar ratio Z₁ : Z₂ of 1 : 1 provided. When using at least one alkali metal aluminum tetrahydride M^AAlH₄ as a first hydridic reducing agent Z₁ according to step C. of the method described here, it is provided that i. at least one second hydridic reducing agent Z₂ selected from the group consisting of alkali metal hydrides M^AH, and/or ii. at least one electron pair donor E, where the electron pair donor E has at least one donor atom, where H₂o except is provided. An advantageous variant of the method provides for at least one first hydridic reducing agent Z₁ and at least one second hydridic reducing agent Z₂ before, where i. at least one first hydridic reducing agent Z₁ is selected from the group consisting of alkali metal aluminum tetrahydrides M^AAlH₄ and ii. at least one second hydridic reducing agent Z₂ is selected from the group consisting of alkali metal hydrides M^AH. For example, as the first hydridic reducing agent, Z₁ LiAlH₄ and as the second hydridic reducing agent, Z₂ LiH can be chosen. In this case will accumulated and/or accumulated aluminum trihydride AlH₃ or (AlH₃)_x by the, especially in aprotic-polar solvents such as ethers, z. B. tetrahydrofuran or diethyl ether, sparingly soluble to insoluble electron pair donor LiH or intercepted by its hydride anion H-. The first hydridic reducing agent LiAlH₄ regenerates. Consequently, the first hydridic reducing agent Z used for the reaction with the azulene or the azulene derivative is₁, which in the respective solvent S_P usually has good to very good solubility, again as a soluble hydride-transferring reagent. Consequently, the relatively expensive first hydridic reducing agent LiAlH₄ - based on the respective starting material azulene or azulene derivative - can also advantageously be used in a substoichiometric amount, in particular in a catalytic amount. This is particularly advantageous with a view to large-scale application of the embodiment variant described here, specifically from an (atomic) economic and ecological point of view. On the one hand, a smaller amount of the relatively expensive first hydridic reducing agent Z₁ needed, and on the other hand it is completely consumed. With regard to the relatively inexpensive second hydridic reducing agent lithium hydride, which is commercially available in large quantities, it can be advantageous, in particular because of its solubility behavior, to use an excess—based on the starting material azulene or azulene derivative used in each case. Any unreacted lithium hydride can be removed by means of a simple filtration step, possibly over silica, e.g. B. Celite^®, and/or be quantitatively separated by centrifugation and/or decantation. An impurity of the compounds according to the general formula M which can be prepared by means of the process described here^AY_n(AzuH)(I) by lithium hydride can thus be excluded. The respective target compound of type M^AY_n(AzuH) (I) usually shows good to very good solubility in the used, in particular aprotic non-polar, solvent S_P. The use of lithium hydride is also advantageous for safety reasons. In contrast to other hydride-transferring reagents, it is not pyrophoric in air and can even be handled in air for a short time due to passivation. The fact that this procedure is particularly advantageous from an (atom) economic and ecological point of view can be easily understood from the three reaction equations (1) to (3) below: (1) Azu + Li[AlH₄] → Li(AzuH) + [AlH₃]_x (2) [AlH₃]_x + LiH → Li[AlH₄] (3) Azu + LiH → Li(AzuH) where Azu and AzuH are as defined above. Li(AzuH) also includes its solvent solvates in which solvated lithium ions are present. A further embodiment of the claimed method provides that at least a first hydridic reducing agent Z₁ is selected from the group consisting of alkali metal aluminum tetrahydrides M^AAlH₄ and at least one second hydridic reducing agent Z₂ is selected from the group consisting of alkali metal hydrides M^AH, where a) a molar ratio A to : Z₁ is at least 1.0:1.0, and b) a molar ratio Z₁ : Z₂ is at least 1:250. The molar ratio A:Z is advantageous₁ (Subpoint a)) between 1.0:1.0 and 20.0:1.0, particularly advantageously between 1.1:1.0 and 20.0:1.0, in particular between 1.1:1.0 and 19.9:1.0, for example 19.8:1.0 or 19.7:1.0 or 19.6:1.0 or 19.5:1.0 or 19.4:1.0 or 19.3 : 1.0 or 19.2 : 1.0 or 19.1 : 1.0 or 19.0 : 1.0 or 18.9 : 1.0 or 18.8 : 1.0 or 18, 7 : 1.0 or 18.6 : 1.0 or 18.5 : 1.0 or 18.4 : 1.0 or 18.3 : 1.0 or 18.2 : 1.0 or 18.1 : 1.0 or 18.0:1.0 or 17.9:1.0 or 17.8:1.0 or 17.7:1.0 or 17.6:1.0 or 17.5:1, 0 or 17.4:1.0 or 17.3:1.0 or 17.2:1.0 or 17.1:1.0 or 17.0:1.0 or 16.9:1.0 or 16.8 : 1.0 or 16.7 : 1.0 or 16.6 : 1.0 or 16.5 : 1.0 or 16.4 : 1.0 or 16.3 : 1.0 or 16, 2 : 1.0 or 16.1 : 1.0 or 16.0 : 1.0 or 15.9 : 1.0 or 15.8:1.0 or 15.7:1.0 or 15.6:1.0 or 15.5:1.0 or 15.4:1.0 or 15.3:1, 0 or 15.2:1.0 or 15.1:1.0 or 15.0:1.0 or 14.9:1.0 or 14.8:1.0 or 14.7:1.0 or 14.6 : 1.0 or 14.5 : 1.0 or 14.4 : 1.0 or 14.3 : 1.0 or 14.2 : 1.0 or 14.1 : 1.0 or 14, 0 : 1.0 or 13.9 : 1.0 or 13.8 : 1.0 or 13.7 : 1.0 or 13.6 : 1.0 or 13.5 : 1.0 or 13.4 : 1.0 or 13.3:1.0 or 13.2:1.0 or 13.1:1.0 or 13.0:1.0 or 12.9:1.0 or 12.8:1, 0 or 12.7:1.0 or 12.6:1.0 or 12.5:1.0 or 12.4:1.0 or 12.3:1.0 or 12.2:1.0 or 12.1 : 1.0 or 12.0 : 1.0 or 11.9 : 1.0 or 11.8 : 1.0 or 11.7 : 1.0 or 11.6 : 1.0 or 11, 5 : 1.0 or 11.4 : 1.0 or 11.3 : 1.0 or 11.2 : 1.0 or 11.1 : 1.0 or 11.0 : 1.0 or 10.9 : 1.0 or 10.8:1.0 or 10.7:1.0 or 10.6:1.0 or 10.5:1.0 or 10.4:1.0 or 10.3:1, 0 or 10.2:1.0 or 10.1:1.0 or 10.0:1.0 or 9.9:1.0 or 9.8:1.0 or 9.7:1.0 or 9, 6 : 1.0 or 9.5 : 1.0 or 9.4 : 1.0 or 9.3 : 1.0 or 9.2 : 1.0 or 9.1 : 1.0 or 9.0 : 1.0 or 8.9:1.0 or 8.8:1.0 or 8.7:1.0 or 8.6:1.0 or 8.5:1.0 or 8.4:1, 0 or 8.3:1.0 or 8.2:1.0 or 8.1:1.0 or 8.0:1.0 or 7.9:1.0 or 7.8:1.0 or 7.7:1.0 or 7.6:1.0 or 7.5:1.0 or 7.4:1.0 or 7.3:1.0 or 7.2:1.0 or 7, 1 : 1.0 or 7.0 : 1.0 or 6.9 : 1.0 or 6.8 : 1.0 or 6.7 : 1.0 or 6.6 : 1.0 or 6.5 : 1.0 or 6.4:1.0 or 6.3:1.0 or 6.2:1.0 or 6.1:1.0 or 6.0:1.0 or 5.9:1, 0 or 5.8:1.0 or 5.7:1.0 or 5.6:1.0 or 5.5:1.0 or 5.4:1.0 or 5.3:1.0 or 5.2 : 1.0 or 5.1 : 1.0 or 5.0 : 1.0 or 4.9 : 1.0 or 4.8 : 1.0 or 4.7 : 1.0 or 4, 6 : 1.0 or 4.5 : 1.0 or 4.4 : 1.0 or 4.3 : 1.0 or 4.2 : 1.0 or 4.1 : 1.0 or 4.0 : 1.0 or 3.9:1.0 or 3.8:1.0 or 3.7:1.0 or 3.6:1.0 or 3.5:1.0 or 3.4:1, 0 or 3.3 : 1.0 or 3.2 : 1.0 or 3.1 : 1.0 or 3.0 : 1.0 or er 2.9 : 1.0 or 2.8 : 1.0 or 2.7 : 1.0 or 2.6 : 1.0 or 2.5 : 1.0 or 2.4 : 1.0 or 2 .3 : 1.0 or 2.2 : 1.0 or 2.1 : 1.0 or 2.0 : 1.0 or 1.9 : 1.0 or 1.8 : 1.0 or 1.7 : 1.0 or 1.6 : 1.0 or 1.5 : 1.0 or 1.4 : 1.0 or 1.3 : 1.0 or 1.2 : 1.0. The molar ratio Z₁ : Z₂ (Subpoint b)) is advantageously between 1:250 and 20:1, particularly advantageously between 1:245 and 19:1, very particularly advantageously between 1:240 and 18:1, in particular between 1:235 and 17:1 molar ratio Z₁ : Z₂ can also be 1:230 or 1:225 or 1:220 or 1:215 or 1:210 or 1:209 or 1:208 or 1:207 or 1:206 or 1:205 or 1:204 or 1: 203 or 1:202 or 1:201 or 1:200 or 1:199 or 1:198 or 1:197 or 1:196 or 1:195 or or 1:194 or 1:193 or 1:192 or 1:191 or 1 : 190 or 1 : 185 or 1 : 180 or 1 : 175 or 1 : 170 or 1 : 165 or 1 : 160 or 1 : 155 or 1 : 150 or 1 : 145 or 1 : 140 or 1 : 135 or 1 : 130 or 1:125 or 1:120 or 1:115 or 1:110 or 1:105 or 1:100 or 1:95 or 1:90 or 1:85 or 1:80 or 1:75 or 1:70 or 1 : 65 or 1 : 60 or 1 : 55 or 1 : 50 or 1 : 45 or 1 : 40 or 1 : 35 or 1 : 30 or 1 : 25 or 1 : 20 or 1 : 19 or 1 : 18 or 1 : 17 or 1:16 or 1:15 or 1:14 or 1:13 or 1:12 or 1:11 or 1:10 or 1:9.5 or 1:9 or 1:8.5 or 1:8 or 1:7.5 or 1:7 or 1:6.5 or 1:6 or 1:5.5 or 1:5 or 1:4.5 or 1:4 or 1:3.5 or 1:3 or 1:2.5 or 1:2 or 1:1.5 or 1:1.4 or 1:1.3 or 1:1.2 or 1:1.1 or 19.5:1 or 18.5 : 1 or 17.5:1 or 16.5:1 or 16.0:1 or 15.5:1 or 15.0:1 or 14.5:1 or 14.0:1 or 13.5:1 or 13.0:1 or 12.5:1 or 12.0:1 or 11.5:1 or 11.0:1 or 10.5:1 or 10.0:1 or 9.5:1 or 9 .0:1 or 8.5:1 or 8.0:1 or 7.5:1 or 7.0:1 or 6.5:1 or 6.0:1 or 5.5:1 or 5.0 : 1 or 4.5:1 or 4.0:1 or 3.5:1 or 3.0:1 or 2.5:1 or 2.0:1 or 1.5:1 or 1.4:1 or 1.3:1 or 1.2:1 or 1.1:1. The molar ratio A to : Z₁ can be, for example, 19.8:1.0, with the molar ratio Z₁ : Z₂is 1 : 200. At this point, reference is made to the Working Instructions section (Example 1, Method C). The electron pair donor E is a Lewis acid scavenger, by means of which, for example, aluminum trihydride AlH, which is and/or is formed as a by-product₃ or (AlH₃)_x to form a Lewis acid/Lewis base complex E-AlH₃ can be intercepted. In other words, the electron pair donor E serves to increase the solubility of the aluminum trihydride AlH₃ or (AlH₃)_x in the solvent S used in each case_P compared to the solubility of the respective M-type target compound^AY_n(AzuH) (I) to be changed in such a way that quantitative separation of the aforementioned hydrides, which are inevitably obtained as by-products, is possible. For this purpose, a solvent S_P poorly soluble and therefore quantitatively precipitating Lewis acid/Lewis base complex E-AlH₃ generated. Alternatively, it can be provided that a solvent S_P particularly soluble Lewis acid/Lewis base complex E-AlH₃ is generated if the respective product according to the general formula M^AY_n(AzuH) (I) a very low to no solubility in the respective solvent S_P having. In the latter case, the amount of the respective target compound present in the reaction mixture is advantageously quantitative or almost quantitative. The electron pair donor E can only be added after the reaction according to step B., ie in step C., and/or already during the reaction according to step B. Alternatively or additionally, the electron pair donor E can be added in step A. and/or in step D. take place. In one embodiment of the method, the solvent comprises S_P the electron pair donor E. The following are non-limiting examples of the electron pair donor E: tertiary amines, such as. B. 1,4-diazabicyclo[2.2.2]octane (DABCO^® = triethylenediamine) and TMEDA, organic amides, such as. B. N,N-dimethylformamide (DMF) and hexamethylphosphoric triamide (HMPT), and the heterocyclic oxygen base 1,4-dioxane. Advantageously, by means of the electron pair donor E, the by-product aluminum trihydride AlH₃ or (AlH₃)_x immediately during step B. and/or in the subsequent step C. and/or step D. The formed AlH₃-E adduct are in the used, in particular aprotic-polar solvent S_P, in particular tetrahydrofuran, 1,4-dioxane, tetrahydropyran, dialkyl ethers, e.g. B. diethyl ether, di-n-butyl ether and tert-butyl methyl ether, and glycol ethers, such as. B.1,2-dimethoxyethane, sparingly soluble to insoluble. Consequently, this precipitate can be obtained by means of a simple filtration step, optionally over silica, e.g. B. Celite^®, and/or be quantitatively separated by centrifugation and/or decantation. A quantitative removal of AlH₃ or (AlH₃)_x from the reaction mixture represents a challenge which cannot be satisfactorily overcome using the methods described in the prior art. The quantitative separation of AlH₃ or (AlH₃)_x however, is mandatory. This is because it is a strong Lewis acid which already shows high reactivity at or slightly above room temperature, in particular towards various metal precursor compounds. Consequently, another implementation of a compound of type M^AY_n(AzuH) (I), which is replaced by AlH₃ or (AlH₃)_x is contaminated, associated with yield losses. This problem is advantageously eliminated using the method described here. Following the above-mentioned filtration step and/or centrifugation and/or decantation, a solvent exchange can take place, for example, by replacing the solvent S_P, in particular tetrahydrofuran, is completely removed in vacuo and another solvent S_P, especially Et₂O, is added. The desired product is - as already mentioned above - in Et₂O insoluble and therefore separable by means of a simple filtration and/or by centrifugation and/or decantation. Optionally - as described above - at least one washing step can be provided. According to another embodiment, the at least one hydridic reducing agent Z is or comprises an alkali metal boron tetrahydride M^Abra₄ and/or alkali metal trialkylborohydride M^A[(R^C)₃BH] and/or alkali metal trialkylaluminum hydride M^A[(R^D)₃AlH] and/or alkali metal dihydrido bis(dialkoxy) aluminates M^A[AlH₂(OR^E)₂], with an electron pair donor E being provided, by means of which the boron trihydride BH which has been produced and/or is produced₃ or B₂H₆ and/or trialkylborane and/or trialkylaluminum and/or [(R^EO)₂AlH]_x is intercepted. For example, LiBH₄ and/or lithium triethylborohydride and/or lithium triethylaluminum hydride and/or Li[AlH₂(O.C₂H₄OH₃)₂] be provided as one of the hydridic reducing agents Z. Then accumulated and / or accumulated boron trihydride BH₃ or B₂H₆ and or Triethylborane Et₃B and/or triethylaluminum Et₃Al or (Et₃Al)₂ and/or [(R^EO)₂AlH]_x to form a Lewis acid/Lewis base complex E-BH₃ or E-BEt₃ or E-AlEt₃ or and/or E-Al(R^EO)₂H intercepted - same as above for AlH₃ or (AlH₃)_x described. A further variant of the method provides for at least one first hydridic reducing agent Z₁ and at least one second hydridic reducing agent Z₂ before, where i. at least one first hydridic reducing agent Z₁ is selected from the group consisting of alkali metal boron tetrahydrides M^Abra₄, alkali metal dihydrido bis(dialkoxy) aluminates M^A[AlH₂(OR^E)₂], alkali metal trialkylaluminum hydrides M^A[(R^D)₃AlH] and alkali metal trialkylborohydrides M^A[(R^C)₃BH], and mixtures thereof, and ii. at least one second hydridic reducing agent Z₂ is selected from the group consisting of alkali metal hydrides M^AH. An alternative or supplementary embodiment of the claimed method provides that a) a molar ratio A to : Z₁ is at least 1.0:1.0, and b) a molar ratio Z₁ : Z₂ is at least 1:250. The molar ratio A:Z is advantageous₁ (Subpoint a)) between 1.0:1.0 and 20.0:1.0, particularly advantageously between 1.1:1.0 and 20.0:1.0, in particular between 1.1:1.0 and 19.9:1.0, for example 19.8:1.0 or 19.7:1.0 or 19.6:1.0 or 19.5:1.0 or 19.4:1.0 or 19.3 : 1.0 or 19.2 : 1.0 or 19.1 : 1.0 or 19.0 : 1.0 or 18.9 : 1.0 or 18.8 : 1.0 or 18, 7 : 1.0 or 18.6 : 1.0 or 18.5 : 1.0 or 18.4 : 1.0 or 18.3 : 1.0 or 18.2 : 1.0 or 18.1 : 1.0 or 18.0:1.0 or 17.9:1.0 or 17.8:1.0 or 17.7:1.0 or 17.6:1.0 or 17.5:1, 0 or 17.4:1.0 or 17.3:1.0 or 17.2:1.0 or 17.1:1.0 or 17.0:1.0 or 16.9:1.0 or 16.8 : 1.0 or 16.7 : 1.0 or 16.6 : 1.0 or 16.5 : 1.0 or 16.4:1.0 or 16.3:1.0 or 16.2:1.0 or 16.1:1.0 or 16.0:1.0 or 15.9:1, 0 or 15.8:1.0 or 15.7:1.0 or 15.6:1.0 or 15.5:1.0 or 15.4:1.0 or 15.3:1.0 or 15.2 : 1.0 or 15.1 : 1.0 or 15.0 : 1.0 or 14.9 : 1.0 or 14.8 : 1.0 or 14.7 : 1.0 or 14, 6 : 1.0 or 14.5 : 1.0 or 14.4 : 1.0 or 14.3 : 1.0 or 14.2 : 1.0 or 14.1 : 1.0 or 14.0 : 1.0 or 13.9 : 1.0 or 13.8 : 1.0 or 13.7 : 1.0 or 13.6 : 1.0 or 13.5 : 1.0 or 13.4 : 1, 0 or 13.3:1.0 or 13.2:1.0 or 13.1:1.0 or 13.0:1.0 or 12.9:1.0 or 12.8:1.0 or 12.7 : 1.0 or 12.6 : 1.0 or 12.5 : 1.0 or 12.4 : 1.0 or 12.3 : 1.0 or 12.2 : 1.0 or 12, 1 : 1.0 or 12.0 : 1.0 or 11.9 : 1.0 or 11.8 : 1.0 or 11.7 : 1.0 or 11.6 : 1.0 or 11.5 : 1.0 or 11.4:1.0 or 11.3:1.0 or 11.2:1.0 or 11.1:1.0 or 11.0:1.0 or 10.9:1, 0 or 10.8:1.0 or 10.7:1.0 or 10.6:1.0 or 10.5:1.0 or 10.4:1.0 or 10.3:1.0 or 10.2 : 1.0 or 10.1 : 1.0 or 10.0 : 1.0 or 9.9 : 1.0 or 9.8 : 1.0 or 9.7 : 1.0 or 9, 6 : 1.0 or 9.5 : 1.0 or 9.4 : 1.0 or 9.3 : 1.0 or 9.2 : 1.0 or 9.1 : 1.0 or 9.0 : 1.0 or 8.9:1.0 or 8.8:1.0 or 8.7:1.0 or 8.6:1.0 or 8.5:1.0 or 8.4:1, 0 or 8.3:1.0 or 8.2:1.0 or 8.1:1.0 or 8.0:1.0 or 7.9:1.0 or 7.8:1.0 or 7.7:1.0 or 7.6:1.0 or 7.5:1.0 or 7.4:1.0 or 7.3:1.0 or 7.2:1.0 or 7, 1 : 1.0 or 7.0 : 1.0 or 6.9 : 1.0 or 6.8 : 1.0 or 6.7 : 1.0 or 6.6 : 1.0 or 6.5 : 1.0 or 6.4:1.0 or 6.3:1.0 or 6.2:1.0 or 6.1:1.0 or 6.0:1.0 or 5.9:1, 0 or 5.8:1.0 or 5.7:1.0 or 5.6:1.0 or 5.5:1.0 or 5.4:1.0 or 5.3:1.0 or 5.2 : 1.0 or 5.1 : 1.0 or 5.0 : 1.0 or 4.9 : 1.0 or 4.8 : 1.0 or 4.7 : 1.0 or 4, 6 : 1.0 or 4.5 : 1.0 or 4.4 : 1.0 or 4.3 : 1.0 or 4.2 : 1.0 or 4.1 : 1.0 or 4.0 : 1.0 or 3.9 : 1.0 or 3.8 : 1.0 or 3.7 : 1.0 or 3.6 : 1.0 or 3.5:1.0 or 3.4:1.0 or 3.3:1.0 or 3.2:1.0 or 3.1:1.0 or 3.0:1, 0 or 2.9:1.0 or 2.8:1.0 or 2.7:1.0 or 2.6:1.0 or 2.5:1.0 or 2.4:1.0 or 2.3 : 1.0 or 2.2 : 1.0 or 2.1 : 1.0 or 2.0 : 1.0 or 1.9 : 1.0 or 1.8 : 1.0 or 1, 7:1.0 or 1.6:1.0 or 1.5:1.0 or 1.4:1.0 or 1.3:1.0 or 1.2:1.0. The molar ratio Z₁ : Z₂ (Subpoint b)) is advantageously between 1:250 and 20:1, particularly advantageously between 1:245 and 19:1, very particularly advantageously between 1:240 and 18:1, in particular between 1:235 and 17:1 molar ratio Z₁ : Z₂ can also be 1 : 230 or 1 : 225 or 1 : 220 or 1 : 215 or 1 : 210 or 1:209 or 1:208 or 1:207 or 1:206 or 1:205 or 1:204 or 1:203 or 1:202 or 1:201 or 1:200 or 1:199 or 1:198 or 1 : 197 or 1 : 196 or 1 : 195 or or 1 : 194 or 1 : 193 or 1 : 192 or 1 : 191 or 1 : 190 or 1 : 185 or 1 : 180 or 1 : 175 or 1 : 170 or 1 : 165 or 1:160 or 1:155 or 1:150 or 1:145 or 1:140 or 1:135 or 1:130 or 1:125 or 1:120 or 1:115 or 1:110 or 1:105 or 1 : 100 or 1 : 95 or 1 : 90 or 1 : 85 or 1 : 80 or 1 : 75 or 1 : 70 or 1 : 65 or 1 : 60 or 1 : 55 or 1 : 50 or 1 : 45 or 1 : 40 or 1:35 or 1:30 or 1:25 or 1:20 or 1:19 or 1:18 or 1:17 or 1:16 or 1:15 or 1:14 or 1:13 or 1:12 or 1 : 11 or 1 : 10 or 1 : 9.5 or 1 : 9 or 1 : 8.5 or 1 : 8 or 1 : 7.5 or 1 : 7 or 1 : 6.5 or 1 : 6 or 1 : 5.5 or 1 : 5 or 1 : 4.5 or 1 : 4 or 1 : 3.5 or 1 : 3 or 1 : 2.5 or 1 : 2 or 1:1.5 or 1:1.4 or 1:1.3 or 1:1.2 or 1:1.1 or 19.5:1 or 18.5:1 or 17.5:1 or 16.5:1 or 16.0:1 or 15.5:1 or 15.0:1 or 14.5:1 or 14.0:1 or 13.5:1 or 13.0:1 or 12, 5 : 1 or 12.0 : 1 or 11.5 : 1 or 11.0 : 1 or 10.5 : 1 or 10.0 : 1 or 9.5 : 1 or 9.0 : 1 or 8.5 : 1 or 8.0:1 or 7.5:1 or 7.0:1 or 6.5:1 or 6.0:1 or 5.5:1 or 5.0:1 or 4.5:1 or 4.0:1 or 3.5:1 or 3.0:1 or 2.5:1 or 2.0:1 or 1.5:1 or 1.4:1 or 1.3:1 or 1, 2:1 or 1.1:1. As the first hydridic reducing agent Z₁ can for example LiBH₄ or Li[AlH₂(O.C₂H₄OH₃)₂] or Li[Et₃AlH] or Li[Et₃BH], or a mixture thereof, and as the second hydridic reducing agent Z₂ LiH can be chosen. In this case, boron trihydride BH₃ or B₂H₆ and/or [(H₃COH₄C₂O)₂AlH]_x and/or triethylaluminum Et₃Al or (Et₃Al)₂ and/or triethylborane Et₃B by the, especially in aprotic-polar solvents such as ethers, z. B. tetrahydrofuran or diethyl ether, sparingly soluble to insoluble electron pair donor LiH or intercepted by its hydride anion H-. Advantageously, without further action, the first hydridic reducing agent is LiBH₄ and/or Li[AlH₂(O.C₂H₄OH₃)₂] and/or Li[Et₃AlH] and/or Li[Et₃BH] regenerates. Consequently, the first hydridic reducing agent Z used for the reaction with the azulene or the azulene derivative is₁, which in the respective solvent S_P usually a good one to very good solubility, again as a soluble, hydride-transferring reagent. Consequently, the relatively expensive first hydridic reducing agent LiBH₄ and/or Li[AlH₂(O.C₂H₄OH₃)₂] and/or Li[Et₃AlH] and/or Li[Et₃BH] - based on the respective starting material azulene or azulene derivative - can advantageously also be used in a substoichiometric amount, in particular in a catalytic amount. This is particularly advantageous with a view to large-scale application of the embodiment variant described here, specifically from an (atomic) economic and ecological point of view. On the one hand, a smaller amount of the relatively expensive first hydridic reducing agent Z₁ needed, and on the other hand it is completely consumed. With regard to the relatively inexpensive second hydridic reducing agent lithium hydride, which is commercially available in large quantities, it can be advantageous, in particular because of its solubility behavior, to use an excess—based on the starting material azulene or azulene derivative used in each case. Any unreacted lithium hydride can be removed by means of a simple filtration step, possibly over silica, e.g. B. Celite^®, and/or be quantitatively separated by centrifugation and/or decantation. An impurity of the compounds according to the general formula M which can be prepared by means of the process described here^AY_n(AzuH)(I) by lithium hydride can thus be excluded. The respective target compound of type M^AY_n(AzuH) (I) usually shows good to very good solubility in the used, in particular aprotic non-polar, solvent S_P. The use of lithium hydride is also advantageous for safety reasons. In contrast to other hydride-transferring reagents, it is not pyrophoric in air and can even be handled in air for a short time due to passivation. The fact that this procedure is particularly advantageous from an (atomic) economic and ecological point of view can be easily understood from the following reaction equations (4) to (6) and (7) to (9) and (10) to (12): ( 4) Azu + Li[BH₄] → Li(AzuH) + BH₃ (5) Bra₃ + LiH → Li[BH₄] (6) Azu + LiH → Li(AzuH) (7) Azu + Li[AlH₂(O.C₂H₄OH₃)₂] → Li(AzuH) + [(H₃COH₄C₂O)₂AlH]_x (8) [(H₃COH₄C₂O)₂AlH]_x + LiH → Li[AlH₂(O.C₂H₄OH₃)₂] (9) Azu + LiH → Li(AzuH) (10) Azu + Li[Et₃BH] → Li(AzuH) + Et₃B(11)Et₃B + LiH → Li[Et₃BH] (12) Azu + LiH → Li(AzuH) where Azu and AzuH are each as defined above. Li(AzuH) also includes its solvent solvates in which solvated lithium ions are present. The reaction equations for the reaction of Azu with Li[Et₃AlH] as the first hydridic reducing agent Z₁ and LiH as the second hydridic reducing agent Z₂ can be formulated analogously to equations (10) to (12). If an azulene derivative is used as starting material in the process described here, the azulene skeleton is attached to one or more carbon atoms selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6, C7 and C8 , a substituent R^f having. At the same time, at least one of the carbon atoms C4, C6 and C8 should carry an H atom. The regioselectivity of the nucleophilic addition of the hydride anion H− provided by the at least one hydridic reducing agent Z can be influenced in particular by the choice of the substitution pattern of the azulene derivative. The number of regioisomers to be expected can therefore be directly influenced. If bicyclo[5.3.0]decapentaene, i.e. azulene, is used as starting material according to the general formula II, the nucleophilic addition of the hydride anion H- in the 4-position (C4), in the 6- position (C6) or in the 8-position (C8) of the azulene. Because the carbon atoms C4, C6 and C8 are known to have comparable nucleophilicity. Consequently, when using unsubstituted azulene as starting material, a mixture of three regioisomers is obtained. In contrast, in the case of the azulene derivative 7-isopropyl-1,4-dimethylazulene (guaiazulene), for example, a regioselective addition of the hydride anion in the 8-position, i. H. at the C8 carbon atom. Using the method described here, in particular depending on the substitution pattern of the azulene derivative selected as starting material, it is also possible to prepare isomerically pure compounds of the general formula M^AY_n(AzuH) (I) possible. An example is lithium 7-isopropyl-1,4-dimethyl-8-H-dihydroazulenide, which can also be referred to as lithium 8-H-dihydroguaiazulenide. According to one embodiment of the method, an azulene derivative is provided in step A., where at least - on the carbon atoms C4 and C6 or - on the carbon atoms C8 and C6 or - on the carbon atom C4 and/or on the carbon atom C8 of the azulene skeleton an H -Atom is provided. According to another variant of the method described here, an azulene derivative is provided in step A., wherein at least one carbon atom of the azulene skeleton, selected from the group consisting of C1, C2 and C3, has a substituent R^f carries and the carbon atoms C4, C5, C6, C7 and C8 of the auzulene skeleton each carry an H atom. In yet another embodiment, at least one carbon atom of the azulene backbone selected from the group consisting of C4, C5, C6, C7, and C8 bears a Substituents R^f, and the carbon atoms C1, C2 and C3 of the azulene skeleton each carry an H atom. In a further variant of the process, a doubly substituted azulene derivative is used as starting material in step A. It is provided, for example, that exactly one carbon atom of the five-membered ring, i.e. C1 or C2 or C3, and exactly one carbon atom of the seven-membered ring, i.e. C4 or C5 or C6 or C7 or C8, has a substituent R^f wear. An alternative embodiment of the process provides, in step A., a trisubstituted azulene derivative as starting material. Here z. B. provided that exactly one carbon atom of the five-membered ring, i.e. C1 or C2 or C3, and exactly two carbon atoms of the seven-membered ring, i.e. two of the carbon atoms C4, C5, C6, C7, C8, a substituent R^f wear. According to yet another process variant, a tetrasubstituted azulene derivative is provided in step A. It is provided, for example, that exactly one carbon atom of the five-membered ring, i.e. C1 or C2 or C3, and exactly three carbon atoms of the seven-membered ring, as three of the carbon atoms C4, C5, C6, C7, C8, have a substituent R^f wear. In a further embodiment of the method, an azulene derivative is provided in step A., wherein at least the carbon atoms C1, C4 and C7 of the azulene skeleton have a substituent R^f carry, or one of its isomers. The azulene derivative can be selected, for example, from the group consisting of 1,4,7-trimethylazulene, 7-ethyl-1,4-dimethylazulene (chamazulene), 7-n-propyl-1,4-dimethylazulene, 7-isopropyl- 1,4-dimethylazulene (guaiazulene), 7-n-butyl-1,4-dimethylazulene, 7-isobutyl-1,4-dimethylazulene, 7-sec-butyl-1,4-dimethylazulene, 7-tert-butyl -1,4-dimethylazulene, 7-n-pentyl-1,4-dimethylazulene, 7-isopentyl-1,4-dimethylazulene, 7-neopentyl-1,4-dimethylazulene, 7-n-hexyl-1,4-dimethylazulene, 7-isohexyl-1,4-dimethylazulene, 7-(3-methylpentane)-1,4-dimethylazulene, 7-neo-hexyl-1,4-dimethylazulene, 7-(2,3-dimethylbutane)-1,4-dimethylazulene, and their isomers. Guajazulene is a natural substance that is contained in chamomile oil and other essential oils and is therefore advantageously available in large quantities at low cost. Synthetically, it can be made from the guajol of guaiac wood oil (guaiac resin). Guajazulene is an intensely blue substance with anti-inflammatory effects. An example of an isomer of guaiazulene is 2-isopropyl-4,8-dimethylazulene (vetivazulene). In another variant of the method, at least one hydridic reducing agent Z is selected from the group consisting of alkali metal hydrides M^AH, alkali metal boron tetrahydrides M^Abra₄, alkali metal trialkylborohydrides M^A[(R^C)₃BH], alkali metal aluminum tetrahydrides M^AAlH₄, alkali metal trialkylaluminum hydrides M^A[(R^D)₃AlH], alkali metal dihydrido bis(dialkoxy) aluminates M^A[AlH₂(OR^E)₂], and mixtures thereof, where i. the remainders R^C and R^D are each independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having from 1 to 10 carbon atoms, wherein any two substituents R^C or two substituents R^D can optionally form a ring, and ii. the remainders OR^E each independently a corresponding base of a glycol ether R^Eoh are In another embodiment of the method, the alkali metal dihydrido bis (dialkoxy) aluminate according to the general formula M^A[AlH₂(OR^E)₂], where M^A = Li, Na or K produced in situ by a reaction of M^AAlH₄, i.e. LiAlH₄, NaAlH₄ or KAlH₄, with a glycol ether R^EOH. There is a molar ratio M^AAlH₄ : glycol ether R^EOH 1:2, i.e. 0.5. In the context of the present invention, the expression “generated/prepared in situ” or “preparation in situ” means that the starting materials required for the synthesis of a compound to be prepared in this way are in a suitable stoichiometry in a solvent or solvent mixture are reacted and the resulting product is not isolated. Rather, the solution or suspension comprising the compound generated in situ is typically used directly, i. H. used without isolation and/or further purification. The in situ preparation of a compound can take place in the reaction vessel provided for its further use or in a different reaction vessel. The terms reaction container and reaction vessel have already been defined above. In yet another embodiment of the claimed process, the glycol ether is R^EOH, which is used for the in situ production of a reducing agent according to the general formula M^A[AlH₂(OR^E)₂] - starting from LiAlH₄, NaAlH₄ or KAlH₄ - is used selected from the group consisting of monooxomethylene monoethers, monoethylene glycol monoethers, monopropylene glycol monoethers, and their isomeric mixtures, and mixtures thereof. In an advantageous variant, a monoethylene glycol monoether is used. For example, the alcoholysis takes place starting from LiAlH₄, NaAlH₄ or KAlH₄ and a monoglycol monoether R^EOH, where in particular R^E = C₂H₄OH₃ or c₂H₄O.C₄H₉, in an aliphatic or aromatic solvent, e.g. B. n-pentane, n-hexane, toluene or p-cymene. The synthesis can be carried out, for example, in a temperature range of −10 °C to 40 °C, with the possibility of gas equalization being absolutely necessary. Polyethers are also understood to be glycol ethers. In one variant of the method, the glycol ether is selected from the group consisting of 2-methoxyethanol CH₃-O-CH₂CH₂-OH, 2-ethoxyethanol CH₃CH₂-O-CH₂CH₂–OH, ethylene glycol mono-n- propyl ether CH₃CH₂CH₂-O-CH₂CH₂-OH, ethylene glycol mono-iso-propyl ether (CH₃)₂CH–O–CH₂CH₂-OH, ethylene glycol mono-n-butyl ether CH₃CH₂CH₂CH₂-O-CH₂CH₂-OH, ethylene glycol mono-n-pentyl ether CH₃CH₂CH₂CH₂CH₂-O-CH₂CH₂-OH, ethylene glycol mono-n-hexyl ether CH₃CH₂CH₂CH₂CH₂CH₂-O-CH₂CH₂–OH, ethylene glycol monophenyl ether C₆H₅-O-CH₂CH₂-OH, ethylene glycol monobenzyl ether C₆H₅CH₂-O-CH₂CH₂-OH, propylene glycol monomethyl ether CH₃-O-CH₂CH₂CH₂-OH, propylene glycol monoethyl ether CH₃CH₂-O-CH₂CH₂CH₂-OH, propylene glycol mono-n-propyl ether CH₃CH₂CH₂-O-CH₂CH₂CH₂-OH, propylene glycol mono-n-butyl ether CH₃CH₂CH₂CH₂-O-CH₂CH₂CH₂-OH, propylene glycol mono-n-pentyl ether CH₃CH₂CH₂CH₂CH₂-O-CH₂CH₂CH₂-OH, propylene glycol mono-n-hexyl ether CH₃CH₂CH₂CH₂CH₂CH₂-O-CH₂CH₂CH₂-OH, propylene glycol monophenyl ether C₆H₅-O-CH₂CH₂CH₂-OH, propylene glycol monobenzyl ether C₆H₅CH₂-O-CH₂CH₂CH₂-OH, iso-propylene glycol monomethyl ether CH₃-O-CH₂-CH(CH₃)-OH, iso-propylene glycol monoethyl ether CH₃CH₂-O-CH₂-CH(CH₃)-OH, iso-propylene glycol mono-n-propyl ether CH₃CH₂CH₂-O-CH₂-CH(CH₃)-OH, iso-propylene glycol mono-iso-propyl ether (CH₃)₂CH-O-CH₂-CH(CH₃)-OH, iso-propylene glycol mono-n-butyl ether CH₃CH₂CH₂CH₂-O-CH₂-CH(CH₃)-OH, iso-propylene glycol mono-n-pentyl ether CH₃CH₂CH₂CH₂CH₂-O-CH₂- CH(CH₃)-OH, iso-propylene glycol mono-n-hexyl ether CH₃CH₂CH₂CH₂CH₂CH₂-O-CH₂- CH(CH₃)-OH, iso-propylene glycol monophenyl ether C₆H₅-O-CH₂-CH(CH₃)-OH, iso-propylene glycol monobenzyl ether C₆H₅CH₂-O-CH₂-CH(CH₃)-OH, 1-methoxy-2-propanol CH₃-O-CH₂CH(CH₃)-OH, 1-butoxypropan-2-ol C₄H₉-O-CH₂CH(CH₃)-OH, 1-propoxy-2-propanol CH₃CH₂CH₂-O-CH₂CH(CH₃)-OH and mixtures thereof. The glycol ethers specified can also be used as isomer mixtures. According to a further embodiment of the method, the electron pair donor E is a base selected from the group consisting of organic, organometallic and inorganic bases, and mixtures thereof. In particular, the electron pair donor E is a Lewis base. In another embodiment of the claimed process, the electron pair donor E is an organic or inorganic base. Advantageously, the electron pair donor E is selected from the group consisting of primary, secondary and tertiary amines, organic amides, heterocyclic oxygen bases, heterocyclic nitrogen bases, ammonia, alkali metal carbonates, alkali metal oxides and alkali metal amides, and mixtures thereof. If the electron pair donor E is an alkali metal oxide and/or an alkali metal amide, it is advantageously selected from the group consisting of lithium, sodium and potassium oxide and lithium, sodium and potassium amide. In particular, the electron pair donor E is selected from the group consisting of amines, organic amides, heterocyclic oxygen bases, heterocyclic nitrogen bases and ammonia. N,N-dimethylformamide (DMF) or hexamethylphosphoric triamide (HMPT), for example, can be provided as the organic amide. The heterocyclic oxygen base can e.g. B. be selected from the group consisting of tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, 1,4-dioxane and tetrahydropyran, and mixtures thereof. If amine is used, it is generally possible to use different amines, also as a mixture, such as e.g. B. primary, secondary or tertiary amines. Here, alkylamines can be used advantageously. These can be methylamine, ethylamine, propylamine, isopropylamine, butylamine, tert-butylamine, cyclohexylamine, dimethylamine, diethylamine, dipropylamine, diisopropylamine, dibutylamine, di-tert-butylamine, dicyclohexylamine, trimethylamine, triethylamine, tripropylamine, tri- iso-propylamine, tributylamine, tri-tert-butylamine, tricyclohexylamine, and derivatives and mixtures thereof. Mixed-substituted amines and mixtures thereof are also conceivable, such as, for. B. Di-isopropylethylamine (DIPEA). Likewise, urotropine, acetamidine, ethylenediamine, triethylenetetramine, morpholine, N-methylmorpholine, 1,8-diazabicyclo[5.4.0]undec-7-ene (DBU), DABCO^®, TMEDA, guanidine, urea, thiourea, imines, aniline, pyridine, pyrazole, pyrimidine, imidazole, hexamethyldisilazane or combinations thereof are used as the base. A further embodiment of the method provides that the reaction of the azulene or the azulene derivative with the at least one hydridic reducing agent Z in the solvent S_P comprises the following step: i) providing the azulene or the azulene derivative as a substance or as a solution or suspension in a solvent which can be mixed with the solvent S_P is miscible or identical, and ii) adding the at least one hydridic reducing agent Z as a substance or as a solution or suspension in a solvent which is compatible with the solvent S_P is miscible or identical, wherein a reaction of the azulene or the azulene derivative with Z occurs during the addition and/or after the addition of Z. The term “substance” includes here in particular solids, liquids and liquid crystals. In an alternative embodiment of the method, provision is made for the hydridic reducing agent Z to be provided in step i) and for the azulene or the azulene derivative to be added in step ii). According to another embodiment variant, at least one electron pair donor E is added in step i) and/or in step ii) and/or in a subsequent step iii). M^AAlH₄ comprises or from one or more alkali metal aluminum tetrahydrides M^AAlH₄ consists. The addition of the at least one electron pair donor E advantageously generally has a quantitative scavenging of a Lewis acid occurring and/or occurring as a by-product, such as aluminum trihydride AlH₃ or (AlH₃)_x result, with the formation of Lewis acid/Lewis base complexes E-AlH₃. Yet another embodiment of the method provides that the addition of the electron pair donor E is carried out by introducing it as a gas or liquid, introducing a solution, advantageously in the solvent S_P or a miscible solvent, in particular an aprotic-polar solvent, or by pressurizing the reaction solution in a closed pressurized container. In a further variant of the method, it is provided that the addition of the at least one hydridic reducing agent Z and/or the at least one electron pair donor E to the solution or suspension of the azulene or the azulene derivative in the, in particular aprotic-polar, solvent or solvent mixture S_P using a dosing device. The addition can be done, for example, by dripping or spraying. Alternatively or additionally, a shut-off valve and/or a shut-off tap can be provided in a supply line of the reaction container. The solvent S_P can optionally represent a mixture of several, in particular aprotic-polar, solvents. Depending on the choice of solvent or solvent mixture S_P, the starting materials used, including the optionally provided electron pair donor E, and the other reaction conditions, such as. B. Addition form of the hydridic reducing agent Z and/or the