WO2007101820A1

WO2007101820A1 - Palladium catalyzed polymerization reaction

Info

Publication number: WO2007101820A1
Application number: PCT/EP2007/051979
Authority: WO
Inventors: Thomas Schäfer; Peter Murer; Tobias Hintermann; Beat Schmidhalter; Kristina Bardon
Original assignee: Ciba Holding Inc.
Priority date: 2006-03-08
Filing date: 2007-03-02
Publication date: 2007-09-13
Also published as: TW200740874A

Abstract

The invention relates to the production of aryl-aryl coupled compounds and materials. These materials play a significant role in industry whereby being used as liquid crystals, pharmaceuticals and agrochemicals to name a few fields of application. Above all, these compounds are of exceptional importance in the fast-growing field for organic semiconductors (e.g. applications in organic or polymeric light-emitting diodes, organic solar cells and organic IC's).

Description

Palladium catalyzed polymerization reaction

The invention relates to the preparation of aryl-aryl coupled polymeric materials. These polymeric materials are of major importance in the high-growth area of organic semi- conductors, in particular in applications in organic or polymeric light-emitting diodes, organic solar cells, organic ICs.

For the synthesis of such compounds an extremely wide variety of alternatives is known but these do not in all cases offer a solution that is, for example, technically, economically and ecologically satisfactory. In many processes there occur undesirable reactions and undesirable products, which have to be separated off and disposed of by costly means or which cannot be removed and then may result in problems when the material is used.

The efficiency of the process (degree of conversion) is especially important when the reaction of one or more multifunctional compound(s) is involved. An example is a polymerisation reaction in which one or more multifunctional compound(s) is/are reacted with one or more further multifunctional compound(s). In many polymer applications, a high molecular weight is required in order to obtain the desired physical properties, for example film formation, flexibility, mechanical stability and other properties. Especially in the case of organic semi-conductors, the electrical properties are greatly influenced by the molecular weight-usually a very high molecular weight is required in order to prevent defects such as short circuits in the electrical device. Furthermore, a high degree of process reproducibility is required for that application. The degree of polymerisation (DP, average number of repeating units in the chain) of a polymer built up by step-wise growth is related to the degree of conversion of the reaction (p) as follows:

DP = 1/(1-p).

When a high DP is desired, the reaction needs to be very efficient, for example p=0.95, DP=20 or p=0.99, DP=100.

The so-called Suzuki reaction (Synthetic Communications, 11 (7), 513, (1981 )) has been found to be a suitable reaction for the preparation of aryl-aryl coupled polymeric compounds. It involves the hetero coupling of a halide- or sulphonoxy-functional aromatic compound with a compound containing an aryl-boron functionality in the presence of a base, a palladium compound and a solvent.

Several variations of the reaction parameters are known. Generally, it is usual to carry out the reaction using two phases: an aqueous phase containing the major part of a base and an organic phase containing the major part of the aryl compounds. As organic solvent there is often used a non-polar aromatic solvent, for example benzene, toluene, xylenes (for example, Chem. Comimun., 1598, (1997)). It is also known to carry out the reaction in a mixture of an aromatic solvent such as, for example, benzene or toluene and an alcohol such as, for example, methanol or ethanol (see, for example, J. Med. Chem., 40(4), 437, (1997)). Those water-miscible solvents serve as reaction accelerators by improving the contact between the base and the aromatic boron compound. U.S. Pat. No. 6,956,095 teaches that the presence of such alpha-H-functional alcohols results in undesirable subsidiary products and accordingly in a reduction in reaction efficiency.

In U.S. Pat. No. 6,956,095 some of the aforementioned disadvantages were addressed and a process for the reaction of a halogen- or sulphonyloxy-functional aryl or heteroaryl compound with an aromatic or heteroaromatic boron compound in the presence of a low catalytic amount of a palladium compound is disclosed wherein, by using certain solvent mixtures in the presence of very low concentrations of palladium compounds which do not contain triphenylphosphine, the reaction proceeds with especially high reaction efficiency and results in aryl-aryl coupled polymeric compounds with a minimum of undesirable side reactions.

In the prior art, aditional components that may be used for the formation of the active palladium compound are, in the widest sense, ligands which can coordinate at the palladium metal centre. According to U.S. Pat. No. 6,956,095, a huge variety of possible ligands may be used including ligands from the group of tri-aryl-phosphines, di-aryl-alkyl-phosphines, aryl- dialkyl-phosphines, trialkyl-phosphines, tri-heteroaryl-phosphines, di-heteroaryl-alkyl- phosphines, heteroaryl-dialkyl-phosphines. U.S. Pat. No. 6,956,095 further teaches that it is possible for the substituents on the phosphorus to be the same or different, chiral or achiral, it is also possible for one or more of the substituents to link the phosphorus groups of a plurality of phosphines and moreover, it is also possible for some of those links to be one or more metal atoms. Furthermore, halo-phosphines, dihalo-phosphines, alkoxy- or aryloxy- phosphines, dialkoxy- or diaryloxy-phosphines may also be used.

