EP3083497A1 - Method for the production of linear, cyclic and/or cage-type perhalogenated oligosilyl and polysilyl anions - Google Patents

Abstract

The invention relates to a method for producing linear, cyclic and/or cage-type perhalogenated oligosilyl and polysilyl anions by reacting perhalogenated monosilanes, oligosilanes or polysilanes with organo-substituted ammonium and/or phosphonium halides at temperatures ranging from -80°C to 85°C, preferably from -80°C to 60°C. The invention also relates to oligosilyl and polysilyl anions produced according to said method.

Description

 Process for the preparation of linear, cyclic and / or cage-like perhalogenated oligo- and polysilyl anions

The present invention relates to a process for the preparation of linear, cyclic and / or cage-like perhalogenated oligo- and polysilyl anions. and then prepared oligo- and polysilyl anions.

Perhalogenated oligo- and polysilane compounds form the basis for various material-oriented applications, such as the production of amorphous silicon, conducting polymers, silicon layers or even hydrogen storage media, which in turn are of great importance in many areas of industry. In the prior art, some processes for the preparation of oligo- and polysilane compounds are already known. For example, perhalogenated polysilanes can be prepared by thermal reactions at high temperatures of several 100 ° C. from tetrahalosilanes and silicon. However, mixtures of perhalogenated polysilanes with high proportions of short-chain, branched and cyclic compounds are frequently obtained in this way. In addition, the resulting mixtures are often produced by other compounds that are required for synthesis contaminated.

In DE 10 2005 024 041 A1, for example, a halosilane and silicon are reacted to produce a plasma discharge to form a halogenated polysilane, which is subsequently decomposed in a second step with heating to give silicon. Spectroscopic studies have shown that in addition to linear and branched halogenated polysilanes are obtained after the first synthesis step.

On the other hand, DE 10 2009 056 437 A1 relates to a process for the preparation of short-chain halogenated oligosilanes of the formula Si ₂ X _{11 +} 2 (n = 2-6) and of silicon subchlorides SiCl _x (x <2) by thermolytic decomposition of long-chain halogenated polysilanes. Disadvantages of this process, however, are a high energy input for the production of a thermal plasma and the elaborate workup of the resulting product mixtures for the isolation of the pure products.

The procedure described in WO 201 1/094191 A1 for the preparation of the cyclic polysilyl anion [Si _fl Cli ₄ ] ^{2 ~} is less expensive. This is obtained from trichlorosilane by reaction with a tertiary polyamine ligand, more specifically an alkyl substituted polyalkylenepolyamine, and a deprotonating agent such as a tertiary amine.

Derivatization sierung using the Si-Cl-Funktionaütät is described in WO 2009/148878 A2. In addition, w ^r a halogenated polysilane as a pure compound or mixtures of compounds, as well as a plasma-chemical process for preparing the same ground described. However, this process leads exclusively to hexasilane or to its Si-substituted derivatives with comparatively low yields.

W. Lerner et al. _t Inorganic Chemistry, 51, 8599-8606 (2012), describe a reaction in which a Si ₂ CVT EDA adduct is dissolved by dissolving in dichloromethane to form the perchlorinated oligo and polysilanes Si _n Cl 2 _n (n-4, 6, 8 , 10) and the chloro-complexed dianion [Si _n Cl _{2n +} 2] ^{2 "} (n = 6, 8, 10, 12).

DE 31 26 240 C2 relates to a process for the preparation of metallic silicon, in which the reaction of perchlorosilane, for example S ^ ^' l ^, with a catalyst from the group of ammonium halides, tertiary organic amines, quaternary ammonium and phosphonium halides at a temperature of 120 ° C to 250 ° C to higher silanes than Si ₂ Cl _{6 is} described. As the catalyst, for example, tetrabutylphosphonium chloride is used. However, this document does not provide details of the structures or product composition of the resulting perchlorinated polysilanes.

A disadvantage of the known processes for the preparation of perhalogenated oligo- and polysilyl anions or oligo- and polysilanes that no targeted and systematic representation of linear, cyclic and cage-like silane compounds is possible. Either these mixtures are mixtures of various oligo- and polysilanes often the structures and compositions can not be determined more accurately, or the methods allow only the preparation of a single oligo- or polysilane, usually in low yield. Furthermore, high temperatures and high energy input are often required for the preparation of such compounds.

It is an object of the present invention to provide a method for the systematic production of linear, cycüschen and / or cage-like perhalogenated oligo- and polysilyl anions, which overcomes the disadvantages known from the prior art, in particular with the method a preparatively controllable and more systematic Construction of linear, cyclic and cage-like perbalogenated oligo- and polysilyl anions and thus the targeted production of individual compounds at relatively low temperatures and be possible with high yields. In addition, based on the oligo- and polysilyl anions, a preparatively simple access to the corresponding uncharged oligo- and polysilane compounds should be ensured. Another object is to provide corresponding oligo- and polysilyl anions.

The first object is achieved by a process for preparing linear, cyclopean and / or cage-like perhalogenated oligo- and polysiyl anions by reacting perhalogenated mono-, oligo- or polysilanes with organosubstituted ammonium and / or phosphonium halides at temperatures in the range of -80 ° C to 85 ° C, preferably -80 ° C to 60 ° C.