electron pair donor E, e.g. B. as a substance, i. H. as a gas, liquid or solid, or dissolved or suspended in a solvent, in particular in the solvent S_P or a solvent miscible therewith, speed of addition of the hydridic reducing agent Z and/or the electron pair donor E, stirring speed, internal temperature of the reaction vessel, the reaction of the azulene or the azulene derivative already takes place during the addition and/or after the addition of the at least one hydridic reducing agent Z and/or the at least one electron pair donor E. Furthermore, a process variant is provided in which the reaction of the azulene or the azulene derivative with the at least one hydridic reducing agent Z, if necessary with the provision of an electron pair donor E, in the, in particular aprotic-polar, solvent or solvent mixture S_P at a temperature T_u is carried out, with the temperature T_u between -30°C and 100°C, advantageously between -20°C and 80°C, in particular between -10°C and 70°C. The reaction is particularly energy-efficient and therefore cost-efficient at a temperature T_u between -10 °C and 60 °C. With temperature T_u is the internal temperature T_u of the respective reaction container. An internal temperature of the respective reaction container can be determined using a temperature sensor or multiple temperature sensors for one area or multiple areas of the reaction container. At least one temperature sensor is used to determine the temperature T_u provided, which usually corresponds to an average temperature TD1 of the reaction mixture. In a further variant of the method, the internal temperature T_u of the reaction vessel using a heat carrier WU regulated and / or controlled. For this purpose, for example, a cryostat can be used, which contains the heat transfer medium WU, which can ideally function both as a coolant and as a heating medium. The use of the WU heat transfer medium can result in deviations in the temperature T_u of a target value T specified for the reaction of the azulene or azulene derivative with the at least one hydridic reducing agent Z, optionally in the presence of the electron pair donor E_S1 be intercepted or compensated for as far as possible. The realization of a constant temperature T_u is hardly possible due to the usual device deviations. By using the heat carrier WU, the reaction of the azulene or azulene derivative with the hydridic reducing agent Z, optionally in the presence of the electron pair donor E, but be carried out at least in a preselected temperature range or in several preselected temperature ranges. For example, depending on the other reaction parameters, it can be advantageous to create a temperature program for even better control of the course of the reaction and/or the exothermicity. For example, during a first phase of the reaction of the azulene or azulene derivative with the hydridic reducing agent Z, a lower temperature or a lower temperature range can be selected than in a second phase of the reaction of the azulene or azulene derivative with the at least one hydride reducing agent Z more than two phases of the addition and thus more than two preselected temperatures or temperature ranges can also be provided. Depending on the choice of the other reaction conditions, such. B. the concentration of the hydridic reducing agent Z and the solvent or solvent mixture, it can be favorable during the addition and / or after the addition of Z and possibly E to increase the internal temperature T_u of the reaction vessel using the heat transfer medium WU. In this way it can be ensured, if appropriate, that the reaction of the azulene or azulene derivative with the at least one hydridic reducing agent Z, if appropriate with the provision of an electron pair donor E, takes place quantitatively. A duration of increase in internal temperature T_u of the reaction vessel using the heat transfer medium WU can be between 10 minutes and 96 hours, for example. In yet another process variant, the solvent is S_P chemically inert. In the context of the present invention, the term “inert solvent” means a solvent which is chemically unreactive under the particular process conditions. Consequently, under the respective reaction conditions, including the purification and/or isolation steps, the inert solvent does not react with a potential reaction partner, in particular not with a starting material and/or an intermediate product and/or a product and/or a by-product, and not with one other solvents, air or water. In a further embodiment of the method it is provided that after the reaction in step B. or after step C. or after step D. a step is carried out, which isolates M^AY_n(AzuH) (I) comprises: - as a suspension or solution containing M^AY_n(AzuH) (I) and at least one, in particular aprotic-polar, solvent S_P includes, or - as a liquid or solid. In a further variant of the method, the isolation comprises a filtration step. Several filtration steps can also be provided, optionally also one or more filtrations over a cleaning medium, such as. B. activated carbon, or silica, z. B. Celite^®. The isolation of the compound according to the general formula M^AY_n(AzuH) (I) as a solution or as a solid may include further process steps, such as. B. reducing the volume of the mother liquor, i. H. constrict, e.g. B. by "bulb-to-bulb", the addition of a solvent and / or a solvent exchange to achieve a precipitation of the product from the mother liquor and / or to remove impurities and / or starting materials, washing, z. B. with pentane and / or hexane, and drying the product. The aforementioned steps can each be provided in different sequences and frequencies. Advantageously, the filtrate, centrifugate or decantate or the solid can be subjected to the purification and/or isolation steps that may be provided and can be carried out quickly and without any particular preparative effort. Overall, the purification and/or isolation of the target compound is designed according to the general formula M^AY_n(AzuH) (I) Relatively simple and inexpensive. In general, the end product can still contain residues of solvents or, for example, impurities from the starting materials. M-type isolated connections^AY_n(AzuH)(I) have a purity of at least 97%, advantageously more than 97%, in particular more than 98% or 99%. The reproducible yield is usually ≧60%, particularly depending on the choice of starting materials and the solvent or solvent mixture—even in the case of upscaling to an industrial scale. In addition, the object is achieved by a solution or a suspension comprising M^AY_n(AzuH) (I) and at least one, in particular aprotic-polar, solvent S_P, obtained or obtainable by a method according to one of the embodiments described above. The solvent S_P is advantageously an aprotic-polar solvent or comprises at least one aprotic-polar solvent. For example, the solvent S_P an ether or comprises at least one ether. The ether may be selected from the group consisting of tetrahydrofuran, methyltetrahydrofuran, 1,4-dioxane, diethyl ether, methyl tert-butyl ether, di-n-propyl ether, diisopropyl ether, cyclopentylmethyl ether, and their isomers, and mixtures thereof. The solutions or suspensions are characterized in particular by the high purity of the type M compound they contain^AY_n(AzuH) (I) off. The compounds according to the general formula M obtainable by means of the process described here^AY_n(AzuH) (I) each have an H-dihydroazulenyl anion (AzuH)^1- on, which is a derivative of the cyclopentadienyl anion or a cyclopentadienyl-like monoanion. It is particularly advantageous that the compounds obtainable by means of the process described here, comprising cyclopentadienyl-type monoanions (AzuH)^1-, have good to very good long-term stability at room temperature. During storage for several months at room temperature, neither Decomposition reactions nor oligomerization or polymerization observed. This is particularly important with a view to the further use of type M connections^AY_n(AzuH)(I), particularly for preparing sandwich and half-sandwich complexes. Furthermore, the production of alkali metal H-dihydroazulenides according to the general formula M^AY_n(AzuH) (I) comprising cyclopentadienyl-type monoanions (AzuH)^1-, according to the method claimed here less laborious and time-consuming compared to the provision of LiCp. Usable starting materials such. B. natural products such as guaiazulene and hydridic reducing agents such as lithium triethylborohydride are not only easier to handle and store, but also cheaper. In addition, fewer and simpler work steps have to be carried out. Consequently, by means of the method claimed here, compounds of type M^AY_n(AzuH) (I) comprising cyclopentadienyl-type monoanions (AzuH)^1-, simple and reproducible and - depending on the choice of educts - available sustainably and comparatively inexpensively. The target compounds obtained have a high purity of at least 97%, advantageously more than 97%, in particular more than 98% or 99%, and good yields, including space-time yields, of ≧60%. This also applies to production on an industrial scale. Furthermore, the object is achieved by compounds of the general formula M^AY_n(AzuH) (I) obtained or obtainable by a process according to any of the embodiments described above. Whether the compounds claimed here according to the general formula M^AY_n(AzuH) (I) as solvent adducts, especially ether adducts, depends on various factors, e.g. B. of the solvent used for the preparation of compounds according to the general formula I and the nature of the alkali metal cation M^A+, ie the hydridic reducing agent Z used. If, for example, in the context of the synthesis, including the purification, a solvent was used which comprised or consisted of one or more ethers and at least one lithium cation If an hydridic reducing agent Z is used, in all probability an ether adduct Li(ether)_n(A to H) (I) where n = 1 or 2. If such an ether adduct finally with a non-ethereal solvent such. B. pentane or hexane, is usually a solvent-free compound according to the general formula Li (AzuH) (I) before. The advantage of the compounds obtainable by means of the process described above is that their production is simple and reproducible and—depending on the choice of starting materials—can be implemented sustainably and relatively inexpensively. Depending on the process, in particular the choice of the hydridic reducing agent Z, the desired compounds of M^AY_n(AzuH) (I)—as already described above—can be isolated, for example, by means of simple filtration and/or by centrifugation and/or by decanting. The target compounds are usually present - even without further purification - in a high purity of 97%, advantageously more than 97%, in particular more than 98% or 99%. In addition, good yields, including space-time yields, of ≧60% are achieved by means of the process claimed here. Production on an industrial scale is advantageously also possible—with comparable purity and yield. In particular compounds according to the general formula M^AY_n(AzuH) (I), where AzuH = GuaH = 7-iso-propyl-1,4-dimethyl-8-H-dihydroazulene, obtained or obtainable by a process according to one of the embodiments described above, are to be evaluated as sustainable. This is because these compounds, which include cyclopentadienyl-like ligands, can be produced using inexpensive renewable raw materials. The target price of starting from the natural substance guajol and other azulene formers by simple dehydration and dehydration (T. Shono, N. Kise, T. Fujimoto, N. Tominaga, H. Morita, J. Org. Chem.1992, 57, 26, 7175 – 7187; CH 314487 A (B. Joos) 01/29/1953) accessible partially synthetic guaiazulens is €74.70 per 25g (Sigma Aldrich, 12/2020). In addition, the object is achieved by compounds of the general formula M^AY_n(AzuH)(I), where - M^A is an alkali metal, - Y is a neutral ligand which can be attached via at least one donor atom to M^A is bonded or coordinated where H₂O is excluded, - n = 0, 1, 2, 3 or 4 and - AzuH = azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom, where Azu = azulene according to the formula (II) or Azu=an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6 , C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, the compounds Li(O(C₂H₅)₂)_n(azuleneH) and Li(O(C₂H₅)₂)_n(GuaH), where - n = 0, 1 or 2, - azuleneH = azulene, which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom, - GuaH = 7-iso -propyl-1,4-dimethyl-8-H-dihydroazulene. Compounds according to the general formula M^AY_n(AzuH)(I) are referred to below as alkali metal H-dihydroazulenides, which may be present as solvent adducts, especially ether adducts, which are also called etherates. Compounds according to the general formula M^AY_n(AzuH) (I) can also be present as isomer mixtures. This also applies to the compound Li(O(C₂H₅)₂)_n(AzuleneH). The compounds claimed here according to the general formula M^AY_n(AzuH) (I) each have an H-dihydroazulenyl anion (AzuH)^1- on, which is a derivative of the cyclopentadienyl anion or a cyclopentadienyl-like monoanion. For the H-dihydroazulenyl anion (AzuH)^1- it can be a 3α,4-H-dihydroazulenyl, an 8,8α-H-dihydroazulenyl, a 3α,6-H-dihydroazulenyl or a 6,8α-H-dihydroazulenyl anion, or a mixture two or more regioisomers. It is particularly advantageous that the compounds of this type comprise cyclopentadienyl-type monoanions (AzuH)^1- have good to very good long-term stability at room temperature. Neither decomposition reactions nor oligomerization or polymerization are observed during storage for several months at room temperature. This is especially with a view to further using the Compounds according to the general formula M^AY_n(AzuH)(I), particularly for preparing sandwich and half-sandwich complexes. Furthermore, the production of alkali metal H-dihydroazulenides according to the general formula M^AY_n(AzuH) (I) comprising cyclopentadienyl-type monoanions (AzuH)^1-, less labor and time consuming compared to deploying LiCp. Usable starting materials such. B. natural products such as guaiazulene and hydridic reducing agents such as lithium triethylborohydride are not only easier to handle and store, but also cheaper. In addition, fewer and simpler work steps have to be carried out. The M-type compounds described here^AY_n(AzuH) (I) comprising cyclopentadienyl-type monoanions (AzuH)^1-, are simple and reproducible and – depending on the choice of educts – available sustainably and comparatively cheaply. In addition, high purity and good yields, including space-time yields, can be achieved. They are therefore also suitable for use in industrial processes. In particular compounds according to the general formula M^AY_n(AzuH) (I), where AzuH = GuaH = 7-iso-propyl-1,4-dimethyl-8-H-dihydroazulene, are to be assessed as sustainable. This is because these compounds, which include cyclopentadienyl-like ligands, can be produced using inexpensive renewable raw materials. The target price of starting from the natural substance guajol and other azulene formers by simple dehydration and dehydration (T. Shono, N. Kise, T. Fujimoto, N. Tominaga, H. Morita, J. Org. Chem.1992, 57, 26, 7175 – 7187; CH 314487 A (B. Joos) 01/29/1953) accessible partially synthetic guaiazulens is €74.70 per 25g (Sigma Aldrich, 12/2020). According to one embodiment of the claimed compounds, it is provided that Azu = azulene, where the compound according to the general formula M^AY_n(AzulenH) (I) is present as a mixture of isomers or as pure isomers, the mixture of isomers containing at least two regioisomers selected from the group consisting of a first regioisomer, a second regioisomer and a third regioisomer. Included the first regioisomer has a CH₂group in the C4 position of the azulene, the second regioisomer has a CH₂group in the C6 position of the azulene, and the third regioisomer has a CH₂group in the C8 position of the azulene. In other words, in the case of the first regioisomer, the carbon atom C4 bears an H atom and a hydride anion H-, in the case of the second regioisomer the carbon atom C6 bears an H atom and a hydride anion H-, and in the case of the third one H- Regiosomiers, the C8 carbon atom bears an H atom and a hydride anion H-. While the carbon atoms C4, C6 and C8 of the bicyclo[5.3.0]decapentaene (= azulene) are known to have a comparable nucleophilicity, the carbon atoms C4, C6 and C8 of an azulene derivative, i. H. a substituted azulene, regularly a different nucleophilicity. Therefore, compounds of the type M^AY_n(AzuH) (I), where Azu = an azulene derivative - depending on the substitution pattern of the azulene derivative - not only present as mixtures of three regioisomers, but advantageously also as isomer mixtures containing only two regioisomers, or particularly advantageously as isomerically pure compounds. In the context of the present invention, “isomerically pure” means that the desired product is or has been obtained in pure isomer form or the desired isomer is present after purification in a proportion of ≧90%, preferably ≧95%, particularly preferably ≧99%. Here, the isomer purity is determined, for example, by means of nuclear magnetic resonance spectroscopy. In another embodiment of the compounds of type M claimed herein^AY_n(AzuH) (I) it is intended that Azu = an azulene derivative, wherein the compound according to the general formula M^AY_n(AzuH) (I) is present as a mixture of isomers or as a single isomer. If Azu = azulene derivative and the compound is according to the general formula M^AY_n(AzuH) (I) as an isomer mixture, the isomer mixture contains at least two regioisomers selected from the group consisting of a first regioisomer, a second regioisomer and a third regioisomer. The first regioisomer has a CH₂group in the C4 position of the azulene skeleton, the second regioisomer has a CH₂group in the C6-position of the azulene skeleton, and the third regioisomer has a CH₂group in the C8 position of the azulene skeleton. In other words, in the case of the first regioisomer, the carbon atom C4 bears an H atom and a hydride anion H-, in the case of the second regioisomer the carbon atom C6 bears an H atom and a hydride anion H-, and in the case of the third one H- Regiosomiers, the C8 carbon atom bears an H atom and a hydride anion H-. If Azu = azulene derivative and the compound is according to the general formula M^AY_n(AzuH) (I) isomerically pure, then either i. the carbon atom C4 of the azulene skeleton or ii. the carbon atom C6 of the azulene skeleton or iii. the C8 carbon atom of the azulene skeleton has a hydride anion H- in addition to the one H atom. Consequently, there is a CH either in the C4 position or alternatively in the C6 position or in the C8 position of the azulene skeleton₂-group before. In other words, there is only one regioisomer. According to a variant of the compounds claimed here according to the general formula M^AY_n(AzuH) (I), where Azu = an azulene derivative, carries at least one carbon atom of the azulene skeleton selected from the group consisting of C1, C2 and C3, a substituent R^f and the carbon atoms C4, C5, C6, C7 and C8 of the auzulene skeleton each carry an H atom. In another embodiment of the compounds of type M described herein^AY_n(AzuH) (I), where Azu = an azulene derivative, carries at least one carbon atom of the azulene skeleton selected from the group consisting of C4, C5, C6, C7 and C8, a substituent R^f, and the carbon atoms C1, C2 and C3 of the azulene skeleton each carry an H atom. In a further variant of the compounds claimed here according to the general formula M^AY_n(AzuH) (I), where Azu = an azulene derivative, it is intended that exactly one carbon atom of the five-membered ring, i.e. C1 or C2 or C3, and exactly one carbon atom of the seven-membered ring, i.e. C4 or C5 or C6 or C7 or C8, one substituents R^f wear. An alternative embodiment of the compounds claimed here according to the general formula M^AY_n(AzuH) (I), where Azu = an azulene derivative, provides that exactly one carbon atom of the five-membered ring, i.e. C1 or C2 or C3, and exactly two carbon atoms of the seven-membered ring, i.e. exactly two of the carbon atoms C4, C5, C6, C7 , C8, a substituent R^f wear. According to yet another variant embodiment of the compounds according to general formula M described here^AY_n(AzuH) (I), where Azu = an azulene derivative, it is intended that exactly one carbon atom of the five-membered ring, i.e. C1 or C2 or C3, and exactly three carbon atoms of the seven-membered ring, i.e. exactly three of the carbon atoms C4, C5, C6, C7 , C8, a substituent R^f wear. In a further embodiment of the compounds claimed here according to the general formula M^AY_n(AzuH) (I), where Azu = an azulene derivative, at least the carbon atoms C1, C4 and C7 of the azulene skeleton carry a substituent R^f. This also includes the isomers of the at least 1,4,7-substituted azulene derivative. Examples of 1,4,7-substituted azulene derivatives are 1,4,7-trimethylazulene, 7-ethyl-1,4-dimethylazulene (chamazulene), 7-n-propyl-1,4-dimethylazulene, 7-isopropyl- 1,4-dimethylazulene (guaiazulene), 7-n-butyl-1,4-dimethylazulene, 7-isobutyl-1,4-dimethylazulene, 7-sec-butyl-1,4-dimethylazulene, 7-tert-butyl -1,4-dimethylazulene, 7-n-pentyl-1,4-dimethylazulene, 7-isopentyl-1,4-dimethylazulene, 7-neopentyl-1,4-dimethylazulene, 7-n-hexyl-1 ,4-dimethylazulene, 7-isohexyl-1,4-dimethylazulene, 7-(3-methylpentane)-1,4-dimethylazulene, 7-neohexyl-1,4-dimethylazulene, 7-(2,3- dimethylbutane)-1,4-dimethylazulene, and isomers thereof. Guajazulene is a natural substance that is contained in chamomile oil and other essential oils and is therefore available in large quantities at low cost. Synthetically, it can be made from the guajol of guaiac wood oil (guaiac resin). Guajazulene is an intensely blue substance with anti-inflammatory effects. An example of an isomer of guaiazulene is 2-isopropyl-4,8-dimethylazulene (vetivazulene). If Azu=guaiazulene, the isomerically pure compound alkali metal 7-isopropyl-1,4-dimethyl-8-H-dihydroazulenide is advantageously present, which can also be referred to as alkali metal 8-H-dihydroguaiazulenide. In another variant of the claimed compounds, the alkali metal is M^A is selected from the group consisting of Li, Na and K. According to yet another embodiment, the neutral ligand Y is an aprotic polar solvent. The neutral ligand is advantageously selected from the group consisting of ethers (=alkoxyalkanes), thioethers and tertiary amines, in particular from the group consisting of ethers (=alkoxyalkanes) and thioethers. In the present case, the term “alkoxyalkane” means any oxygen-containing ether, for example also glycol dialkyl ether and crown ether. The term "thioether" includes both non-cyclic and cyclic thioethers. Terminally dialkylated mono-, di- or trialkylene glycol dialkyl ethers are also understood as glycol dialkyl ethers. Non-limiting examples of glycol dialkyl ethers are given above. A definition of the term "crown ether" and a selection of crown ethers has already been given above. Diisopropylethylamine (DIPEA) or N,N,N',N'-tetramethylethylenediamine (TMEDA), for example, can be provided as the tertiary amine. According to yet another embodiment of the claimed compounds, the neutral ligand Y is an ether. For example, the ether can be a non-cyclic or a cyclic ether selected from the group consisting of dialkyl ethers, cyclopentylmethyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 3-methyltetrahydrofuran, tetrahydropyran, 1,4-dioxane, and their isomers, and mixtures thereof, in particular from the group consisting of diethyl ether, methyl tert-butyl ether, di-n-propyl ether, diisopropyl ether, di-n-butyl ether, diisobutyl ether, di-tert-butyl ether, tetrahydrofuran, 2-methyltetrahydrofuran, 3 -Methyltetrahydrofuran, tetrahydropyran, 1,4-dioxane, and their isomers, and mixtures thereof. In a further variant of the compounds described here, the neutral ligand Y is a crown ether which is selected from the group consisting of macrocyclic polyethers and their aza, phospha and thia derivatives, with an inner diameter of the crown ether and an ionic radius of M^A correspond with each other. Whether the compounds claimed here according to the general formula M^AY_n(AzuH) (I) as solvent adducts, especially ether adducts, depends on various factors, e.g. B. of the solvent or solvent mixture used for the preparation of compounds according to the general formula I and the nature of the alkali metal cation M^A+, i.e. the hydridic reducing agent Z used. For example, during the synthesis, including purification, a solvent is used, which comprised or consisted of one or more ethers, and at least one hydridic reducing agent Z having lithium cations is used, in all probability an ether adduct Li(ether)_n(A to H) (I) where n = 1 or 2. If such an ether adduct finally with a non-ethereal solvent such. B. pentane or hexane, is usually a solvent-free compound according to the general formula Li (AzuH) (I) before. The object is also achieved by using a) a compound of the general formula M^AY_n(AzuH) (I) - according to an embodiment of the compounds according to the general formula M described above^AY_n(AzuH) (I) or - obtained or obtainable by a process for preparing such compounds according to one of the embodiments described above, or b) a solution or a suspension comprising a compound of the general formula M^AY_n(AzuH) (I) and at least one, in particular aprotic-polar, solvent S_P, obtained or obtainable by a method according to one of the embodiments described above, wherein - M^A is an alkali metal, - Y is a neutral ligand which can be attached via at least one donor atom to M^A is bonded or coordinated where H₂O is excluded, - n = 0, 1, 2, 3 or 4 and - AzuH = azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom, whereby Azu = azulene according to the formula or Azu = an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6, C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, for the preparation of metal complexes according to the general formula M(L_K)_f(AzuH)_m (III) or M(L_N)(AzuH)_q (IV) or [M(L_S)_G(AzuH)_v]X (V) or [M(L_T)(AzuH)_e.g]X (VI), where M = central metal atom selected from Group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12, L_K = optional neutral sigma donor ligand or optional neutral pi donor ligand, f = number of ligands L_K, where f = 0, 1, 2, 3, 4, 5, or 6, m = number of ligands AtoH, where m = 1, 2, 3, 4, 5, 6, or 7, L_N = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum u of the negative charges of all ligands L_N is -1, -2, -3, -4, -5 or -6, q = number of ligands A to H, where q = w₂ – |u|, where w₂ > |u| and w₂ = 2, 3, 4, 5, 6 or 7, and where |u| an absolute value of the sum of the negative charges of all ligands L_N where |u| = 1, 2, 3, 4, 5 or 6, L_S = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands L_S, where g = 0, 1, 2, 3, 4, 5 or 6, v = number of ligands AzuH, where v = w₃ – 1, where w₃ = 2, 3, 4, 5, 6 or 7, L_T = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum h of the negative charges of all ligands L_T is -1, -2, -3, -4 or -5, z = number of ligands A to H, where z = w₄ – (|h| + 1), where w₄ > (|h| + 1) and w₄ = 3, 4, 5, 6 or 7, and where |h| an absolute value of the sum of the negative charges of all ligands L_T where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, and AzuH and Azu are as defined above. In the aforementioned use of a compound according to the general formula M^AY_n(AzuH) (I) or a solution or suspension comprising a compound according to of the general formula M^AY_n(AzuH) (I) and at least one, in particular aprotic-polar, solvent S_P, for the production of metal complexes is a process for the production of metal complexes according to the general formula M(L_K)_f(AzuH)_m (III) or M(L_N)(AzuH)_q (IV) or [M(L_S)_G(AzuH)_v]X (V) or [M(L_T)(AzuH)_e.g]X (VI), where M = central metal atom selected from Group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12, L_K = optional neutral sigma donor ligand or optional neutral pi donor ligand, f = number of ligands L_K, where f=0, 1, 2, 3, 4, 5 or 6, AzuH=azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom , m = number of ligands AzuH, where m = 1, 2, 3, 4, 5, 6 or 7, L_N = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum u of the negative charges of all ligands L_N is -1, -2, -3, -4, -5 or -6, q = number of ligands A to H, where q = w₂ – |u|, where w₂ > |u| and w₂ = 2, 3, 4, 5, 6 or 7, and where |u| an absolute value of the sum of the negative charges of all ligands L_N where |u| = 1, 2, 3, 4, 5 or 6, L_S = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands L_S, where g = 0, 1, 2, 3, 4, 5 or 6, v = number of ligands AzuH, where v = w₃ – 1, where w₃ = 2, 3, 4, 5, 6 or 7, L_T = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum h of the negative charges of all ligands L_T is -1, -2, -3, -4 or -5, z = number of ligands A to H, where z = w₄ – (|h| + 1), where w₄ > (|h| + 1) and w₄ = 3, 4, 5, 6 or 7, and where |h| an absolute value of the sum of the negative charges of all ligands L_T where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, and where Azu = azulene according to formula or Azu=an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6 , C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, using ■ a compound according to the general formula M^AY_n(AzuH) (I), - according to an embodiment of the compounds according to the general formula M described above^AY_n(AzuH) (I) or - obtained or obtainable by a process for preparing such compounds according to one of the embodiments described above, or ■ a solution or a suspension comprising a compound of the general formula M^AY_n(AzuH) (I) and at least one, in particular aprotic-polar, solvent S_P, obtained or obtainable by a method according to one of the embodiments described above, wherein - M^A is an alkali metal, - Y is a neutral ligand which can be attached via at least one donor atom to M^A is bonded or coordinated where H₂O is excluded, - n = 0, 1, 2, 3 or 4 and - AzuH and Azu are as defined above, comprising the steps: A. Providing the compound according to the general formula M^AY_n(AzuH) (I) or the solution or the suspension comprising the compound according to the general formula M^AY_n(AzuH) (I) and the at least one, in particular aprotic-polar, solvent S_P, and B. Synthesis of the metal complex M(L_K)_f(AzuH)_m (III) or M(L_N)(AzuH)_q (IV) or [M(L_S)_G(AzuH)_v]X (V) or [M(L_T)(AzuH)_e.g]X (VI) using the compound according to the general formula M^AY_n(AzuH) (I) as starting material. The general formulas III, IV, V and VI include both the monomers and any oligomers, in particular dimers. The respective central metal atom M can in principle have a formal oxidation state or oxidation number of 0, 1, 2, 3, 4, 5, 6 or 7. The higher oxidation states, in particular the oxidation states 4, 5, 6 and 7, are usually formed by anionic, especially monoanionic, ligands, e.g. B. fluoride anions (see. In particular, formulas IV, V and VI), and / or dianionic ligands, z. B.O^2- (cf. in particular formula VI), stabilized. The index q can have the value 1, 2, 3, 4, 5 or 6. Alternatively, q=1, 2, 3, 4 or 5, q=1, 2, 3 or 4 is advantageous, in particular q=1, 2 or 3. The index v can also be 1, 2, 3, 4, 5 or 6. Alternatively, v=1, 2, 3, 4 or 5, v=1, 2, 3 or 4 is advantageous, in particular v=1, 2 or 3. The index z can have the value 1, 2, 3, 4 or accept 5 Alternatively, z=1, 2, 3 or 4, in particular z=1, 2 or 3. The term “weakly coordinating” also includes the expressions “very weakly coordinating” and “moderately strongly coordinating”. In particular, the halide anions are selected from the group consisting of fluoride, chloride and bromide. For monovalent weakly coordinating and monovalent non-coordinating anions it is in particular perfluorinated anions such. B.PF₆-, BF₄- and [(CF₃SO₂)₂N]-. The metal complexes according to the general formulas III, IV, V and VI are usually solvent-free, i. H. not as solvent adducts. However, it is also possible to prepare solvent adducts of these metal complexes. In the case of a solvent adduct, the solvent is in particular with the solvent S_P identical. Alternatively or additionally, one or more of the neutral donor ligands L_K or L_S (cf. Formula III or Formula V) be selected from the group consisting of acetonitrile, dimethyl sulfoxide and tetrahydrothiophene. The type M connection used in each case^AY_n(AzuH) (I) can be present as pure isomers or as a mixture of two or three isomers. In the case of the isomers according to the general formula M^AY_n(AzuH) (I) is in particular an alkali metal 3α,4-H-dihydroazulenide, an alkali metal 8,8α-H-dihydroazulenide, an alkali metal 3α,6-H-dihydroazulenide and/or an alkali metal 6,8α-H-dihydroazulenide. These can be adduct-free or solvent-free, namely when n = 0, or as adducts or solvates with one (n = 1), two (n = 2), three (n = 3) or four (n = 4) neutral ligands Y The neutral ligand Y is advantageously selected from the group consisting of ethers (=alkoxyalkanes), thioethers and tertiary amines, in particular from the group consisting of ethers (=alkoxyalkanes) and thioethers. Examples of Y are given above. With the solvent S_P it can also be a solvent mixture. The solvent S_P is advantageously an aprotic-polar solvent or comprises at least one aprotic-polar solvent. For example, the solvent S_P an ether or comprises at least one ether. The ether may be selected from the group consisting of tetrahydrofuran, methyltetrahydrofuran, 1,4-dioxane, diethyl ether, methyl tert-butyl ether, di-n-propyl ether, diisopropyl ether, cyclopentylmethyl ether, and their isomers, and mixtures thereof. Surprisingly, by means of the use claimed here of compounds of the general formula M^AY_n(AzuH) (I) or, by means of the method described here, metal complexes of medium transition metals (groups 6, 7 and 8), in particular of group 8 metals, and later transition metals, i.e. of group 9, group 10, group 11 metals and group 12, in good purity of 97%, advantageously more than 97%, in particular more than 98% or 99%, and good yield, also space-time yield. Specifically, these are metal complexes according to the general formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V), [M(L_T)(AzuH)_e.g]X (VI). M is a central metal atom selected from group 6, group 7, group 8, group 9, group 10, group 11 or group 12. It was also surprisingly found that strongly reducing H-dihydroazulenyl- Ligands (AzuH)^1-, such as B. the 8-H-Dihydroguaiazulenyl Ligand (GuaH)^1- , for the preparation of complexes of the middle transition metals (groups 6, 7 and 8), e.g. starting with chloride salts of Group 8 metals and late transition metals, for example starting with chloride salts of Group 9, Group 10, Group 11 and Group 12 metals. In addition, these complexes are advantageously obtainable in good yield and good purity, in many cases also as isomerically pure. The above facts are surprising because those skilled in the art know that strongly reducing H-dihydroazulenyl ligands (AzuH)^1-, such as B. the 8-H-Dihydroguaiazulenyl Ligand (GuaH)^1-, especially for complex formation with early transition metals, e.g. As titanium and zirconium, is predestined. (cf. J. Richter, P. Liebing, FT Edelmann Inorg. Chim. Acta 2018, 475, 18-27). By means of the use claimed here of compounds according to the general formula M^AY_n(AzuH) (I) or by means of the method described here are on the one hand highly pure homoleptic sandwich complexes of middle transition metals (groups 6, 7 and 8), in particular from group 8 metals, and later transition metals, i.e. from group 9, group 10, group 11 and group 12 metals, in particular: ■ neutral sandwich complexes of the type M(L_K)_f(AzuH)_m (III) with f = 0, i.e. H. without neutral donor