In U.S. Pat. No. 6,956,095 special preference is given to substituted triphenylphosphines according to general formula (I),

wherein

Y₁ to Yi5 are the same or different and are hydrogen, alkyl, aryl, alkoxy, dialkylamino, chlorine, fluorine, sulphonic acid, cyano or nitro radicals, with the proviso that at least 1 but preferably 3 or more of the substituents Yi to Yi₅ are not hydrogen. Examples of the variants to which very special preference is given are tris(o- or m- or p-tolyl)phosphine, tris(o- or m- or p-anisyl)phosphine, tris(o- or m- or p-fluorophenyl)-phosphine, tris(o- or m- or p- chlorophenyl)-phosphine, tris(2,6-dimethylphenyl)-phosphine, tris(2,6- dimethoxyphenyl)phosphine, tris(mesityl)phosphine, tris(2,4,6-trimethoxyphenyl)phosphine and tris(pentafluorophenyl)phosphine.

Further preferred ligands mentioned ligands in U.S. Pat. No. 6,956,095 include tert-butyl-di- o-tolylphosphine, di-tert-butyl-o-tolyl-phosphine, dicyclohexyl-2-biphenylphosphine, di-tert- butyl-2-biphenylphosphine, triethylphosphine, tri-iso-propyl-phosphine, tri- cyclohexylphosphine, tri-tert-butylphosphine, tri-tert-pentylphosphine, bis(di-tert- butylphosphino)methane and 1 ,1 '-bis(di-tert-butylphosphino)ferrocene.

Further, U.S. Pat. No. 6,956,095 teaches that triphenylphosphine ligands are less suitable as they cause an especially high level of undesirable reactions. However, there is still a confusing variety in the ligands to be used, without any pointers being given to possible further improvements. In all the cases mentioned above, efficiency of the process (degree of conversion), the achievable molecular weight and in conjunction therewith, the electrical properties of the resulting polymeric materials are still unable to meet satisfactorily all of the ever growing demands.

According to this invention it has now been found, surprisingly, that it is possible to provide aryl-aryl coupled polymeric materials with a very high molecular weight obtained by a process with a high degree of process reproducibility when using an active palladium compound as catalyst that is formed with specifically selected aryl-dialkyl-phosphine ligands. Thus, a solution is offered that meets the technical, economical and ecological demands more satisfactorily than the solutions described in the prior art. More specifically, the extent is substantially been reduced to which undesirable reactions and undesirable products occur, which have to be separated off and disposed of by costly means or which cannot be removed and then may result in problems when the material is used. Moreover, the efficiency of the process (degree of conversion) is increased and aryl-aryl coupled polymeric materials with a high molecular weight are obtained which better satisfy the criteria with regard to the physical properties, for example film formation, flexibility, mechanical stability as well as the electrical properties required for use of the material in a number electrical applications.

The invention accordingly relates to a process for the polymerisation reaction of a first monomer (i) being a halogen- or sulphonyloxy-functional aryl or heteroaryl compound with a second monomer (ii) being an aromatic or heteroaromatic boron compound in the presence of a catalytic amount of a palladium compound wherein aryl-aryl or aryl-heteroaryl or heteroaryl-heteroaryl C-C bonds are formed, and wherein the palladium compound consists of a palladium source and at least one ligand of general formula (II) which can coordinate at the palladium metal centre

(II) wherein

R¹ and R² are independently of each other Ci-C-i₈alkyl, C₃-Ci₈cycloalkyl, C₄-Ci₈bicycloalkyl; R³ is Ci-Ci₈alkyl, C_rCi₈cycloalkyl, C_rCi₈alkoxy, or -N(R¹²)₂; R⁴ is H, d-Ciβalkyl, C_rCi₈cycloalkyl, C_rCi₈alkoxy, or -N(R¹²)₂; R⁵ to R¹¹ are independently of each other H, CrCi₈alkyl, Ci-Ci₈cycloalkyl; Ci-Ci₈alkoxy, -N(R¹²)₂, C₆-Ci₈aryl, or C₆-Ci₈aryl which is substituted by D; R¹² is d-Ciβalkyl; and D is Ci-Ci₈alkyl, C_rCi₈alkoxy, or -N(R¹²)₂.

In a preferred embodiment of the present invention, the inventive process for the polymerisation reaction of a first monomer (i) being a halogen- or sulphonyloxy-functional aryl or heteroaryl compound with a second monomer (ii) being an aromatic or heteroaromatic boron compound is characterized in that the at least one ligand of general formula (II) is defined as follows: R¹ and R² are independently of each other C_rC₇alkyl, C₄-C₇cycloalkyl; R³ is CrC₆alkyl, C_rCi₈cycloalkyl, C_rC₆alkoxy, or -N(R¹²)₂; R⁴ is H, Ci-C₆alkyl, C_rCi₈cycloalkyl, C_rC₆alkoxy, or -N(R¹²)₂; R⁵ to R¹¹ are independently of each other H, Ci-Cβalkyl, Ci-Ci₈cycloalkyl; CrC₆alkoxy, -N(R¹²)₂, C₆-Ci₈aryl, or C₆-Ci₈aryl which is substituted by D; R¹² is Ci-C₆alkyl; and

D is Ci-C₆alkyl, C_rC₆alkoxy, or -N(R¹²)₂.