According to the invention, the process, depending on the production conditions, linear, cyclic or cage-like perhalo genierte oligo- or polysilyl anions produced separately. However, depending on the choice of production conditions, it is also conceivable that linear, cyclic and cage-like anions are simultaneously produced side by side, which can then be separated from one another.

Perchlorinated or perbrominated oligo- and polysilyl anions are preferably used in the present invention.

In the case of the ammonium and / or phosphonium halides used, the halogen is likewise preferably F, Cl and / or Br. The ammonium and / or phosphonium halides are preferably completely organo-substituted, ie, for example, [P ^ Nj with X = halide, preferably Cl and / or Br. As the organo substituent, there can be preferably selected aryl, alkyl, alkenyl and the like and mixed organo substituents. Particular preference is given to using ethyl, butyl and phenyl, also in mixed substitution.

In the context of the present invention, "oligosilyl anions" and "oligosilanes" should be compounds which have two to five silicon atoms.

Furthermore, in the context of the present invention, "polysilyl anions" and "polysilanes" are to be compounds which have more than five silicon atoms.

For the purposes of the invention, "perlialogenated oligo- and polysilyl anions" are predominantly or completely substituted by halogen atoms In the context of the present invention, particular preference is given to trichlorosilane being understood as a perchlorinated monosilane.

In the context of the present invention, "linear oligo- and polysilyl anions" are to be unbranched compounds, whereas "cyclic oligo- and polysilyl anions" are substituted and Si-substituted monocyclic oligo- and polysilyl anions. "Cage-like polysilyl Anions "are for the purposes of the invention substituted and Si-substituted polycyclic polysilyl anions,

According to the invention, a stoichiometric ratio of perhalogenated mono-, oligo- or polysilanes and organo-substituted ammonium and / or phosphonium halides is preferably in a range from 50: 1 to 1: 5.

One embodiment is characterized in that an additional Lewis base, preferably amine and / or phosphine, is added.

Furthermore, it is preferably provided that the process is carried out in a temperature range from -80 ° C to -30 ° C. At such low temperatures, predominantly linear perhalogenated oligo- and polysilyl anions are obtained. In a further preferred embodiment, the process is carried out in a temperature range from -1 0 ° C to 60 ° C, preferably 0 ° C to 30 ° C, more preferably at room temperature, to obtain cyclic perhalogenated polysilyl anions.

Further, it is preferred that the process be carried out in a temperature range of from 0 ° C to 85 ° C, preferably 0 ° C to 60 ° C, preferably 10 ° C to 30 ° C, more preferably at room temperature, to form cage-like perhalogenated polysilyl anions to obtain when also mono- or Oligochlorsilane or possibly polychlorosilanes are reacted.

It is further preferred according to the invention that the stoichiometric ratio of perhalogenated mono-, oligo- or polysilanes and organo-substituted ammonium and / or phosphonium halides in a range of 50: 1 to 1: 1, preferably 40: 1 to 1: 1, more preferably 10 : 1 to 1: 1, is.

In a further preferred embodiment, a substoichiometric amount of organo-substituted ammonium and / or phosphonium halides is added. Optionally, a catalytic amount of an amine can be added.

Further, it is preferred that the organosubstituted ammonium and / or phosphonium halides are the corresponding chlorides and bromides, more preferably [oBu ₄ N] Cl, [Et ₄ N] Cl, [Ph P] Cl, and [iBu ₄ ] P] Cl acts. Ethyl is also particularly preferred as an organic substituent.

It is preferred that it is in the monosilane trichlorosilane, wherein the perhalogenated oligosilanes preferably S12X6, Si ₃ Xg, Si ₄ X _{f 0} and S15X12, wherein X is selected from chlorine and bromine, and wherein the perhalogenated polysilanes preferably polysilanes of Formula X 3 Si - (Si ₂ ) _n -SiX 3, wherein X is selected from chlorine, bromine, fluorine and iodine and. n is 3 to 20, acts. It is also conceivable that X may be partially replaced by H in the perhalogenated oligosilanes and polysilanes.

Perhalogenated polysilanes for preparing the oligo- and polysilyl anions. can preferably be generated plasmachemisch. Methods for producing perhalogenated polysilanes are known in the art. The process according to the invention is preferably carried out using an organic solvent.

According to the invention, the solvent is preferably benzene, chlorobenzene, 1, 2-dichloroethane and / or dichloromethane, but preferably dichloromethane.

The second object is achieved according to the invention by oligo- and polysilyl anions or their H-substituted uncharged derivatives, which are obtainable by a process according to the invention.

It is preferred that the linear oligomers and perhalogenated Polysilyl anions [S13X9] ^"[Sij jo] ^2", [S14X1 1] ^{"and [SigXis]"} where X is selected from chlorine, bromine, iodine and / or Fluorine, preferably chlorine or bromine.

Further, it is preferred that the cyclic perhalogenated oligo- and polysilyl anions [Si ₆ X, ₄ ] ² \ [(SiX ₃ ) Si ₆ X _{! 3} ] ^{2 "} , [1, I- (SiX ₃ ) 2 Si ₆ Xi ₂ ] ² ; [l, 4- (SiX ₃ ) ₂ Si X ₁₂ , ie isomers of the empirical formula [SigXisJ ^{2 "} , where X is selected from chlorine, bromine, iodine and / or fluorine, preferably chlorine or bromine.