ligand L_K, e.g. B.Fe(GuaH)₂, Ru(GuaH)₂, Co(GuaH)₂, Zn(GuaH)₂, where the formal oxidation state is 2, M = Fe, Ru, Co or Zn, f = 0, m = 2 and AzuH = GuaH and ■ cationic sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 0, i.e. H. without neutral donor ligand L_S, e.g. B. [Co(GuaH)₂]PF₆, where the formal oxidation state is 3, M = Co, g = 0, v = 3 − 1 = 2, AzuH = GuaH, and X = PF₆. On the other hand, by means of the use claimed here of compounds of the general formula M^AY_n(AzuH) (I) or using the method described here, high-purity heteroleptic complexes of medium transition metals (groups 6, 7 and 8), in particular of group 8 metals, and later transition metals, i.e. of group 9 metals, group 10 metals, the Group 11 and Group 12, in particular: ■ neutral half-sandwich complexes of the M(L_K)_f(AzuH)_m (III) with f = 1 or 2, i. H. with exactly one neutral sigma donor ligand or with exactly one neutral nonplanar pi donor ligand, e.g. B. Cu(PPh₃)(GuaH), Rh(nbd)(GuaH), Rh(cod)(GuaH), where the formal oxidation state is 1, M = Cu or Rh, L_K = PPh₃, NBD or COD, each f is 1, each m is 1 and AzuH = GuaH, or two planar, neutral pi-donor ligands, e.g. B. Rh(ethene)₂(GuaH), where the formal oxidation state is 1, M = Rh, L_K = ethene, f = 2, m = 1 and AzuH = GuaH ■ neutral half-sandwich complexes of the type M(L_N)(AzuH)_q (IV), for example with |u| = 1, 2 or 3, i. H. for example with one, two or three monoanionic sigma donor ligands, e.g. B. Zn(Mes)(GuaH), where the formal oxidation state is 2, M = Zn, L_N = Mes-, |u| = 1, q = 2 - |-1| = 1 and AzuH = GuaH, and PtMe₃(GuaH), where the formal oxidation state is 4, M = Pt, L_N = CH₃-, |u| = 3, q = 4 - |-3| = 1 and AzuH = GuaH ■ neutral sandwich complexes of the type M(L_N)(AzuH)_q (IV), for example with |u| = 1, i.e. H. with exactly one monoanionic, planar pi-donor ligand, e.g. B. Ru(Cp*)(GuaH), where the formal oxidation state is 2, M = Ru, L_N = Cp*, |u| = 1, q = 2 - |-1| = 1 and AzuH = GuaH ■ cationic sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 1, i.e. h with exactly one neutral, planar pi-donor ligand, e.g. B. [Ru(p-cymene)(GuaH)]PF₆, where the formal oxidation state is 2, M = Ru, L_S = p-cymene, g = 1, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆ ■ cationic half-sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 1 or 2, i.e. H. with a neutral non-planar pi-donor ligand, e.g. B. [Pt(cod)(GuaH)]PF₆, where the formal oxidation state is 2, M = Pt, L_S = COD, g = 1, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆ or with two planar, neutral pi-donor ligands, e.g. B. [Pt(ethene)₂(GuaH)]PF₆, where the formal oxidation state is 2, M = Pt, L_S = ethene, g = 2, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆ ■ cationic sandwich complexes of the type [M(L_T)(AzuH)_e.g]X (VI) with |h| = 1, i.e. H. with exactly one anionic, planar pi-donor ligand, e.g. B. [Rh(Cp*)(GuaH)]Cl, [Rh(Cp*)(GuaH)]PF₆, where the formal oxidation state is 3 in each case, M = Rh, L_T = Cp*, |h| = 1, z = 3 - (|-1| + 1) = 1, AzuH = GuaH and X = Cl or PF₆. Purity here means both the absence of undesired impurities, in particular from starting materials, by-products and solvents, and the isomeric purity. Because both of the aforementioned types of purity can be important with a view to the later use of the metal complexes that can be prepared using this method. A definition of the term “isomerically pure” and thus implicitly also of the term “isomerically pure” has already been given above. In the context of the present invention, the term "high purity" also refers to a total content of impurities, including in particular Impurities from metals, semi-metals, atmospheric oxygen, water and oxygen-containing compounds of less than 1 ppm, ideally less than 100 ppb. In one embodiment of the claimed use or the method claimed here, the production of metal complexes according to the general formula M(L_K)_f(AzuH)_m (III) provided. According to yet another embodiment of the claimed use or the claimed method, the central metal atom M of the metal complex to be prepared is of the general formula M(L_K)_f(AzuH)_m (III) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury . Another variant of the use or the method provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver , zinc and cadmium. According to yet another embodiment of the use or the method, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc , in particular from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the use claimed here or of the method claimed here provides that the central metal atom M has a formal oxidation state of 1, 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the use or the method, it is provided that the index m and the formal oxidation state of the central metal atom M of the metal complex to be produced in each case correspond to the general formula M(L_K)_f(AzuH)_m (III) are identical, i. H. are the same natural number except for zero. Thus m=1, 2, 3, 4, 5, 6 or 7 can be. According to a further embodiment of the use or the method, the production of a metal complex according to the general formula M(L_K)_f(AzuH)_m (III) provided, wherein the central metal atom M has a formal oxidation state of 1, 2, 3 or 4, advantageously 1, 2 or 3, in particular 1 or 2. In an alternative or supplementary embodiment of the claimed use or of the claimed method is the index m 1, 2, 3 or 4, advantageously 1, 2 or 3, in particular 1 or 2. Another alternative or supplementary embodiment of the claimed use or the claimed method provides that the index f, which the Number of neutral ligands L_K in a metal complex according to the general formula M(L_K)_f(AzuH)_m (III) indicates zero, 1, 2, 3, 4 or 5, advantageously zero, 1, 2, 3 or 4, in particular zero, 1, 2 or 3. In another embodiment of the use claimed here or of the here claimed method is the sum of the number m of the ligands AzuH and the number f of the neutral ligands L_K, i.e. Σ (f + m), 2, 3, 4, 5, 6 or 7. Another embodiment provides that the sum of the number m of ligands AzuH and the number f of neutral ligands L_K, ie Σ(f+m), is 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. A further embodiment provides that the neutral sigma donor ligand L_K or pi donor ligand L_K is selected from the group consisting of monodentate and polydentate phosphorus donor ligands, alkenes, cyclic dienes and cyclic polyenes, and mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes, and their derivatives. In the present case, the term phosphorus donor ligand means any monodentate or polydentate ligand which has at least one phosphorus donor atom via which the neutral ligand L_K can coordinate to a metal ion. These include phosphanes and Diphosphanes and phosphorus donor ligands such. B. 2-(Dicyclohexylphosphino)-2'-(N,N-dimethylamino))-1,1'-biphenyl (DavePhos). Examples of the ligand L_K are the alkenes ethene, propene, butene, pentene, hexene, heptene, octene, nonene, decene and their isomers, the bicyclic alkene bicyclo[2.2.1]hept-2-ene, the cyclic diene cycloocta-1,5-diene (COD), the bicyclic diene bicyclo[2.2.1]hepta-2,5-diene (NBD), the monocyclic cycloocta-1,3,5,7-tetraene (COT). Examples of a mononuclear arene and derivatives of a mononuclear arene are benzene and benzene derivatives, e.g. B. toluene, p-cymene and halogenated benzenes. Naphthalene and naphthalene derivatives are examples of a polynuclear arene and a polynuclear arene derivative. An example of a heteroarene is pyridine. A binuclear or bicyclic heteroarene is, for example, indole. The mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes can also be substituted, in particular have alkyl groups and/or alkenyl groups and/or alkynyl groups and/or aryl groups and/or heteroaryl groups and/or halogen substituents. In a variant of the claimed use or the claimed method, the ligand is L_K selected from the group consisting of 2-(dicyclohexylphosphino)-2'-(N,N-dimethylamino))-1,1'-biphenyl (DavePhos), 2-(dicyclohexylphosphino)-2',4',6'-tri -iso-propyl-1,1'-biphenyl (XPhos), 2-Dicyclohexylphosphino-2',6'-dimethoxy-1,1'-biphenyl (SPhos), 2-Dicyclohexylphosphino-2',6'-di-iso -propoxy-1,1'-biphenyl (RuPhos), 2-(Dicyclohexylphosphino)-3,6-dimethoxy-2',4',6'-tri-iso-propyl-1,1'-biphenyl (BrettPhos), [4-(N,N-dimethylamino)phenyl]di-tert-butylphosphine (amphos), 9,9-dimethyl-4,5-bis(diphenylphosphino)_xanthene (Xantphos), 2-dicyclohexylphosphino-2',6'-bis(dimethylamino)-1,1'-biphenyl (CPhos), tricyclohexylphosphine (PCy3), butyldi-1-adamantylphosphine (cataCXium^® A), 2-Di-tert-butylphosphino-2',4',6'-tri-iso-propyl-1,1'-biphenyl (t-BuXPhos), 2-(Di-tert-butylphosphino)-3, 6-dimethoxy-2',4',6'-triisopropyl-1,1'- biphenyl (tert-BuBrettPhos), 2-(di-tert-butylphosphino)-3-methoxy-6-methyl-2',4',6'-tri-iso-propyl-1,1'-biphenyl (RockPhos), 2-Di[3,5-bis(trifluoromethyl)phenylphosphino]-3,6-dimethoxy-2',4',6'-triisopropyl-1,1'-biphenyl (JackiePhos), (R)- (-)-1-[(S)-2-(Dicyclohexylphosphino)ferrocenyl]ethyldi-tert-butylphosphine, Di-tert-butyl(n-butyl)phosphine, 2-(Di-1-adamantylphosphino)-3,6- dimethoxy-2',4',6'-triisopropyl-1,1'-biphenyl (AdBrettPhos), 2-Diethylphosphino-2',6'-bis(dimethylamino)-1,1'-biphenyl, racemic -2-Di-tert-butylphosphino-1,1'-binaphthyl (TrixiePhos), Tri-tert-butylphosphine (PtBu3), 1,3,5,7-Tetramethyl-8-phenyl-2,4,6-trioxa- 8-phosphaadamantane (MeCgPPh), N-[2-(di-1-adamantylphosphino)phenyl]morpholine (MorDalPhos), 4,6-bis(diphenylphosphino)phenoxazine (NiXantphos), 1,1'-bis(diphenylphosphino)ferrocene ( dppf), 2-Di-tert-butylphosphino-2'-(N,N-dimethylamino))-1,1'-biphenyl (tBuDavePhos), racemic-2,2'-bis(diphenylphosphino)-1,1'- binaphthyl (rac-BINAP), 1,1'-bis(di-tert-butylpho sphino)ferrocene (DTBPF), 2-Di-tert-butylphosphino-3,4,5,6-tetramethyl-2',4',6'-tri-iso-propyl)-1,1'-biphenyl (Me4t- BuXPhos), 2-dicyclohexylphosphino-4-(N,N-dimethylamino)-1,1'-biphenyl, trimethylphosphine (PMe₃), tris-p-tolylphosphine (P(p-tolyl)₃), tris-o-tolylphosphine (P(p-tolyl)₃), methyldiphenylphosphine, triphenylphosphine (PPh₃), trifluorophosphine, 1,2-bis(diphenylphosphino)ethane (dppe), phenyl-di-tert-butylphosphine, di-tert-butyl-neopentylphosphine, 1,2,3,4,5-pentaphenyl-1'-(di -tert-butylphosphino)ferrocene, tris(p-methoxyphenyl)phosphine, tris(p-trifluoromethylphenyl)phosphine, tris(2,4,6-trimethoxyphenyl)phosphine, tris(2,4,6-trimethyl)phosphine, tris( 2,6-dimethylphenyl)phosphine, 1-adamantyl-di-tert-butylphosphine, benzyldi-1-adamantylphosphine, butyldi-1-adamantylphosphine, tris(1-adamantyl)phosphine (PAd3), cyclohexyldi-tert-butylphosphine, cyclohexyldiphenylphosphine, 2 -di-tert-butylphosphino-1,1'-binaphthyl, 2-(di-tert-butylphosphino)biphenyl, 2-di-tert-butylphosphino-2'-methylbiphenyl, 2-di-tert-butylphosphino-2',4 ',6'-triisopropyl-1,1'-biphenyl, 2-di-tert-butylphosphino-3,4,5,6-tetramethyl-2',4',6'-triisopropylbiphenyl, 2-( Dicyclohexylphosphino)biphenyl, 2-(Dicyclohexylphosphino)-2',6'-dimethoxy-1,1'-biphenyl, 2-Di-tert-cyclohexylphosphino-2'-(N,N-dimethylamino)biphenyl, 2-Di- tert-cyclohexylphosphino- 2',6'-diisopropoxy-1,1'-biphenyl, 2-(dicyclohexylphosphino)-2',4',6'-triisopropyl-1,1'-biphenyl, 2-dicyclohexylphosphino-2 '-methylbiphenyl, 2- Diphenylphosphino-2'-(N,N-dimethylamino)biphenyl, (4-dimethylaminophenyl)(tert-butyl)₂- phosphine, 1,2-bis(di-tert-butylphosphinomethyl)benzene, 1,3-bis(di-tert-butylphosphinomethyl)propane, 1,2-bis(diphenylphosphinomethyl)benzene, 1,2-bis(di-phenylphosphino )ethane, 1,2-bis(diphenylphosphino)propane, 1,2-bis(diphenylphosphino)butane, N-(2-methoxyphenyl)-2-(di-tert-butylphosphino)pyrrole, 1-(2- methoxyphenyl)- 2-(di-cyclohexylphosphino)pyrrole, N-phenyl-2-(di-tert-butylphosphino)indole, N-phenyl-2-(di-tert-butylphosphino)pyrrole, N-phenyl-2-(dicyclohexylphosphino)indole, N -phenyl-2-(dicyclohexylphosphino)pyrrole and 1-(2,4,6-trimethylphenyl)-2(dicyclohexylphosphino)imidazole. A further advantageous embodiment of the use or of the method provides that the central metal atom M of the metal complex to be prepared is of the general formula M(L_K)_f(AzuH)_m (III) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the metal central atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In a further embodiment of the claimed use or the method claimed here, the production of a metal complex according to the general formula M(L_N)(AzuH)_q (IV) provided. According to yet another embodiment of the claimed use or the claimed method, the central metal atom M of the metal complex to be prepared is of the general formula M(L_N)(AzuH)_q (IV) selected from the Group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Another variant of the use or the method provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver , zinc and cadmium. According to yet another embodiment of the use or the method, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc , in particular from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the use claimed here or of the method claimed here provides that the central metal atom M has a formal oxidation state of 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the use or the method, it is provided that w₂ and the formal oxidation state of the central metal atom M of the metal complex to be prepared in each case according to the general formula M(L_N)(AzuH)_q (IV) are identical, i. H. are the same natural number except for zero. Consequently w₂ = 2, 3, 4, 5, 6 or 7. According to a further embodiment of the claimed use or the claimed method, the production of a metal complex according to the general formula M(L_N)(AzuH)_q (IV) provided, wherein the central metal atom M has a formal oxidation state of 2, 3, 4, 5 or 6, advantageously of 2, 3, 4 or 5, in particular of 2, 3 or 4. In an alternative or supplementary embodiment of the claimed use or method is w₂ = 2, 3, 4, 5 or 6, w is advantageous₂ = 2, 3, 4 or 5, in particular w₂ = 2, 3 or 4. A further alternative or supplementary embodiment of the claimed use or the claimed method provides that |u|, ie the absolute amount of the sum of negative charges of all anionic ligands L_N in a metal complex according to the general formula M(L_N)(AzuH)_q (IV) is 1, 2, 3, 4, 5, or 6. In yet another embodiment variant, |u|, i.e. the absolute amount of the sum of the negative charges of all anionic ligands L_N in a metal complex according to the general formula M(L_N)(AzuH)_q (IV), 1, 2, 3, 4 or 5, advantageously 1, 2, 3 or 4, in particular 1, 2 or 3. In another embodiment of the use claimed here or of the method claimed here, the sum of the number is q of the ligands AzuH and the number of anionic ligands L_N 2, 3, 4, 5, 6 or 7. A further embodiment provides that the sum of the number q of the ligands AzuH and the number of anionic ligands L_N 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. Yet another embodiment of the use claimed here or of the method claimed here for the preparation of metal complexes according to the general formula M (L_N)(AzuH)_q (IV) provides that the anionic sigma donor ligand L_N or pi donor ligand L_N is advantageously a monoanionic ligand selected from the group consisting of anions of cyclopentadiene and its derivatives, alkyl anions and aryl anions. Alternatively or additionally, a fluoride anion can be used as at least one of the monoanionic ligands L_N be provided. Examples of the anionic ligand L_N are the cyclopentadienyl anion C₅H₅- (Cp-) and the 1,2,3,4,5-pentamethylcyclopentadienyl anion C₅me₅ ⁻ (Cp^*), the methyl anion CH₃- (Me-) and the mesityl anion Me₃C₆H₂ ⁻ (Mes-). The aforementioned anions can be used as monoanionic pi-donor ligands or sigma-donor ligands L_N in the production of neutral sandwich or half-sandwich complexes of the type M(L_N)(AzuH)_q (IV) function. A further advantageous embodiment of the use or the method provides that the central metal atom M of the metal complex to be prepared according to the general formula M(L_N)(AzuH)_q (IV) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously the metal central atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. The complexes Ru(Cp*)(GuaH), Zn(Mes)(GuaH), and PtMe₃(GuaH) exist in isolated form as liquids. The latter is particularly advantageous with a view to use as metal precursor compounds for gas phase deposition processes. In addition, it is advantageous to use a liquid catalyst in the catalysis, for example the Pt(IV) compound PtMe₃(GuaH) for light-induced platinum-catalyzed hydrosilylation reactions. The aforementioned Pt(IV) compound also shows absorption in the Vis range. This represents a further advantage in the context of light-induced platinum-catalyzed hydrosilylation reactions. Because the use of UV/Vis light is regularly provided for, which usually requires special safety measures to reduce the risk of skin cancer. Such security measures are when using PtMe₃(GuaH) not mandatory. In another embodiment of the claimed use or the method claimed here, the preparation of metal complexes according to the general formula [M(L_S)_G(AzuH)_v]X (V) provided. According to a further embodiment of the claimed use or the claimed method, the central metal atom M of the metal complex to be prepared is of the general formula [M(L_S)_G(AzuH)_v]X (V) selected from the Group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Another variant of the use or the method provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver , zinc and cadmium. According to yet another embodiment of the use or the method, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc , in particular from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the use claimed here or of the method claimed here provides that the central metal atom M has a formal oxidation state of 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the use or the method, it is provided that w₃ and the formal oxidation state of the central metal atom M of the metal complex to be prepared in each case according to the general formula [M(L_S)_G(AzuH)_v]X (V) are identical, i.e. H. are the same natural number except for zero. Consequently w₃ = 2, 3, 4, 5, 6 or 7. According to a further embodiment of the use or the method, the production of a metal complex according to the general formula [M(L_S)_G(AzuH)_v] X (V) provided, wherein the central metal atom M has a formal oxidation state of 2, 3, 4, 5 or 6, advantageously of 2, 3, 4 or 5, in particular of 2, 3 or 4. In an alternative or supplementary embodiment variant of the claimed use or the claimed method is w₃ = 2, 3, 4, 5 or 6, w is advantageous₃ = 2, 3, 4 or 5, in particular w₃ = 2, 3 or 4. A further alternative or supplementary embodiment of the claimed use or the claimed method provides that the index g, which denotes the number of neutral ligands L_S in one Metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) is zero, 1, 2, 3, 4, 5 or 6. In yet another embodiment variant, the index g, which indicates the number of neutral ligands L_S in a metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) indicates zero, 1, 2, 3, 4 or 5, advantageously zero, 1, 2, 3 or 4, in particular zero, 1, 2 or 3. In another embodiment of the use claimed here or of the The method claimed here is the sum of the number v of the ligands AzuH and the number g of neutral ligands L_S, i.e. Σ (g + v), 2, 3, 4, 5, 6 or 7. A further embodiment provides that the sum of the number v of the ligands AzuH and the number g of neutral ligands L_S, ie Σ (g + v), is 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. In a further variant of the claimed use or the method for the production of metal complexes is the neutral sigma donor ligand L_S or the neutral pi-donor ligand L_S selected from the group consisting of monodentate and polydentate phosphorus donor ligands, alkenes, cyclic dienes and cyclic polyenes, and mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes, and derivatives thereof. The term "phosphorus donor ligand" is defined above. A non-limiting example of a selection of phosphorus donor ligands is also given above. Other examples of the neutral, especially pi-donor, ligand, L_S are the alkenes ethene, propene, butene, pentene, hexene, heptene, octene, nonene, decene and their isomers, the bicyclic alkene bicyclo[2.2.1]hept-2-ene, the cyclic diene cycloocta-1,5-diene (COD), the bicyclic diene bicyclo[2.2.1]hepta-2,5-diene (NBD), the monocyclic cycloocta-1,3,5,7-tetraene (COT). Examples of a mononuclear arene and derivatives of a mononuclear arene are benzene and benzene derivatives, e.g. B. toluene, p-cymene and halogenated benzenes. Naphthalene and naphthalene derivatives are examples of a polynuclear arene and a polynuclear arene derivative. An example of a heteroarene is pyridine. A binuclear or bicyclic heteroarene is, for example, indole. The mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes can also be substituted, in particular have alkyl groups and/or alkenyl groups and/or alkynyl groups and/or aryl groups and/or heteroaryl groups and/or halogen substituents. A further advantageous embodiment of the use or of the method provides that the central metal atom M of the metal complex to be prepared is of the general formula [M(L_S)_G(AzuH)_v]X (V) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the metal central atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, Rhodium, Iridium, Nickel, Palladium, Platinum, Copper, Silver, Gold, Zinc, Cadmium and Mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In yet another embodiment of the claimed use or method claimed herein, the preparation of metal complexes according to the general formula [M(L_T)(AzuH)_e.g]X (VI) provided. According to a further embodiment of the claimed use or the claimed method, the central metal atom M of the metal complex to be prepared in each case is of the general formula [M(L_T)(AzuH)_e.g]X (VI) selected from the Group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Another variant of the use or the method provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver , zinc and cadmium. According to yet another embodiment of the use or the method, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc , in particular from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the use claimed here or of the method claimed here provides that the central metal atom M has a formal oxidation state of 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the use or the method, it is provided that w₄ and the formal oxidation state of the central metal atom M of the metal complex to be prepared in each case according to the general formula [M(L_T)(AzuH)_e.g]X (VI) are identical, i.e. H. are the same natural number except for zero. Consequently w₄ = 3, 4, 5, 6 or 7. According to a further embodiment of the claimed use or the claimed method, the production of a metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI) provided, where the central metal atom M has a formal oxidation state of 3, 4, 5 or 6, in particular of 3, 4 or 5. In an alternative or additional embodiment variant of the claimed use or the claimed method, w₄ = 3, 4, 5 or 6, in particular w₄ = 3, 4 or 5. A further alternative or supplementary embodiment of the claimed use or the claimed method provides that |h|, i.e. the absolute amount of the sum of the negative charges of all anionic ligands L_T in one Metal complex according to the general formula [M(L_T)(AzuH)_e.g]X(VI), 1, 2, 3 or 4, in particular 1, 2 or 3. In another embodiment of the use claimed here or of the method claimed here, the sum of the number z of ligands is AzuH and the number of anionic ones Ligands L_T 2, 3, 4, 5 or 6. A further embodiment provides that the sum of the number z of ligands AzuH and the number of anionic ligands L_T is 2, 3, 4 or 5, in particular 2, 3 or 4. A further embodiment of the use claimed here or of the method claimed here for the preparation of metal complexes of the general formula [M(L_T)(AzuH)_e.g]X(VI) provides that the ligand L_T is a monoanionic ligand selected from the group consisting of anions of cyclopentadiene and its derivatives and a fluoride anion, or a dianionic ligand. A dianionic ligand L_T is selected, for example, from the group consisting of an oxidoligand O^2-, an imido ligand (NR^Q)^2- and an alkylidene ligand (CR^PR^V)^2-. There are R^Q, R^P and R^V independently selected from primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where the substituents are R^P and R^V can optionally form a ring. The leftovers R^Q, R^P and R^V can also be substituted independently of one another, in particular halogenated. Examples of cyclopentadiene (Cp) anions are the cyclopentadienyl anion C₅H₅- (Cp-) and the 1,2,3,4,5-pentamethylcyclopentadienyl anion C₅me₅ ⁻ (Cp^*). The aforementioned anions can be used as planar pi-donor ligands L_T for the synthesis of cationic sandwich complexes of the type [M(L_T)(AzuH)_e.g]X (VI) can be used. A further advantageous embodiment of the use or of the method provides that the central metal atom M of the metal complex to be produced in each case according to general formula [M(L_T)(AzuH)_e.g]X (VI) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the metal central atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, Rhodium, Iridium, Nickel, Palladium, Platinum, Copper, Silver, Gold, Zinc, Cadmium and Mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. The person skilled in the art knows which metal precursor compounds are commercially available or can be prepared—possibly also in situ—and which reaction conditions, e.g. B. stoichiometry of the starting materials, solvent, reaction temperature, reaction time, and work steps, including any required solvent change, isolation and purification, if necessary, in step B. are required for the synthesis of the respective metal complex according to one of the formulas III, IV, V and VI . In one embodiment of the method it is provided that the synthesis of the respective metal complex according to step B. is carried out in a solvent which in particular comprises or is an aprotic-polar solvent. A further variant of the method provides that the synthesis of the respective metal complex according to step B. is carried out in a solvent which, in particular, contains the solvent S_P is identical or miscible. Then – the inertness of the solvent S_P and the solvent provided in step B. - no need to change the solvent, which is particularly advantageous from a (procedural) economic and ecological point of view. The term “miscible” has already been defined above. The process described herein for preparing homoleptic or heteroleptic metal complexes according to formulas III, IV, V and VI can be carried out as a batch process or as a continuous process. As part of the process claimed here for the preparation of metal complexes according to the general formulas III, IV, V and VI, in step A., in particular previously isolated and optionally purified compounds according to the general formula M^AY_n(AzuH) (I) used. This is particularly advantageous because using (isomerically) pure starting materials of the type M^AY_n(AzuH) (I) a synthesis of the desired metal complexes according to the general formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V), [M(L_T)(AzuH)_e.g]X (VI) can be guaranteed in a particularly simple, relatively inexpensive and—depending on the choice of starting materials—sustainable and reproducible. In addition, the target compounds are obtained in high (isomer) purity of 97%, advantageously more than 97%, in particular more than 98% or 99%, and good to very good yield, also space-time yield. If in step A. a suspension is provided comprising a compound according to the general formula M^AY_n(AzuH) (I) and a, in particular aprotic-polar, solvent S_P, it is particularly advantageous if the provision according to step A. comprises at least one filtration step. Because this allows by-products that are produced during the production of M^AY_n(AzuH) (I) have failed and/or possibly unreacted ones in the solvent S_P insoluble starting materials and/or other impurities are separated. As a result, the purity and/or the yields, including space-time yields, of the metal complexes obtainable by means of the use described here or the method described here can be improved in a simple and rapid manner. An embodiment of the claimed process for preparing metal complexes provides that the provision in step A. involves in situ preparation of the compound of the general formula M^AY_n(AzuH) (I). Included the in situ production takes place in particular according to an embodiment of the process described above for the production of compounds of the general formula M^AY_n(AzuH) (I). The in situ preparation of the compound according to the general formula M^AY_n(AzuH) (I) can, for example, in a, in particular aprotic-polar, solvent or solvent mixture S_L take place. The solvent S_L may be selected from the group consisting of tetrahydrofuran, methyltetrahydrofuran, 1,4-dioxane, diethyl ether, methyl tert-butyl ether, di-n-propyl ether, diisopropyl ether, cyclopentyl methyl ether, and their isomers, acetonitrile, chloroform, dichloromethane, and mixtures thereof. It is particularly advantageous if the in situ preparation comprises at least one filtration step in order to remove by-products precipitated during the synthesis and/or any non-reacted ones in the solvent S_L to separate insoluble starting materials and/or other impurities. In another variant of the process for preparing metal complexes, it is provided that the synthesis in step B. comprises at least one salt-metathetical reaction. In particular, in the context of the synthesis of complexes according to the general formula [M(L_S)_G(AzuH)_v]X (V) or [M(L_T)(AzuH)_e.g]X (VI) at least two salt metathetic reactions may be required. For example, the respective precursor compound can be prepared in situ in a first salt-metathetical reaction. The precursor compound can in particular be a halide, such as. B. [Pt(cod)(GuaH)]Cl (GuaH = 7-iso-propyl-1,4-dimethyl-8-H-dihydroazulene). The target compound is then prepared in a second salt-metathetical reaction which follows the in situ preparation of the precursor compound. In the above example, the target compound can be [Pt(cod)(GuaH)]PF₆ act. As an alternative or in addition to the at least one salt-metathetical reaction, step B. can comprise at least one oxidation reaction. For example, a salt-metathetical reaction of a compound according to the general formula M^AY_n(AzuH) (I) followed by oxidation, e.g. B. using atmospheric oxygen, and a reaction of the oxidation product with a salt comprising a weakly coordinating or a non-coordinating anion, z. B. KPF₆ or NH₄PF₆. An example of such a reaction sequence is the reaction of Li(GuaH) with cobalt(II) chloride to form Co(GuaH)₂ (meso form and racemate) according to the general formula III, followed by an oxidation of the isolated or in situ prepared compound Co(GuaH)₂ in the presence of atmospheric oxygen and a conversion of the oxidation product with KPF₆ or NH₄PF₆. The product of this reaction sequence is a cobalt(III) compound according to the general formula V, namely [Co(GuaH)₂]PF₆, which is present as a mixture of three isomers (meso form and racemate). The at least one salt-metathetical reaction in step B. takes place in a solvent S_M, in particular an aprotic-polar solvent S_M. The aprotic polar solvent S_M can for example be selected from the group consisting of ethers, acetonitrile, halogenated aliphatic and aromatic hydrocarbons. In a further variant of the process, the aprotic-polar solvent S_M selected from the group consisting of tetrahydrofuran, methyltetrahydrofuran, 1,4-dioxane, diethyl ether, methyl tert-butyl ether, di-n-propyl ether, diisopropyl ether, cyclopentylmethyl ether, and their isomers, acetonitrile, chloroform, dichloromethane, and mixtures thereof. In another variant, the solvents S_P and the solvent provided in step B., in particular the solvent S_L and S_M, chemically inert. The term "inert solvent" has already been defined above. The at least one oxidation reaction can take place in a polar solvent, in particular water, in the presence of oxygen, in particular atmospheric oxygen. It is particularly advantageous that the use of compounds according to the general formula M^AY_n(AzuH) (I) for the production of metal complexes or the process for the production of metal complexes according to the general formulas III, IV, V and VI using compounds according to the general formula M^AY_n(AzuH) (I) enable the preparation of high-purity metal complexes. In particular, a large number of isomerically pure metal complexes can be made available in good to very good, in some cases quantitative, yields by means of the process described here. Examples of such isomerically pure metal complexes are Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF₆, Rh(nbd)(GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF₆, PtMe₃(GuaH), [Pt(cod)(GuaH)]PF₆, Cu(PPh₃)(GuaH), Zn(GuaH)₂ and Zn(Mes)(GuaH). In the case of the metal complexes Fe(GuaH)₂ and Ru(GuaH)₂ the rac diastereomer could be isolated as the main product in good yields of > 70 % and > 60 %, respectively. The metal complexes Co(GuaH)₂ and [Co(GuaH)₂]PF₆ were each obtained as a mixture of isomers of the meso form and a racemate. The object is also achieved by metal complexes of the general formula M(L_K)_f(AzuH)_m (III) or M(L_N)(AzuH)_q (IV) or [M(L_S)_G(AzuH)_v]X (V) or [M(L_T)(AzuH)_e.g]X (VI) where M = central metal atom selected from Group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12, L_K = optional neutral sigma donor ligand or optional neutral pi donor ligand, f = number of ligands L_K, where f=0, 1, 2, 3, 4, 5 or 6, AzuH=azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom , m = number of ligands AzuH, where m = 1, 2, 3, 4, 5, 6 or 7, L_N = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum u of the negative charges of all ligands L_N is -1, -2, -3, -4, -5 or -6, q = number of ligands A to H, where q = w₂ – |u|, where w₂ > |u| and w₂ = 2, 3, 4, 5, 6 or 7, and where |u| an absolute value of the sum of the negative charges of all ligands L_N where |u| = 1, 2, 3, 4, 5 or 6, L_S = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands L_S, where g = 0, 1, 2, 3, 4, 5 or 6, v = number of ligands AzuH, where v = w₃ – 1, where w₃ = 2, 3, 4, 5, 6 or 7, L_T = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum h of the negative charges of all ligands L_T is -1, -2, -3, -4 or -5, z = number of ligands A to H, where z = w₄ – (|h| + 1), where w₄ > (|h| + 1) and w₄ = 3, 4, 5, 6 or 7, and where |h| an absolute value of the sum of the negative charges of all ligands L_T where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, where Azu = azulene according to the formula (II), or Azu=an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6 , C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, obtained or obtainable by a process for the preparation of such metal complexes according to one of the above described embodiments. Furthermore, the object is achieved by solutions or suspensions comprising a metal complex of the general formula M(L_K)_f(AzuH)_m (III) or M(L_N)(AzuH)_q (IV) or [M(L_S)_G(AzuH)_v]X (V) or [M(L_T)(AzuH)_e.g]X (VI) and at least one solvent which can be mixed with the, in particular aprotic-polar, solvent S_P is miscible or identical, where M = central metal atom selected from Group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12, L_K = optional neutral sigma donor ligand or optional neutral pi donor ligand, f = number of ligands L_K, where f=0, 1, 2, 3, 4, 5 or 6, AzuH=azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom , m = number of ligands AzuH, where m = 1, 2, 3, 4, 5, 6 or 7, L_N = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum u of the negative charges of all ligands L_N is -1, -2, -3, -4, -5 or -6, q = number of ligands A to H, where q = w₂ – |u|, where w₂ > |u| and w₂ = 2, 3, 4, 5, 6 or 7, and where |u| an absolute value of the sum of the negative charges of all ligands L_N where |u| = 1, 2, 3, 4, 5 or 6, L_S = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands L_S, where g = 0, 1, 2, 3, 4, 5 or 6, v = number of ligands AzuH, where v = w₃ – 1, where w₃ = 2, 3, 4, 5, 6 or 7, L_T = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum h of the negative charges of all ligands L_T is -1, -2, -3, -4 or -5, z = number of ligands A to H, where z = w₄ – (|h| + 1), where w₄ > (|h| + 1) and w₄ = 3, 4, 5, 6 or 7, and where |h| an absolute value of the sum of the negative charges of all ligands L_T where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, where Azu = azulene according to formula (II), or Azu = an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6, C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, obtained or obtainable by a process for the preparation of such solutions or suspensions according to one of embodiments described above. The general formulas III, IV, V and VI include both the monomers and any oligomers, in particular dimers. The respective central metal atom M can in principle have a formal oxidation state or oxidation number of 0, 1, 2, 3, 4, 5, 6 or 7. The higher oxidation states, in particular the oxidation states 4, 5, 6 and 7, are usually formed by anionic, especially monoanionic, ligands, e.g. B. fluoride anions (see. In particular, formulas IV, V and VI), and / or dianionic ligands, z. B.O^2- (cf. in particular formula VI), stabilized. The index q can have the value 1, 2, 3, 4, 5 or 6. Alternatively, q=1, 2, 3, 4 or 5, q=1, 2, 3 or 4 is advantageous, in particular q=1, 2 or 3. The index v can also be 1, 2, 3, 4, 5 or 6. Alternatively, v=1, 2, 3, 4 or 5, v=1, 2, 3 or 4 is advantageous, in particular v=1, 2 or 3. The index z can have the value 1, 2, 3, 4 or accept 5 Alternatively, z=1, 2, 3 or 4, in particular z=1, 2 or 3. The metal complexes of the general formulas III, IV, V and VI are usually solvent-free, i. H. not as solvent adducts. However, solvent adducts of these metal complexes can also be obtained by means of the process described above for preparing such metal complexes. In the case of a solvent adduct, the solvent is in particular the solvent S used in the process described above_P identical. Alternatively or additionally, one or more of the neutral donor ligands L_K or L_S (cf. Formula III or Formula V) be selected from the group consisting of acetonitrile, dimethyl sulfoxide and tetrahydrothiophene. The term "weakly coordinating" also includes the expressions "very weakly coordinating" and "moderately strongly coordinating". In particular, the halide anions are selected from the group consisting of fluoride, chloride and bromide. For monovalent weakly coordinating and monovalent non-coordinating anions it is in particular perfluorinated anions such. B.PF₆-, BF₄- and [(CF₃SO₂)₂N]-. A definition of the term “miscible” has already been given above. Metal complexes according to the general formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V), [M(L_T)(AzuH)_e.g]X (VI) each have at least one H-dihydroazulenyl anion (AzuH)^1- which is a simply hydrogenated azulene or azulene derivative in the 4-position, in the 6-position or in the 8-position. The respective H-dihydroazulenyl anion (AzuH)^1- has a hydride anion H- in the 4-position or in the 6-position or in the 8-position in addition to an H atom. Consequently, there is a CH in the C4 position or in the C6 position or in the C8 position of the azulene skeleton₂-group before. The H-dihydroazulenyl anion is a derivative of the cyclopentadienyl anion or a cyclopentadienyl-like monoanion. The H-dihydroazulenyl anion can be a 3α,4-H-dihydroazulenyl, an 8,8α-H- dihydroazulenyl, a 3α,6-H-dihydroazulenyl or a 6,8α-H-dihydroazulenyl anion, or a mixture of two or more regioisomers. The metal complexes of types III, IV, V and VI and their solutions or suspensions in at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P is miscible or identical, e.g. B.S_L and/or S_M, are by means of the process claimed here for the preparation of such metal complexes and solutions advantageously in a simple, reproducible and comparatively inexpensive manner with a high (isomer) purity of 97%, advantageously more than 97%, in particular more than 98% or 99%, and good to very good, partly quantitative, yield. In particular, a large number of these metal complexes are present in pure isomer form. According to all of this, metal complexes of the general formulas III, IV, V and VI obtainable by means of the process claimed here, as well as solutions or suspensions comprising such metal complexes, are suitable as high-quality starting materials for further reactions and/or applications, even on an industrial scale. Due to the presence of at least one H-dihydroazulenyl anion, i.e. at least one cyclopentadienyl-like monoanion, the compounds of the general formulas III, IV, V and VI are particularly suitable as precatalysts, as catalysts and as electron transfer reagents for chemical reactions in which otherwise metal complexes are used which have cyclopentadienyl ligands. This is particularly advantageous because providing an H-dihydroazulenyl ligand is less laborious and time consuming compared to providing the cyclopentadienyl ligand. Because the starting materials, e.g. B. natural products such as guaiazulene and hydridic reducing agents such as lithium triethylborohydride are not only easier to handle and store, but also cheaper. In addition, fewer and simpler work steps have to be carried out. As a result, the synthesis effort and the production costs for the metal complexes claimed here, as well as solutions or suspensions, comprising such a compound and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P miscible or identical is lower than for analogous metal-Cp complexes. Consequently, the metal complexes described here and their solutions and suspensions represent an alternative to metal-Cp complexes, particularly with regard to industrial application Quantities are accessible at low cost. Synthetically, it can be made from the guajol of guaiac wood oil (guaiac resin). Guajazulene is an intensely blue substance with anti-inflammatory effects. An example of an isomer of guaiazulene is 2-isopropyl-4,8-dimethylazulene (vetivazulene). In an advantageous embodiment of the metal complexes claimed here according to the general formulas III, IV, V and VI and the claimed solutions or suspensions, comprising such a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P miscible or is identical, in each case obtained or obtainable by a process for preparing such metal complexes or solutions or suspensions according to one of the embodiments described above, Azu=Gua=7-isopropyl-1,4-dimethylazulene and AzuH=GuaH=7-iso -propyl-1,4-dimethyl-8-H-dihydroazulene. Examples of the metal complexes claimed here according to the general formulas III, IV, V and VI, each comprising at least one anion of the type (AzuH)^1-, which as an isolated solid or as an isolated liquid, i. H. in substance, present or in a solution or suspension, comprising such a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P miscible or identical are, on the one hand, high-purity homoleptic sandwich complexes of middle transition metals (groups 6, 7 and 8), in particular of group 8 metals, and later transition metals, i.e. of group 9, group 10, group 11 and of Group 12, in particular: ■ neutral sandwich complexes of the type M(L_K)_f(AzuH)_m (III) with f = 0, i.e. H. without neutral donor ligand L_K, e.g. B.Fe(GuaH)₂, Ru(GuaH)₂, Co(GuaH)₂, Zn(GuaH)₂, where the formal oxidation state is 2, M = Fe, Ru, Co or Zn, f = 0, m = 2 and AzuH = GuaH and ■ cationic sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 0, i.e. H. without neutral donor ligand L_S, e.g. B. [Co(GuaH)₂]PF₆, where the formal oxidation state is 3, M = Co, g = 0, v = 3 − 1 = 2, AzuH = GuaH, and X = PF₆. On the other hand, the metal complexes claimed here according to the general formulas III, IV, V and VI, each comprising at least one anion of the type (AzuH)^1-, which as an isolated solid or as an isolated liquid, i. H. in substance, present or in a solution or suspension, comprising such a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P is miscible or identical to high purity heteroleptic complexes of middle transition metals (Groups 6, 7 and 8), particularly of Group metals 8, and later transition metals, i.e. Group 9, Group 10, Group 11 and Group 12 metals, in particular: ■ neutral half-sandwich complexes of the type M(L_K)_f(AzuH)_m (III) with f = 1 or 2, i. H. with exactly one neutral sigma donor ligand or with exactly one neutral nonplanar pi donor ligand, e.g. B. Cu(PPh₃)(GuaH), Rh(nbd)(GuaH), Rh(cod)(GuaH), where the formal oxidation state is 1, M = Cu or Rh, L_K = PPh₃, NBD or COD, each f is 1, each m is 1 and AzuH = GuaH, or two planar, neutral pi-donor ligands, e.g. B. Rh(ethene)₂(GuaH), where the formal oxidation state is 1, M = Rh, L_K = ethene, f = 2, m = 1 and AzuH = GuaH ■ neutral half-sandwich complexes of the type M(L_N)(AzuH)_q (IV), for example with |u| = 1, 2 or 3, i. H. for example with one, two or three monoanionic sigma donor ligands, e.g. B. Zn(Mes)(GuaH), where the formal oxidation state is 2, M = Zn, L_N = Mes-, |u| = 1, q = 2 - |-1| = 1 and AzuH = GuaH, and PtMe₃(GuaH), where the formal oxidation state is 4, M = Pt, L_N = CH₃-, |u| = 3, q = 4 - |-3| = 1 and AzuH = GuaH ■ neutral sandwich complexes of the type M(L_N)(AzuH)_q (IV), for example with |u| = 1, i.e. H. with exactly one monoanionic, planar pi-donor ligand, e.g. B. Ru(Cp*)(GuaH), where the formal oxidation state is 2, M = Ru, L_N = Cp*, |u| = 1, q = 2 - |-1| = 1 and AzuH = GuaH ■ cationic sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 1, i.e. h with exactly one neutral, planar pi-donor ligand, e.g. B. [Ru(p-cymene)(GuaH)]PF₆, where the formal oxidation state is 2, M = Ru, L_S = p-cymene, g = 1, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆ ■ cationic half-sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 1 or 2, i.e. H. with a neutral non-planar pi-donor ligand, e.g. B. [Pt(cod)(GuaH)]PF₆, where the formal oxidation state is 2, M = Pt, L_S = COD, g = 1, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆ or with two planar, neutral pi-donor ligands, e.g. B. [Pt(ethene)₂(GuaH)]PF₆, where the formal oxidation state is 2, M = Pt, L_S = ethene, g = 2, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆ ■ cationic sandwich complexes of the type [M(L_T)(AzuH)_e.g]X (VI) with |h| = 1, i.e. H. with exactly one anionic, planar pi-donor ligand, e.g. B. [Rh(Cp*)(GuaH)]Cl, [Rh(Cp*)(GuaH)]PF₆, where the formal oxidation state is 3 in each case, M = Rh, L_T = Cp*, |h| = 1, z = 3 - (|-1| + 1) = 1, AzuH = GuaH and X = Cl or PF₆. The terms “purity” and “high purity” have already been defined above. In one embodiment of the claimed metal complexes, which are present as an isolated solid or as an isolated liquid, i. H. in substance, or solutions or suspensions, comprising such a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P is miscible or identical, in each case obtained or obtainable by a process for the preparation of such metal complexes or solutions or suspensions according to one of the embodiments described above, the metal complex has the general formula M(L_K)_f(AzuH)_m (III) on. According to yet another embodiment of the claimed metal complexes or solutions or suspensions, the central metal atom M of the metal complex is of the general formula M(L_K)_f(AzuH)_m (III) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury . Another variant of the claimed compounds or solutions or suspensions provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper , silver, zinc and cadmium. According to yet another embodiment of the claimed compounds or solutions or suspensions, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the compounds or solutions or suspensions claimed here provides that the central metal atom M has a formal oxidation state of 1, 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed compounds or solutions or suspensions, it is provided that the index m and the formal oxidation state of the central metal atom M of the respective metal complex according to the general formula M(L_K)_f(AzuH)_m (III) are identical, i. H. are the same natural number except for zero. Thus m=1, 2, 3, 4, 5, 6 or 7 can be. According to a further embodiment of the claimed compounds or solutions or suspensions, the metal complex has the general formula M(L_K)_f(AzuH)_m (III), where the central metal atom M has a formal oxidation state of 1, 2, 3 or 4, advantageously 1, 2 or 3, in particular 1 or 2. In an alternative or additional embodiment of the claimed compounds or solutions or suspensions, the index m is 1, 2, 3 or 4, advantageously 1, 2 or 3, in particular 1 or 2. Another alternative or supplementary embodiment of the claimed compounds or solutions or suspensions provides that the index f, which the Number of neutral ligands L_K in a metal complex according to the general formula M(L_K)_f(AzuH)_m (III) indicates zero, 1, 2, 3, 4 or 5, advantageously zero, 1, 2, 3 or 4, in particular zero, 1, 2 or 3. In another embodiment of the claimed metal complexes according to the general formula M (L_K)_f(AzuH)_m (III) or solutions or suspensions comprising such a metal complex is the sum of the number m of the ligands AzuH and the number f of the neutral ligands L_K, i.e. Σ (f + m), is 2, 3, 4, 5, 6 or 7. Another embodiment provides that the sum of the number m of the ligands AzuH and the number f of neutral ligands L_K, so^Σ (f + m), 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. A further embodiment provides that the neutral sigma donor ligand L_K or pi donor ligand L_K is selected from the group consisting of monodentate and polydentate phosphorus donor ligands, alkenes, cyclic dienes and cyclic polyenes, and mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes, and their derivatives. The term "phosphorus donor ligand" is defined above. A non-limiting example of a selection of phosphorus donor ligands is also given above. Other examples of the ligand L_K are the alkenes ethene, propene, butene, pentene, hexene, heptene, octene, nonene, decene and their isomers, the bicyclic alkene bicyclo[2.2.1]hept-2-ene, the cyclic diene cycloocta-1,5-diene (COD), the bicyclic diene bicyclo[2.2.1]hepta-2,5-diene (NBD), the monocyclic cycloocta-1,3,5,7-tetraene (COT). Examples of a mononuclear arene and derivatives of a mononuclear arene are benzene and benzene derivatives, e.g. B. toluene, p-cymene and halogenated benzenes. Naphthalene and naphthalene derivatives are examples of a polynuclear arene and a polynuclear arene derivative. An example of a heteroarene is pyridine. A binuclear or bicyclic heteroarene is, for example, indole. The mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes can also be substituted, in particular have alkyl groups and/or alkenyl groups and/or alkynyl groups and/or aryl groups and/or heteroaryl groups and/or halogen substituents. A further advantageous embodiment of the claimed metal complexes or solutions or suspensions comprising such a metal complex provides that the central metal atom M of the metal complex according to the general formula M(L_K)_f(AzuH)_m (III) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In a further embodiment of the claimed metal complexes, which are present as an isolated solid or as an isolated liquid, i. H. in substance, or solutions or suspensions, comprising such a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P is miscible or identical, in each case obtained or obtainable by a process for the preparation of such metal complexes or solutions or suspensions according to one of the embodiments described above, the metal complex has the general formula M(L_N)(AzuH)_q (IV) on. According to yet another embodiment of the claimed compounds or solutions or suspensions, the central metal atom M of the metal complex is of the general formula M(L_N)(AzuH)_q (IV) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury . Another variant of the claimed compounds or solutions or suspensions provides that the central metal atom M is selected from the Group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. According to yet another embodiment of the claimed compounds or solutions or suspensions, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, especially from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed metal complexes according to the general formula M(L_N)(AzuH)_q (IV) or solutions or suspensions comprising such a metal complex provides that the central metal atom M has a formal oxidation state of 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed compounds or solutions or suspensions, it is provided that w₂ and the formal oxidation state of the central metal atom M of the metal complex to be prepared in each case according to the general formula M(L_N)(AzuH)_q (IV) are identical, i. H. are the same natural number except for zero. Consequently w₂ = 2, 3, 4, 5, 6 or 7. According to a further embodiment of the claimed compounds or solutions or suspensions, the metal complex has the general formula M(L_N)(AzuH)_q (IV), where the central metal atom M has a formal oxidation state of 2, 3, 4, 5 or 6, advantageously of 2, 3, 4 or 5, in particular of 2, 3 or 4. In an alternative or additional embodiment variant of the claimed compounds or solutions or suspensions is w₂ = 2, 3, 4, 5 or 6, w is advantageous₂ = 2, 3, 4 or 5, in particular w₂ = 2, 3 or 4. A further alternative or supplementary embodiment of the claimed compounds or solutions or suspensions provides that |u|, i.e. the absolute amount of the sum of the negative charges of all anionic ligands L_N in a metal complex according to the general formula M(L_N)(AzuH)_q (IV) is 1, 2, 3, 4, 5, or 6. In yet another embodiment variant |u|, i.e. the absolute amount of the sum of the negative charges of all anionic ligands L_N in a metal complex according to the general formula M(L_N)(AzuH)_q (IV), 1, 2, 3, 4 or 5, advantageously 1, 2, 3 or 4, in particular 1, 2 or 3. In another embodiment of the claimed metal complexes of the general formula M(L_N)(AzuH)_q (IV) or solutions or suspensions comprising such a metal complex is the sum of the number q of the ligands AzuH and the number of anionic ligands L_N 2, 3, 4, 5, 6 or 7. A further embodiment provides that the sum of the number q of the ligands AzuH and the number of anionic ligands L_N is 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. Yet another embodiment of the claimed compounds or solutions or suspensions provides that the metal complex has the general formula M( L_N)(AzuH)_q (IV) wherein the anionic sigma donor ligand L_N or pi-donor ligand L_N is advantageously a monoanionic ligand selected from the group consisting of anions of cyclopentadiene and its derivatives, alkyl anions and aryl anions. Alternatively or additionally, a fluoride anion can be used as at least one of the monoanionic ligands L_N be provided. Examples of the anionic ligand L_N are the cyclopentadienyl anion C₅H₅- (Cp-) and the 1,2,3,4,5-pentamethylcyclopentadienyl anion C₅me₅ ⁻ (Cp^*), the methyl anion CH₃- (Me-) and the mesityl anion Me₃C₆H₂ ⁻ (Mes-). The aforementioned anions can be used as monoanionic pi-donor ligands or sigma-donor ligands L_N in the production of neutral sandwich or half-sandwich complexes of the type M(L_N)(AzuH)_q (IV) function. A further advantageous embodiment of the claimed compounds or solutions or suspensions provides that the central metal atom M of the metal complex according to the general formula M(L_N)(AzuH)_q (IV) is selected from the Group 8, Group 9, Group 10, Group 11 or Group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum , copper, silver, gold, zinc, cadmium and mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In another embodiment of the claimed metal complexes, which are present as an isolated solid or as an isolated liquid, i. H. in substance, or solutions or suspensions, comprising such a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P is miscible or identical, in each case obtained or obtainable by a process for the preparation of such metal complexes or solutions or suspensions according to one of the embodiments described above, the metal complex has the general formula [M(L_S)_G(AzuH)_v]X (V) on. According to a further embodiment of the claimed compounds or solutions or suspensions, the central metal atom M of the metal complex is of the general formula [M(L_S)_G(AzuH)_v]X (V) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Another variant of the claimed compounds or solutions or suspensions provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper , silver, zinc and cadmium. According to yet another embodiment of the claimed compounds or solutions or suspensions, the central metal atom M is selected from the group consisting of Chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed metal complexes according to the general formula [M(L_S)_G(AzuH)_v]X(V) or solutions or suspensions comprising such a metal complex provides that the central metal atom M has a formal oxidation state of 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed compounds or solutions or suspensions, it is provided that w₃ and the formal oxidation state of the central metal atom M of the respective metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) are identical, i.e. H. are the same natural number except for zero. Consequently w₃ = 2, 3, 4, 5, 6 or 7. According to a further variant of the claimed compounds or solutions or suspensions, the metal complex has the general formula [M(L_S)_G(AzuH)_v] X (V), wherein the central metal atom M has a formal oxidation state of 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. In an alternative or supplementary variant of the claimed compounds or solutions or suspensions is w₃ = 2, 3, 4, 5 or 6, w is advantageous₃ = 2, 3, 4 or 5, in particular w₃ = 2, 3 or 4. A further alternative or supplementary embodiment of the claimed compounds or solutions or suspensions provides that the index g, which denotes the number of neutral ligands L_S in a metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) is zero, 1, 2, 3, 4, 5 or 6. In yet another embodiment variant, the index g, which indicates the number of neutral ligands L_S in a metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) indicates zero, 1, 2, 3, 4 or 5, advantageously zero, 1, 2, 3 or 4, in particular zero, 1, 2 or 3. In another embodiment of the claimed compounds or solutions or suspensions, the sum of the number v of ligands is AzuH and the number g of neutral ligands is L_S, i.e. Σ (g + v), 2, 3, 4, 5, 6 or 7. A further embodiment provides that the sum of the number v of the ligands AzuH and the number g of neutral ligands L_S, ie Σ (g + v), is 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. In another variant of the claimed compounds or solutions or suspensions is the neutral sigma donor ligand L_S or the neutral pi-donor ligand L_S selected from the group consisting of monodentate and polydentate phosphorus donor ligands, alkenes, cyclic dienes and cyclic polyenes, and mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes, and derivatives thereof. The term "phosphorus donor ligand" is defined above. A non-limiting example of a selection of phosphorus donor ligands is also given above. Other examples of the neutral, especially pi-donor, ligand, L_S are the alkenes ethene, propene, butene, pentene, hexene, heptene, octene, nonene, decene and their isomers, the bicyclic alkene bicyclo[2.2.1]hept-2-ene, the cyclic diene cycloocta-1,5-diene (COD), the bicyclic diene bicyclo[2.2.1]hepta-2,5-diene (NBD), the monocyclic cycloocta-1,3,5,7-tetraene (COT). Examples of a mononuclear arene and derivatives of a mononuclear arene are benzene and benzene derivatives, e.g. B. toluene, p-cymene and halogenated benzenes. Naphthalene and naphthalene derivatives are examples of a polynuclear arene and a polynuclear arene derivative. An example of a heteroarene is pyridine. A binuclear or bicyclic heteroarene is, for example, indole. The mononuclear arenes, polynuclear arenes, mononuclear heteroarenes, and polynuclear heteroarenes can also be substituted be, in particular alkyl groups and/or alkenyl groups and/or alkynyl groups and/or aryl groups and/or heteroaryl groups and/or halogen substituents. A further advantageous embodiment of the claimed compounds or solutions or suspensions provides that the central metal atom M of the metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, Rhodium, Iridium, Nickel, Palladium, Platinum, Copper, Silver, Gold, Zinc, Cadmium and Mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In yet another embodiment of the claimed metal complexes, which are present as an isolated solid or as an isolated liquid, i. H. in substance, or solutions or suspensions comprising such a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P is miscible or identical, in each case obtained or obtainable by a process for the preparation of such metal complexes or solutions or suspensions according to one of the embodiments described above, the metal complex has the general formula [M(L_T)(AzuH)_e.g]X (VI) on. According to a further embodiment of the claimed compounds or solutions or suspensions, the central metal atom M of the metal complex is of the general formula [M(L_T)(AzuH)_e.g]X (VI) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, Cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Another variant of the claimed compounds or solutions or suspensions provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper , silver, zinc and cadmium. According to yet another embodiment of the claimed compounds or solutions or suspensions, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, especially from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed compounds according to the general formula [M(L_T)(AzuH)_e.g]X(VI) or solutions or suspensions comprising such a compound provides that the central metal atom M has a formal oxidation state of 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed compounds or solutions or suspensions, it is provided that w₄ and the formal oxidation state of the central metal atom M of the metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI) are identical, i.e. H. are the same natural number except for zero. Consequently w₄ = 3, 4, 5, 6 or 7. According to a further variant of the claimed compounds or solutions or suspensions, a metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI) provided, wherein the central metal atom M has a formal oxidation state of 3, 4, 5 or 6, in particular 3, 4 or 5. In an alternative or additional embodiment variant of the claimed metal complexes or solutions or suspensions, comprising such a metal complex, w₄ = 3, 4, 5 or 6, in particular w₄ = 3, 4 or 5. A further alternative or supplementary embodiment of the claimed compounds or solutions or suspensions provides that |h|, ie the absolute amount of the sum of negative charges of all anionic ligands L_T in a metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI), 1, 2, 3 or 4, in particular 1, 2 or 3. In another embodiment of the claimed metal complexes of the general formula [M(L_T)(AzuH)_e.g]X (VI) or solutions or suspensions comprising such a metal complex is the sum of the number z of ligands AzuH and the number of anionic ligands L_T 2, 3, 4, 5 or 6. A further embodiment provides that the sum of the number z of ligands AzuH and the number of anionic ligands L_T is 2, 3, 4 or 5, in particular 2, 3 or 4. A further embodiment of the claimed compounds or solutions or suspensions is a metal complex of the general formula [M(L_T)(AzuH)_e.g]X (VI) where the ligand L_T is a monoanionic ligand selected from the group consisting of anions of cyclopentadiene and its derivatives and a fluoride anion, or a dianionic ligand. A dianionic ligand L_T is selected, for example, from the group consisting of an oxidoligand O^2-, an imido ligand (NR^Q)^2- and an alkylidene ligand (CR^PR^V)^2-. There are R^Q, R^P and R^V independently selected from primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where the substituents are R^P and R^V can optionally form a ring. The leftovers R^Q, R^P and R^V can also be substituted independently of one another, in particular halogenated. Examples of cyclopentadiene (Cp) anions are the cyclopentadienyl anion C₅H₅- (Cp-) and the 1,2,3,4,5-pentamethylcyclopentadienyl anion C₅me₅ ⁻ (Cp^*). The aforementioned anions can be used as planar pi-donor ligands L_T in cationic sandwich complexes of the type [M(L_T)(AzuH)_e.g]X (VI) may be provided. A further advantageous embodiment of the claimed compounds or solutions or suspensions provides that the central metal atom M of the respective metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, Rhodium, Iridium, Nickel, Palladium, Platinum, Copper, Silver, Gold, Zinc, Cadmium and Mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. It is particularly advantageous that the use of compounds according to the general formula M^AY_n(AzuH) (I) for the production of metal complexes or the process for the production of metal complexes according to the general formulas III, IV, V and VI using compounds according to the general formula M^AY_n(AzuH) (I) enable the preparation of high-purity metal complexes. In particular, a large number of isomerically pure metal complexes can be made available in good to very good, in some cases quantitative, yields by means of the process described here. Examples of such isomerically pure metal complexes obtained or obtainable as solids, liquids, solutions or suspensions by a process according to one of the embodiments described above are Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF₆, Rh(nbd)(GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF₆, PtMe₃(GuaH), [Pt(cod)(GuaH)]PF₆, Cu(PPh₃)(GuaH), Zn(GuaH)₂ and Zn(Mes)(GuaH). In one embodiment of the metal complexes or solutions or suspensions claimed here, comprising such a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P is miscible or identical, each obtained or obtainable by a process for the production of such Metal complexes or solutions or suspensions according to one of the embodiments described above, the metal complex is selected from the group consisting of Fe(GuaH)₂, Ru(GuaH)₂, Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF₆, Co(GuaH)₂, [Co(GuaH)₂]PF₆, Rh(nbd)(GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF₆, PtMe₃(GuaH), [Pt(cod)(GuaH)]PF₆, Cu(PPh₃)(GuaH), Zn(GuaH)₂ and Zn(Mes)(GuaH), advantageously from the group consisting of Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF₆, Rh(nbd)(GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF₆, PtMe₃(GuaH), [Pt(cod)(GuaH)]PF₆, Cu(PPh₃)(GuaH), Zn(GuaH)₂ and Zn(Mes)(GuaH), particularly preferably from the group consisting of Ru(Cp*)(GuaH), Zn(Mes)(GuaH) and PtMe₃(GuaH). In particular, the metal complex is PtMe₃(GuaH). The complexes Ru(Cp*)(GuaH), Zn(Mes)(GuaH), and PtMe₃(GuaH) exist in isolated form as liquids. This is advantageous in particular with a view to use as metal precursor compounds for gas phase deposition processes. In addition, it is advantageous to use a liquid catalyst in the catalysis, for example the Pt(IV) compound PtMe₃(GuaH) for light-induced platinum-catalyzed hydrosilylation reactions. The aforementioned Pt(IV) compound also shows absorption in the Vis range. This represents a further advantage in the context of light-induced platinum-catalyzed hydrosilylation reactions. Because the use of UV/Vis light is regularly provided for, which usually requires special safety measures to reduce the risk of skin cancer. Such security measures are when using PtMe₃(GuaH) not mandatory. The cobalt complex Co(GuaH) obtained as a mixture of isomers of the meso form and a racemate, which is also present as a liquid in isolated form₂ metallocene type, for example, can be used as an electron transfer reagent. In the case of the metal complexes Fe(GuaH)₂ and Ru(GuaH)₂ the rac diastereomer could be isolated as the main product in good yields of > 70 % and > 60 %, respectively. The metal complexes Co(GuaH)₂ and [Co(GuaH)₂]PF₆ were each obtained as a mixture of isomers of the meso form and a racemate. The object is also achieved by metal complexes of the general formula M(L_K)_f(AzuH)_m (III) or M(L_N)(AzuH)_q (IV) or [M(L_S)_G(AzuH)_v]X (V) or [M(L_T)(AzuH)_e.g]X (VI) where M = central metal atom selected from Group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12, L_K = optional neutral sigma donor ligand or optional neutral pi donor ligand, f = number of ligands L_K, where f=0, 1, 2, 3, 4, 5 or 6, AzuH=azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom , m = number of ligands AzuH, where m = 1, 2, 3, 4, 5, 6 or 7, L_N = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum u of the negative charges of all ligands L_N is -1, -2, -3, -4, -5 or -6, q = number of ligands A to H, where q = w₂ – |u|, where w₂ > |u| and w₂ = 2, 3, 4, 5, 6 or 7, and where |u| an absolute value of the sum of the negative charges of all ligands L_N where |u| = 1, 2, 3, 4, 5 or 6, L_S = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands L_S, where g = 0, 1, 2, 3, 4, 5 or 6, v = number of ligands AzuH, where v = w₃ – 1, where w₃ = 2, 3, 4, 5, 6 or 7, L_T = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum h of the negative charges of all ligands L_T is -1, -2, -3, -4 or -5, z = number of ligands A to H, where z = w₄ – (|h| + 1), where w₄ > (|h| + 1) and w₄ = 3, 4, 5, 6 or 7, and where |h| an absolute value of the sum of the negative charges of all ligands L_T where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, where Azu = azulene according to formula (II), or Azu=an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6 , C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, where the compounds Fe(AzulenH)₂ and Cr(azuleneH)₂, and their isomers, are excluded. The d⁶-Metal complex Fe(AzulenH)₂ (= Bis-(3α,4-dihydroazulenyl)iron)) with two H-dihydroazulenyl ligands (AzulenH)^1- and that described by Fischer and Müller (J. Organomet. Chem. 1964, 1, 464-470) d⁶-Cr(0) complex Cr(AzulenH)₂, which has an azulenium chromium(0) azuleniate unit, i.e. only one H-dihydroazulenyl ligand (AzulenH)^1-, are not the subject of the present invention. The general formulas III, IV, V and VI include both the monomers and any oligomers, especially dimers. The respective central metal atom M can in principle have a formal oxidation state or oxidation number of 0, 1, 2, 3, 4, 5, 6 or 7. The higher oxidation states, in particular the oxidation states 4, 5, 6 and 7, are usually formed by anionic, especially monoanionic, ligands, e.g. B. fluoride anions (see. In particular, formulas IV, V and VI), and / or dianionic ligands, z. B.O^2- (cf. in particular formula VI), stabilized. The index q can have the value 1, 2, 3, 4, 5 or 6. Alternatively, q=1, 2, 3, 4 or 5, q=1, 2, 3 or 4 is advantageous, in particular q=1, 2 or 3. The index v can also be 1, 2, 3, 4, 5 or 6. Alternatively, v=1, 2, 3, 4 or 5, v=1, 2, 3 or 4 is advantageous, in particular v=1, 2 or 3. The index z can have the value 1, 2, 3, 4 or accept 5 Alternatively z = 1, 2, 3 or 4, in particular z = 1, 2 or 3. The general formulas III, IV, V and VI each include both solvent-free metal complexes, ie metal complexes not present as solvent adducts, and solvent adducts of the respective metal complexes. In the case of a solvent adduct, the solvent is in particular with the solvent S defined above_P identical. Alternatively or additionally, one or more of the neutral