WO2019219696A1 - METHOD FOR PRODUCING 2,5-DI(ALKYLTHIO)-α,α'-DIBROMO-P-XYLENES AND USE OF SAID 2,5-DI(ALKYLTHIO)-α,α'-DIBROMO-P-XYLENES TO PRODUCE ALKYLTHIO-SUBSTITUTED POLY(P-PHENYLENE VINYLENE) POLYMERS - Google Patents

Abstract

The invention relates to a method for producing 2,5-di(alkylthio)-α,α'-dibromo-p-xylenes of formula (3) below, in which R and R' are each selected independently from saturated, linear, branched or cyclic C1-C20 alkyl groups, comprising the conversion of 1,4-diiodobenzene (1a) into 1,4-di(alkylthio)benzenes (2) and the para-bromomethylation thereof by reaction with formaldehyde (CH2O) in the presence of hydrogen bromide (HBr) to form the corresponding 2,5-di(alkylthio)-α,α'-dibromo-p-xylenes (3), wherein either i) if R = R', 1,4-diiodobenzene (1a) is directly reacted with 2 mol thiol of the formula R-SH using copper(I) iodide (CuI) as a catalyst and using potassium phosphate (K3PO4) as a base at temperatures of ≥ 160°C to form the corresponding 1,4-di(alkylthio)benzene (2) and thereafter is converted into the corresponding 2,5-di(alkylthio)-α,α'-dibromo-p-xylene (3) by reaction with formaldehyde in formic acid (HCOOH) or a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) as a reaction medium and the addition of a solution of hydrogen bromide (HBr); or ii) if R ≠ R', 1,4-diiodobenzene (1a) is first reacted with 1 mol alkyl iodide of the formula R-I to form the corresponding 4-(alkylthio)iodobenzene (1b), thereafter with 1 mol thiol of the formula R'-SH to form the mixed 1,4-di(alkylthio)benzene (2), and finally, analogously to the above, with formaldehyde (CH2O) in formic acid (HCOOH) or a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) as a reaction medium, with the addition of a solution of hydrogen bromide (HBr), to form the mixed 2,5-di(alkylthio)-α,α'-dibromo-p-xylene (3).

Description

 A process for the preparation of 2,5-di (alkylthio) -a, a'-dibromo-p-xylenes and their use for the preparation of alkylthio-substituted

 Poly (p-phenylene vinylene) polymers

The present invention relates to the preparation of 2,5-di (alkylthio) -a, a'-dibromo-p-xylenes and their use as monomers for the preparation of alkylthio-substituted poly (p-phenylene-vinylene) polymers.

STATE OF THE ART

 Poly (p-phenylene-vinylene) (PPV) polymers are conjugated backbone polymers consisting of alternating phenylene and vinylene units. These have dominated the field of organic electronics, and new applications are already being developed, such as e.g. Bioimaging and Drug Delivery, which exploit the excellent fluorescence properties, low toxicity and biocompatibility of PPVs.

For many applications, substituents are attached to the conjugated PPV backbone. The substituents serve to solubilize the polymers but are also useful for adjusting electronic, spectral, morphological and self-organization properties. Alkoxy substituents are most frequently chosen (O-PPVs), with 2,5-dialkoxy-substituted PPVs with methoxy and 2-ethylhexyloxy (MEH-PPVs) or methoxy and 3,7-dimethyloctyl (MDMO-PPVs) as substituents probably the best studied represent substituted PPVs.

MEH-PPV MDMO-PPV Recent applications of these two polymers include moisture sensors, thermoelectric devices, wave modulators, memory devices, mixing and crosslinking studies in OLEDs, light emitting electrochemical cells, hole transport layers in perovskite solar cells, photodetectors, donor acceptor systems in micelles, and a study of the Formation mechanism of PPV nanoparticles. Nanoparticles of dialkoxy-substituted PPVs have recently been used for light-curing composites, charge-transfer studies, long-term tumor cell tracking, and as bioimaging probes for cell assays demonstrating biocompatibility.

Interestingly, despite the many applications of O-PPVs, dialkylthio-substituted analogues of O-PPVs, that is, S-PPVs, have not previously been described in the peer review literature. This is surprising since, due to the simple structure of PPVs, possible structural variations are very limited and it is known that the replacement of oxygen by the larger sulfur atom due to the weaker electron donating properties of the alkylthio substituents to be expected thereby provides a slight but very effective variation for PPVs can represent. For other classes of conjugated polymers, this effect has already been investigated (see the review by Cui and Wong, "Effects of Alkylthio and Alkoxy Side Chains in Polymer Donor Materials for Organic Solar Cells", Macromol., Rapid Comm., 37, 287-302 (2016 )).