In addition, it may preferably be provided that the cage-like perhalogenated polysilyl anion [8132 5] ^" i ^st _> wherein X is selected from chlorine, bromine, iodine and / or fluorine, preferably chlorine or bromine.

It is further according to the invention that the perhalogenated oligo- and polysilyl anions are converted by additional hydrogenation into the corresponding uncharged H-substituted linear, cyclic and cage-like perhalogenated oligo- and polysilanes.

Surprisingly, it has been found that in the process according to the invention the use of simple halide ions, preferably chloride ions, provided by the organo-substituted ammonium and / or phosphonium halides as donors as a function of the temperature, the systematic production of perhalogenated oligo- and polysilyl anions allows. The entire series of linear, cyclic and cage-like perhalogenated oligo- and polysilyl anions can thereby be targeted comparatively low temperatures and with high yields are obtained. The perhalogenated oligo- and polysilyl anions obtained by the process according to the invention can also be isolated and unequivocally characterized by single-crystal X-ray structure analysis. Furthermore, the obtained perhalogenated oligo- and polysilyl anions can be converted to the corresponding uncharged H-substituted oligo- and polysilanes in a preparatively simple manner, for example by hydrogenation with conventional hydrogenation reagents such as L1AlH ₄ or DTBAL-H. The resulting better solubility of the compounds in all common solvents subsequently allows Reiünktionalisierung to the uncharged molecular and halogenated compounds.

Based on the polarity of the Si-halogen bond, in particular the Si-Cl and Si-Br bond polarity, an interesting and far-reaching sequence chemistry can be carried out from the molecular products, such as substitution reactions, incorporation into polymer skeletons, deposition reactions, doping, ring opening reactions followed by construction of higher oligo- and. Polysilanes, etc., through defined substitution products to materials with polysilane backbones, amorphous. Siiicium and leads to new inorganic conductive polymers with Si-Si bond units. As a result, the targeted representation of organo-, amine- and oxygen-substituted oligo- and polysilanes is possible, which are not or only with difficulty accessible to alternative synthetic routes.

Further features and advantages of the invention will become apparent from the following description, schematic drawings and exemplary embodiments. It shows: a chloride-induced formation mechanism of [S13CI] ^" from Si ₂ C] 6 as well as the formation of the oligosilyl anion [Si ₄ CIi]

Figure 2 shows a putative chain-growth mechanism (left) and intramolecular ring-closure of a cyclic polysilyl anion [Si ₆ Cl ₁₄ ] ^{2 "} (right).

Figure 3 shows pathways resulting in the formation of experimentally observed species N ^' and Q ^" . Fig. 4 show reaction pathways that result in the formation of ό-membered ring species.

FIG. 5 shows a molecular crystal structure of [nBu ₄ N] [Si 3 Clc)] in the solid state, wherein the

 Cation is not shown.

6 shows a molecular crystal structure of [wBu ₄ N] ₂ [Si ₃ Clio] in the solid state, wherein the cation is not shown.

7 is a molecular crystal structure of [οΒυ ₄ Ν] [8ί ₄ απ] in the solid, wherein the cation is not shown,

FIG. 8 shows a molecular crystal structure of [nBu ₄ N] [Si ₆ Cl | 5] in the solid state, where the cation is not shown.

Fig. 9 is a molecular crystal structure of "Bu ₄ N] ₂ Si ₆ Cl] 4] u solid, wherein the cation is not shown.

10 is a molecular crystal structure of [Phi.P] ₂ [(Ci3Si) Si ₆ Cl _{i 3} ] in the solid state, wherein the cation is not shown.

Fig. 1 1 shows a molecular crystal structure of [«Bu ₄ P] ₂ [l, l - (ChSi ^ SieCi ^] im

 Solid, where the cation is not shown.

12 is a molecular crystal structure of [Ph ₄ P] ₂ [l, 4- (Cl ₃ Si) 2 Si ₆ Cli 2] im

 Solid, where the cation is not shown.

Fig. 13 is a molecular crystal structure of [ "Bu ₄ N] [ ^'81 ₃₂ 0 ₄₅ j in the solid state, wherein the cation is not shown.

14 shows a molecular crystal structure of [Et ₄ N] [Si ₃₂ Cl ₄₅ ] in the solid state, wherein the

Cation is not shown. FIG. 15 shows a simulated X-ray powder diffractogram (bottom) calculated from FIGS

Single-crystal data of [«Bu ₄ N] 2 Si _? Clio], and an associated experimentally measured X-ray powder diffraction pattern (top).

FIG. 16 shows a simulated X-ray powder diffractogram (bottom) calculated from FIGS

Single crystal data of [/ iBu4N] ₂ [Si ₆ Cl i 4], and an associated experimentally measured X-ray powder diffraction pattern (top).