Even more preferred is an embodiment of the present invention wherein the at least one ligand of general formula (II) is defined as follows: R¹ and R² are independently of each other cyclohexyl, t-butyl;

R³ and R⁴ are independently of each other Ci-Cβalkoxy, most preferably methoxy or iso- propoxy;

R⁵ to R¹¹ are independently of each other H, Ci-Cβalkyl, Ci-Cβalkoxy, phenyl, or phenyl which is substituted by D; and D is CrC₆alkyl or C_rC₄alkoxy.

Best results are obtained when the at least one ligand of general formula (II) is selected from the group consisting of:

wherein

The palladium source of the palladium compound may be either a palladium compound or metallic palladium. Suitable palladium sources are salts of palladium(ll), or palladium(O) compounds or complexes. Preferred palladium sources are palladium(ll) halides, palladium(ll) carboxylates, palladium(ll)[beta]-diketonates, tris(dibenzylideneacetone)dipalladium(0) (Pd2 dba3), dichloro(bisbenzonitrile)palladium(ll), dichloro(1 ,5-cyclooctadiene)-palladium(ll), tetrakis(triarylphosphino)palladium(0) or discrete compounds of palladium with the at least one ligand of general formula (II) as described hereinbefore.

It is also possible to use a pre-formed complex of palladium with at least on of the above ligandes for this process.

The palladium compound may be either in solid (that is to say heterogeneous) or dissolved form and, in the latter case, may be dissolved either in the organic phase or in the aqueous phase.

In the process according to the invention, the palladium compound is usually employed in an amount of from 0.00001 mol % to 5 mol % (palladium), based on the amount of C-C links to be closed. Preference is given here to the range from 0.001 % to 5%, especially the range from 0.01 % to 2%. The at least one ligand of general formula (II) as described hereinbefore is usually added in the range from 10:1 to 1 :2, preferably in the range from 8:1 to 1 :1 , based on the palladium content.

The reaction according to the invention can then proceed (depending on the exact composition and temperature) with either one or more than one phase or may also change in that regard whilst the reaction is being carried out. However, the reaction according to the invention preferably proceeds with more than one phase.

Aryl or heteroaryl compounds and the aromatic or heteroaromatic radicals of the corresponding boron compounds are aromatic or heteroaromatic entities containing from 2 to 40 C atoms which may be substituted by one or more linear, branched or cyclic alkyl or alkoxy radicals containing from 1 to 20 C atoms wherein one or more non-consecutive CH₂ groups may also have been replaced by O, S, C-O or a carboxy group, substituted or unsubstituted C-2 to C-20 aryl or heteroaryl radicals, fluorine, cyano, nitro or, sulphonic acid derivatives, or which may be unsubstituted. Simple compounds which may preferably be used are the corresponding substituted or unsubstituted derivatives of benzene, naphthalene, anthracene, pyrene, biphenyl, fluorene, spiro-9,9'-bifluorene, phenanthrene, heterocyclic bright phenanthrenes, triptycene, pyridine, furan, thiophene, benzothiadiazole, pyrrole, quinoline, quinoxaline, pyrimidine, and pyrazine. There are, furthermore, expressly included corresponding (as defined by the text hereinbefore) multifunctional compounds and also oligomers formed during polymerisation which have functional aryl or heteroaryl terminal groups.

The starting compounds for the process according to the invention are, on the one hand, halogen- or sulphonyloxy-functionalised aryl or heteroaryl compounds of formula (III)

Ar-(X)_n (III)

wherein Ar is an aryl or heteroaryl radical as defined hereinbefore, X denotes -Cl, -Br, -I, - OS(O)₂R¹ , and R¹ is an alkyl, aryl or fluorinated alkyl radical and n denotes at least 1 , preferably from 1 to 20, especially 1 , 2, 3, 4, 5 or 6. The second class of starting compounds for the process according to the invention comprises aromatic or heteroaromatic boron compounds of the general formula (IV)

Ar-(BQ₁Q₂), (IV)

wherein Ar is an aryl or heteroaryl radical as defined hereinbefore, Qi and Q₂ are the same or different on each occurrence and denote -OH, Ci-C₄alkoxy, Ci-C₄aryloxy, CrC₄alkyl or halogen, or Q₁ and Q₂ together form a CrC₄alkylenedioxy group which may optionally be substituted by one or more CrC₄alkyl groups, or Q₁ and Q₂ and the boron atom together are part of a boroxine ring of formula (V) or of similar boronic anhydrides or partial anhydrides

Ar

I I

Ar^O^Ar _(γ)

and m denotes at least 1 , preferably from 1 to 20, especially 1 , 2, 3, 4, 5 or 6.

Additionally, the second class of starting material can also be of the following type:

Ar-(BF₃)^" _m (M⁺)_m

wherein M is Li, Na, or K, especially K.

For the synthesis of linear polymers, the value 2 is preferably selected for n and m simultaneously.