For S-PPVs, it is likely that similar conformational effects as reported for O-PPVs will also play a major role. Part 1: Polym. Chem. 35, 2253-2258 (1997), Shim et al., Synth. Met. 101, for the alkylthio-substituted PPVs disclosed heretofore in a reliable manner (Yoon et al., J. Polym. 134-135 (1999); Hou et al., J. Polym., Part A: Polym. Chem. 44, 1279-1290 (2006)):

each having only one alkylthio substituent on the phenylene moieties and either no or methoxy as the second substituent, however, an effect similar to that for dialkoxy-substituted O-PPVs has not been reported and is not expected.

However, advantageous properties have not only been found for S-PPVs but also for SO2-PPVs, i. Dialkylsulfonylsubstituierte PPVs, ie the oxidation products of S-PPVs, expected and reported in a single case: Hubijar et al. (J. Phys. Chem. B 117, 4442-4448 (2013)) disclose the synthesis of 1, 4-dibromo-2,5-di (2-ethylhexylthio) benzene 2, the subsequent oxidation to 1, 4- Dibromo-2,5-di (2-ethylhexylsulfonyl) benzene 3 and its polymerization to the corresponding SO 2 PPV:

Dabei wird zunächst Diiodbenzol in Gegenwart von 20 Mol-% Kupfer(l)-iodid und Neo- cuproin, einem speziellen Chelatkomplexbildner für Cu(l)-lonen, und 4 Äquivalenten K3PO4 in DMF mit 2-Ethylhexanthiol bei 115 °C binnen 48 h zum 1 ,4-Di(2-ethylhexyl- thio)benzol 1 umgesetzt, das anschließend 3 d lang einer para-Dihalogenierung mit Br2 in Gegenwart von I2 in CFI2CI2 bei Raumtemperatur unterzogen wird, um 2 zu er halten. Dessen Oxidation zu 3 erfolgte gemäß Hubijar et al., s.o., mit FI2O2 in Essig säure unter Rückfluss.

Diiodobenzene is first prepared in the presence of 20 mol% copper (I) iodide and neocuproine, a special chelate complexing agent for Cu (I) ions, and 4 equivalents of K3PO4 in DMF with 2-ethylhexanethiol at 115 ° C within 48 h to 1, 4-di (2-ethylhexyl thio) benzene 1, which is then subjected to para-dihalogenation with Br2 in the presence of I2 in CFI2CI2 for 3 d at room temperature to get 2 to it. Its oxidation to 3 was carried out according to Hubijar et al., So, with FI2O2 in acetic acid under reflux.

The polymerization of 3 into the di (2-ethylhexyl) -SO 2 -PPV ("SO 2EH-PPV") was carried out via a Stille coupling reaction with trans-1,2-bis (tri-n-butylstannyl) ethylene under palladium catalysis Tetrakis (triphenylphosphine) palladium (0), Pd (PPh3) 4, in toluene at reflux for 24 h.

This way to obtain SO2-PPVS by Stille coupling polymerization is therefore very complicated and costly and also provided only a relatively niedermole Kulares SO2-PPV (M _n : 10,600, M _w : 27,800). The usual polymerization method for obtaining PPVs are therefore different variants of the Gilch reaction, in particular starting from optionally substituted a, a'-dihalo-p-xylenes with elimination of flhalogen in the presence of a base, for example of potassium tert-butanol. oxide:

For S-PPVs, however, such a polymerization reaction was just as little described in the peer review literature as the synthesis of suitable 2,5-di- (alkylthio) -a, a'-dihalo-p-xylenes. Although there are two preprints from authors of the same group (Gutierrez et al., Polymer Preprints 45 (1), 172-173 (2004), and Zepeda et al., PMSE Preprints - Polymerie Materials: Science and Engineering 99, 815 -816 (2008)), in each of which the same general synthetic route to Preparation of 2,5-di (2-ethylhexylthio) -a, a'-dibromo-p-xylene or 2,5-di (3,7-dimethyl-octylthio) -a, a'-dibromo-p-xylene specified and their polymerization is described to the corre sponding S-PPVs. However, both publications were never reviewed, the synthetic conditions for obtaining the monomers in both articles, the reaction conditions are not fully specified (molar ratios, order of addition and reaction time is missing), and characterizations of the products obtained based on physical data is completely absent.

The synthetic route from Zepeda et al., Supra, for obtaining 2,5-di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene is shown below:

That to 2,5-di (2-ethylhexylthio) -a, a'-dibromo-p-xylene from Gutierrez et al., Supra, is essentially identical except for the use of 2-ethylhexyl bromide instead of 3.7 -Dimethyloctylbromid as reagent in the penultimate and of THF instead of Et20 as solvent in the last stage. Even assuming that this reaction scheme actually proceeds as indicated, such a five-step synthesis is in any case very time-consuming and costly, and it is doubtful that the respective product in acceptable overall yield - over five stages - is obtained.

EP 567,429 A1 describes the synthesis of 2,5-di (alkylthio) -α, α'-dichloro-p-xylenes from corresponding 1,4-di (alkylthio) benzenes using (para) formaldehyde in acetic acid (CH 3 COOH ) and concentrated hydrochloric acid (HCl):

Tatsächlich hergestellt wurde allerdings nur 2,5-Di(methylthio)-a,a'-dichlor-p-xylol, und dieses wurde in der Folge auch nicht polymerisiert, sondern unter Substitution beider Chloratome zu verschiedenen Cyano-Derivaten weiter umgesetzt.