Fig. 1 shows the chloride-induced formation of [S13CI9 ^"of Si? Cl6 and formation of the more highly substituted oligosilyl anion [Si ₄ ^Cl]" by subsequent Äufbaureaktion. Relative energies in Fig. 1 are given in kcal mol-1. Underpinned by experimental results, and mechanistically underpinned by DFT calculation, the construction of linear oligosilyl anions is systematic, the reaction paths are experimentally controllable. The results of quantum mechanics and experimental mechanistic studies based on Dichtefunktionairechnung, X-ray crystallography and ^'Si ~ NMR measurements as a function of varying temperatures create subsequent reaction path near: The addition of chloride anions of Si ₂ Cl 6 first forms the pentavalent Audukt Λ ^"the. with a low barrier to form S1CI4 and [SiCIs] ^' , the silyl anion [SiCl ₃ j ^~ subsequently adds to another molecule with a likewise low barrier formation of the higher anion B ^" , which was characterized by X-ray crystallography at low temperatures, which forms the higher trisilane S13C intermediate after chloride abstraction by SijC, which also forms A ^" decomposes into SiCl ₃ ^" , as described above added to the SijClg to form the higher anion, wherein it is the perhalogenated oligosilyl anion [S14CI] 1] ^".

These corresponding elementary steps can be combined in the sense of a build-up cycle leading to the formation of higher oligo- and polysilyl anions:

Figure 2 (left) shows a corresponding suspected chain-building mechanism with chain propagation and termination steps. The chain termination is kinetically competitive with chain propagation and leads, with elimination of S12CI6, to the formation of terminal higher silanide anions. The formation of the unsubstituted cyclic [Si _(, Cl _14] ^{2 "can} be in this way, for example, via an intramolecular ring closure reaction explain higher terminal silanide anions with a chain length of n = 4 and subsequent chloride addition. This reaction is strongly favored compared to ring closure reactions of shorter silanide anions with n = 2 and n = 3.

The formation of the experimentally observed dianionic perchlorosilacyclohexane chloride adducts and the SiClj substitution patterns found can be explained by an alternative formation mechanism. As shown in Figure 3, the anion C ^{~ can} undergo intramolecular isomerization steps (Berry pseudorotation, BPR, chloride and silyl shifts) with moderate Banier heights. This leads to the formation of the silanide anions P ^~ and S ^" or in a competing reaction to the formation of LT. Along the reaction paths shown, the branched oligosilyl anions N ^" and experiment, which are experimentally detected at low temperatures, occur, which corroborates the proposed mechanism.

The thus formed silanide anions can dimerize with very little kinetic inhibition intermolecularly. As shown by way of example in FIG. 4, the formation of (a) the unsubstituted eyelike [Si ₆ Cli ₄ ] ^{2 "can be} achieved by dimerization of L or heterodimerization of LT and P ^" and (b) of the doubly silyl-substituted eylic dianions by dimerization of Explain S ~. All shown pathways involve the intermediate formation of five-membered ring systems, which isomerize by intramolecular ring expansion steps with low barrier to the thermodynamically highly preferred six-membered ring systems. The formation of the experimentally observed silyl substitution patterns in the compounds [1, y- (SiC) ₂ (Si ₆ C! 12)] ² (y = 1, 3, and 4) can be explained in this picture by ring expansion steps at different positions after dimerization of S- formed five-membered eyelic species X ^2- (Figure 4, bottom right).

Figures 5-12 show the molecular crystal structures of linear and eyelic perchlorinated oligo- and polysilyl anions in the solid state, the corresponding cations are not shown.

Figures 13 and 14 show the molecular crystal structures of ["Bu N] [Si 32 Cl ₄₅ ] and [Et ₄ N] [Si 32 Cl 4s] n solid, with the corresponding cations not shown. The crystals were measured with a STOE 1PDS-II diffractometer. [Et ₄ N] [Si ₃ 2Cl4s] crystallizes from CH 2 Cl 2 together with 2 equivalents of SiCl ₄ in the monoclinic Space group C2 / ([Et ₄ N] [Si ₃₂ Cl ₄ 5] · 2 SiCl ₄ ). All methylene groups of the cation are disordered over two identically occupied positions. Two Cl atoms of the SiCl ₄ molecule are also disordered. Fig. 14 shows for clarity only the asymmetric unit as ORTEP plot. The vibrational ellipsoids are shown with a probability of 30%. [nBu ₄ N] [Si ₃ 2Ci ₄₅ ] crystallizes from CH CI ₂ in the hexagonal space group P6 / m (a = b = 1 5.016 (2) Ä, c - 28.130 (6) Ä, α = ß = 90 °, γ = 120 °, V = 5493 (1) A ³ ). This cage-like polysilyl anion is an Si ₂ O-dodecahedron with endohedral coordinated chloride anions substituted with twelve SiCl ₃ groups. This perchlorinated polysilyl anion can be understood as the preliminary end product of a systematic synthesis reaction.

Fig. 15 shows a simulated X-ray powder diffraction pattern (below) calculated from single crystal data of [oBu ₄ N] ₂ [Si 3 Cl 10] and an experimentally measured X-ray powder diffraction pattern taken from the obtained crude product (above). A comparison of both powder diffractograms shows the phase purity of the resulting crude product [/? Bu ₄ N] 2 [Si ₃ Cl! O]. The single-crystal data were recorded at a temperature of -100 ° C, whereas the powder data were collected at room temperature.