The inventive process for the polymerisation reaction of a first monomer (i) being a halogen- or sulphonyloxy-functional aryl or heteroaryl compound with a second monomer (ii) being an aromatic or heteroaromatic boron compound in the presence of a catalytic amount of a palladium compound wherein aryl-aryl or aryl-heteroaryl or heteroaryl-heteroaryl C-C bonds are formed further requires a suitable base(s) and solvent system.

The bases are used, for example, analogously to U.S. Pat. No. 5,777,070. There are used, for example, alkali and alkaline earth metal hydroxides, carboxylates, carbonates, fluorides and phosphates such as sodium and potassium hydroxide, acetate, carbonate, fluoride and phosphate or also metal alcoholates, preferably corresponding phosphates or carbonates. Where appropriate, mixtures of bases may be used.

The solvent system is preferably a solvent mixture comprising at least 0.1 % by volume of a compound from each of the following groups (1 ) water-miscible organic solvents, (2) water- immiscible organic solvents, and (3) water.

The term "water-miscible organic solvent" means a solvent which forms a clear, single-phase solution at room temperature both when at least 5% by weight water is present in the solvent and when at least 5% by weight solvent is present in water.

Preferred solvents of that kind are organic ethers, esters, nitrites, tertiary alcohols, sulphoxides, amides and carbonates, especially ethers and very especially dioxane, tetrahydrofuran, ethylene glycol ether, DME and various polyethylene glycol ethers. In the process according to the invention, preference is given to one or more solvents selected from that class in a range (based on the total volume of the reaction mixture at the end of the reaction) from 1 to 70%, especially in a range from 5 to 60%, very especially in a range from 5 to 50%.

The term "water-immiscible organic solvent" means a solvent which no longer forms a clear, single-phase solution at room temperature, that is to say phase separation is already discernible, even when less than 5% by weight water is present in the solvent or even when less than 5% by weight solvent is present in water.

Preferred water-immiscible solvents are aromatic and aliphatic hydrocarbons, non-polar ethers, chlorine-containing hydrocarbons, preferably aromatic hydrocarbons, very especially toluene, xylenes or anisole.

In the process according to the invention, preference is given to one or more solvents selected from that class in a range (based on the total volume of the reaction mixture at the end of the reaction) from 1 to 90%, especially in a range from 25 to 80%, very especially in a range from 50 to 80%. The water used is usually of normal quality, that is to say tap water, where appropriate having been deionised. For special requirements it is of course possible also to use grades which are of better purity or from which salts have been removed. In the process according to the invention, preference is given to using water in a range (based on the total volume of the reaction mixture at the end of the reaction) from 1 to 50%, especially from 5 to 35%.

The process according to the invention is usually slightly exothermic, although generally requires slight activation. The reaction is, therefore, frequently carried out at temperatures above room temperature. A preferred temperature range is, therefore, the range between room temperature and the boiling point of the reaction mixture, especially the temperature range between 40 and 120°C, very especially the range between 40 and 100°C. However, it is also possible that the reaction will proceed sufficiently rapidly even at room temperature so that no active heating is required.

The reaction is performed with stirring, it being possible to use simple stirrers or high- viscosity stirrers depending on the viscosity of the reaction mixture. In the case of high viscosities, vortex breakers may also be used.

The concentrations of the reaction components will depend greatly on the reaction in question. Preferably, the polymerization reactions according to the present invention are carried out at concentrations in the range below 1 mol/l (based on the C-C bonds to be closed).

The reaction time may, in principle, be freely selected and will be based on the speed of the reaction in question. A technically sensible frame of reference will certainly be in the range from a few minutes up to 100 hours, preferably in the range from 15 minutes 1 hours to 48 hours.

The reaction per se proceeds at normal pressure. However, it may well also be technically advantageous to proceed at elevated or reduced pressure. This will depend greatly on the individual reaction and, especially, on the equipment available. The inventive process provides for an outstanding efficiency (degree of conversion) and the resulting polymeric chains are characterized by both an extraordinarily great length and extraordinarily high molecular weights.

A particular advantage of the present invention is that, by virtue of the improved efficiency of the Suzuki reaction, the amount of expensive palladium catalyst employed can be reduced. This means that manufacturing costs are reduced and, in addition, the amounts of residual palladium in the product are dramatically reduced. This brings technical advantages, for example avoidance of an impaired product color, although the reduction in such impurities is advantageous especially in the case of organic semi-conductors because the presence of metal residues will result in impairments in use.

In accordance with the present invention, a polymeric character is present when the characterising properties (for example, solubility, melting point, glass transition temperature etc.) do not change or change only insubstantially when an individual repeating unit is added or omitted. A simpler definition is the indication of molecular weight, according to which a "polymeric character" is to be defined as a molecular weight of >10000 g/mol.

The polyarylenes (this term is here intended also to include copolymers that do not contain arylene or heteroarylene units in the main chain) thereby produced are distinguished by a high (but also readily controllable) molecular weight and by the absence (or a very low content) of structural defects produced by the polymerisation. Those polymers, produced by the process according to the invention, consequently exhibit significant improvements over the prior art.