donor ligands L_K or L_S (cf. Formula III or Formula V) be selected from the group consisting of acetonitrile, dimethyl sulfoxide and tetrahydrothiophene. The term "weakly coordinating" also includes the expressions "very weakly coordinating" and "moderately strongly coordinating". In particular, the halide anions are selected from the group consisting of fluoride, chloride and bromide. The monovalent weakly coordinating and monovalent non-coordinating anions are in particular perfluorinated anions, such as. B.PF₆-, BF₄- and [(CF₃SO₂)₂N]-. Metal complexes according to the general formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V), [M(L_T)(AzuH)_e.g]X (VI) each have at least one H-dihydroazulenyl anion (AzuH)^1- which is a simply hydrogenated azulene or azulene derivative in the 4-position, in the 6-position or in the 8-position. The H-dihydroazulenyl anion is a derivative of the cyclopentadienyl anion or a cyclopentadienyl-like monoanion. The H-dihydroazulenyl anion can be a 3α,4-H-dihydroazulenyl, an 8,8α-H- dihydroazulenyl, a 3α,6-H-dihydroazulenyl or a 6,8α-H-dihydroazulenyl anion, or a mixture of two or more regioisomers. Due to the presence of at least one H-dihydroazulenyl anion, ie at least one cyclopentadienyl-like monoanion, the compounds of the general formulas III, IV, V and VI described here are particularly suitable as precatalysts, as catalysts and as electron transfer reagents for chemical reactions , in which metal complexes are otherwise used which have cyclopentadienyl ligands. This is particularly advantageous because providing an H-dihydroazulenyl ligand is less laborious and time consuming compared to providing the cyclopentadienyl ligand. Because the starting materials, e.g. B. natural products such as guaiazulene and hydridic reducing agents such as lithium triethylborohydride are not only easier to handle and store, but also cheaper. In addition, fewer and simpler work steps have to be carried out. As a result, the outlay on synthesis and the production costs for the metal complexes of the general formulas III, IV, V and VI claimed here are also lower than for analogous metal-Cp complexes. Consequently, the metal complexes described here and their solutions and suspensions represent an alternative to metal-Cp complexes, particularly with a view to industrial application. Also with regard to use as metal precursor compounds in gas phase deposition processes. Guajazulene is a natural substance that is contained in chamomile oil and other essential oils and is therefore advantageously available in large quantities at low cost. Synthetically, it can be made from the guajol of guaiac wood oil (guaiac resin). Guajazulene is an intensely blue substance with anti-inflammatory effects. An example of an isomer of guaiazulene is 2-isopropyl-4,8-dimethylazulene (vetivazulene). In an advantageous embodiment of the metal complexes claimed here according to the general formulas III, IV, V and VI, Azu=Gua=7-isopropyl-1,4-dimethylazulene and AzuH=GuaH=7-isopropyl-1,4- dimethyl-8-H-dihydroazulene. Examples of the metal complexes claimed here are, on the one hand, homoleptic sandwich complexes of medium transition metals (groups 6, 7 and 8), in particular of group 8 metals, and later transition metals, i.e. of group 9, group 10, group 11 and of Group 12, in particular: ■ neutral sandwich complexes of the type M(L_K)_f(AzuH)_m (III) with f = 0, i.e. H. without neutral donor ligand L_K, e.g. B.Fe(GuaH)₂, Ru(GuaH)₂, Co(GuaH)₂, Zn(GuaH)₂, where each the formal oxidation state is 2, M = Fe, Ru, Co or Zn, f = 0, m = 2 and AzuH = GuaH and ■ cationic sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 0, i.e. H. without neutral donor ligand L_S, e.g. B. the d⁶-Complex [Co(GuaH)₂]PF₆, where the formal oxidation state is 3, M = Co, g = 0, v = 3 − 1 = 2, AzuH = GuaH, and X = PF₆. On the other hand, the compounds claimed here are heteroleptic complexes of medium transition metals (groups 6, 7 and 8), in particular of group 8 metals, and later transition metals, i.e. of group 9, group 10, group 11 and of Group 12, in particular: ■ neutral half-sandwich complexes of the type M(L_K)_f(AzuH)_m (III) with f = 1 or 2, i. H. with exactly one neutral sigma donor ligand or with exactly one neutral nonplanar pi donor ligand, e.g. B. Cu(PPh₃)(GuaH), Rh(nbd)(GuaH), Rh(cod)(GuaH), where the formal oxidation state is 1, M = Cu or Rh, L_K = PPh₃, NBD or COD, each f is 1, each m is 1 and AzuH = GuaH, or two planar, neutral pi-donor ligands, e.g. B. Rh(ethene)₂(GuaH), where the formal oxidation state is 1, M = Rh, L_K = ethene, f = 2, m = 1 and AzuH = GuaH ■ neutral half-sandwich complexes of the type M(L_N)(AzuH)_q (IV), for example with |u| = 1, 2 or 3, i. H. for example with one, two or three monoanionic sigma donor ligands, e.g. B. Zn(Mes)(GuaH), where the formal oxidation state is 2, M = Zn, L_N = Mes-, |u| = 1, q = 2 - |-1| = 1 and AzuH = GuaH, and PtMe₃(GuaH), where the formal oxidation state is 4, M = Pt, L_N = CH₃-, |u| = 3, q = 4 - |-3| = 1 and AzuH = GuaH ■ neutral sandwich complexes of the type M(L_N)(AzuH)_q (IV), for example with |u| = 1, i.e. H. with exactly one monoanionic, planar pi-donor ligand, e.g. B. Ru(Cp*)(GuaH), where the formal oxidation state is 2, M = Ru, L_N = Cp*, |u| = 1, q = 2 - |-1| = 1 and AzuH = GuaH ■ cationic sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 1, i.e. h with exactly one neutral, planar pi-donor ligand, e.g. B. [Ru(p-cymene)(GuaH)]PF₆, where the formal oxidation state is 2, M = Ru, L_S = p-cymene, g = 1, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆ ■ cationic half-sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 1 or 2, i.e. H. with a neutral non-planar pi-donor ligand, e.g. B. [Pt(cod)(GuaH)]PF₆, where the formal oxidation state is 2, M = Pt, L_S = COD, g = 1, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆, or with two planar, neutral pi-donor ligands, e.g. B. [Pt(ethene)₂(GuaH)]PF₆, where the formal oxidation state is 2, M = Pt, L_S = ethene, g = 2, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆ ■ cationic sandwich complexes of the type [M(L_T)(AzuH)_e.g]X (VI) with |h| = 1, i.e. H. with exactly one anionic, planar pi-donor ligand, e.g. B. [Rh(Cp*)(GuaH)]Cl, [Rh(Cp*)(GuaH)]PF₆, where the formal oxidation state is 3 in each case, M = Rh, L_T = Cp*, |h| = 1, z = 3 - (|-1| + 1) = 1, AzuH = GuaH and X = Cl or PF₆. In one embodiment of the compounds claimed here, metal complexes according to the general formula M(L_K)_f(AzuH)_m (III) provided. According to another embodiment of the claimed compounds, the metal central atom M of the metal complex is according to the general formula M(L_K)_f(AzuH)_m (III) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury . Another variant of the metal complexes described here provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. According to yet another embodiment of the claimed metal complexes, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed metal complexes provides that the central metal atom M has a formal oxidation state of 1, 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed metal complexes, it is provided that the index m and the formal oxidation state of the central metal atom M of the metal complex correspond to the general formula M(L_K)_f(AzuH)_m (III) are identical, i. H. are the same natural number except for zero. Thus m=1, 2, 3, 4, 5, 6 or 7 can be. According to a further embodiment variant of the compounds claimed here, a metal complex according to the general formula M(L_K)_f(AzuH)_m (III) provided, where the central metal atom M has a formal oxidation state of 1, 2, 3 or 4, advantageously 1, 2 or 3, in particular 1 or 2. In an alternative or additional embodiment of the claimed metal complexes, the index is m is 1, 2, 3 or 4, advantageously 1, 2 or 3, in particular 1 or 2. A further alternative or supplementary embodiment of the claimed metal complexes provides that the index f, which denotes the number of neutral ligands L_K in a metal complex according to the general formula M(L_K)_f(AzuH)_m (III) indicates zero, 1, 2, 3, 4 or 5, advantageously zero, 1, 2, 3 or 4, in particular zero, 1, 2 or 3. In another embodiment of the claimed metal complexes according to the general formula M (L_K)_f(AzuH)_m (III) is the sum of the number m of ligands AzuH and the number f of neutral ligands L_K, so^Σ (f + m), 2, 3, 4, 5, 6 or 7. Another embodiment provides that the sum of the number m of the ligands AzuH and the number f of the neutral ligands L_K, ie Σ(f+m), is 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. A further embodiment provides that the neutral sigma donor ligand L_K or pi donor ligand L_K is selected from the group consisting of monodentate and polydentate phosphorus donor ligands, alkenes, cyclic dienes, and cyclic Polyenes, and mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes, and their derivatives. The term "phosphorus donor ligand" is defined above. A non-limiting example of a selection of phosphorus donor ligands is also given above. Other examples of the ligand L_K are the alkenes ethene, propene, butene, pentene, hexene, heptene, octene, nonene, decene and their isomers, the bicyclic alkene bicyclo[2.2.1]hept-2-ene, the cyclic diene cycloocta-1,5-diene (COD), the bicyclic diene bicyclo[2.2.1]hepta-2,5-diene (NBD), the monocyclic cycloocta-1,3,5,7-tetraene (COT). Examples of a mononuclear arene and derivatives of a mononuclear arene are benzene and benzene derivatives, e.g. B. toluene, p-cymene and halogenated benzenes. Naphthalene and naphthalene derivatives are examples of a polynuclear arene and a polynuclear arene derivative. An example of a heteroarene is pyridine. A binuclear or bicyclic heteroarene is, for example, indole. The mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes can also be substituted, in particular have alkyl groups and/or alkenyl groups and/or alkynyl groups and/or aryl groups and/or heteroaryl groups and/or halogen substituents. A further advantageous embodiment of the compounds claimed here provides that the central metal atom M of the metal complex according to the general formula M(L_K)_f(AzuH)_m (III) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Even more advantageously, the central metal atom M is selected from the group consisting of Iron, Ruthenium, Cobalt, Rhodium, Nickel, Platinum, Copper, Silver, Zinc and Cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In a further embodiment of the compounds described here, metal complexes according to the general formula M(L_N)(AzuH)_q (IV) provided. According to yet another embodiment of the claimed compounds, the central metal atom M of the metal complex is according to the general formula M(L_N)(AzuH)_q (IV) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury . Another variant of the claimed metal complexes provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, and zinc Cadmium. According to yet another embodiment of the claimed metal complexes, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed metal complexes according to the general formula M(L_N)(AzuH)_q (IV) provides that the central metal atom M has a formal oxidation state of 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed metal complexes, it is provided that w₂ and the formal oxidation state of the central metal atom M of the metal complex according to general formula M(L_N)(AzuH)_q (IV) are identical, i. H. are the same natural number except for zero. Consequently w₂ = 2, 3, 4, 5, 6 or 7. According to a further embodiment variant of the compounds claimed here, metal complexes according to the general formula M(L_N)(AzuH)_q (IV) provided, wherein the central metal atom M has a formal oxidation state of 2, 3, 4, 5 or 6, advantageously of 2, 3, 4 or 5, in particular of 2, 3 or 4. In an alternative or supplementary embodiment of the claimed metal complexes is w₂ = 2, 3, 4, 5 or 6, w is advantageous₂ = 2, 3, 4 or 5, in particular w₂ = 2, 3 or 4. A further alternative or supplementary embodiment of the claimed metal complexes provides that |u|, i.e. the absolute amount of the sum of the negative charges of all anionic ligands L_N in a metal complex according to the general formula M(L_N)(AzuH)_q (IV) is 1, 2, 3, 4, 5, or 6. In yet another embodiment variant, |u|, i.e. the absolute amount of the sum of the negative charges of all anionic ligands L_N in a metal complex according to the general formula M(L_N)(AzuH)_q (IV), 1, 2, 3, 4 or 5, advantageously 1, 2, 3 or 4, in particular 1, 2 or 3. In another embodiment of the claimed metal complexes, the sum of the number q of the ligands AzuH and the number of anionic ligands L_N 2, 3, 4, 5, 6 or 7. A further embodiment provides that the sum of the number q of the ligands AzuH and the number of anionic ligands L_N is 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. Yet another embodiment of the compounds claimed here are metal complexes according to the general formula M(L_N)(AzuH)_q (IV) where the anionic sigma donor ligand L_N or pi-donor ligand L_N is advantageously a monoanionic ligand selected from the group consisting of anions of cyclopentadiene and its derivatives, alkyl anions and aryl anions. Alternatively or additionally, a fluoride anion can be used as at least one of the monoanionic ligands L_N be provided. Examples of the anionic ligand L_N are the cyclopentadienyl anion C₅H₅- (Cp-) and the 1,2,3,4,5-pentamethylcyclopentadienyl anion C₅me₅ ⁻ (Cp^*), the methyl anion CH₃- (Me-) and the mesityl anion Me₃C₆H₂ ⁻ (Mes-). The aforementioned anions can be used as monoanionic pi-donor ligands or sigma-donor ligands L_N in the production of neutral sandwich or half-sandwich complexes of the type M(L_N)(AzuH)_q (IV) function. A further advantageous embodiment of the claimed metal complexes provides that the central metal atom M of the metal complex according to the general formula M(L_N)(AzuH)_q (IV) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. The complexes Ru(Cp*)(GuaH), Zn(Mes)(GuaH), and PtMe₃(GuaH) exist in isolated form as liquids. The latter is particularly advantageous with a view to use as metal precursor compounds for gas phase deposition processes. In addition, it is advantageous to use a liquid catalyst in the catalysis, for example the Pt(IV) compound PtMe₃(GuaH) for light-induced platinum-catalyzed hydrosilylation reactions. The aforementioned Pt(IV) compound also shows absorption in the Vis range. This represents a further advantage in the context of light-induced platinum-catalyzed hydrosilylation reactions. Because the use of UV/Vis light is regularly provided for, which usually means special Safety measures are needed to reduce the risk of skin cancer. Such security measures are when using PtMe₃(GuaH) not mandatory. In another embodiment of the compounds claimed here, metal complexes according to the general formula [M(L_S)_G(AzuH)_v]X (V) provided. According to a further embodiment of the compounds described here, the central metal atom M of the metal complex is according to the general formula [M(L_S)_G(AzuH)_v]X (V) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Another variant of the claimed metal complexes provides that the metal central atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, and zinc Cadmium. According to yet another embodiment of the claimed metal complexes, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed metal complexes provides that the central metal atom M has a formal oxidation state of 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed metal complexes, it is provided that w₃ and the formal oxidation state of the central metal atom M of the metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) are identical, i.e. H. are the same natural number except for zero. Consequently w₃ = 2, 3, 4, 5, 6 or 7. According to a further embodiment of the compounds claimed here, metal complexes of the general formula [M(L_S)_G(AzuH)_v] X (V) provided, wherein the central metal atom M has a formal oxidation state of 2, 3, 4, 5 or 6, advantageously of 2, 3, 4 or 5, in particular of 2, 3 or 4. In an alternative or supplementary variant of the claimed metal complexes is w₃ = 2, 3, 4, 5 or 6, w is advantageous₃ = 2, 3, 4 or 5, in particular w₃ = 2, 3 or 4. A further alternative or supplementary embodiment of the claimed metal complexes provides that the index g, which denotes the number of neutral ligands L_S in a metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) is zero, 1, 2, 3, 4, 5 or 6. In yet another embodiment variant, the index g, which indicates the number of neutral ligands L_S in a metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) indicates zero, 1, 2, 3, 4 or 5, advantageously zero, 1, 2, 3 or 4, in particular zero, 1, 2 or 3. In another embodiment of the claimed metal complexes according to the general formula [M(L_S)_G(AzuH)_v]X (V) is the sum of the number v of the ligands AzuH and the number g of the neutral ligands L_S, i.e. Σ (g + v), 2, 3, 4, 5, 6 or 7. A further embodiment provides that the sum of the number v of the ligands AzuH and the number g of the neutral ligands L_S, ie Σ (g + v), is 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. In a further variant of the claimed metal complexes, the neutral sigma donor Ligand L_S or the neutral pi-donor ligand L_S selected from the group consisting of monodentate and polydentate phosphorus donor ligands, alkenes, cyclic dienes and cyclic polyenes, and mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes, and derivatives thereof. The term "phosphorus donor ligand" is defined above. A non-limiting example of a selection of phosphorus donor ligands is also given above. Other examples of the neutral, especially pi-donor, ligand, L_S are the alkenes ethene, propene, butene, pentene, hexene, heptene, octene, nonene, decene and their isomers, the bicyclic alkene bicyclo[2.2.1]hept-2-ene, the cyclic diene cycloocta-1,5-diene (COD), the bicyclic diene bicyclo[2.2.1]hepta-2,5-diene (NBD), the monocyclic cycloocta-1,3,5,7-tetraene (COT). Examples of a mononuclear arene and derivatives of a mononuclear arene are benzene and benzene derivatives, e.g. B. toluene, p-cymene and halogenated benzenes. Naphthalene and naphthalene derivatives are examples of a polynuclear arene and a polynuclear arene derivative. An example of a heteroarene is pyridine. A binuclear or bicyclic heteroarene is, for example, indole. The mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes can also be substituted, in particular have alkyl groups and/or alkenyl groups and/or alkynyl groups and/or aryl groups and/or heteroaryl groups and/or halogen substituents. A further advantageous embodiment of the metal complexes claimed here provides that the central metal atom M of the metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, Rhodium, Iridium, Nickel, Palladium, Platinum, Copper, Silver, Gold, Zinc, Cadmium and Mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In yet another embodiment of the compounds claimed herein, metal complexes according to the general formula [M(L_T)(AzuH)_e.g]X (VI) provided. According to a further embodiment of the compounds described here, the central metal atom M of the metal complex is according to the general formula [M(L_T)(AzuH)_e.g]X (VI) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Another variant of the claimed metal complexes provides that the metal central atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, and zinc Cadmium. According to yet another embodiment of the claimed metal complexes, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed metal complexes according to the general formula [M(L_T)(AzuH)_e.g]X (VI) provides that the central metal atom M has a formal oxidation state of 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed metal complexes, it is provided that w₄ and the formal oxidation state of the central metal atom M of the metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI) are identical, i.e. H. are the same natural number except for zero. Consequently w₄ = 3, 4, 5, 6 or 7. According to a further embodiment of the compounds claimed here, metal complexes of the general formula [M(L_T)(AzuH)_e.g]X (VI) provided, wherein the central metal atom M has a formal oxidation state of 3, 4, 5 or 6, in particular 3, 4 or 5. In an alternative or additional embodiment of the claimed metal complexes is w₄ = 3, 4, 5 or 6, in particular w₄ = 3, 4 or 5. A further alternative or supplementary embodiment of the claimed metal complexes provides that |h|, i.e. the absolute amount of the sum of the negative charges of all anionic ligands L_T in a metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI), 1, 2, 3 or 4, in particular 1, 2 or 3. In another embodiment of the claimed metal complexes of the general formula [M(L_T)(AzuH)_e.g]X (VI) is the sum of the number z of ligands AzuH and the number of anionic ligands L_T 2, 3, 4, 5 or 6. A further embodiment provides that the sum of the number z of ligands AzuH and the number of anionic ligands L_T is 2, 3, 4 or 5, in particular 2, 3 or 4. Another embodiment of the compounds claimed here are metal complexes of the general formula [M(L_T)(AzuH)_e.g]X (VI) where the ligand L_T is a monoanionic ligand selected from the group consisting of anions of cyclopentadiene and its derivatives and a fluoride anion, or a dianionic ligand. A dianionic ligand L_T is selected, for example, from the group consisting of an oxidoligand O^2-, an imido ligand (NR^Q)^2- and an alkylidene ligand (CR^PR^V)^2-. There are R^Q, R^P and R^V independently selected from primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where the substituents are R^P and R^V can optionally form a ring. The leftovers R^Q, R^P and R^V can also be substituted independently of one another, in particular halogenated. Examples of cyclopentadiene (Cp) anions are the cyclopentadienyl anion C₅H₅- (Cp-) and the 1,2,3,4,5-pentamethylcyclopentadienyl anion C₅me₅ ⁻ (Cp^*). The aforementioned anions can be used as planar pi-donor ligands L_T in cationic sandwich complexes of the type [M(L_T)(AzuH)_e.g]X (VI) may be provided. A further advantageous embodiment of the compounds claimed here provides that the central metal atom M of the metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, Rhodium, Iridium, Nickel, Palladium, Platinum, Copper, Silver, Gold, Zinc, Cadmium and Mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In one embodiment of the compounds claimed here, the metal complex is selected from the group consisting of Fe(GuaH)₂, Ru(GuaH)₂, Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF₆, Co(GuaH)₂, [Co(GuaH)₂]PF₆, Rh(nbd)(GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF₆, PtMe₃(GuaH), [Pt(cod)(GuaH)]PF₆, Cu(PPh₃)(GuaH), Zn(GuaH)₂ and Zn(Mes)(GuaH), advantageously from the group consisting of Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF₆, Rh(nbd)(GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF₆, PtMe₃(GuaH), [Pt(cod)(GuaH)]PF₆, Cu(PPh₃)(GuaH), Zn(GuaH)₂ and Zn(Mes)(GuaH), particularly preferably from the group consisting of Ru(Cp*)(GuaH), Zn(Mes)(GuaH) and PtMe₃(GuaH). In particular, the metal complex is PtMe₃(GuaH). In particular with regard to use as metal precursor compounds for gas phase deposition processes, it is advantageous that the complexes Ru(Cp*)(GuaH), Zn(Mes)(GuaH) and PtMe₃(GuaH) not only in high (isomer) purity of 97%, advantageously more than 97%, in particular more than 98% or 99%, and good yield, including space-time yield, but - in isolated form - also exist as liquids. In addition, it is advantageous in catalysis to use a liquid Use catalyst, for example the Pt (IV) compound PtMe₃(GuaH) for light-induced platinum-catalyzed hydrosilylation reactions. The aforementioned Pt(IV) compound also shows absorption in the Vis range. This represents a further advantage in the context of light-induced platinum-catalyzed hydrosilylation reactions. Because the use of UV/Vis light is regularly provided for, which usually requires special safety measures to reduce the risk of skin cancer. Such security measures are when using PtMe₃(GuaH) not mandatory. The cobalt complex Co(GuaH), which is available as a mixture of isomers of the meso form and a racemate and is also available as a liquid in isolated form₂ metallocene type, for example, can be used as an electron transfer reagent. The object is also achieved by using at least one metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) or at least one solution or suspension comprising a metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) and at least one solvent which can be mixed with the, in particular aprotic-polar, solvent S_P is miscible or identical, - according to one embodiment of the compounds described above or - obtained or obtainable by a process for the preparation of such compounds or solutions or suspensions according to one of the embodiments described above, where M = central metal atom selected from group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12, L_K = optional neutral sigma donor ligand or optional neutral pi donor ligand, f = number of ligands L_K, where f = 0, 1, 2, 3, 4, 5 or 6, AzuH = azulene or an azulene derivative which is in the 4-position, 6-position or 8-position carries a hydride anion in addition to an H atom, m = number of ligands AzuH, where m = 1, 2, 3, 4, 5, 6 or 7, L_N = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum u of the negative charges of all ligands L_N is -1, -2, -3, -4, -5 or -6, q = number of ligands A to H, where q = w₂ – |u|, where w₂ > |u| and w₂ = 2, 3, 4, 5, 6 or 7, and where |u| an absolute value of the sum of the negative charges of all ligands L_N where |u| = 1, 2, 3, 4, 5 or 6, L_S = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands L_S, where g = 0, 1, 2, 3, 4, 5 or 6, v = number of ligands AzuH, where v = w₃ – 1, where w₃ = 2, 3, 4, 5, 6 or 7, L_T = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum h of the negative charges of all ligands L_T is -1, -2, -3, -4 or -5, z = number of ligands A to H, where z = w₄ – (|h| + 1), where w₄ > (|h| + 1) and w₄ = 3, 4, 5, 6 or 7, and where |h| an absolute value of the sum of the negative charges of all ligands L_T where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, where Azu = azulene according to formula (II), or Azu = an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6, C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, as i. Solution or suspension containing precatalyst or precatalyst in a chemical reaction and/or ii. Catalyst or catalyst-containing solution or suspension in a chemical reaction and/or iii. Electron transfer reagent or solution or suspension containing electron transfer reagent in a chemical reaction and/or iv. Solution or suspension containing precursor compound or precursor compound for producing at least one layer which contains a metal M, or at least one metal layer consisting of the metal M, in particular on at least one surface of a substrate. On the one hand, the aforementioned use is a method for carrying out a chemical reaction using at least one metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (iv), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) or at least one solution or suspension comprising a metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) and at least one solvent which can be mixed with the, in particular aprotic-polar, solvent S_P is miscible or identical, - according to one embodiment of the compounds described above or - obtained or obtainable by a process for the preparation of such compounds or solutions or suspensions according to one of the embodiments described above, where M = central metal atom selected from group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12, L_K = optional neutral sigma donor ligand or optional neutral pi donor ligand, f = number of ligands L_K, where f=0, 1, 2, 3, 4, 5 or 6, AzuH=azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom , m = number of ligands AzuH, where m = 1, 2, 3, 4, 5, 6 or 7, L_N = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum u of the negative charges of all ligands L_N is -1, -2, -3, -4, -5 or -6, q = number of ligands A to H, where q = w₂ – |u|, where w₂ > |u| and w₂ = 2, 3, 4, 5, 6 or 7, and where |u| an absolute value of the sum of the negative charges of all ligands L_N where |u| = 1, 2, 3, 4, 5 or 6, L_S = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands L_S, where g = 0, 1, 2, 3, 4, 5 or 6, v = number of ligands AzuH, where v = w₃ – 1, where w₃ = 2, 3, 4, 5, 6 or 7, L_T = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum h of the negative charges of all ligands L_T is -1, -2, -3, -4 or -5, z = number of ligands A to H, where z = w₄ – (|h| + 1), where w₄ > (|h| + 1) and w₄ = 3, 4, 5, 6 or 7, and where |h| an absolute value of the sum of the negative charges of all ligands L_T where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, where Azu = azulene according to formula (II), or Azu=an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6 , C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, comprising the steps: A) providing the at least one metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) or the at least one solution or suspension comprising a metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) and at least one solvent which can be mixed with the, in particular aprotic-polar, solvent S_P is miscible or identical, and B) carrying out the chemical reaction using the at least one metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) as a precatalyst, as a catalyst, or as an electron transfer reagent. The general formulas III, IV, V and VI include both the monomers and any oligomers, in particular dimers. The metal complexes to be made available according to the general formulas III, IV, V and VI can—depending on the application—be present without solvent, ie not as solvent adducts, or as solvent adducts of the respective metal complexes. In the case of a solvent adduct, the solvent is in particular with the solvent S_P identical. Alternatively or additionally, one or more of the neutral donor ligands L_K or L_S (cf. Formula III or Formula V) be selected from the group consisting of acetonitrile, dimethyl sulfoxide and tetrahydrothiophene. In particular with a view to use as metal precursor compounds in gas phase deposition processes, it is advantageous if the metal complexes of the general formulas III, IV, V and VI are in particular ether-free. The central metal atom M can have a formal oxidation state of 0, 1, 2, 3, 4, 5, 6 or 7. Higher oxidation states, in particular oxidation states 4, 5, 6 or 7, are usually achieved by anionic, especially monoanionic, ligands, e.g. B. fluoride anions, and / or dianionic ligands, z. B.O^2-, Stabilized (cf. Formulas IV, V and VI). L_N is advantageously a monoanionic ligand. L_T can be a monoanionic or a dianionic ligand. A dianionic ligand L_T is selected, for example, from the group consisting of an oxidoligand O^2-, an imido ligand (NR^Q)^2- and an alkylidene ligand (CR^PR^V)^2-. The index q can have the value 1, 2, 3, 4, 5 or 6. Alternatively, q=1, 2, 3, 4 or 5, q=1, 2, 3 or 4 is advantageous, in particular q=1, 2 or 3. The index v can also be 1, 2, 3, 4, 5 or 6. Alternatively, v=1, 2, 3, 4 or 5, v=1, 2, 3 or 4 is advantageous, in particular v=1, 2 or 3. The index z can have the value 1, 2, 3, 4 or accept 5 Alternatively, z=1, 2, 3 or 4, in particular z=1, 2 or 3. The halide anion X- functions as a leaving group. The term "weakly coordinating" also includes the expressions "very weakly coordinating" and "moderately strongly coordinating". In particular, the halide anions are selected from the group consisting of fluoride, chloride and bromide. The monovalent weakly coordinating and monovalent non-coordinating anions are in particular perfluorinated anions, such as. B.PF₆-, BF₄- and [(CF₃SO₂)₂N]-. A definition of the term “miscible” has already been given above. For example the complexes Ru(Cp*)(GuaH), Zn(Mes)(GuaH) and PtMe₃(GuaH) are available in high (isomeric) purity of 97%, advantageously more than 97%, in particular more than 98% or 99%, and good yield, including space-time yield, and are in isolated form as liquids before. In catalysis, it is advantageous to use a liquid catalyst, for example the Pt(IV) compound PtMe₃(GuaH) for light-induced platinum-catalyzed hydrosilylation reactions. The aforementioned Pt(IV) compound also shows absorption in the Vis range. This represents a further advantage in the context of light-induced platinum-catalyzed hydrosilylation reactions. Because the use of UV/Vis light is regularly provided for, which usually requires special safety measures to reduce the risk of skin cancer. Such security measures are when using PtMe₃(GuaH) not mandatory. The cobalt complex Co(GuaH), which is available as a mixture of isomers of the meso form and a racemate and is also available as a liquid in isolated form₂ metallocene type, for example, can be used as an electron transfer reagent. On the other hand, the aforementioned use is a process for the production i. at least one metal layer consisting of a metal M or ii. at least one layer containing a metal M on at least one surface of a substrate using at least one metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) or at least one solution or suspension comprising a metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) and at least one solvent which can be mixed with the solvent S_P is miscible or identical, - according to an embodiment of the compounds described above or - obtained or obtainable by a process for preparing such compounds or solutions or suspensions according to one of the embodiments described above, where M=central metal atom selected from group 6, group 7, group 8, group 9, group 10, group 11 or group 12, L_K = optional neutral sigma donor ligand or optional neutral pi donor ligand, f = number of ligands L_K, where f=0, 1, 2, 3, 4, 5 or 6, AzuH=azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom , m = number of ligands AzuH, where m = 1, 2, 3, 4, 5, 6 or 7, L_N = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum u of the negative charges of all ligands L_N is -1, -2, -3, -4, -5 or -6, q = number of ligands A to H, where q = w₂ – |u|, where w₂ > |u| and w₂ = 2, 3, 4, 5, 6 or 7, and where |u| an absolute value of the sum of the negative charges of all ligands L_N where |u| = 1, 2, 3, 4, 5 or 6, L_S = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands L_S, where g = 0, 1, 2, 3, 4, 5 or 6, v = number of ligands AzuH, where v = w₃ – 1, where w₃ = 2, 3, 4, 5, 6 or 7, L_T = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum h of the negative charges of all ligands L_T is -1, -2, -3, -4 or -5, z = number of ligands A to H, where z = w₄ – (|h| + 1), where w₄ > (|h| + 1) and w₄ = 3, 4, 5, 6 or 7, and where |h| an absolute value of the sum of the negative charges of all ligands L_T where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, where Azu = azulene according to formula (II), or Azu = an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6, C7 and C8, a substituent R^f carries, where the substituents R^f are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R^f can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, comprising the steps: A) providing the at least one metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) or the at least one solution or suspension comprising a metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) and at least one solvent which can be mixed with the solvent S_P is miscible or identical, and B) deposition i. the at least one metal layer consisting of the metal M or ii. the at least one layer containing the metal M on the at least one surface of the substrate using the at least one metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) as a precursor compound. The general formulas III, IV, V and VI include both the monomers and any oligomers, in particular dimers. The central metal atom M can have a formal oxidation state of 0, 1, 2, 3, 4, 5, 6 or 7. Higher oxidation states, in particular oxidation states 4, 5, 6 or 7, are usually achieved by anionic, especially monoanionic, ligands, e.g. B. fluoride anions, and / or dianionic ligands, z. B.O^2-, Stabilized (cf. Formulas IV, V and VI). L_N is advantageously a monoanionic ligand. L_T can be a monoanionic or a dianionic ligand. A dianionic ligand L_T is selected, for example, from the group consisting of an oxidoligand O^2-, an imido ligand (NR^Q)^2- and an alkylidene ligand (CR^PR^V)^2-. The index q can have the value 1, 2, 3, 4, 5 or 6. Alternatively, q=1, 2, 3, 4 or 5, q=1, 2, 3 or 4 is advantageous, in particular q=1, 2 or 3. The index v can also be 1, 2, 3, 4, 5 or 6. Alternatively, v=1, 2, 3, 4 or 5, v=1, 2, 3 or 4 is advantageous, in particular v=1, 2 or 3. The index z can have the value 1, 2, 3, 4 or 5. Alternatively, z=1, 2, 3 or 4, in particular z=1, 2 or 3. The halide anion X- functions as a leaving group. The term "weakly coordinating" also includes the expressions "very weakly coordinating" and "moderately strongly coordinating". In particular, the halide anions are selected from the group consisting of fluoride, chloride and bromide. The monovalent weakly coordinating and monovalent non-coordinating anions are in particular perfluorinated anions, such as. B.PF₆-, BF₄- and [(CF₃SO₂)₂N]-. A definition of the term “miscible” has already been given above. In the uses described here or the methods claimed here for carrying out a chemical reaction or for producing at least one metal layer consisting of the metal M or at least one layer containing a metal M, the metal complexes as solids or liquids according to one embodiment of the further compounds described above or as a solid or liquid or as a solution or suspension, comprising a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P is miscible or identical, e.g. B.S_L and/or S_M, are used, each obtained or obtainable by a process for the preparation of such complex compounds or solutions or suspensions according to one of the embodiments described above. Due to their high purity, the aforementioned complex compounds according to the formulas III, IV, V and VI are suitable both for use as precatalysts or catalysts in a large number of reactions which are carried out by metals selected from Group 6, Group 7, Group 8 , Group 9, Group 10, Group 11 and Group 12, as well as metal precursor compounds in chemical vapor deposition processes. Some of these metal complexes are advantageously not only isomerically pure, but also liquid. It is particularly advantageous that the metal complexes of the types M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) in each case at least one H-dihydroazulenyl anion (AzuH)^1- which is a simply hydrogenated azulene or azulene derivative in the 4-position, in the 6-position or in the 8-position. The respective H-dihydroazulenyl anion (AzuH)^1- has a hydride anion H- in the 4-position or in the 6-position or in the 8-position in addition to an H atom. Consequently, there is a CH in the C4 position or in the C6 position or in the C8 position of the azulene skeleton₂-group before. The H-dihydroazulenyl anion is a derivative of the cyclopentadienyl anion or a cyclopentadienyl-like monoanion. The H-dihydroazulenyl anion can be a 3α,4-H-dihydroazulenyl, an 8,8α-H- dihydroazulenyl, a 3α,6-H-dihydroazulenyl or a 6,8α-H-dihydroazulenyl anion, or a mixture of two or more regioisomers. Due to the presence of at least one H-dihydroazulenyl anion, i.e. at least one cyclopentadienyl-like monoanion, the compounds of the general formulas III, IV, V and VI are particularly suitable as precatalysts, as catalysts and as electron transfer reagents for chemical reactions in which otherwise metal complexes are used which have cyclopentadienyl ligands. This is particularly advantageous because providing an H-dihydroazulenyl ligand is less laborious and time consuming compared to providing the cyclopentadienyl ligand. Because the starting materials, e.g. B. natural products such as guaiazulene and hydridic reducing agents such as lithium triethylborohydride are not only easier to handle and store, but also cheaper. In addition, fewer and simpler work steps have to be carried out. As a result, the outlay on synthesis and the production costs for the metal complexes used here are also lower than for analogous metal-Cp complexes. The metal complexes described here therefore represent an alternative to metal-Cp complexes, particularly with regard to industrial application. Guajazulene is a natural substance that is contained in chamomile oil and other essential oils and is therefore advantageously available in large quantities at low cost. Synthetically, it can be made from the guajol of guaiac wood oil (guaiac resin). Guajazulene is an intensely blue substance with anti-inflammatory effects. An example of an isomer of guaiazulene is 2-isopropyl-4,8-dimethylazulene (vetivazulene). In an advantageous variant of the uses claimed here or the methods claimed here for carrying out a chemical reaction or for producing at least one metal layer consisting of the metal M or at least one layer which contains a metal M, Azu=Gu=7-iso- propyl-1,4-dimethylazulene and AzuH = GuaH = 7-iso-propyl-1,4-dimethyl-8-H-dihydroazulene. Examples of the metal complexes used here are, on the one hand, homoleptic sandwich complexes of medium transition metals (groups 6, 7 and 8), in particular of group 8 metals, and later transition metals, i.e. of group 9, group 10, group 11 and of Group 12, in particular: ■ neutral sandwich complexes of the type M(L_K)_f(AzuH)_m (III) with f = 0, i.e. H. without neutral donor ligand L_K, e.g. B.Fe(GuaH)₂, Ru(GuaH)₂, Co(GuaH)₂, Zn(GuaH)₂, where the formal oxidation state is 2, M = Fe, Ru, Co or Zn, f = 0, m = 2 and AzuH = GuaH and ■ cationic sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 0, i.e. H. without neutral donor ligand L_S, e.g. B. the d⁶-Complex [Co(GuaH)₂]PF₆, where the formal oxidation state is 3, M = Co, g = 0, v = 3 − 1 = 2, AzuH = GuaH, and X = PF₆. On the other hand, the compounds used here are heteroleptic complexes of medium transition metals (groups 6, 7 and 8), in particular of group 8 metals, and later transition metals, i.e. of group 9, group 10, group 11 and of group 12, in particular: ■ neutral half-sandwich complexes of the type M(L_K)_f(AzuH)_m (III) with f = 1 or 2, i. H. with exactly one neutral sigma donor ligand or with exactly one neutral nonplanar pi donor ligand, e.g. B. Cu(PPh₃)(GuaH), Rh(nbd)(GuaH), Rh(cod)(GuaH), where the formal oxidation state is 1, M = Cu or Rh, L_K = PPh₃, NBD or COD, each f is 1, each m is 1 and AzuH = GuaH, or two planar, neutral pi-donor ligands, e.g. B. Rh(ethene)₂(GuaH), where the formal oxidation state is 1, M = Rh, L_K = ethene, f = 2, m = 1 and AzuH = GuaH ■ neutral half-sandwich complexes of the type M(L_N)(AzuH)_q (IV), for example with |u| = 1, 2 or 3, i. H. for example with one, two or three monoanionic sigma donor ligands, e.g. B. Zn(Mes)(GuaH), where the formal oxidation state is 2, M = Zn, L_N = Mes-, |u| = 1, q = 2 - |-1| = 1 and AzuH = GuaH, and PtMe₃(GuaH), where the formal oxidation state is 4, M = Pt, L_N = CH₃-, |u| = 3, q = 4 - |-3| = 1 and AzuH = GuaH ■ neutral sandwich complexes of the type M(L_N)(AzuH)_q (IV), for example with |u| = 1, i.e. H. with exactly one monoanionic, planar pi-donor ligand, e.g. B. Ru(Cp*)(GuaH), where the formal oxidation state is 2, M = Ru, L_N = Cp*, |u| = 1, q = 2 - |-1| = 1 and AzuH = GuaH ■ cationic sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 1, i.e. h with exactly one neutral, planar pi-donor ligand, e.g. B. [Ru(p-cymene)(GuaH)]PF₆, where the formal oxidation state is 2, M = Ru, L_S = p-cymene, g = 1, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆ ■ cationic half-sandwich complexes of the type [M(L_S)_G(AzuH)_v]X (V) with g = 1 or 2, i.e. H. with a neutral non-planar pi-donor ligand, e.g. B. [Pt(cod)(GuaH)]PF₆, where the formal oxidation state is 2, M = Pt, L_S = COD, g = 1, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆, or with two planar, neutral pi-donor ligands, e.g. B. [Pt(ethene)₂(GuaH)]PF₆, where the formal oxidation state is 2, M = Pt, L_S = ethene, g = 2, v = 2 - 1 = 1, AzuH = GuaH and X = PF₆ ■ cationic sandwich complexes of the type [M(L_T)(AzuH)_e.g]X (VI) with |h| = 1, i.e. H. with exactly one anionic, planar pi-donor ligand, e.g. B. [Rh(Cp*)(GuaH)]Cl, [Rh(Cp*)(GuaH)]PF₆, where the formal oxidation state is 3 in each case, M = Rh, L_T = Cp*, |h| = 1, z = 3 - (|-1| + 1) = 1, AzuH = GuaH and X = Cl or PF₆. Examples of isomerically pure metal complexes are Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF₆, Rh(nbd)(GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF₆, PtMe₃(GuaH), [Pt(cod)(GuaH)]PF₆, Cu(PPh₃)(GuaH), Zn(GuaH)₂ and Zn(Mes)(GuaH). In the context of the present invention, “isomerically pure” means that the desired product is or has been obtained in pure isomer form or the desired isomer is present after purification in a proportion of ≧90%, preferably ≧95%, particularly preferably ≧99%. Here, the isomer purity is determined, for example, by means of nuclear magnetic resonance spectroscopy. In particular with regard to use as metal precursor compounds for gas phase deposition processes, it is advantageous that the complexes Ru(Cp*)(GuaH), Zn(Mes)(GuaH) and PtMe₃(GuaH) not only in high (isomer) purity of 97%, advantageously more than 97%, in particular more than 98% or 99% and good yield, space-time yield, but - in isolated Form - also exist as liquids. In step A) of the methods described here for carrying out a chemical reaction or for producing at least one metal layer consisting of the metal M or at least one layer which contains a metal M, the provision of a metal complex or a plurality of metal complexes can be provided in each case. In one embodiment of the respective method, it is provided that in step A) at least one metal complex is made available as a solid, as a liquid or as a solution or suspension comprising a metal complex. Alternatively or in addition, several metal complexes can be present independently of one another as separate solids or as solid mixtures or as separate liquids or as liquid mixtures or as separate solutions or suspensions, each comprising a metal complex, or as a solution or suspensions comprising multiple metal complexes. At this point and in the following, the specification of an exact stoichiometry of the depositable metal-containing layers or films is dispensed with. The term layer is synonymous with the term film and makes no statement about the layer thickness or the film thickness. In addition, according to the present invention, a metal layer consisting of the metal M or a layer containing a metal M, nanoparticles of a metal M or nanoparticles of different metals M or nanoparticles, each comprising a plurality of metals M, contain or consist of such nanoparticles. Because of their high (isomeric) purity, the metal complexes used are particularly suitable as precursor compounds for producing high-quality metal layers or layers containing metal M on a surface of a substrate. This is in particular due to their production by a process according to one of the embodiments described above, namely using alkali metal H-dihydroazulenides obtained or obtainable by a process for the production of alkali metal H-dihydroazulenides according to one of the embodiments described above. In addition, the metal complexes or solutions or suspensions to be made available according to step A), comprising such metal complexes, can be prepared particularly simply and comparatively inexpensively using a method for producing such compounds or solutions or suspensions according to one of the embodiments described above. The latter enables their use on an industrial scale. In one embodiment of the uses described here or the methods claimed here for carrying out a chemical reaction or for producing at least one metal layer consisting of the metal M or at least one layer containing a metal M, metal complexes according to the general formula M(L_K)_f(AzuH)_m (III) provided. According to yet another embodiment of the claimed uses or the claimed methods, the central metal atom M of the metal complex is according to the general formula M(L_K)_f(AzuH)_m (III) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury . Another variant of the claimed uses or the claimed methods provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper , silver, zinc and cadmium. According to yet another embodiment of the claimed uses or the claimed methods, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, especially from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed uses or the claimed methods provides that the central metal atom M has a formal oxidation state of 1, 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed uses or the claimed methods, it is provided that the index m and the formal oxidation state of the central metal atom M of the metal complex according to the general formula M(L_K)_f(AzuH)_m (III) are identical, i. H. are the same natural number except for zero. Thus m=1, 2, 3, 4, 5, 6 or 7 can be. According to a further embodiment of the claimed uses or the claimed methods, a metal complex according to the general formula M(L_K)_f(AzuH)_m (III) provided, wherein the central metal atom M has a formal oxidation state of 1, 2, 3 or 4, advantageously of 1, 2 or 3, in particular of 1 or 2. In an alternative or supplementary embodiment of the claimed Uses or the claimed methods, the index m is 1, 2, 3 or 4, advantageously 1, 2 or 3, in particular 1 or 2. A further alternative or supplementary embodiment of the claimed uses or the claimed methods provides that the index f, which is the number of neutral ligands L_K in a metal complex according to the general formula M(L_K)_f(AzuH)_m (III) indicates zero, 1, 2, 3, 4 or 5, advantageously zero, 1, 2, 3 or 4, in particular zero, 1, 2 or 3. In another embodiment of the claimed uses or the claimed methods is the sum of the number m of ligands AzuH and the number f of neutral ligands L_K, i.e. Σ (f + m), 2, 3, 4, 5, 6 or 7. Another embodiment provides that the sum of the number m of ligands AzuH and the number f of neutral ligands L_K, ie Σ(f+m), is 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. A further embodiment provides that the neutral sigma donor ligand L_K or pi donor ligand L_K is selected from the group consisting of monodentate and polydentate phosphorus donor ligands, alkenes, cyclic dienes and cyclic polyenes, and mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes, and their derivatives. The term "phosphorus donor ligand" is defined above. A non-limiting example of a selection of phosphorus donor ligands is also given above. Other examples of the ligand L_K are the alkenes ethene, propene, butene, pentene, hexene, heptene, octene, nonene, decene and their isomers, the bicyclic alkene bicyclo[2.2.1]hept-2-ene, the cyclic diene cycloocta-1,5-diene (COD), the bicyclic diene bicyclo[2.2.1]hepta-2,5-diene (NBD), the monocyclic cycloocta-1,3,5,7-tetraene (COT). Examples of a mononuclear arene and derivatives of a mononuclear arene are benzene and benzene derivatives, e.g. B. toluene, p-cymene and halogenated benzenes. Naphthalene and naphthalene derivatives are examples of a polynuclear arene and a polynuclear arene derivative. An example of a heteroarene is pyridine. A binuclear or bicyclic heteroarene is, for example, indole. The mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes can also be substituted, in particular have alkyl groups and/or alkenyl groups and/or alkynyl groups and/or aryl groups and/or heteroaryl groups and/or halogen substituents. A further advantageous embodiment of the uses described here or the methods claimed here for carrying out a chemical reaction or for producing at least one metal layer consisting of the metal M or at least one layer containing a metal M provides that the central metal atom M of the metal complex according to the general formula M(L_K)_f(AzuH)_m (III) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In a further embodiment of the uses described here or the methods claimed here for carrying out a chemical reaction or for producing at least one metal layer consisting of the metal M or at least one layer containing a metal M, metal complexes according to the general formula M(L_N)(AzuH)_q (IV) provided. According to yet another embodiment of the claimed uses or the claimed methods, the central metal atom M of the metal complex is according to the general formula M(L_N)(AzuH)_q (IV) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury . Another variant of the claimed uses or the claimed methods provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper , silver, zinc and cadmium. According to yet another embodiment of the claimed uses or the claimed methods, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, especially from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed uses or the claimed methods provides that the central metal atom M has a formal oxidation state of 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed uses or the claimed methods, it is provided that w₂ and the formal oxidation state of the central metal atom M of the metal complex according to the general formula M(L_N)(AzuH)_q (IV) are identical, i. H. are the same natural number except for zero. Consequently w₂ = 2, 3, 4, 5, 6 or 7. According to a further embodiment of the claimed uses or the claimed methods, metal complexes according to the general formula M(L_N)(AzuH)_q (IV) provided, wherein the central metal atom M has a formal oxidation state of 2, 3, 4, 5 or 6, advantageously of 2, 3, 4 or 5, in particular of 2, 3 or 4. In an alternative or supplementary embodiment of the claimed uses or the claimed processes is w₂ = 2, 3, 4, 5 or 6, is advantageous w₂ = 2, 3, 4 or 5, in particular w₂ = 2, 3 or 4. A further alternative or supplementary embodiment of the claimed uses or the claimed methods provides that |u|, i.e. the absolute amount of the sum of the negative charges of all anionic ligands L_N in a metal complex according to the general formula M(L_N)(AzuH)_q (IV) is 1, 2, 3, 4, 5, or 6. In yet another embodiment variant, |u|, i.e. the absolute amount of the sum of the negative charges of all anionic ligands L_N in a metal complex according to the general formula M(L_N)(AzuH)_q (IV), 1, 2, 3, 4 or 5, advantageously 1, 2, 3 or 4, in particular 1, 2 or 3. In another embodiment of the claimed uses or the claimed methods, the sum of the number q is q of the ligands AzuH and the number of anionic ligands L_N 2, 3, 4, 5, 6 or 7. A further embodiment provides that the sum of the number q of the ligands AzuH and the number of anionic ligands L_N is 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. Yet another embodiment of the claimed uses or the claimed methods provides metal complexes according to the general formula M(L_N)(AzuH)_q (IV) where the anionic sigma donor ligand L_N or pi-donor ligand L_N is advantageously a monoanionic ligand selected from the group consisting of anions of cyclopentadiene and its derivatives, alkyl anions and aryl anions. Alternatively or additionally, a fluoride anion can be used as at least one of the monoanionic ligands L_N be provided. Examples of the anionic ligand L_N are the cyclopentadienyl anion C₅H₅- (Cp-) and the 1,2,3,4,5-pentamethylcyclopentadienyl anion C₅me₅ ⁻ (Cp^*), the methyl anion CH₃- (Me-) and the mesityl anion Me₃C₆H₂ ⁻ (Mes-). The aforementioned anions can be used as monoanionic pi-donor ligands or sigma-donor ligands L_N in the production of neutral sandwich or half-sandwich complexes of the type M(L_N)(AzuH)_q (IV) function. A further advantageous embodiment of the uses described here or the methods claimed here for carrying out a chemical reaction or for producing at least one metal layer consisting of the metal M or at least one layer containing a metal M, provides that the central metal atom M of the metal complex according to the general formula M(L_N)(AzuH)_q (IV) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In another embodiment of the uses described here or the methods claimed here for carrying out a chemical reaction or for producing at least one metal layer consisting of the metal M or at least one layer containing a metal M, metal complexes according to the general formula [M( L_S)_G(AzuH)_v]X (V) provided. According to a further embodiment of the claimed uses or the claimed processes, the central metal atom M of the metal complex is of the general formula [M(L_S)_G(AzuH)_v]X (V) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Another variant of the claimed uses or the claimed methods provides that the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. According to yet another embodiment of the claimed uses or the claimed methods, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, especially from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed uses or the claimed methods provides that the central metal atom M has a formal oxidation state of 2, 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed uses or the claimed methods, it is provided that w₃ and the formal oxidation state of the central metal atom M of the metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) are identical, i.e. H. are the same natural number except for zero. Consequently w₃ = 2, 3, 4, 5, 6 or 7. According to a further embodiment of the claimed uses or the claimed methods, metal complexes of the general formula [M(L_S)_G(AzuH)_v] X (V) provided, wherein the central metal atom M has a formal oxidation state of 2, 3, 4, 5 or 6, advantageously of 2, 3, 4 or 5, in particular of 2, 3 or 4. In an alternative or supplementary embodiment variant of the claimed uses or the claimed methods is w₃ = 2, 3, 4, 5 or 6, w is advantageous₃ = 2, 3, 4 or 5, in particular w₃ = 2, 3 or 4. A further alternative or supplementary embodiment of the claimed uses or the claimed methods provides that the index g, which denotes the number of neutral ligands L_S in a metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) is zero, 1, 2, 3, 4, 5 or 6. In yet another embodiment variant, the index g, which indicates the number of neutral ligands L_S in a metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) indicates zero, 1, 2, 3, 4 or 5, advantageously zero, 1, 2, 3 or 4, in particular zero, 1, 2 or 3. In another embodiment of the claimed uses or the claimed methods, the sum of the number v of the ligands is AzuH and the number g of the neutral ligands L_S, i.e. Σ (g + v), 2, 3, 4, 5, 6 or 7. A further embodiment provides that the sum of the number v of the ligands AzuH and the number g of the neutral ligands L_S, ie Σ (g + v), is 2, 3, 4, 5 or 6, advantageously 2, 3, 4 or 5, in particular 2, 3 or 4. In a further variant of the claimed uses or the claimed methods neutral sigma donor ligand L_S or the neutral pi-donor ligand L_S selected from the group consisting of monodentate and polydentate phosphorus donor ligands, alkenes, cyclic dienes and cyclic polyenes, and mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes, and derivatives thereof. The term "phosphorus donor ligand" is defined above. A non-limiting example of a selection of phosphorus donor ligands is also given above. Other examples of the neutral, especially pi-donor, ligand, L_S are the alkenes ethene, propene, butene, pentene, hexene, heptene, octene, nonene, decene and their isomers, the bicyclic alkene bicyclo[2.2.1]hept-2-ene, the cyclic diene cycloocta-1,5-diene (COD), the bicyclic diene bicyclo[2.2.1]hepta-2,5-diene (NBD), the monocyclic cycloocta-1,3,5,7-tetraene (COT). Examples of a mononuclear arene and derivatives of a mononuclear arene are benzene and benzene derivatives, e.g. B. toluene, p-cymene and halogenated benzenes. Naphthalene and naphthalene derivatives are examples of a polynuclear arene and a polynuclear arene derivative. An example of a heteroarene is pyridine. A binuclear or bicyclic heteroarene is, for example, indole. The mononuclear arenes, polynuclear arenes, mononuclear heteroarenes, and polynuclear heteroarenes can also be substituted be, in particular alkyl groups and/or alkenyl groups and/or alkynyl groups and/or aryl groups and/or heteroaryl groups and/or halogen substituents. A further advantageous embodiment of the claimed uses or the claimed methods provides that the central metal atom M of the metal complex according to the general formula [M(L_S)_G(AzuH)_v]X (V) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, Rhodium, Iridium, Nickel, Palladium, Platinum, Copper, Silver, Gold, Zinc, Cadmium and Mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In yet another embodiment of the uses described here or the methods claimed here for carrying out a chemical reaction or for producing at least one metal layer consisting of the metal M or at least one layer containing a metal M, metal complexes according to the general formula [M (L_T)(AzuH)_e.g]X (VI) provided. According to a further embodiment of the claimed uses or the claimed processes, the central metal atom M of the metal complex is of the general formula [M(L_T)(AzuH)_e.g]X (VI) selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury. Another variant of the claimed uses or the claimed method provides that the central metal atom M is selected from the Group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. According to yet another embodiment of the claimed uses or the claimed methods, the central metal atom M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, rhenium, iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, especially from the group consisting of chromium, molybdenum, tungsten, manganese, iron, ruthenium, cobalt, rhodium, platinum, copper and zinc. A further embodiment of the claimed uses or the claimed methods provides that the central metal atom M has a formal oxidation state of 3, 4, 5, 6 or 7. According to an alternative or supplementary embodiment of the claimed uses or the claimed methods, it is provided that w₄ and the formal oxidation state of the central metal atom M of the metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI) are identical, i.e. H. are the same natural number except for zero. Consequently w₄ = 3, 4, 5, 6 or 7. According to a further embodiment of the claimed uses or the claimed methods, metal complexes of the general formula [M(L_T)(AzuH)_e.g]X (VI) provided, where the central metal atom M has a formal oxidation state of 3, 4, 5 or 6, in particular of 3, 4 or 5. In an alternative or additional embodiment variant of the claimed uses or the claimed methods, w₄ = 3, 4, 5 or 6, in particular w₄ = 3, 4 or 5. A further alternative or supplementary embodiment of the claimed uses or the claimed methods provides that |h|, i.e. the absolute amount of the sum of the negative charges of all anionic ligands L_T in a metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI), 1, 2, 3 or 4, in particular 1, 2 or 3. In another embodiment of the claimed uses or the claimed methods, the sum of the number z of the ligands AzuH and the Number of anionic ligands L_T 2, 3, 4, 5 or 6. A further embodiment provides that the sum of the number z of ligands AzuH and the number of anionic ligands L_T is 2, 3, 4 or 5, in particular 2, 3 or 4. A further embodiment of the claimed uses or the claimed methods provides metal complexes of the general formula [M(L_T)(AzuH)_e.g]X (VI) where the ligand L_T is a monoanionic ligand selected from the group consisting of anions of cyclopentadiene and its derivatives and a fluoride anion, or a dianionic ligand. A dianionic ligand L_T is selected, for example, from the group consisting of an oxidoligand O^2-, an imido ligand (NR^Q)^2- and an alkylidene ligand (CR^PR^V)^2-. There are R^Q, R^P and R^V independently selected from primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where the substituents are R^P and R^V can optionally form a ring. The leftovers R^Q, R^P and R^V can also be substituted independently of one another, in particular halogenated. Examples of cyclopentadiene (Cp) anions are the cyclopentadienyl anion C₅H₅- (Cp-) and the 1,2,3,4,5-pentamethylcyclopentadienyl anion C₅me₅ ⁻ (Cp^*). The aforementioned anions can be used as planar pi-donor ligands L_T in cationic sandwich complexes of the type [M(L_T)(AzuH)_e.g]X (VI) may be provided. A further advantageous embodiment of the claimed uses or the claimed methods provides that the central metal atom M of the metal complex according to the general formula [M(L_T)(AzuH)_e.g]X (VI) is selected from group 8, group 9, group 10, group 11 or group 12. Advantageously, the central metal atom M is then selected from the group consisting of iron, ruthenium, osmium, cobalt, Rhodium, Iridium, Nickel, Palladium, Platinum, Copper, Silver, Gold, Zinc, Cadmium and Mercury. Even more advantageously, the central metal atom M is selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver, zinc and cadmium. The central metal atom M is particularly advantageously selected from the group consisting of iron, ruthenium, cobalt, rhodium, nickel, platinum, copper, silver and zinc, in particular from the group consisting of iron, ruthenium, cobalt, rhodium, platinum, and copper Zinc. In one embodiment of the uses described here or the methods claimed here for carrying out a chemical reaction or for producing at least one metal layer consisting of the metal M or at least one layer containing a metal M, the metal complex is selected from the group consisting of Fe (GuaH)₂, Ru(GuaH)₂, Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF₆, Co(GuaH)₂, [Co(GuaH)₂]PF₆, Rh(nbd)(GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF₆, PtMe₃(GuaH), [Pt(cod)(GuaH)]PF₆, Cu(PPh₃)(GuaH), Zn(GuaH)₂ and Zn(Mes)(GuaH), and mixtures thereof, advantageously from the group consisting of Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF₆, Rh(nbd)(GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF₆, PtMe₃(GuaH), [Pt(cod)(GuaH)]PF₆, Cu(PPh₃)(GuaH), Zn(GuaH)₂ and Zn(Mes)(GuaH), and mixtures thereof, particularly advantageously from the group consisting of Ru(Cp*)(GuaH), Zn(Mes)(GuaH) and PtMe₃(GuaH). In particular, the metal complex is PtMe₃(GuaH). In another embodiment of the method claimed here for producing a metal layer or a layer containing metal M, the metal layer or the layer containing metal M is deposited in step B) by means of a gas phase deposition process. The metal layer or the layer containing metal M is advantageously deposited using an ALD method or an MOCVD method, in particular using an MOVPE method. Alternatively, a sol-gel method can be used, in which case the sol can be deposited on one surface or several surfaces of the substrate, for example by means of spin or dip coating. A further variant of the use described here or of the claimed method provides for a sequential deposition of a plurality of metal layers and/or metal-containing layers on the surface of the substrate. In this case, step B) is repeated, the respective metal-containing layers and/or metal layers being deposited one after the other. The first layer in each case is deposited directly on the surface of the substrate, while the further layers are deposited on the surface of the previously deposited layer in each case. The substrate can, for example, comprise a non-metal or a number of non-noble metals or be made of a non-metal or a number of non-noble metals. Alternatively or additionally, the substrate can comprise a non-metallic material or a plurality of non-metallic materials or consist entirely of a non-metallic material or a plurality of such materials. As a substrate z. B. corundum foils or thin metallic foils can be used. The substrate can itself be part of a component. In one embodiment of the aforementioned use of a metal complex as a precursor compound for producing a metal layer or a layer containing metal M or in one embodiment of the method for producing a metal layer or a layer containing metal M on a surface of a substrate, the substrate is a wafer. The wafer can be silicon, silicon carbide, germanium, gallium arsenide, indium phosphide, a glass such as e.g. B. SiO₂, and / or a plastic such. As silicone, include or consist entirely of one or more of these materials. In addition, the wafer can have one wafer layer or multiple wafer layers, each with a surface. The production of a metal layer or a layer containing metal M can be provided on the surface of one wafer layer or several wafer layers. Substrates obtained or obtainable by means of the use claimed here or the method described here, comprising a metal layer or a layer containing metal M, in particular a platinum layer or a layer containing platinum, possibly comprising metal nanoparticles or consisting of metal nanoparticles, can be used particularly well for the production of an electronic component, in particular an electronic semiconductor component, or a redox-active electrode for a fuel cell due to the high purity of the metal layer or the layer containing metal M. In the latter case, the platinum layer or the layer containing platinum nanoparticles functions as the catalytic layer. The object is also achieved by a substrate which on at least one surface i. at least one metal layer consisting of the metal M or ii. has at least one layer containing a metal M, wherein the at least one metal layer consisting of the metal M or the at least one layer containing a metal M can be produced or produced using a metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) or a solution or suspension comprising such a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P is miscible or identical, - according to one embodiment of the compounds described above, or - obtained or obtainable by a process for the preparation of such metal complexes or such solutions or suspensions according to one of the embodiments described above. There are M, L_K, f, m, L_N, q, L_S, g, v, L_T, z, X-, AzuH and Azu as defined above. With regard to a selection of usable metal complexes according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) and of solutions or suspensions comprising such a metal complex and at least one, in particular aprotic-polar, solvent which can be mixed with the solvent S_P is miscible or identical, reference is made to the statements relating to the method described above for the production of such a substrate. A definition of the term “miscible” has already been given above. With regard to the advantages of such a substrate, reference is made to the advantages which are mentioned for the method described above for producing such a substrate. In an advantageous embodiment of the substrate claimed here, the at least one metal layer consisting of the metal M or the at least one layer containing a metal M can be produced or produced using a metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI) where Azu = Gua = 7-iso-propyl-1,4-dimethylazulene and AzuH = GuaH = 7-iso-propyl-1,4-dimethyl-8-H-dihydroazulene. Further features, details and advantages of the invention result from the wording of the claims and from the following description of exemplary embodiments with reference to the drawings. Show: Fig.1¹H NMR spectra to determine the conversion of the hydrosilylation reaction of 1-octene with pentamethylsiloxane using 5 ppm PtMe₃(GuaH) as a catalyst, where GuaH = 7-iso-propyl-1,4-dimethyl-8-H-dihydroazulene, and FIG. 2 shows a diagram relating to the conversion of the hydrosilylation reaction of 1-octene with pentamethylsiloxane using 5 ppm PtMe₃(GuaH) as a catalyst. Those shown in Fig.1¹H NMR spectra were recorded in C₆D₆ recorded at 298K and 300MHz. The chemical shift δ in ppm is plotted on the x-axis. During the hydrosilylation reaction of 1-octene with pentamethylsiloxane using 5 ppm PtMe³(GuaH) as a catalyst (cf. Example 15, NMR experiments with 5 ppm Pt) were shown in Fig.1¹H NMR spectra recorded at predefined time intervals. The bottom¹H NMR spectra were recorded at time 0 h, ie before the start of the hydrosilylation reaction. Above this¹H NMR spectra are - in ascending order - those recorded after about 0.25 h, 1 h, 8 h and 48 h¹H NMR spectra shown. Other, not shown here,¹H NMR spectra after about 0.5 h, 2 h, 4 h and 24 h in C₆D₆ recorded at 298K and 300MHz. The reaction equation for the hydrosilylation of 1-octene is as follows: Sales were based on CH₂-Group of the product (shaded gray in the product molecule) determined with a shift of 0.60 ppm. As part of the calculation of the aforementioned sales, the¹H NMR spectra recorded after about 0.50 h, 2 h, 4 h and 24 h in C₆D₆ recorded at 298K and 300MHz. Table 1 shows the calculated conversions of the hydrosilylation reaction of 1-octene with pentamethylsiloxane using 5 ppm PtMe₃(GuaH) listed as a catalyst (see column 2). Table 1: The graphical evaluation of the results listed in Table 2 is shown in FIG. The time in hours (h) is plotted on the abscissa and the conversion in percent (%) on the ordinate. It can be seen that the hydrosilylation reaction using 5 ppm PtMe₃(GuaH) as a catalyst has almost completely expired after about 8 hours. Thus, a satisfactory response speed is achieved. Advantageously, the Pt(IV) compound is PtMe₃(GuaH) as a liquid and shows absorption in the Vis range. The latter represents a further advantage of the Pt(IV) compound used here. This is because UV/Vis light is regularly used in light-induced platinum-catalyzed hydrosilylation reactions, which usually means that special safety measures are required to reduce the risk of skin cancer. Such security measures are when using PtMe₃(GuaH) not mandatory. According to conventional wisdom, the photolysis of a known catalyst containing a cyclopentadienyl anion, such as e.g. B. CpPtMe₃ and (MeCp)PtMe₃, in the presence of a silane, e.g. B. pentamethylsiloxane, to form a platinum colloid as an active hydrosilylation catalyst. (L.D. Boardman, Organometallics 1992, 11, 4194-4201) Boardman gives a catalyst concentration of 10 ppm platinum as CpPtMe for the hydrosilylation reaction of 1-octene with pentamethylsiloxane (equimolar mixture).