16 shows a simulated X-ray powder diffractogram (bottom) calculated from the single crystal data of [Βα Ν] ₂ [8ίή01] ₄ ] and an experimentally measured X-ray powder diffractogram taken from the obtained crude product (above). A comparison of both powder diffractograms shows the phase purity of the obtained crude product ["Bu ₄ N] ₂ [Si6CI | 4]. The single crystal data were taken at a temperature of -100 ° C, the powder data, however, were collected at room temperature,

embodiments

1. General working conditions

All reactions were carried out under dry argon or nitrogen, CH ₂ Cl ₂ was dried over CaH ₂ and freshly distilled before use; CD ₂ C1 ₂ was dried in the presence of silver foil over molecular sieve (4 Å). [Dg] THF was dried over sodium. Si ₂ Cl ₆ , [fiBu ₄ N] Cl, [Et ₄ N] Cl, [PruPJCl and [nBu ₄ P] Cl are commercially available; the chlorides were dried in vacuo at room temperature for 2 d. ["Bu N] Cl usually contains traces of KCl, so it was basically dissolved in CH 2 Cl 2 and the insoluble KCl removed by filtration. The temperature for low temperature experiments was monitored with a Haake EK 90 cryostat. Si NMR spectra were recorded on a Bruker Avance ΠΙ HD 500 MHz spectrometer; the spectra were calibrated against the external standard SiMe ₄ (S (Si) = 0). X-ray powder was collected with a STOE STADI P diffractometer (linear PSD; CuKa radiation (= 1.5406 Å)). Elemental analyzes (EA) were performed by the micro analytical laboratory of Goethe University Frankfurt. LDI-MS spectra were recorded with a MALDI LTQ Orbitrap XL.

2. Synthesis of Linear Perhalogenated Oligo- and Polysilyl Anions 2.1. Synthesis of [nBuTNlfSi ^ C] and [nBu ₄ N] [Si _ö Cl _{! 5} ]

2 Si ₂ Cl _e + [nBu ₄ N] Cl * - [nBu ₄ N] [Si ₃ Cy + SiCl ₄

Scheme 1. Reaction equation for the synthesis of , [NBu4N] Ci = 40:: For the experiment, a stoichiometric ratio of Si2Cl ₆ was selected. 1

Si ₂ Cl ₆ (5.0 mL, 7.8 g, 29 mmol) was added to a solution of D ?Bu ₄ N] Cl (0.20 g, 0.72 mmol) in CH without stirring at -50 ° C ₂ CI ₂ (15 mL). During this process, Si ₂ Cl ₆ solidified on addition and dissolved only slowly in the solvent. The reaction mixture was kept at -50 ° C for 24 h with the aid of a cryostat to form colorless acicular single crystals of [f Bu ₄ N] [Si ₃ Cl 9] (Figure 5). No other residue was observed in the clear mother liquor. Some of the air- and moisture-sensitive crystals were removed from the cold (~ 50 ° C) reaction flask, selected under a cold nitrogen stream, and examined by X-ray diffraction. After identification of ["Bu N] [Si 3 ClO], the solution was warmed to -40 ° C with the remaining crystals and stored at this temperature. After 12 days, the shape of the crystals, although still acicular, had visibly changed and their amount had increased. The crystals were isolated in the cold and their structure determined by X-ray diffractometry on single crystal as [nBu ₄ N] [Si ₆ Cli 5] (Figure 8). 2.2. Synthesis of [iiBu4N] ₂ [Si3 Clio]

2 Si ₂ Cl ₆ + 2 [nBu ₄ N] Ci • »- [nBu ₄ N] ₂ [Si ₃ Cl ₁ O] + SiCl,

Scheme 2. Reaction equation for the synthesis of [nBu ₄ N] 2 [Si Clio].

SiiCl ^ (5.0 mL, 7.8 g, 29 mmol) was added at -78 ° C without stirring to a solution of [nBu ₄ N] Cl (8.1 g, 29 mmol) in CH ₂ Cl ₂ (20 mL). Si ₂ Cl6 solidified upon addition and dissolved only slowly. The reaction mixture was held at -78 ° C with a krvostat for 1 week. In this case, a large amount of crystals had formed in the upper part of the solution. A single crystal was isolated and determined by X-ray analysis as [nBu4] 2 [Si ₃ Cl 10] (Figure 6). The phase purity of the crude product was detected by means of X-ray powder diffractometry (FIG. 15). Yield of crystalline material: 6.5 g (49%). EA (%) calcd for C ₃₂ H ₇ 2Cl | oN ₂ Si ₃ [923.69]: C 41.61, H 7.86, N 3.03; C 41.32, H 7.96, 3.34.

2.3. Synthesis of [«Bu ₄ N] [Si ₄ Cln _. ]

3 Si ₂ Cl ₆ + [nBu ₄ N] CI [nBu ₄ N] [Si ₄ Cl _11] 2 + SiCl ₄

Scheme 3. Reaction equation for the synthesis of ["Bu ₄ N] [Si ₄ Cl ₁ ]]. For the experiment a stoichiometric ratio of Si ₂ Ci6: ["BujNJCi = 10: 1 was chosen.