This process makes possible the preparation of poly-arylenes or -heteroarylenes having higher molecular weights than previously known. The highest previously published weight- average degree of polymerisation (M_w, measured by GPC, divided by the average molecular weight of the repeating unit(s)) is about 3000 and the process according to the invention yields polymers which in some cases have significantly higher values. The invention accordingly relates also to poly-arylenes or -heteroarylenes having a weight-average degree of polymerisation of more than 3000. Additionally this new process makes it possible to prepare poly-arylenes or -heteroarylenes with high molecular weights (> 200 000 g/mol) which gave with the previously known best process only moderate molecular weights (14 000 g/mol).

A preferred polymerisation process according to the invention may be described as follows:

As "water-miscible organic solvent" there is used dioxane or THF in the range from 5 to 75% (based on the total volume of the solution). Preverable are 5 to 50 % (based on the total volume of the solution at the end of the reaction).

As "water-immiscible organic solvent" there is used an aromatic solvent, for example toluene, a xylene, chlorobenzene or anisole, preferably toluene or a xylene, in the range from 20 to 95% (based on the total volume of the solution at the end of the reaction).

Water is added in the range from about 2 to 50% (based on the total volume of the solution at the end of the reaction).

The monomers (i) and (ii) are used in a concentration range from 20 to 200 mimol/l. Either the two different functionalities (halide or sulphonyloxy versus boron groups) are set out in the ratio 1 :1 (as exactly as possible) at the outset or that ratio is brought about in the course of the reaction by subsequent (either continuous or batch-wise) addition of one of the two functionalities to an excess of the other functionality.

Where appropriate, small amounts of monofunctional compounds ("end-cappers") or tri- or multi-functional groups ("branchers") are added.

The palladium compound is added in a ratio of from 1 :10000 to 1 :50, preferably from 1 :5000 to 1 :200, based on the number of bonds to be closed. In this case, preference is given, for example, to the use of palladium(ll) salts such as PdAc₂ or Pd₂dba₃ and to the addition of ligands selected from the group consisting of

The ligand is added in a ratio of from 1 :1 to 1 :10, based on Pd.

It is also possible to use a preformd complex of palladium with at least on of the above ligandes for this process.

As base there is preferably used, for example, K₃PO₄, which is preferably added in a ratio of from 1 :1 to 5:1 , based on the number of bonds to be closed.

The reaction is maintained under reflux with vigorous stirring and carried out over a period of about from 1 hour to 48 hours.

It has been found to be advantageous at the end of the reaction to carry out so-called end- capping, that is to say to add monofunctional compounds which will catch any reactive end groups in the polymers.

At the end of the reaction, the polymer may be further purified by customary purification procedures such as, for example, precipitation, reprecipitation, extraction and the like. For use in high-quality applications (for example, polymeric light-emitting diodes), contamination with organic (for example, oligomeric) and inorganic substances (for example, Pd residues, base residues) usually has to be brought to as low a level as possible. That may be achieved, - for Pd, in a very great variety of ways, for example by means of ion-exchangers, liquid- liquid extraction, extraction with complex-formers and other procedures, for the removal of low-molecular-weight substances, for example by solid-liquid or liquid-liquid extraction or also by reprecipitation a number of times, for the removal of further inorganic impurities, for example by the procedures already described for Pd and low-molecular-weight substances and also by extraction with, for example, inorganic mineral acids.

In a further possible embodiment of the polymerisation described above, the polymerisation is carried out in at least two steps, an excess of one of the monomers being employed in the first step so that a short-chain polymer having a first composition is formed. "Short-chain" herein means that there is only formed, at first, an oligomer having a few (for example, between 3 and 20) repeating units. The remaining monomers are subsequently added in one or more further step(s) so that finally the ratio of boron-containing reactive groups and halogen- or sulphonyloxy-containing reactive groups is 1 :1.

The monomer composition of the second or further steps is preferably different to that of the first step, as a result of which polymers having a block-like structure are formed.

A "block-like structure" herein means the following: as a result of the first step there is formed, for example, an oligomer having the sequence B(AB)_n wherein A and B are the two monomer units used, B being the monomer used in excess and n being the average length of those oligomers. Subsequently, there is then added, for example, a monomer C so that the total number of reactive end groups is balanced out. This results finally in a polymer mainly comprising sequences as follows: (C[B(AB )_n])_m wherein m is the average chain length of the polymer thereby defined; that is to say blocks having the structure B(AB)N alternate with C and the polymer has a block-like structure. Of course it is also possible, depending on the sequence of monomer addition, to produce further block-like structures by means of the process described.

The process according to the invention makes possible the preparation of high-molecular- weight polymers having that block-like form because it has an especially non-damaging effect on the boron-, halogen- or sulphonyloxy-containing reactive groups in the absence of the corresponding counterpart groups.

Using the process described herein, it is now possible to prepare, for example, polyarylenes as described in EP-A-842.208, WO 00/22026, WO 00/46321 , WO 99/54385, WO 00/55927, WO 97/31048, WO 97/39045, WO 92/18552, WO 95/07955, EP-A-690.086, and WO 02/044060. The polymers prepared by the process according to the invention frequently exhibit advantages over the statements made in the cited literature, for example with respect to freedom from defects, molecular weight, molecular weight distribution and frequently also, therefore, with respect to the corresponding properties of use.