₃ on. When using the precatalyst PtMe presented for the first time within the scope of the present invention₃(GuaH) is already at 50% of the catalyst concentration selected in the literature, ie at a catalyst concentration of 5 ppm platinum as PtMe₃(GuaH), complete conversion of the substrates 1-octene and pentamethylsiloxane was observed. Another advantage of the compound PtMe used here as a precatalyst₃(GuaH) over Pt(IV) compounds containing cyclopentadienyl anions is that the guaiazulene required for its production is synthesized using renewable raw materials instead of petroleum. Consequently, the representation of the Pt(IV) complex is PtMe₃(GuaH) comparatively sustainable, easy and inexpensive to implement. Consequently, the half-sandwich complex PtMe₃(GuaH) a relatively sustainable and inexpensive alternative to previously known hydrosilylation catalysts such as CpPtMe₃ and (MeCp)PtMe₃ Working procedures for the synthesis of Li(GuaH), Na([15]-crown-5)(GuaH), K([18]-crown-6)(GuaH), Fe(GuaH)₂, Ru(GuaH)₂, Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF₆, Co(GuaH)₂, [Co(GuaH)₂]PF₆, Rh(nbd)(GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF₆, PtMe₃(GuaH), [Pt(cod)(GuaH)]PF₆, Cu(PPh₃)(GuaH), Zn(GuaH)₂ and Zn(Mes)(GuaH)(GuaH)- = 7-iso-propyl-1,4-dimethyl-8-H-dihydroazulenyl, C₁₅H₁₉- Cp* = 1,2,3,4,5-pentamethylcyclopentadienyl, C₅me₅- Materials and methods All reactions were performed under standard inert gas conditions. The solvents and reagents used were cleaned and dried according to standard procedures. In the case of reagents that were used as a solution, the content was determined by means of a titration or by ICP-MS/OES. All nuclear magnetic resonance measurements were carried out on a Bruker AV II 300, Bruker AV II HD 300, DRX 400 or AV III 500 device.¹³C NMR spectra were standard¹H-broadband decoupled measured at 300 K.¹Dog¹³C NMR spectra were calibrated to the corresponding residual proton signal from the solvent as an internal standard:¹H: DMSO[i.e₆]: 2.50ppm;¹³C: DMSO[i.e₆]: 39.52ppm. Chemical shifts are reported in ppm and are referenced to the δ scale. All signals are given the following abbreviations according to their splitting pattern: s (singlet), d (doublet), t (triplet), q (quartet), sept (septet), m (multiplet), br (broad signal). The measurements of infrared spectra in substance were usually carried out on a Bruker Alpha ATR-IR spectrometer. The absorption bands are given in wave numbers (cm⁻¹) and the intensity is described with the following abbreviations: w (weak), m (medium), st (strong), vst (very strong), br (broad). The spectra were always normalized to the band with the highest intensity. High-resolution LIFDI mass spectra were obtained using an AccuTOF-GCv-TOF mass spectrometer (JEOL). The elemental analyzes were carried out on a Vario-Micro-Cube combustion device from Elementar. The samples were prepared in a glove box flooded with nitrogen by weighing the substance into tin crucibles, which were cold-sealed and stored in a protective gas atmosphere until the measurement. The elements hydrogen, carbon and nitrogen were determined via a combustion analysis, with the information always being given in percent by mass. Data collection for crystal structure analysis was performed on a Stoe Stadivari diffractometer or a Bruker D8 Quest diffractometer by the Department of Chemistry, University of Marburg. After the solution (SHELXT) and refinement process (SHELXL 2017/1), the data was validated using Plato. The molecular structures were graphically represented with Diamond 4. Example 1: Representation of Li(GuaH) Method A. Guajazulene (5.00 g, 25.0 mmol, 1.00 eq.) and lithium triethylborohydride (1.7 M in THF) (15 mL, 25.5 mmol, 1.02 eq.) were placed in a with Argon gas flushed flask and the solvent was removed in vacuo. After adding Et₂O (150 mL), the reaction mixture was warmed to 40°C and stirred at this temperature for three days. The disappearance of the blue color indicated the completion of the reaction. The precipitated colorless solid was collected by filtration, washed with Et₂O (3 x 15 mL) and pentane (3 x 15 mL) and dried in vacuo. Li(GuaH) was obtained in about 60% yield. Method B. Guajazulene (5.00 g, 25.0 mmol, 1.00 eq.) and LiAlH₄ (950 mg, 25.0 mmol, 1.00 eq.) was placed in an argon-flushed flask and suspended in THF (150 mL). The reaction mixture was heated to 60°C and stirred at this temperature for 24 h. The disappearance of the blue color indicated the completion of the reaction. Aluminum hydride was prepared by adding 1,4-diazabicyclo[2.2.2]octane (DABCO^®) intercepted. The precipitated solid was removed by filtration and the solvent removed in vacuo. Et₂O (150 mL) was added to the residue and the undissolved colorless greyish solid was isolated by filtration, washed with Et₂O (3 x 15 mL) and pentane (3 x 15 mL) and dried in vacuo. Li(GuaH) was obtained in about 60% yield. Method C. Guajazulene (5.00 g, 25.0 mmol, 1.00 eq.), LiH (2.00 g, 250 mmol, ~10 eq.) and LiAlH₄ (48 mg, 1.26 mmol, 0.05 eq., 5 mol%) was placed in an argon-flushed flask and suspended in THF (150 mL). The reaction mixture was heated to 60°C and stirred at this temperature for 7 days. The disappearance of the blue color indicated the completion of the reaction. Excess lithium hydride was removed by filtration and the solvent removed in vacuo. Et₂O (150 mL) was added to the residue and the undissolved colorless greyish solid was isolated by filtration, washed with Et₂O (3 x 15 mL) and pentane (3 x 15 mL) and dried in vacuo. Li(GuaH) was obtained in about 60% yield.¹H NMR (300.1 MHz, [D₆]DMSO): δ_H = 5.37 (q,⁴J_HH= 2.91Hz, 2H), 5.30 (d,³J_HH= 6.87Hz, 1H), 4.87 (d,³J_HH= 6.41 Hz, 1H), 2.77 (s, 2H), 2.32 (sept,³J_HH= 6.41Hz, 1H), 2.01(s), 1.96(s), 1.01(d,³J_HH= 6.85Hz, 6H)ppm;¹³13C NMR (75.5MHz, [D₆]DMSO): δ_C = 136.7 (s, 1C), 135.4 (s, 1C), 121.9 (s, 1C), 118.8 (s, 1C), 115.0 (s, 1C), 108.5 ( s, 1C), 106.9 (s, 1C), 106.7 (s, 1C), 100.3 (s, 1C), 36.0 (s, 1C), 29.1 (s, 1C), 24.2 (s, 1C), 22.4 (s, 2C), 13.8 (s, 1C) ppm.Note: The compound Li(GuaH) can also be obtained by reacting guaiazulene with lithium tri-sec.- butylborohydride (L-Selectride^®solution, 1.0 M in THF). The compounds Na(GuaH) and K(GuaH) can be obtained by reacting guaiazulene with sodium triethylborohydride (e.g. 1.0 M in THF), sodium tri-sec.butylborohydride solution (N-Selectride^®solution, 1.0M in THF), potassium triethylborohydride (e.g. 1.0M in THF) or potassium tri-sec-butylborohydride (K-Selectride^®solution, 1.0M in THF). An isolatable solid was obtained by adding the corresponding crown ether, where Na([15]-crown-5)(GuaH) and K([18]-crown-6)(GuaH) are formed. Yellow needles of K([18]-crown-6)(GuaH), suitable for crystal structure analysis, were obtained from a saturated pentane-layered THF solution at -20 °C. Example 2: Representation of Fe(GuaH)₂ Li(GuaH) (500 mg, 2.42 mmol, 2.0 eq.) and FeCl₂ (154 mg, 1.21 mmol, 1.0 eq.) was suspended in diethyl ether (40 mL) and the suspension was stirred at room temperature for 20 h. The solvent was removed in vacuo. The residue was taken up in pentane and the inorganic salts separated off by filtration. The residual red oil was purified by column chromatography (Al₂O₃, CH₂class₂) cleaned. By recrystallizing the isolated product from ethyl acetate or methanol at -20°C overnight, the rac diastereomer (main product) was obtained as a red solid and isolated by filtration (72%).¹H NMR (300.1 MHz, CDCl₃): δ_H = 5.99 (d,³J_HH = 6.52Hz, 2H), 5.57 (d,³J_HH = 6.57Hz, 2H), 4.10 (d,⁴J_HH = 2.39Hz, 2H), 3.76 (d,⁴J_HH = 2.56 Hz, 2H) 3.06 (m, 4H), 2.36 (sept.,³J_HH = 6.8 Hz, 2H), 2.23 (s, 6H), 1.97 (s, -CH₃, 6H), 1.03 (m, 12H)ppm;¹³13C NMR (75.5MHz, CDCl₃): δ_C = 145.49 (s, 2C), 136.80 (s, 2C), 123.74 (s, 2C), 120.14 (s, 2C), 85.81 (s, 2C), 81.34 ( s, 2C), 81.31 (s, 2C), 71.32 (s, 2C), 66.25 (s, 2C), 36.54 (s, 2C), 27.35 (s, 2C), 23.32 (s, 2C), 21.89 (s, 2C), 21.56 (s, 2C), 11.69 (s, 2C) ppm; HR-MS (EI(+)): m/z [FeC₃₀H₃₈] found: 454.1879 [M], calculated: 454.2177; Elemental analysis calculated (%) for C₃₀H₃₈Fe (454.48 g/mol): C, 79.28; H, 8.43; Found: C, 79.12, H, 8.32; IR (KBr pellet): = 2957 (s), 2898 (m), 2866 (m), 1631 (fw), 1593 (w), 1448 (m), 1345 (w), 1310 (w), 1275 (w), 1194 (w) , 1181 (f), 1094 (m), 1078 (s), 1042 (f), 1026 (f), 987 (f), 952 (f), 863 (f), 841 (s), 815 (s) , 803 (vs), 768 (vs), 694 (m), 590 (s), 551 (m), 538 (s), 511 (vw), 489 (m), 478 (f), 452 (vs) , 445 (s), 423 (w) cm^-1. Example 3: Representation of Ru(GuaH)₂ Li(GuaH) (500 mg, 2.42 mmol, 2.0 eq.) and Ru(tht)₄class₂ (636 mg, 1.21 mmol, 1.0 eq.) or Ru(dmso)₄class₂ (586 mg, 1.21 mmol, 1.0 eq) were suspended in THF (40 mL), and the Suspension was stirred at room temperature for 20 h. The solvent was removed in vacuo. The residue was taken up in pentane and the precipitated inorganic salts were removed by filtration. The solvent was removed in vacuo and the remaining crude product was purified by column chromatography (Al₂O₃, CH₂class₂) cleaned. By recrystallizing the isolated product from ethyl acetate or methanol at -20°C overnight, the rac diastereomer (major product) was obtained as a colorless solid and isolated by filtration (62%).¹H NMR (300.1 MHz, CDCl₃): δ_H = 5.94 (d,³J_HH = 5.9Hz, 2H), 5.61 (d,³J_HH = 5.8Hz, 2H), 4.49 (d,⁴J_HH = 2.2Hz, 2H), 4.31 (d,⁴J_HH = 2.1Hz, 2H), 2.92 (d,²J_HH = 14.3Hz, 2H), 2.83 (d,²J_HH = 14.4Hz, 2H), 2.39 (sept,³J_HH = 6.7Hz, 2H), 2.06 (s, 6H), 1.88 (s, 6H), 1.05 (dd,³J_HH = 6.8Hz,⁴J_HH = 1.8Hz, 12H)ppm;¹³13C NMR (75.5MHz, CDCl₃): δ_C = 146.52 (s, 2C), 135.82 (s, 2C), 122.95 (s, 2C), 120.33 (s, 2C), 90.47 (s, 2C), 86.15 ( s, 2C), 84.29 (s, 2C), 73.82 (s, 2C), 68.14 (s, 2C), 36.50 (s, 2C), 27.23 (s, 2C), 23.24 (s, 2C), 21.94 (s, 2C), 21.64 (s, 2C), 12.06 (s, 2C) ppm; HR-MS (EI(+)): m/z [RuC₃₀H₃₈] found: 500.1545 [M], calculated: 500.1871; Elemental analysis calculated (%) for C₃₀H₃₈Ru (499.71 g/mol): C, 72.11; H, 8.08; N,7.67; Found: C, 71.98, H, 7.59; IR (KBr pellet): v^ = 2995 (w), 2958 (s), 2895 (m), 2965 (m), 1631 (w), 1598 (w), 1481 (w), 1461 (s), 1447 (s), 1366 (m), 1343 (f), 1310 (f), 1278 (f), 1193 (f), 1180 (f), 1159 (f), 1140 (f), 1107 (f), 1094 (f), 1077 (f), 1043 (m), 1026 (s), 953 (m), 891 (f), 860 (f), 841 (f), 827 (s), 815 (vs), 803 (s), 761 (f), 694 (m), 677 (f), 657 (f), 588 (m), 549 (f), 535 (m), 466 (f), 428 (s), 411 (w) cm^-1. Example 4: Preparation of Ru(Cp*)(GuaH) Li(GuaH) (200 mg, 0.97 mmol, 1.0 eq.) and [Ru(Cp*)Cl]₄ (264 mg, 0.24 mmol, 0.25 eq.) were stirred in THF (20 mL) at room temperature for 20 h. The solvent was removed in vacuo. The residue was taken up in dichloromethane and the inorganic salts which had precipitated were removed by filtration. The solvent was removed in vacuo and the remaining crude product was purified by column chromatography (Al₂O₃, CH₂class₂) cleaned. The faction that has a yellow Gang caused contained the desired product. Ru(Cp*)(GuaH) was isolated as a brown oil after removing the solvent in vacuo.¹H NMR (300.1MHz, C₆D₆): δ_H = 6.05 (d, J = 6.8Hz, 1H), 5.74 (d, J = 6.2Hz, 1H), 4.21 (d, J = 2.3Hz, 1H), 3.98 (d, J=2.3Hz, 1H), 2.86 (d, J=4.4Hz, 1H), 2.38 (m, J=5.6Hz, 1H), 1.79 (s , 1H), 1.78 (s, 1H), 1.07 (s, 1H), 1.05 (s, 1H) ppm; HR-MS (FD(+)): m/z [RuC₂₅H₃₄] found: 436.1721 [M], calculated: 436.1637. Example 5: Preparation of [Ru(p-cymene)(GuaH)]PF₆ The starting material [Ru(MeCN)₂(p-cymene)Cl]PF₆ was prepared according to the following literature protocols: F.B. McCormick, D.D. Cox, W.B. Gleason, Organometallics 1993, 12, 610-612; S.B. Jensen, S.J. Rodger, M.D. Spicer, J. Organomet. Chem. 1998, 556, 151-158; L. Biancalana et al., New J. Chem.2018, 42, 17574 – 17586. Li(GuaH) (200 mg, 0.97 mmol, 1.0 eq.) and [Ru(MeCN)₂(p-cymene)Cl]PF₆ (353 mg, 0.97 mmol, 1.0 eq.) generated from [Ru(p-cymene)RuCl₂]₂, were stirred in THF (20 mL) for 20 h at room temperature. The solvent was removed in vacuo and the residue taken up in dichloromethane to precipitate the inorganic salts and separate them by filtration. The solvent was removed and the crude product taken up in acetonitrile. The concentrated solution was layered with diethyl ether and stored at 0°C overnight. The product precipitated as a colorless solid and was isolated by filtration (69%).¹H NMR (300.1 MHz, DMSO-d₆): δ_H = 6.25 (d,³J_HH = 6.1Hz, 1H), 6.21 (d,³J_HH = 6.2Hz, 1H), 6.15 (d,³J_HH = 6.1Hz, 1H), 6.09 (d,³J_HH = 6.1Hz, 1H), 6.03 (d,³J_HH = 6.0Hz, 1H), 5.74 (d,³J_HH = 6.0Hz, 1H), 5.40 (d,⁴J_HH = 2.3Hz, 1H), 5.25 (d,⁴J_HH = 2.2Hz, 1H), 3.14 (d,²J_HH = 14.4Hz, 1H), 2.69 (sept,³J_HH = 6.9Hz, 1H), 2.62 (d,²J_HH = 15.0 Hz, 1H), 2.42 (sept,³J_HH = 6.7 Hz, 1H), 2.14 (s, 1H), 2.05 (s, 1H), 1.21 (d,³J_HH = 4.7Hz, 3H), 1.19 (d,³J_HH = 4.7Hz, 6H), 1.02 (t,³J_HH = 6.0Hz, 6H)ppm;¹³C-NMR (75.5 MHz, DMSO-d₆): δ_C = 147.35 (s, 1C), 130.53 (s, 1C), 128.96 (s, 1C), 120.96 (s, 1C), 111.30 (s, 1C), 101.19 (s, 1C) , 99.83 (s, 1C), 95.49 (s, 1C), 95.20 (s, 1C), 88.08 (s, 1C), 87.79 (s, 1C), 84.98 ( s, 1C), 84.87 (s, 1C), 80.62 (s, 1C), 75.24 (s, 1C), 36.07 (s, 1C), 31.49 (s, 1C), 26.04 (s, 1C), 23.58 (s, 1C), 23.20 (s, 1C), 22.77 (s, 1C), 21.87 (s, 1C), 21.68 (s , 1C), 18.06 (s, 1C), 12.21 (s, 1C) ppm; HR-MS (FD(+)): m/z [RuC₂₅H₃₃ ⁺] found: 435.1619 [M], calculated: 435.1553; Elemental analysis calculated (%) for C₂₅H₃₃f₆PRu (579.57 g/mol): C, 51.81; H, 5.74; Found: C, 51.72, H, 5.63; IR (KBr pellet): = 2968 (f), 1478 (f), 1447 (f), 1390 (f), 1059 (fw), 908 (f), 884 (m), 834 (vs), 696 (fw), 679 (fw) , 590 (f), 557 (s), 523 (vw), 449 (f), 421 (m) cm^-1. Example 6: Representation of Co(GuaH)₂ A suspension of Li(GuaH) (500 mg, 2.42 mmol, 2.0 eq.) and CoCl₂ (157 mg, 1.21 mmol, 1.0 eq.) were stirred in diethyl ether (40 mL) at room temperature for 4 h. A green-blue solution was obtained. The inorganic salts were separated by filtration. Co(GuaH)₂ was isolated as a green-blue oil. Example 7: Preparation of [Co(GuaH)₂]PF₆ For the synthesis of [Co(GuaH)₂]PF₆ a method was developed which is based on that of Vanicek et al. (Vanicek, S.; Kopacka, H.; Wurst, K.; Müller, T.; Schottenberger, H.; Bildstein, B., Organometallics 2014, 33, 1152-1156) and Bockman and Kochi (Bockman, T.M.; Kochi , J.K., J. Am. Chem. Soc.1989, 111, 4669-4683): A suspension of Li(GuaH) (500 mg, 2.42 mmol, 2.0 eq.) and CoCl₂ (157 mg, 1.21 mmol, 1.0 eq.) were stirred in diethyl ether (40 mL) at room temperature for 4 h. A green-blue solution was obtained. The inorganic salts were separated by filtration. Hot water (50 mL) was added to the filtrate and the reaction mixture was stirred for 18 h. After separating a brown solid, a yellow aqueous solution containing the product was obtained. the brown one Solid was washed several times with water. The combined aqueous solutions were washed twice with diethyl ether, decolorized with activated charcoal. The aqueous solution was reduced to a minimum volume (10 mL) on a rotary evaporator. An aqueous solution of KPF₆ (334 mg in 20 mL H₂O, 1.81 mmol, 1.5 eq.) was added and crystallization was facilitated by cooling in an ice bath. The yellow crude product was separated by filtration, washed thoroughly, once with ice water and twice with diethyl ether, and dried in vacuo. After recrystallization from acetonitrile layered with ethyl acetate, [Co(GuaH)₂]PF₆ separated by filtration and dried in vacuo (60%).¹H NMR (300.1 MHz, CDCl₃): δ_H = 6.47 (d,³J_HH = 6.5Hz, 2H), 5.77 (d,³J_HH = 6.5 Hz, 2H), 5.45 (br s, 2H), 5.36 (br s, 2H), 3.08 (d,²J_HH= 14.1Hz, 2H), 2.78 (d,²J_HH= 14.1 Hz, 2H), 2.44 (sept.,³J_HH = 6.1 Hz, 2H), 2.24 (s, 6H), 1.96 (s, 6H), 1.06 (m, 12H) ppm;¹³C NMR (75.5 MHz, CDCl₃): δ_C = 145.37 (s, 2C), 133.08 (s, 2C), 128.36 (s, 2C), 121.31 (s, 2C), 102.63 (s, 2C), 96.96 ( s, 2C), 94.78 (s, 2C), 83.27 (s, 2C), 77.81 (s, 2C), 36.55 (s, 2C), 26.05 (s, 2C), 23.16 (s, 2C), 21.70 (s, 2C), 21.43 (s, 2C), 10.64 (s, 2C) ppm; HR-MS (FD(+)): m/z [CoC₃₀H₃₈ ⁺] found: 457.23157, calculated: 457.23055; Elemental analysis calculated (%) for CoC₃₀H₃₈PF₆ (602.53 g/mol): C, 59.80; H, 6.36; Found: C, 59.67, H, 6.24; IR (KBr pellet): = 2964 (f), 1465 (f), 1386 (f), 1363 (f), 1285 (f), 1187 (fw), 1084 (fw), 1043 (fw), 958 (fw), 922 (fw) , 876 (m), 832 (vs), 699 (vw), 614 (w), 594 (m), 457 (w), 422 (w) cm^-1. Note: The representation of [Co(GuaH)₂]PF₆ analogously starting from isolated Co(GuaH)₂ be performed. Example 8: Preparation of Rh(nbd)(GuaH) Li(GuaH) (200 mg, 0.97 mmol, 1.0 eq.) and [Rh(nbd)Cl]₂ (224 mg, 0.48 mmol, 0.5 eq.) was stirred in THF (20 mL) for 20 h at room temperature. The solvent was Removed vacuum and the residue taken up in dichloromethane, diethyl ether or pentane to precipitate the inorganic salts and separate by filtration. The solvent was removed and the oily product stored in the refrigerator for a few days. Afterwards, Rh(nbd)(GuaH) was present as a yellow solid (quantitative yield).¹H NMR (300.1 MHz, DMSO-d₆): δ_H = 5.80 (d,³J_HH = 6.3Hz, 1H), 5.60 (d,³J_HH = 6.2Hz, 1H), 5.29 (d,⁴J_HH = 2.5Hz, 1H), 4.83 (d,⁴J_HH = 2.7 Hz, 1H), 3.32 (m, 2H), 2.91 (m, 6H), 2.39 (sept,³J_HH = 6.1 Hz, 1H), 1.99 (s, 3H), 1.84 (s, 3H), 1.03 (m, 6H), 0.84 (m, 2H) ppm;¹³C-NMR (126 MHz, DMSO-d₆): δ_C = 146.80 (s, 1C), 144.09 (s, 1C), 132.97 (s, 1C), 129.54 (s, 1C), 121.25 (s, 1C), 119.88 ( s, 1C), 112.13 (s, 1C), 103.97 (d,¹J_RhC = 4.5Hz, 1C), 99.92 (d,¹J_RhC = 4.1Hz, 1C), 95.40 (d,¹J_RhC = 4.3Hz, 1C), 85.18 (d,¹J_RhC = 4.6Hz, 1C), 77.36 (d,¹J_RhC = 4.6Hz, 1C), 56.10 (d,¹J_RhC = 6.9Hz, 1C), 46.40 (d,¹J_RhC = 2.4Hz, 1C), 35.75 (s, 1C), 32.40 (d,¹J_RhC = 10.3Hz, 1C), 31.89 (d,¹J_RhC = 10.2 Hz, 1C), 26.34 (s, 1C), 23.37 (s, 1C), 21.73 (s, 1C), 21.63 (s, 1C), 11.50 (s , 1C) ppm; HR-MS (FD(+)): m/z [RhC₂₂H₂₇] found: 394.11539 [M], calculated: 394.11678; Elemental analysis calculated (%) for RhC₂₂H₂₇ (394.36 g/mol): C, 67.00; H, 6.90; Found: C, 66.87, H, 6.86; IR (KBr pellet): = 3041(w), 3027(w), 2991(m), 2955(m), 2923(s), 2886(m), 2860(m), 2842(m), 1627( f), 1588 (m), 1456 (m), 1444 (m), 1435 (m), 1407 (f), 1370 (m), 1295 (m), 1276 (f), 1261 (f), 1224 ( f), 1196 (f), 1172 (f), 1158 (f), 1101 (f), 1086 (f), 1051 (f), 1044 (f), 1028 (m), 1019 (m), 992 ( f), 958 (f), 923 (f), 910 (f), 890 (f), 857 (f), 837 (s), 810 (vs), 792 (s), 779 (s), 764 ( m), 757 (m), 691 (f), 660 (f), 619 (f), 587 (f), 556 (f), 531 (f), 507 (f), 494 (f), 472 ( w), 440 (w) cm^-1. Example 9: Preparation of Rh(cod)(GuaH) Li(GuaH) (200 mg, 0.97 mmol, 1.0 eq.) and [Rh(cod)Cl]₂ (239 mg, 0.48 mmol, 0.5 eq.) was stirred in THF (20 mL) for 20 h at room temperature. The solvent was removed in vacuo and the residue taken up in dichloromethane, diethyl ether or pentane in order to precipitate the inorganic salts and separate them off by filtration. The solvent was removed and the oily product stored in the refrigerator for a few days. Afterwards, Rh(nbd)(GuaH) was present as a yellow solid (quantitative yield).¹H NMR (300.1 MHz, DMSO-d₆): δ_H = 5.99 (d,³J_HH = 5.8Hz, 1H), 5.77 (d,³J_HH= 6.3Hz, 1H), 5.08 (d,⁴J_HH= 2.6Hz, 1H), 4.70 (d,⁴J_HH= 2.7 Hz, 1H), 3.69 (m, 2H), 3.63 (m, 2H), 2.85 (d,²J_HH= 14.1Hz, 1H), 2.71 (d,²J_HH= 14.1 Hz, 1H), 2.34 (sept,³J_HH=6.7 Hz, 1H), 2.24 (m, 4H), 2.10 (s, 3H), 2.00 (m, 4H), 1.76 (s, 3H), 1.03 (dd ,³J_HH= 6.8Hz,⁴J_HH= 0.6Hz, 6H)ppm;¹³C-NMR (75.5 MHz, DMSO-d₆): δ_C = 143.98 (s, 1C), 132.98 (s, 1C), 122.55 (s, 1C), 120.89 (s, 1C), 106.74 (d,¹J_RhC = 3.9Hz, 1C), 100.76 (d,¹J_RhC = 3.2Hz, 1C), 97.40 (d,¹J_RhC = 3.7Hz, 1C), 87.54 (d,¹J_RhC = 4.1Hz, 1C), 79.86 (d,¹J_RhC = 4.2Hz, 1C), 68.14 (d,¹J_RhC = 14.0Hz, 2C), 67.88 (d,¹J_RhC = 14.1 Hz, 2C), 36.83 (s, 1C), 33.15 (s, 2C), 32.73 (s, 2C), 26.56 (s, 1C), 23.56 (s , 1C), 22.07 (s, 1C), 21.99 (s, 1C), 11.41 (s, 1C) ppm; HR-MS (FD(+)): m/z [RhC₂₃H₃₁] found: 410.1484 [M], calculated: 410.1408; Elemental analysis calculated (%) for RhC₂₃H₃₁ (410.41 g/mol): C, 67.31; H, 7.61; Found: C 67.12, H 7.60; IR (KBr pellet): = 2996 (w), 2982 (m), 2962 (s), 2952 (s), 2932 (s), 2910 (s), 2889 (s), 2862 (s), 2820 (s), 1587 (m) , 1444 (s), 1405 (m), 1380 (m), 1371 (m), 1358 (m), 1320 (m), 1294 (m), 1279 (w), 1261 (w), 1235 (w) , 1201 (m), 1179 (m), 1153 (m), 1080 (m), 1045 (m), 1026 (m) 992 (m), 955 (m), 884 (w), 868 (s), 841 (s), 813 (vs), 791 (s), 776 (m), 762 (m), 693 (f), 678 (f), 580 (f), 537 (f), 485 (f), 469 (w), 437 (w) cm^-1. Example 10: Representation of [Rh(Cp*)(GuaH)]PF₆ Li(GuaH) (200 mg, 0.97 mmol, 1.0 eq,) and [RhCp*Cl₂]₂ (300 mg, 0.48 mmol, 0.5 eq) was stirred in THF (20 mL) for 20 h at room temperature. After that, NH₄PF₆ added and the reaction mixture stirred for a further 2 h. The solvent was removed in vacuo and the residue taken up in dichloromethane to give NH⁴To precipitate Cl and then separate by filtration. The solvent of the filtrate was removed in vacuo. The resulting yellow product was obtained in good yield (72%) after washing with pentane and diethyl ether. [Rh(Cp*)(GuaH)]PF₆ was recrystallized from a concentrated solution in dichloromethane layered with pentane and recrystallized in Preserved in the form of yellow crystalline blocks. These were separated by filtration and dried in vacuo.¹H NMR (300.1 MHz, DMSO-d₆): δ_H = 6.34 (d,³J_HH = 6.3Hz, 1H), 5.76 (d,³J_HH = 6.2Hz, 1H), 5.68 (d,⁴J_HH = 2.4Hz, 1H), 5.46 (d,⁴J_HH = 2.0Hz, 1H), 3.17 (d,²J_HH = 14.4Hz, 1H), 2.44 (sept,³J_HH = 7.0Hz, 1H), 2.40 (d,²J_HH = 13.8 Hz, 2H), 2.03 (s, 3H), 1.97 (s, 3H), 1.94 (s, 15H), 1.03 (t,³J_HH = 6.7Hz, 6H)ppm;¹³C-NMR (75.5 MHz, DMSO-d₆): δ_C = 145.71 (s, 1C), 129.49 (s, 1C), 127.89 (s, 1C), 120.35 (s, 1C), 105.62 (d,¹J_RhC = 7.0Hz, 1C), 99.63 (d,¹J_RhC = 7.8Hz, 5C), 98.77 (d,¹J_RhC = 6.9Hz, 1C), 96.07 (d,¹J_RhC = 6.5Hz, 1C), 88.10 (d,¹J_RhC = 7.5Hz, 1C), 81.81 (d,¹J_RhC = 7.6 Hz, 1C), 35.59 (s, 1C), 24.08 (s, 1C), 21.36 (s, 1C), 21.19 (s, 1C), 21.10 (s , 1C), 9.49 (s, 1C), 8.99 (s, 5C), ppm; HR-MS (FD(+)): m/z [RhC₂₅H₃₄] found: 437.17261 [M], calculated: 437.17155; Elemental analysis calculated (%) for RhC₂₅H₃₄PF₆ (582.42 g/mol): C, 51.56; H, 5.88; Found: C, 51.52, H, 5.84; IR (KBr pellet): = 2960 (f), 1464 (f), 1385 (f), 1031 (fw), 874 (f), 836 (vs), 764 (f), 739 (f), 699 (f), 611 (f) , 591 (w), 557 (s), 506 (w), 492 (w), 462 (w), 438 (w) cm^-1. Example 11: Representation of PtMe₃(GuaH)Li(GuaH) (500 mg, 2.42 mmol, 1.0 eq,) and [PtMe₃I]₄ (890 mg, 0.61 mmol, 0.25 eq) was suspended in diethyl ether (40 mL) and the suspension was stirred for 30 min at 40 °C, then for 4 h at room temperature. A yellow solution was obtained. The solvent was removed in vacuo. It is very important to remove the solvent completely, otherwise lithium iodide will remain in solution and contamination of the product cannot be ruled out. The oily residue is taken up in pentane (40 mL), inorganic salts and any unreacted starting materials are removed by filtration. The solvent of the filtrate is removed in vacuo and PtMe₃(GuaH) is obtained as a yellow oil in good yield (82%). The product can be further purified by column chromatography (silica, hexane). ¹H NMR (300.1 MHz, DMSO-d₆): δ_H = 6.00 (d,³J_HH = 6.3Hz, 1H), 5.73 (d,⁴J_HH = 2.8Hz, 1H), 5.56 (d,³J = 6.2Hz, 1H,), 5.38 (d,³J = 3.0Hz, 1H), 2.98 (d,²J_HH = 14.3Hz, 1H), 2.53 (d, 1H,²J_HH= 14.3 Hz, 1H), 2.40 (sept,,³J_HH = 6.8Hz, 1H), 1.94 (s, 3H), 1.90 (s, 3H), 1.03 (d,³J_HH= 6.8Hz, 3H), 1.01 (d,³J_HH= 6.8 Hz, 3H), 0.66 (s, J_195Pt-1H= 80.8Hz, 9H, PtMe₃)ppm;¹³C-NMR (75.5 MHz, DMSO-d₆): δ_C = 144.79 (s, 1C), 130.01 (s, 1C), 123.75 (s, 1C), 119.74 (s, 1C), 110.77 (s, 1C), 106.83 ( s, 1C), 106.18 (s, 1C), 91.60 (s, 1C), 90.04 (s, 1C), 35.81 (s, 1C), 24.10 (s, 1C), 22.06 (s, 1C), 21.56 (s, 1C), 21.26 (s, 1C), 9.54 (s, 1C), -14.76 (PtMe₃); HR-MS (FD(+)): m/z [PtC₁₈H₂₈] found: 439.18065 [M], calculated: 439.18387; IR (KBr pellet): = 2957 (vs), 2891 (vs), 2809 (m), 1634 (vw), 1598 (w), 1461 (m), 1431 (m), 1376 (m), 1359 (s), 1314 (s) , 1285 (m), 1251 (f), 1210 (f), 1192 (s), 1095 (f), 1081 (f), 1028 (s), 998 (s), 955 (s), 886 (vs) , 839 (m), 812 (f), 786 (f), 759 (f), 693 (f), 673 (f), 653 (f), 583 (f), 555 (s), 533 (m) , 504 (w), 469 (w), 425 (m) cm^-1. Example 12: Representation of [Pt(cod)(GuaH)]PF₆ Li(GuaH) (200 mg, 0.97 mmol, 1.0 eq,) and [Pt(cod)Cl₂] (363 mg, 0.97 mmol, 1.0 eq,) was stirred in THF (20 mL) for 24 h at room temperature. The reaction mixture changed color to orange during the reaction time. NH₄PF₆ was added. After further stirring for 2 h, the solvent was removed in vacuo, acetonitrile (20 mL) added and NH₄Cl separated by filtration. The solvent of the filtrate was removed in vacuo. [Pt(cod)(GuaH)]PF₆ was obtained as an orange solid in good yield (78%). [Pt(cod)(GuaH)]PF₆ can be recrystallized from THF overlaid with pentane at -20°C.¹H NMR (300.1 MHz, DMSO-d₆): δ_H = 6.31 (d,³J_HH = 6.3Hz, 1H), 6.30-6.14 (m, 2H), 5.83 (d,³J_HH = 6.4Hz, 1H), 5.28-4.95 (m, 4H), 3.24 (d,²J_HH = 14.6Hz, 1H), 2.78 (d,²J_HH = 14.6 Hz, 1H), 2.42 (m, 7H), 2.18 (s, 3H), 2.11 (s, 3H), 1.09 (d,⁴J_HH = 0.9Hz, 3H), 1.07 (d,⁴J_HH = 0.9Hz, 3H)ppm;¹³C-NMR (75.5 MHz, DMSO-d₆): δ_C = 146.36 (s, 1C), 128.54 (s, 1C), 127.40 (s, 1C), 120.63 (s, 1C), 115.07 (s, 1C), 111.05 ( s, 1C), 109.92 (s, 1C), 93.42 (s, 1C), 87.76 (s, 1C), 82.72 (s, 2C), 81.73 (s, 2C), 35.72 (s, 1C), 31.90 (s, 1C), 31.56 (s, 2C), 24.92 (s, 1C), 22.19 (s, 1C), 21.39 (s, 1C), 21.37 (s, 1C), 10.14 (s, 1C) ppm; HR-MS (FD(+)): m/z [PtC₂₃H₃₁] found: 501.20506 [M], calculated: 501.20524; Elemental analysis calculated (%) for PtC₂₃H₃₁PF₆ (647.55 g/mol): C, 42.66; H, 4.83; Found: C, 42.55, H, 4.78; IR (KBr pellet): v^{^} = 2964 (f), 1435 (f), 1386 (f), 1363 (f), 1285 (f), 1032 (fw), 874 (f), 826 (vs), 697 (f), 556 (s) , 471 (fw) cm^-1. Example 13: Preparation of Cu(PPh₃)(GuaH)Li(GuaH) (200 mg, 0.97 mmol, 1.0 eq,) and [Cu(PPh₃)Cl]₄ (350 mg, 0.24 mmol, 0.25 eq) was stirred in THF at -78° C. for about 3 h. The reaction mixture was slowly warmed to room temperature with stirring overnight. It changed its color to green-yellow. The solvent was removed in vacuo and diethyl ether was added to precipitate inorganic salts and separate them by filtration. The solvent of the filtrate was removed in vacuo. The residue was washed with pentane and Cu(PPh₃)(GuaH) a pale yellow solid was obtained in almost quantitative yield.¹H NMR (300.1MHz, C₆D₆): δ_H = 7.35 (m, 6H), 6.99 (m, 9H), 6.22 (d,³J_HH = 3.0Hz, 1H), 6.17 (d,³J_HH = 3.0Hz, 1H), 6.06 (dd,³J_HH = 6.3Hz,⁴J_HH = 2.4Hz, 1H), 5.85 (d,³J_HH = 6.2Hz, 1H), 3.33 (d,²J_HH = 15.1Hz, 1H), 3.23 (d,²J_HH = 15.1 Hz, 1H), 2.45 (s, 3H), 2.38 (s, 3H), 2.33 (sept,³J_HH= 6.8Hz, 1H), 0.95 (d,³J_HH = 6.8Hz, 3H), 0.90 (d,³J_HH = 6.8Hz, 3H)ppm;¹³C NMR (75.5MHz, C₆D₆): δ_C = 145.04 (s, 1C), 135.27 (s, 3C), 134.07 (d,²JPC = 15.8Hz, 6C), 133.37 (d,¹J_{personal computer} = 43.5 Hz, 3C), 130.35 (s, 1C), 128.76 (d,³J_{personal computer} = 10.4 Hz, 6C), 120.94 (s, 1C), 118.50 (s, 1C), 116.14 (s, 1C), 115.42 (s, 1C), 103.64 (s , 1C), 94.73 (s, 1C), 89.24 (s, 1C), 37.11 (s, 1C), 28.17 (s, 1C), 24.43 (s, 1C), 22 .32 (s, 1C), 22.11 (s, 1C), 13.19 (s, 1C) ppm; HR-MS (FD(+)): m/z [C³³H³⁴CuP] found: 524.17053 [M], calculated: 524.16941; Elemental analysis calculated (%) for C₃₃H₃₄CuP (525.15 g/mol): C, 75.48; H, 6.53; Found: C, 75.34, H, 6.49; IR (KBr pellet): = 2963(m), 2871(f), 1632(f), 1593(f), 1464(m), 1435(m), 1385(m), 1362(m), 1315(f), 1284(f) , 1246 (f), 1199 (f), 1186 (f), 1083 (f), 1043 (f), 1029 (f), 996 (f), 958 (f), 872 (m), 798 (vs), 696 (m), 592 (w), 548 (m), 499 (w), 455 (w), 420 (w) cm^-1. Example 14: Preparation of Zn(Mes)(GuaH) Li(GuaH) (200 mg, 0.97 mmol, 1.0 eq,) and ZnCl₂ (66 mg, 0.48 mmol, 0.5 eq) was suspended in THF (20 mL) and stirred at room temperature for 24 h. A yellow solution was obtained. The inorganic salts were separated by filtration. To the filtrate containing the desired intermediate Zn(GuaH)₂ ZnMes2 (146 mg, 0.48 mmol, 0.5 eq,) was added. The reaction mixture was stirred for 3 h before the solvent was removed in vacuo. The residue was taken up in pentane and the solution was stored at -80°C overnight to remove any unreacted Zn(GuaH)₂ and to precipitate ZnMes2. After filtration through a syringe filter, the solvent of the filtrate was removed in vacuo. Zn(Mes)(GuaH) was obtained as a yellow-orange oil in good yield (80%).¹H NMR (300.1MHz, C₆D₆): δ_H = 6.78 (s, 1H), 6.02 (q,⁴J_HH = 2.4Hz, 1H), 6.00 (d,⁴J_HH = 3.1Hz, 1H), 5.97 (d,⁴J_HH = 3.0Hz, 1H), 5.71 (d,³J_HH = 6.2Hz, 1H), 3.12 (d,²J_HH = 14.0Hz, 1H), 2.86 (d,²J_HH = 14.0 Hz, 1H), 2.27 (sept,³J_HH = 6.8 Hz, 1H), 2.20 (s, 3H), 2.17 (s, 3H), 2.16 (s, 6H), 0.91 (t,³J_HH = 6.4Hz, 6H)ppm;¹³C NMR (75.5MHz, C₆D₆): δ_C = 147.11 (s, 1C), 145.64 (s, 1C), 140.55 (s, 1C), 137.27 (s, 2C), 133.54 (s, 1C), 126.18 ( s, 2C), 122.72 (s, 1C), 122.07 (s, 1C), 120.94 (s, 1C), 119.82 (s, 1C), 110.58 (s, 1C), 101.31 (s, 1C), 93.76 (s, 1C), 36.98 (s, 1C), 28.42 (s, 1C), 27.01 (s, 2C), 23.88 (s , 1C), 22.05 (s, 1C), 22.03 (s, 1C), 21.25 (s, 1C), 12.18 (s, 1C) ppm; HR-MS (FD(+)): m/z [C₂₄H₃₀Zn] found: 382.16545 [M], calculated: 382.16390; IR (KBr pellet): = 2957(s), 2914(s), 2865(m), 2724(w), 1631(w), 1594(w), 1553(w), 1443(s), 1373(m), 1359(w) , 1335 (f), 1313 (f), 1288 (f), 1236 (f), 1193 (f), 1081 (s), 953 (m), 844 (s), 815 (s), 771 (s) , 756 (vs), 702 (m), 659 (f), 619 (f), 584 (f), 564 (f), 537 (m), 484 (f), 468 (f), 418 (f) . Example 15: Photohydrosilylation of 1-octene with pentamethylsiloxane using PtMe₃(GuaH) as a catalyst to a solution of PtMe₃(GuaH) (see example 11) in cyclohexane (25 mL; 10 ppm = 2.5 x 10^-5 mol/L) 661 mg pentamethylsiloxane (4.45 mmol) and 500 mg 1-octene (4.45 mmol) were added. The solution was irradiated with UV light while stirring for 30 min and then stirred for a further 18 h. The crude product was purified by column chromatography (hexane). Noisy¹H-NMR spectrum of the isolated product showed no impurities. yield loud¹H-NMR spectrum (before purification): quantitative; isolated yield about 80%. NMR experiments with 5 ppm Pt: Stock solution (1.78 M): 500 mg 1-octene (4.45 mmol), 661 mg pentamethylsiloxane (4.45 mmol), 2.5 mL C₆D₆ Pt complex solution (0.0889 mM = 0.0005 mol% compared to stock solution): 0.391 mg PtMe₃(GuaH), 5 mL C₆D₆ 0.25 mL stock solution and 0.25 mL Pt complex solution were filled into an NMR tube. The tube was shaken and then irradiated with UV light (Osram Ultra Vitalux, 300 W, 220 V, plant lamp) for 5 min. There were¹H-NMR spectra recorded at time 0 h and after about 0.25 h, 0.50 h, 1 h, 2 h, 4 h, 8 h, 24 h and 48 h. The invention is not limited to one of the embodiments described above, but can be modified in many ways. It can be seen that the invention is a process for the preparation of compounds according to the general formula M^AY_n(AzuH) (I) where M^A = alkali metal, Y = neutral ligand, n = 0, 1, 2, 3 or 4 and AzuH azulene (bicyclo[5.3.0]decapentaene) or an azulene derivative is, which carries an H atom and a hydride anion H- in the 4-position, 6-position or 8-position. The invention also relates to compounds obtainable by this process and a process using such compounds for preparing complexes of metals from groups 6 to 12. The invention also relates to complexes of medium transition metals (groups 6, 7 and 8) and later transition metals ( Groups 9, 10, 11 and 12) each containing at least one H-dihydroazulenyl anion (AzuH)^1- have, and the use of all the aforementioned transition metal complexes as precatalysts or catalysts or electron transfer reagents in a chemical reaction or as precursor compounds for producing a layer containing a metal M, or a metal layer consisting of the metal M, in particular on at least one surface of a substrate . In addition, the subject of the invention is a substrate obtainable by such a method, i. H. using a metal complex according to one of the formulas M(L_K)_f(AzuH)_m (III), M(L_N)(AzuH)_q (IV), [M(L_S)_G(AzuH)_v]X (V) and [M(L_T)(AzuH)_e.g]X (VI). With the method described, defined alkali metal H-dihydroazulenyl compounds of type M^AY_n(AzuH) (I) can be prepared in a simple, inexpensive, and reproducible manner with high purity and good yield. The process can also be carried out on an industrial scale. After isolation, the compounds usually do not have any impurities that can be detected by NMR spectroscopy—without laborious purification. Due to their high purity, they are suitable as starting materials for the preparation of transition metal complexes, in particular group 6, group 7, group 8, group 9, group 10, group 11 and group 12 metals. Using the process described here such metal complexes of middle and late transition metals are simple, reproducible and comparatively inexpensive and can be obtained in good (isomeric) purity and good to very good yields. They represent a relatively inexpensive and z. T. represents a particularly sustainable alternative to metal complexes containing cyclopentadienyl ligands. Specifically, in particular with regard to use as precatalysts, catalysts and electron transfer reagents in chemical reactions. In addition, they are particularly suitable as precursor compounds for the production of high-quality substrates which have at least one metal-containing layer or at least one metal layer on at least one surface. The metal or metals are selected from group 6, group 7, group 8, group 9, group 10, group 11 and group 12. All features and Advantages, including structural details, spatial arrangements and process steps, can be essential to the invention both on their own and in a wide variety of combinations.