Si ₂ Cl 6 (9.0 mL, 14 g, 52 mmol) was added at -50 ° C with gentle stirring to a solution of jftBu ₄ N] Cl (1, 5 g, 5.4 mmol) in CH ₂ Cl ₂ ( 30 mL). The reaction mixture was stored without stirring at -50 ° C for 4 days. Subsequently, colorless, air- and moisture-sensitive single crystals could be isolated from the reaction solution and the crystal structure of [/? Bu ₄ N] [Si ₄ Cli j] determined (FIG. 7).

3. Synthesis of cyclic perhalogenated polysilyl anions

Basically, Si ₂ Clr was added to a solution of the corresponding chloride salt ([nBu ₄ N] Cl, ["Bu ₄ P] Cl or [Ph ₄ P] Cl) in CH ₂ Cl ₂ . Also with C ₆ H ₅ C1 and C ₆ H ₆ as the solvent, chloride adducts of cyclic perchlorinated hexasilyl anions could be obtained, but CH 2 Cl 2, by virtue of its properties, proved to be the preferred reaction medium.

According to in situ ²⁹ Si NMR spectroscopy, the formation of significant amounts of (substituted) cyclic hexasilyl anions between -10 ° C and 0 ° C begins. Regardless of the chloride salt used, formation of only one (substituted) cyclic hexasilyl anion was never observed. The ratio of S12CI6 to Cf ions was varied in the range 1: 5 to 10: 1. It turned out that the stoichiometry has hardly any influence on the product distribution. However, the formation of the relative amounts of different (substituted) cyclic hexasilyl anions in the reaction solution can be influenced by the reaction temperature. Preparatively usable amounts of a particular (substituted) cyclic hexasilyl anion were obtained by fractional crystallization; (i) Substituted cyclic llexasilyl anions generally crystallize before the unsubstituted cyclic hexasilyl anions. (ii) Different densities of the different crystals obtained can be used to separate the substituted rings from the unsubstituted ring: In CH2CL, [m3u ₄ N] [Si (, Ci i4] floats on the surface while the doubly substituted rings sink to the bottom. Larger amounts of [/? Bu N] Si6Cl j] can also be obtained by controlled temperature control of a mixture of substituted cyclic hexasilyl anions, replacing the CI3S1 substituents with Cl substituents and thereby [nBu N] [Si ₆ Cl _i4 ] educated.

Indicated yields refer to the amounts of S12CI0 used, assuming that each S12CI6 molecule contributes exactly one SiCl ₂ building block to the product molecules.

3.1. Synthesis of as main component in a mixture with other isomers of [- Bu4N] ₂ [SigCl _{! S} ]

S1 CI0 (9.30 mL, 14.5 g, 53.9 mmol) was added at room temperature without stirring to a solution of ["Bu ₄ N] Cl (5.0 g, 18 mmol) in CH 2 Cl 2 (20 mL) , The clear reaction mixture turned slightly yellowish. After 12 h at room temperature, the solution was colorless again and after a few days, crystals began to precipitate. The crystalline material was removed from the solution after a total of 20 days. Overall yield [rtBu ₄ N] ₂ [Si ₈ Cl, ₈ ]: 2.96 g (33%). EA (%) calcd for Cszf ^ Cl igNaSi »[1 347.74]: C 28.52, H 5.38, N 2.08; C 28.66, H 5.68, N 1.71. ²⁹ Si NMR data of a solution of several selected single crystals of [nBuiNBt L MSiCh ^ Si ^ Cln] (99.4 MHz, CD ₂ Cl ₂ , 298 K): δ = 11 .4 ('./(Si, Si) = 73 Hz , ² J (Si, Si) = 14 Hz, 2Si, SiCl ₃ ), -22.3 ('J (Si, Si) = 148 Hz, ² J (Si, Si) = 29 Hz, ² J (Si, Si) - 14 Hz, 2 Si Si-2), -24.8 ⁽² J (Si, Si) - 29 Hz, I Si; Si-4), -27.3 ⁽² ./(Si,Si) = 21 Hz, 2 Si; Si-3), -52.5 ppm ('J (Si, Si) = 148 Hz,' J (Si, Si) = 73 Hz, ² J (Si, Si) = 21 Hz, I Si, Si). Note: The assignment of the ²⁹ Si resonances was based on (i) relative integral areas and (ii) Si, Si coupling constants measured between the resonances of the Si satellites. The ²⁹ Si satellites necessary for the determination of J (Si, Si) coupling constants between Si-2 / Si-3 and Si-3 / Si-4 are not sufficiently resolved to obtain reliable values.