Accordingly, it is another aspect of the present invention to provide a process for the polymerisation reaction of a first monomer (i) being a halogen- or sulphonyloxy-functional aryl or heteroaryl compound with a second monomer (ii) being an aromatic or heteroaromatic boron compound in the presence of a catalytic amount of a palladium compound, wherein the polymerization reaction is carried out in at least two steps, an excess of either the first monomer (i) or the second monomer (ii) being employed in a first step so that a short-chain polymer having a first composition is formed, and the remaining monomers being subsequently added in one or more further step(s) so that finally the ratio of boron-containing reactive groups and halogen- or sulphonyloxy-containing reactive groups is 1 :1.

It is even more preferred when the monomer composition of the second or further steps is different to that of the first step, as a result of which polymers having a block-like structure are formed.

Yet another aspect of the present invention relates to the use of the at least one ligand of general formula (II) or the palladium compound as defined hereinbefore in a process for the polymerization reaction of a first monomer (i) being a halogen- or sulphonyloxy-functional aryl or heteroaryl compound with a second monomer (ii) being an aromatic or heteroaromatic boron compound in the presence of a catalytic amount of a palladium compound wherein aryl-aryl or aryl-heteroaryl or heteroaryl-heteroaryl C-C bonds are formed.

The polymers according to the invention can be used in electronic components such as organic light-emitting diodes (OLEDs), organic integrated circuits (0-ICs), organic field-effect transistors (OFETs), organic thin-film transistors (OTFTs), organic solar cells (0-SCs), organic laser diodes (O-lasers), organic colour filters for liquid crystal displays or organic photoreceptors, to which the present invention also relates.

Accordingly, it is another aspect of the present invention to provide a poly-arylene or - heteroarylene obtainable by the inventive process described hereinbefore, wherein said poly- arylene or -heteroarylene has an average molecular weight of at least 200,000 g/mol, preferably of at least 350,000 g/mol and more preferably of at least 500,000 g/mol.

Finally, it is also an aspect of the present invention to provide an electronic component comprising at least one poly-arylene or -heteroarylene obtainable by the inventive process described hereinbefore.

The described invention is illustrated by the description and the examples that are given hereinbelow although it is in no way limited thereto but may of course be readily applied by the person skilled in the art to the systems indicated above or described in the cited literature.

The following examples are included for illustrative purposes only and do not limit the scope of the claims. Unless otherwise stated, all parts and percentages are by weight.

Weight-average molecular weight (M_w) and polydispersity (M_w/M_n = PD) are determined by Gel Permeation Chromatography (GPC). Apparatus: GPC_max + TDA 302 from Viscotek (Houston, TX, USA) yielding the responses form refractive index (Rl), low angle light scattering (LALS), right angle light scattering (RALS) and differential viscosity (DP) measurements.

Chromatographic conditions: Column: PL_geι mixed C (300 x 7.5 mm, 5 μm particles) covering the molecular weight range from about 1 x 10³ to about 2.5 x 10⁶ Da from Polymer Laboratories (Church Stretton, UK); Mobile phase: tetrahydrofuran containing 5 g/l of sodium trifluoroacetate; Mobile phase flow: either 0.5 or 0.7 ml/min; Solute concentration: about 1-2 mg/ml; Injection volume: 100 μl; Detection: Rl, LALS, RALS, DP.

Procedure of molecular weight calibration: Relative calibration is done by use of a set of 10 polystyrene calibration standards obtained from Polymer Laboratories (Church Stretton, UK) spanning the molecular weight range from 1 '930'0OO Da - 5'050 Da, i. e., PS 1 '930OOO, PS 1 '46O¹OOO, PS 1 O75O00, PS 560O00, PS 330O00, PS 96O00, PS 52O00, PS 30'300, PS 10'100, PS 5'05O Da. Absolute calibration is done on the base of the responses of LALS, RALS and DP. As experienced in a large number of investigations this combination provides optimum calculation of molecular weight data. Usually PS 96'00O is used as the molecular weight calibration standard, but in general every other PS standard lying in the molecular weight range to be determined can be chosen for this purpose.

All polymer structures given in the examples below are idealized representations of the polymer products obtained via the polymerization procedures described. If more than two components are copolymerized with each other sequences in the polymers can be either alternating or random depending on the polymerisation conditions. Example 1

To 2.4470 g (2.530 mmol) of the dibromide 1 and 0.8351 g (2.5300 mmol) of the diboronic ester 2 are dissolved in 10 ml dioxane and 10 ml toluene. The mixture is degassed with argon. 62.3 mg (0.152 mmol) 2-dicyclohexylphoshino-2',6'-dimethoxy-1 ,1 '-biphenyl (sPhos) is added and the reaction mixture is degassed with argon. 5.7 mg (0.025 mmol) palladium(ll)acetate is added and the reaction mixture is degassed with argon. 3.07 g (12.7 mmol) potassium phosphate tribasic monohydrate in 3 ml water are degassed and added to the reaction mixture.