Claims

1. A process for preparing compounds of the general formula M ^A Y _n (AzuH) (I), where - M ^A is an alkali metal, - Y is a neutral ligand which is bonded or coordinated to M ^A via at least one donor atom, where H ₂ O is excluded, - n = 0, 1, 2, 3 or 4 and - AzuH = azulene or an azulene derivative which has a hydride in the 4-position, 6-position or 8-position in addition to an H atom carries anion, where Azu = azulene according to the formula (II), or Azu = an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6, C7 and C8, a substituent R ^F carries, wherein the substituents R ^F are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 Carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R ^F can optionally form a ring, and b) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C4, C6 and C8 , carries an H atom, comprising the following steps: A. Providing i. Azulene or an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where - at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6, C7 and C8, a substituent R ^F carries, wherein the substituents R ^F are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R ^F can optionally form a ring, and - at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, an H -atom carries, and ii. at least one hydridic reducing agent Z, B. reaction of the azulene or the azulene derivative with the at least one hydridic reducing agent Z in a solvent S _P , and - when using at least one alkali metal aluminum tetrahydride M ^A AlH ₄ as a first hydridic reducing agent Z ₁ - C. Providing i. at least one second hydridic reducing agent Z ₂ selected from the group consisting of alkali metal hydrides M ^A H and/or ii. at least one electron pair donor E, wherein the electron pair donor E has at least one donor atom, with the exception of H ₂ _O , and D. optionally adding a neutral ligand Y when Y is not equal to SP and Y is not equal to E.

2. The method of claim 1, wherein at least one ^hydridic reducing agent Z is selected from the group consisting of alkali metal hydrides MA H, alkali metal boron tetrahydrides MA BH ₄ , alkali metal trialkylborohydrides MA [( ^{R C} ⁾ ₃ BH], alkali metal aluminum tetrahydrides ^MA ^AlH ₄ , alkali metal trialkylaluminum hydrides MA [(R ^D ) ₃ ^AlH ], alkali metal dihydrido bis( ^dialkoxy ) aluminates MA [AlH ₂ (OR ^E ) ₂ ], and mixtures thereof, where i. each R ^C and R ^D is independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl groups having from 1 to 10 carbon atoms wherein any two R ^C or two R ^D substituents optionally form a ring can, and ii. the radicals OR ^E are each independently a corresponding base of a glycol ether R ^E OH.

3. The method according to claim 2, wherein the glycol ethers R ^E OH are independently selected from the group consisting of monooxomethylene monoethers, monoethylene glycol monoethers, monopropylene glycol monoethers, and mixtures of their isomers, and mixtures thereof.

4. The method according to any one of the preceding claims, wherein - the solvent _SP and the neutral ligand Y and / or - the neutral ligand Y and the electron pair donor E and / or - the solvent _SP and the electron pair donor E are miscible or identical.

5. The method according to any one of the preceding claims, wherein the electron pair donor E is a base selected from the group consisting of organic, organometallic and inorganic bases, and mixtures thereof.

6. The method according to any one of the preceding claims, wherein in step A. an azulene derivative is provided, wherein at least - on the carbon atoms C4 and C6 or - on the carbon atoms C8 and C6 or - on the carbon atom C4 and/or on the carbon atom C8 of the azulene framework an H atom is provided.

7. The method according to any one of the preceding claims, wherein after the reaction in step B. or after step C. or after step D. a step is carried out which comprises isolation of M ^A Y _n (AzuH) (I): - als Suspension or solution comprising M ^A Y _n (AzuH) (I) and at least one solvent S _P , or - as a liquid or solid.

8. Solution or suspension comprising M ^A Y _n (AzuH) (I) and at least one solvent S _P obtained or obtainable by a process according to any one of the preceding claims.

9. Compounds according to the general formula M ^A Y _n (AzuH) (I), obtained or obtainable by a process according to any one of claims 1 to 7.

10. Compounds according to the general formula M ^A Y _n (AzuH) (I), where - M ^A is an alkali metal, - Y is a neutral ligand which is bonded or coordinated to M ^A via at least one donor atom, with the exception of H ₂ O is, - n = 0, 1, 2, 3 or 4 and - AzuH = azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom, where Azu = azulene according to the formula (II) or Azu = an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6, C7 and C8, carries a substituent R ^F , where the substituents R ^F are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R ^F optionally one Ring can form, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, the compounds Li(O(C ₂ H ₅ ) ₂ ) _n (AzulenH ) and Li(O(C ₂ H ₅ ) ₂ ) _n (GuaH), where - n = 0, 1 or 2, - azuleneH = azulene, which is in 4-position, 6-position or 8-position in addition to an H -atom carries a hydride anion, - GuaH = 7-iso-propyl-1,4-dimethyl-8-H-dihydroazulene are excluded.

11. Compounds according to claim 10, wherein Azu=an azulene derivative and the compound according to the general formula M ^A Y _n (AzuH) (I) is present as a pure isomer.

12. Compounds according to claim 10 or 11, wherein Azu=an azulene derivative, and wherein at least the carbon atoms C1, C4 and C7 of the azulene skeleton carry a substituent R ^F , and isomers thereof.

13. Compounds according to any one of claims 10 to 12, wherein the alkali metal M ^A is selected from the group consisting of Li, Na and K.

14. Compounds according to any one of claims 10 to 13, wherein the neutral ligand Y is a) an aprotic-polar solvent or b) a crown ether which is selected from the group consisting of macrocyclic polyethers and their aza, phospha and thia derivatives, where an inner diameter of the crown ether and an ionic radius of M ^A correspond to each other.

15. A compound according to claim 10 having the formula where M ^A is an alkali metal, in particular selected from the group Li, Na or K.

16. Process for preparing metal complexes according to the general formula M(L _K ) _f (AzuH) _m (III) or M(L _N )(AzuH) _q (IV) or [M(L _S ) _g (AzuH) _v ] X (V) or [M(L _T )(AzuH) _z ]X (VI), where M = central metal atom selected from Group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12, L _K = optional neutral sigma donor ligand or optional neutral pi- donor ligand, f = number of ligands L _K , where f = 0, 1, 2, 3, 4, 5 or 6, AzuH = azulene or an azulene derivative which is in the 4-position, 6-position or 8-position carries a hydride anion in addition to an H atom, m = number of ligands AzuH, where m = 1, 2, 3, 4, 5, 6 or 7, L _N = at least one anionic sigma donor ligand or at least an anionic pi-donor ligand, where a sum u of the negative charges of all ligands L _N is -1, -2, -3, -4, -5 or -6, q = number of ligands AzuH, where q = w ₂ – |u|, where w ₂ > |u| and w ₂ = 2, 3, 4, 5, 6 or 7, and where |u| is an absolute value of the sum of the negative charges of all ligands L _N , where |u| = 1, 2, 3, 4, 5 or 6, _LS = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands _LS , where g = 0, 1, 2, 3 , 4, 5 or 6, v = number of ligands AzuH, where v = w ₃ - 1, where w ₃ = 2, 3, 4, 5, 6 or 7, L _T = at least one anionic sigma donor Ligand or at least one anionic pi-donor ligand, where a sum h of the negative charges of all ligands L _T is -1, -2, -3, -4 or -5, z = number of ligands AzuH, where z = w ₄ - (|h| + 1), where w ₄ > (|h| + 1) and w ₄ = 3, 4, 5, 6 or 7, and where |h| is an absolute value of the sum of the negative charges of all ligands L _T , where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, where Azu = azulene according to the formula (II), or Azu=an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6 , C7 and C8, carries a substituent R ^F , wherein the substituents R ^F are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms , a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R ^F can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, using ■ a compound according to the general formula M ^A Y _n (AzuH) (I), - obtained or obtained I according to a method according to any one of claims 1 to 7, - according to claim 9 or - according to any one of claims 10 to 15 or ■ a solution or a suspension, comprising a compound according to the general formula M ^A Y _n (AzuH) (I) and at least one solvent S _P , - obtained or obtainable by a process according to any one of claims 1 to 7, or - according to claim 8, wherein - M ^A a is alkali metal, - Y is a neutral ligand which is bonded or coordinated to M ^A via at least one donor atom, with the exception of H ₂ O, - n = 0, 1, 2, 3 or 4 and - AzuH and Azu are as defined above , comprising the steps: A. Providing the compound according to the general formula M ^A Y _n (AzuH) (I) or the solution or the suspension comprising the compound according to the general formula M ^A Y _n (AzuH) (I) and that at least one solvent S _P , and B. Synthesis of the metal complex M(L _K ) _f (AzuH) _m (III) or M(L _N )(AzuH) _q (IV) or [M(L _S ) _g (AzuH) _v ]X (V) or [M(L _T )(AzuH) _z ]X (VI) using the compound of the general formula M ^A Y _n (AzuH) (I) as starting material.

17. The method according to claim 16, wherein the synthesis in step B. comprises at least one salt-metathetical reaction and/or at least one oxidation reaction.

18. The method according to claim 16 or 17, wherein M is selected from the group consisting of chromium, molybdenum, tungsten, manganese, technetium, rhenium, iron, ruthenium, osmium, cobalt, rhodium, iridium, nickel, palladium, platinum, copper, silver, gold, zinc, cadmium and mercury.

19. The method according to any one of claims 16 to 18, wherein - the ligands L _K and L _S are independently selected from the group consisting of monodentate and polydentate phosphorus donor ligands, alkenes, cyclic dienes and cyclic polyenes, and mononuclear arenes, polynuclear arenes, mononuclear heteroarenes and polynuclear heteroarenes, and derivatives thereof, and/or - the ligand L _N is a monoanionic ligand which is selected from the group consisting of anions of cyclopentadiene and its derivatives, alkyl anions, aryl anions and one Fluoride anion and/or - the ligand L _T is a monoanionic ligand which is selected from the group consisting of anions of cyclopentadiene and its derivatives and a fluoride anion, or a dianionic ligand.

20. Metal complexes according to the general formula M(L _K ) _f (AzuH) _m (III) or M(L _N )(AzuH) _q (IV) or [M(L _S ) _g (AzuH) _v ]X (V) or [M(L _T )(AzuH) _z ]X (VI), or solutions or suspensions comprising a metal complex according to the general formula M(L _K ) _f (AzuH) _m (III) or M(L _N )(AzuH) _q (IV) or [M(L _S ) _g (AzuH) _v ]X (V) or [M(L _T )(AzuH) _z ]X (VI) and at least one solvent which is miscible with the solvent S _P or is identical, where M = central metal atom selected from Group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12, L _K = optional neutral sigma donor ligand or optional neutral pi-donor ligand, f = number of ligands L _K , where f = 0, 1, 2, 3, 4, 5 or 6, AzuH = azulene or an azulene derivative located in 4-position, 6-position or 8-position carries a hydride anion in addition to an H atom, m = number of ligands AzuH, where m = 1, 2, 3, 4, 5, 6 or 7, L _N = at least one anionic sigma donor -ligand or at least one anionic pi-donor ligand, where a sum u of the negative charges of all ligands L _N is -1, -2, -3, -4, -5 or -6, q = number of ligands AzuH, where q = w ₂ - |u|, where w ₂ > |u| and w ₂ = 2, 3, 4, 5, 6 or 7, and where |u| is an absolute value of the sum of the negative charges of all ligands L _N , where |u| = 1, 2, 3, 4, 5 or 6, _LS = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands _LS , where g = 0, 1, 2, 3, 4, 5 or 6, v = number of ligands AzuH, where v = w ₃ - 1, where w ₃ = 2, 3, 4, 5, 6 or 7, L _T = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, wherein a Sum h of negative charges of all ligands L _T is -1, -2, -3, -4 or -5, z = number of ligands AzuH, where z = w ₄ - (|h| + 1), where w ₄ > (|h| + 1) and w ₄ = 3, 4, 5, 6 or 7, and where |h| is an absolute value of the sum of the negative charges of all ligands L _T , where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, where Azu = azulene according to formula (II), or Azu=an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6 , C7 and C8, carries a substituent R ^F , wherein the substituents R ^F are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms , a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R ^F can optionally form a ring, and b) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C4, C6 and C8 carries an H atom, obtained or obtainable by a process according to any one of the claims 15 to 18

21. Metal complexes according to the general formula M(L _K ) _f (AzuH) _m (III) or M(L _N )(AzuH) _q (IV) or [M(L _S ) _g (AzuH) _v ]X (V) or [M(L _T )(AzuH) _z ]X (VI) where M = central metal atom selected from Group 6, Group 7, Group 8, Group 9, Group 10, Group 11 or Group 12, LK = optional neutral sigma donor ligand or optional neutral pi donor ligand, f = number of ligands _LK where f = 0, 1, 2, 3, 4, 5 or 6, _AzuH = azulene or an azulene derivative which carries a hydride anion in the 4-position, 6-position or 8-position in addition to an H atom, m=number of ligands AzuH, where m=1, 2, 3, 4, 5, 6 or 7, L _N = at least one anionic sigma donor ligand or at least one anionic pi donor ligand, where a sum u of the negative charges of all ligands L _N is -1, -2, -3, -4, -5 or -6, q = number of ligands AzuH, where q = w ₂ - |u|, where w ₂ > |u| and w ₂ = 2, 3, 4, 5, 6 or 7, and where |u| is an absolute value of the sum of the negative charges of all ligands L _N , where |u| = 1, 2, 3, 4, 5 or 6, _LS = optional neutral sigma donor ligand or optional neutral pi donor ligand, g = number of ligands _LS , where g = 0, 1, 2, 3 , 4, 5 or 6, v = number of ligands AzuH, where v = w ₃ - 1, where w ₃ = 2, 3, 4, 5, 6 or 7, L _T = at least one anionic sigma donor Ligand or at least one anionic pi-donor ligand, where a sum h of the negative charges of all ligands L _T is -1, -2, -3, -4 or -5, z = number of ligands AzuH, where z = w ₄ - (|h| + 1), where w ₄ > (|h| + 1) and w ₄ = 3, 4, 5, 6 or 7, and where |h| is an absolute value of the sum of the negative charges of all ligands L _T , where |h| = 1, 2, 3, 4 or 5, X- = halide anion or monovalent weakly coordinating anion or monovalent non-coordinating anion, where Azu = azulene according to formula (II), or Azu=an azulene derivative which has an azulene skeleton of the formula II consisting of a five-membered ring and a seven-membered ring, where a) at least one carbon atom of the azulene skeleton selected from the group consisting of the carbon atoms C1, C2, C3, C4, C5, C6 , C7 and C8, a substituent R ^F carries, wherein the substituents R ^F are independently selected from the group consisting of primary, secondary, tertiary alkyl, alkenyl and Alkynyl radicals having 1 to 10 carbon atoms, cyclic alkyl radicals having 3 to 10 carbon atoms, a benzyl radical, a mononuclear or polynuclear arene and a mononuclear or polynuclear heteroarene, where two substituents R ^F can optionally form a ring, and b) at least one carbon atom of the azulene skeleton, selected from the group consisting of the carbon atoms C4, C6 and C8, carries an H atom, with the exception of the compound Fe(AzulenH) ₂ and Cr(AzulenH) ₂ and their isomers.

22. Metal complex according to claim 20 or 21 or solution or suspension according to claim 20, comprising a metal complex and at least one solvent which is miscible or identical to the solvent SP, wherein the metal complex is selected from the group consisting of Fe( _GuaH ) ₂ , Ru(GuaH) ₂ , Ru(Cp*)(GuaH), [Ru(p-cymene)(GuaH)]PF ₆ , Co(GuaH) ₂ , [Co(GuaH) ₂ ]PF ₆ , Rh(nbd) (GuaH), Rh(cod)(GuaH), [Rh(Cp*)(GuaH)]PF ₆ , PtMe ₃ (GuaH), [Pt(cod)(GuaH)]PF ₆ , Cu(PPh ₃ )(GuaH ), Zn(GuaH) ₂ and Zn(Mes)(GuaH).

23. Use of at least one metal complex according to any one of claims 20 to 22 or at least one solution or suspension according to claim 20 or 22, as i. Solution or suspension containing precatalyst or precatalyst in a chemical reaction and/or ii. Catalyst or catalyst-containing solution or suspension in a chemical reaction and/or iii. Electron transfer reagent or solution or suspension containing electron transfer reagent in a chemical reaction and/or IV. Solution or suspension containing precursor compound or precursor compound for producing at least one layer which contains a metal M, or at least one metal layer consisting of the metal M on at least one surface of a substrate.

24. Method for carrying out a chemical reaction using at least one metal complex according to one of claims 20 to 22 or at least one solution or suspension according to claim 20 or 22, comprising the steps: A) providing the at least one metal complex or the at least one solution or suspension , comprising a metal complex and at least one solvent which is miscible or identical to the solvent SP, and _B ) carrying out the chemical reaction using the at least one metal complex as a precatalyst, as a catalyst or as an electron transfer reagent.

25. Method of manufacture i. at least one metal layer consisting of a metal M or ii. at least one layer containing a metal M on at least one surface of a substrate using at least one metal complex according to any one of claims 20 to 22 or at least one solution or suspension according to claim 20 or 22, comprising the steps of: A) providing the at least one metal complex or the at least one solution or suspension comprising a metal complex and at least one solvent which is miscible or identical to the solvent SP, and _B ) deposition i. the at least one metal layer consisting of the metal M or ii. the at least one layer containing the metal M on the at least one surface of the substrate using the at least one metal complex as a precursor compound.

26. The method according to any one of claims 1 to 7 or solution or suspension according to claim 8 or compounds according to claim 9 or compounds according to any one of claims 10 to 15 or method according to any one of claims 16 to 19 or metal complexes or solutions or suspensions according to claim 20 or Metal complexes according to claim 21 or use according to claim 23 or method according to claim 24 or method according to claim 25, wherein Azu = Gua = 7-isopropyl-1,4-dimethylazulene and AzuH = GuaH = 7-isopropyl-1,4 -dimethyl-8-H-dihydroazulene.