X-ray diffraction analysis of numerous single crystals selected from the obtained crystalline material revealed in all cases the constitution of the anion [l, l - (SiCi3) ₂ Si ₆ Cl | ₂ ^~ j

3.2. Synthesis of OBU ₄ N] 2 [Si (Cl] 4]

Method A: A second product from the synthesis of [jiBu4N] ₂ [l, l - (SiCi ₃ ) ₂ Sii5Cli ₂ ] (see above) showed crystals of [rtBu ₄ N] 2 [Si ₆ Cl | ] are isolated from the mother liquor after the crystals of the substituted Sic rings have been separated. After a storage time of 60 d, [nBu ₄ ] ₂ [Si ₆ Cl [ ₄ ] was obtained with a yield of 3.50 g (34%). The crystals could be measured by X-ray diffractometry. (Fig. 9); the phase purity of the crude product was confirmed by X-ray powder diffractometry (FIG. 16) and ⁹ Si NMR spectroscopy ^{11 '21} . ²⁹ Si NMR of [ηΒα ₄ Ν] ₂ [8ί ₆ α ₁₄ ] (99.4 MHz, CD ₂ Cl ₂ , 298 K): <5 = -21 .7 ppm (SiCl ₂ ).

Method B: HSiCL (6.7 mL, 9.0 g, 66 mmol) was added at room temperature with stirring to a Schrauhdeckel glass with a solution of [/ iBu ₄ N] Cl (6, 1 g, 22 mmol) and Bu ₃ N (8.6 mL, 12 g, 65 mmol) in CH 2 Cl 2 (20 mL). The clear solution was stirred for 10 d. Then C <., (1 5 mL) was added, whereupon crystals deposited on the bottom of the solution. The crystals were isolated after 20 d and identified by X-ray analysis as [7Bu ₄ N] 2 [Si Cl [4l. It was 3, 5 g product isolated (yield 27%). 3.3. Synthesis of [PruPMCChS SieClu] and [Ph4P] ₂ [Si ₆ Cl _l4 ]

The reaction was carried out in a flask divided into two equal halves through a glass wall. A solution of Si ₂ Cl (. 1, 0 mL, 1, 6 g 6.0 mmol) in Cf l- ( _^"l;. (1 mL) was filled into one half, the other side was treated with a solution from [PtuPjCl (0.60 g, 1.6 mmol) in CH 2 Cl 2 (2 mL).] The sealed flask under nitrogen was stored at room temperature, and small crystals were obtained on the side of the salt after 7 days, and X-ray diffractometry provided the structure of [Ph P] ₂ [Si ₆ Cli ₄ ] After all the crystals were removed, the flask was resealed to continue the gas diffusion process During the following 50 d, large crystals of [Ph4PM (Cl ₃ Si) Si 6 Cl ₁₃ ] formed. (Figure 10) in the half of the flask filled with [P1] PjCl solution, the other side of the flask was nearly empty at this point in time ²⁹ Si NMR data of a single dissolved crystal of [Pru MCC SiJSieClu] (99.4 MHz, [ DgjTHF, 298 K): δ = 9.9 (ISi, SiCl ₃ ), -20.6 (I Si, Si-4), -21.6 (2Si, Si-2 or 3), -22.5 (2Si, Si-2 or 3), -49.0 ppm

• 90

(ISi, Si-1). Note: The assignment of the Si resonances is based on the relative integral surfaces and the comparison with chemical shifts of similar compounds; ²⁹ Si satellites were unresolved.

3.4. Synthesis of [«Bu4P] 2 [1, 1 - (Cl ₃ Si) ₂ Si ₆ Cl 12] and [« Bu ₄ P] ₂ [Si ₆ Cl _{I 4} ]

S12CI6 (0.20 mL, 0.31 g, 1.2 mmol) was added at -1 6 ° C in an NMR tube to a frozen solution of ["Bu P] Cl (86 mg, 0.29 mmol) in CD2G2 (0.5 mL). The NMR tube was sealed in vacuo and the reaction solution was rapidly brought to -60 ° C; then the solution was slowly warmed to room temperature, whereupon a white solid precipitated out of clear solution. Crystals selected from this solid gave the structures of [nBmP] ₂ [1 M £ $ i) iS C ₂ ] (FIG. 11) and

3.5. Synthesis of [Ph ₄ P] 2 [l, 4- (Cl ₃ Si) 2 Si ₆ Cl [2] and [P 4P] ₂ [Si ₆ Cl i 4]

Si ₂ Cl (5 (0.17 mL, 0.27 g, L0 mmol) was added to a NMR tube to a solution of [Ph ₄ P] Ci (0.15 g, 0.40 mmol) in CD ₂ Cl ₂ The NMR tube was sealed in vacuo and stored at room temperature, crystals were obtained after a few days to give the crystal structures of [Pb4P] 2 [1, 4- (Cl3 Si) ₂ Si6Cl1 ₂ ] (Figure 12) and [Ph4P] ₂ [Si ₆ Cl ₁₄ ]. 4. Synthesis of cage-like perhalogenated polysilylanions

4.1. Synthesis of "BufN" [Si3 ₂ Cl45]

Method A: SijCU (5 mL, 7.8 g, 29 mmol) was dissolved in a flask at 0 ° C over a colorless solution of ["Bu ₄ N] Cl (0.8 g, 2.9 mmol) and Bu ₃ N (" 0.5 mL, 0.37 g, 3.6 mmol) in CH ₂ Cl ₂ (5 mL). The two-phase system was brought to room temperature overnight, with both phases turning bright orange and crystals forming at the interface. After a further 24 h, the lower phase had turned brown; the two phases were separated. Crystals were isolated from the lower phase after three weeks and analyzed by laser-induced mass spectrometry and X-ray diffraction analysis (Fig. 1 3) identified. 100 mg of product were isolated (yield 5%).