The reaction mixture is heated at 90 °C under argon for 48 h. After 20 h 20 ml degassed toluene is added to the viscose reaction mixture. After 44 h 5 ml degassed toluene is added to the viscose reaction mixture.

710 mg (3.80 mmol) of degassed 4-bromanisole is added and the reaction mixture is heated under reflux for two hours. A degassed solution of 1.48 mg (3.80 mmol) of 2-(4- methoxyphenyl)-4,4,5,5-tetramethyl-2-phenyl-[1 ,3,2]dioxaborolane in 3 ml of toluene is added.

The reaction mixture is heated under reflux for two hours, cooled to 25°C and treated with 100 ml of 1 % aqueous NaCN solution. The water phase is removed and the organic phase is poured in 250 ml methanol. The polymer is filtered of and is washed with methanol, water, acetone and again methanol. The polymer is dissolved in 100 ml toluene and is treated with 100 ml of 1 % aqueous NaCN solution for 16 h at 100 °C. The water is removed and the organic phase is poured in 250 ml methanol. The polymer is filtered of and is washed with methanol, water and again methanol. The polymer is dissolved in 50 ml tetrahydrofurane and poured in 250 ml methanol. The polymer is filtered of and is washed with methanol. The polymer is again dissolved in 50 ml tetrahydrofurane and poured in 250 ml methanol. The polymer is filtered of and is washed with methanol.

GPC (polystyrene standard): M_w = 250 200 g/mol, DP = 4.30.

Example 2 (Comparison Example)

To 1.5239 g (1.5600 mmol) of the dibromide 1 and 0.5164 g (1.5600 mmol) of the diboronic ester 2 are dissolved in 15 ml dioxane and 5 ml toluene. The mixture is degassed with argon. 28.8 mg (0.0936 mmol) tri-o-tolylphoshine is added and the reaction mixture is degassed with argon. 3.5 mg (0.0156 mmol) palladium(ll)acetate is added and the reaction mixture is degassed with argon. 1.8909 g (7.8000 mmol) potassium phosphate tribasic monohydrate in 3 ml water are degassed and added to the reaction micture.

The reaction mixture is heated at 90 °C under argon for 20 h. After 20 h no viscosity increase is observed.

370 mg (2.34 mmol) of degassed brombenzene is added and the reaction mixture is heated under reflux for two hours. A degassed solution of 800 mg (3.90 mmol) of 4,4,5,5- tetramethyl-2-phenyl-[1 ,3,2]dioxaborolane in 3 ml of toluene is added. The reaction mixture is heated under reflux for two hours. The purification is done analog to the example 1.

GPC (polystyrene standard): M_w = 14 047 g/mol, DP = 3.77. Example 3 (Comparison Example)

To 1.5239 g (1.5600 mmol) of the dibromide 1 and 0.5164 g (1.5600 mmol) of the diboronic ester 2 are dissolved in 10 ml dioxane and 10 ml toluene. The mixture is degassed with argon. 28.8 mg (0.0936 mmol) tri-o-tolylphoshine is added and the reaction mixture is degassed with argon. 3.5 mg (0.0156 mmol) palladium(ll)acetate is added and the reaction mixture is degassed with argon. 1.89 g (7.80 mmol) potassium phosphate tribasic monohydrate in 3 ml water are degassed and added to the reaction micture.

GPC (polystyrene standard): M_w = 33 958 g/mol, DP = 3.42.

Example 4

To 10.196 g (14.722 mmol) of the dibromide 1 and 4.8587 g (14.722 mmol) of the diboronic ester 2 are dissolved in 25 ml dioxane and 25 ml toluene. The mixture is degassed with argon. 363 mg (0.883 mmol) 2-dicyclohexylphoshino-2',6'-dimethoxy-1 ,1 '-biphenyl (sPhos) is added and the reaction mixture is degassed with argon. 33.0 mg (0.147 mmol) palladium(ll)acetate is added and the reaction mixture is degassed with argon. 17.8 g (73.6 mmol) potassium phosphate tribasic monohydrate in 15 ml water are degassed and added to the reaction mixture.

The reaction mixture is heated at 90 °C under argon for 23 h. The reaktion mixture is several times deluted with degassed toluene (410 ml) during the reaction.

4.13 g (22.1 mmol) of degassed 4-bromanisole is added and the reaction mixture is heated under reflux for 3 hours. A degassed solution of 8.62 g (36.8 mmol) of 2-(4-methoxyphenyl)- 4,4,5,5-tetramethyl-2-phenyl-[1 ,3,2]dioxaborolane in 3 ml of toluene is added. The reaction mixture is heated under reflux for 16 hours. The purification is done analog to the example 1.

GPC (absolute calibration): M_w = 2 362 000 g/mol, DP = 1.85.