Method B: A screw-capped Schott flask was filled, in an argon-filled glove box, with ["Bu" _{4 "} N) Cl (1.0 g, 3.6 mmol), Bu" _{3 "} N (0.36 g, 1.9 mmol) and CFLC1" _{2 "} (9 mL) , Si ₂ C 6 (6.4 mL, 10 g, 37 mmol) was added by syringe, in one portion, at room temperature and with stirring. The initially colorless solution turned yellow. After two days of stirring, the color had changed to brown / orange and a colorless solid had formed. The solid, essentially ["Bu 4 N] ₂ [1, 1 - (SiCl ₃ ) ₂ Si ₆ C] | o ^" 2 Cl], was removed by filtration. The slightly turbid filtrate was mixed with CH ₂ Cl ₂ (10 mL) and the resulting clear solution stored in a Schott flask. After about one week, colorless crystals of hexagonal cross-section were obtained. The mother liquor was decanted off and the resulting crystals were washed with CFI ₂ Cl ₂ (4x5 mL). Yield of [Bu ₄ N] [Si ₃ 2Cl45]: 0.70 g (29%). ² Si NMR (99.37 MHz, THF [D _g]): 5 31.1 (Si (I)), 1 0.3 (Si (III)), -60.4 ppm (Si (0)); LDI-MS (m / z): [Mf calculated for [S132CI45] ^~ , 2492.8; found, 2492.8; LDI-MS (m / z): [M] ⁺ calculated for [m3u ₄ N] \ 242.3; found, 242.3.

Method C: The anion of the desired target substance can also be obtained starting from HSiCl ₃ (1 ml) with Bu ₃ N (1 ml) and addition of [nBi] NjCl without solvent. The yield of [rcBu4N] [Si3 ₂ Cl45j is then slightly lower (about 10%).

4.2. Preparation of single crystal material of [i7Bu ₄ N] [Si32Cl ₄₅ 1 and [Et ₄ N] [Si 3 ₂ Cl45] X-ray crystallography on

anions; [oBu ₄ N] ^† Counterions and probably CH ₂ Cl ₂ SiCl ₄ molecules occupy the space between the spherical anions. Both the cation and the solvent molecules are disordered to such an extent that a clear solution of the measurement data is not possible. The molecular structure of the cluster anion could finally be solved by using the SQUEEZE function of the Piaton program.

In order to reduce the disorder of the cation, the synthesis was also carried out with [Et ₄ N] Cl as the chloride source. The reaction produced a large amount of insoluble solid, which explains why [Et ₄ N] ⁺ as the counterion is slightly less suitable for preparative synthesis. Nevertheless, single crystals of high quality could be obtained. By means of X-ray structural analysis, these could be unambiguously characterized as [Et4N] [Si3 ₂ Cl45] .2SClCl4 (FIG. 14).

The features of the invention disclosed in the foregoing description, the claims and the drawings may be essential both individually and in any combination for the realization of the invention in its different embodiments.

Claims

claims 1. A process for the preparation of linear, cyclic and / or cage-like perhalogenated oligo- and polysilyl anions by reacting perhalogenated mono-, oligo- or polysilanes with organo-substituted ammonium and / or phosphonium halides at temperatures in a range from -80 ° C to 85 ° C, preferably -80 ° C to 60 ° C. 2. The method of claim 1, wherein a stoichiometric ratio of perhalogenated mono-, oligo- or polysilanes and organo-substituted ammonium and / or Phosphoniumhalogeniden in one. Range from 50: 1 to 1: 5. 3. The method according to any one of the preceding claims, wherein an additional Lewis base, preferably amine and / or phosphine, is added. 4. The method according to any one of the preceding claims, wherein it is carried out in a temperature range of -80 ° C to -30 ° C. 5. The method according to any one of claims 1 to 3, wherein it is carried out in a temperature range of -10 ° C to 85 ° C, preferably -10 ° C to 60 ° C, preferably 0 ° C to 30 ° C, more preferably at room temperature becomes. 6. The method according to any one of claims 1 to 3, wherein it is carried out in a temperature range of 0 ° C to 60 ° C, preferably 10 ° C to 30 ° C, more preferably at room temperature and perhalogenated polysilane is reacted. A process according to any one of the preceding claims, wherein the stoichiometric ratio of perhalogenated mono-, oligo- or polysilanes and organo-substituted ammonium and / or phosphonium halides ranges from 50: 1 to 1: 1, preferably 40: 1 to 1: 1 , more preferably 10: 1 to 1: 1. A process according to any one of claims 1 and 3 to 6, wherein a substoichiometric amount of organo-substituted ammonium and / or phosphonium halides is added, optionally with the addition of a catalytic amount of an amine. A process according to any one of the preceding claims, wherein the perhalogenated oligo- and polysilyl anions are converted by subsequent hydrogenation into the corresponding uncharged H-substituted linear, cyclic and cage-like oligo- and polysilanes. Perhalogenated oligo- and polysilyl anions or their H-substituted derivatives, obtainable by a process according to one of claims 1 to 8 or a process according to claim 9.