Claims

1. A process for the polymerization reaction of a first monomer (i) being a halogen- or sulphonyloxy-functional aryl or heteroaryl compound with a second monomer (ii) being an aromatic or heteroaromatic boron compound in the presence of a catalytic amount of a palladium compound wherein aryl-aryl or aryl-heteroaryl or heteroaryl-heteroaryl C- C bonds are formed, and wherein the palladium compound consists of a palladium source and at least one ligand of general formula (II) which can coordinate at the palladium metal centre

wherein

R¹ and R² are independently of each other Ci-C-ι₈alkyl, C3-Ci8cycloalkyl, Or C₄-CiS bicycloalkyl;

R³ is CrCi₈alkyl, C_rCi₈cycloalkyl, C_rCi₈alkoxy, or -N(R¹²)₂;

R⁴ is H, CrCi₈alkyl, C_rCi₈cycloalkyl, C_rCi₈alkoxy, or -N(R¹²)₂;

R⁵ to R¹¹ are independently of each other H, Ci-Ci₈alkyl, Ci-Ci₈cycloalkyl;

Ci-Ci₈alkoxy, -N(R¹²)₂, C₆-Ci₈aryl, or C₆-Ci₈aryl which is substituted by D; R¹² is Ci-Ci₈alkyl; and

D is CrCi₈alkyl, C_rCi₈alkoxy, or -N(R¹²)₂.

2. The process according to claim 1 , wherein

R¹ and R² are independently of each other C_rC₇alkyl, or C₄-C₇cycloalkyl; R³ is CrC₆alkyl, C_rCi₈cycloalkyl, C_rC₆alkoxy, or -N(R¹²)₂;

R⁴ is H, CrC₆alkyl, C_rCi₈cycloalkyl, C_rC₆alkoxy, or -N(R¹²)₂; R⁵ to R¹¹ are independently of each other H, Ci-Cβalkyl, Ci-Ci₈cycloalkyl; CrC₆alkoxy, -N(R¹²)₂, C₆-Ci₈aryl, or C₆-Ci₈aryl which is substituted by D; R¹² is Ci-C₆alkyl; and D is Ci-C₆alkyl, C_rC₆alkoxy, or

The process according to claim 1 , wherein

R¹ and R² are independently of each other cyclohexyl or t-butyl;

R³ and R⁴ are independently of each other CrC₆alkoxy, preferably methoxy or iso- propoxy;

R⁵ to R¹¹ are independently of each other H, CrC₆alkyl, CrC₆alkoxy, phenyl, or phenyl which is substituted by D; and

D is CrC₆alkyl or d-C₄alkoxy.

The process according to claim 1 , wherein the at least one ligand of general formula (II) is selected from the group consisting of:

wherein

5. The process according to any of claims 1 to 4, wherein the palladium source is selcted from the group consisting of salts of palladium(ll), palladium(O) compounds, palladium(O) complexes and metallic palladium.

6. The process according to any of claims 1 to 5 , wherein the aryl or heteroaryl compounds and the aromatic or heteroaromatic radicals of the corresponding boron compounds denote aromatic or heteroaromatic entities containing from 2 to 40 C atoms which may be substituted by one or more linear, branched or cyclic alkyl or alkoxy radicals containing from 1 to 20 C atoms wherein one or more non-consecutive CH₂ groups may also have been replaced by O, S, C=O or a carboxy group, substituted or unsubstituted C-2 to C-20 aryl or heteroaryl radicals, fluorine, cyano, nitro or sulphonic acid derivatives, or which may be unsubstituted.

7. The process according to claim 6, wherein the halogen- or sulphonyloxy-functionalized aryl or heteroaryl compounds are of general formula (III)

Ar-(X)_n (III)

wherein

Ar is an aryl or heteroaryl radical as defined in claim 6,

X denotes -Cl, -Br, -I, -OS(O)₂R¹, and R¹ is an alkyl, aryl or fluorinated alkyl radical, and n denotes at least 1 , preferably n is 1 to 20.

8. The process according to claim 6, wherein the aromatic or heteroaromatic boron compounds are of general formula (IV)

Ar-(BQ₁Q₂), (IV) wherein

Ar is an aryl or heteroaryl radical as defined in claim 6,

Qi and Q₂ are the same or different and denote -OH, d-C₄alkoxy, Ci-C₄aryloxy, C₁- C₄alkyl or halogen, or Q₁ and Q₂ together form a CrC₄alkylenedioxy group which may optionally be substituted by one or more C-ι-C₄alkyl groups, or Q₁ and Q₂ and the boron atom together are part of a boroxine ring of formula (V)

Ar I

^B_v

O O

I I

.B.

Ar' O ^Ar

(V)

and m denotes at least 1 , preferably m is 1 to 20.

9. Use of the at least one ligand of general formula (II) or the palladium compound as defined in any of claims 1 to 4 in a process for the polymerization reaction of a first monomer (i) being a halogen- or sulphonyloxy-functional aryl or heteroaryl compound with a second monomer (ii) being an aromatic or heteroaromatic boron compound in the presence of a catalytic amount of a palladium compound wherein aryl-aryl or aryl- heteroaryl or heteroaryl-heteroaryl C-C bonds are formed.

10. A poly-arylene or -heteroarylene obtainable by the process according to any of claims 1 to 8, having an average molecular weight of at least 200,000 g/mol, preferably of at least 350,000 g/mol and more preferably of at least 500,000 g/mol.

1 1. An electronic component comprising at least one poly-arylene or -heteroarylene according to claim 10.