In fact, however, only 2,5-di (methylthio) -α, a'-dichloro-p-xylene was prepared, and this was not polymerized in the sequence, but further reacted with substitution of both chlorine atoms to different cyano derivatives.

No. 5,817,430 A discloses, theoretically, the synthesis of a large number of poly (arylene-vinylene) polymers by means of the Gilch reaction of various monomers in the presence of regulators ("chain end controlling additives"), ie, the chain growth is terminated Monovalent monomers, which are sometimes added in considerable proportions, namely in ratios between monomer and regulator from 1000: 1 up to 1: 2. Among the polymers to be obtained in this way are also O-PPVs and S-PPVs, of which, as a possible monomer among many others, 2,5-di (n-octylthio) -a, a'-dibromo-p -xylol is listed. As a possible reaction Tempera ture of a low temperatures, namely down to -78 ° C, up to high temperatures of 150 ° C reaching bandwidth is called. In fact, however, a single type of O-PPV was prepared by polymerizing a dichloro derivative, namely 2- (2-ethylhexyloxy) -5-methoxy-a, a'-dichloro-p-xylene at room temperature and in the presence of 4- t-butylbenzyl chloride as a regulator whose amount was varied between about 5.5 mol% and 40 mol%. However, there is no indication in this document that the polymerisation to all other poly (arylene-vinylene) polymers, such as S-PPVs, actually works in an analogous manner.

No. 7,112,697 B1 describes the synthesis of various mono- and dialkylthio- or seleno-substituted aromatics, including mono- and di-n-butylthiobenzene, using copper (I) iodide as the catalyst, a bidentate ligand as a complexing agent for the Cu (I) ions and the corresponding amount (1 or 2 mol) of jewei time thiol (R-SH) or selenol (R-SeH) disclosed. Analogous to the instructions of Hubijar et al. (see above), neocuproin is preferably used as the ligand, and the reactions were carried out at 110 ° C. for 24 hours in toluene as a solvent.

Against this background, the aim of the invention was the development of a new, less complicated synthetic route for the preparation of 2,5-di (alkylthio) -α, α'-dihalo-p-xylene monomers as starting materials for Gilch polymerization reactions to obtain corresponding Alkylthio-substituted S-PPVs or their sulfonyl-substituted oxidation products.

SUMMARY OF THE INVENTION

The present invention achieves this object in a first aspect by providing a process for the preparation of 2,5-di (alkylthio) -α, α'-dibromo-p-xylenes of the following formula (3),

wherein R and R 'are each independently selected from saturated, linear, branched or cyclic C 1 -C 20 -alkyl radicals,

comprising the reaction of 1,4-diiodobenzene (1 a) to 1,4-di (alkylthio) benzenes (2) and their para-bromomethylation by reaction with formaldehyde (CH 2 O) in the presence of hydrogen bromide (HBr) to give the corresponding 2 , 5-di (alkylthio) -a, a'-dibromo-p-xylenes (3), where either:

 i) when R = R ', 1, 4-diiodobenzene (1 a) directly with 2 moles of thiol of the formula R-SFI using copper (I) iodide (Cul) as catalyst and of potassium phosphate (K3PO4) as base at temperatures> 160 ° C to the corresponding 1, 4-di (alkylthio) - benzene (2) and then by reaction with formaldehyde in formic acid (FICOOFI) or a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) as the reaction medium and adding a Reacted solution of hydrogen bromide (FIBr) to the corresponding 2,5-di (alkylthio) -a, a'-dibromo-p-xylene (3):

or ii) when RFR 'is 1, 4-diiodobenzene (1 a) first with 1 mol of alkyl iodide of the formula Rl to the corresponding 4- (alkylthio) iodobenzene (1 b), then with 1 mol of thiol the For- mel R'-SH to the mixed 1,4-di (alkylthio) benzene (2) and finally in analogous manner as above with formaldehyde (CH 2 O) in formic acid (HCOOH) or a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) as Reaktionsme medium and adding a solution of hydrogen bromide (HBr) to the mixed 2,5-di- (alkylthio) -a, a'-dibromo-p-xylene (3) is reacted:

This new synthesis makes it possible to prepare the desired 2,5-di (alkylthio) -a, a'-dibromo-p-xylenes of the formula (3) in only two stages for products having identical alkyl radicals R and R 'or three steps for "mixed" products, which are to be understood herein as having two different alkyl radicals R and R '. The reaction sequence represents a new combination of partially known individual reactions, which have also been subjected by the inventors almost all of an optimization, as executed by standing. In particular, the present invention is limited to dibromo-p-xylenes, as it has been found that the use of the chlorides in place of the bromides according to the invention for both the polymerization and for subsequent applications of the S-PPVs disadvantages: On the one hand, the bromide monomers are clear More reactive than the chlorides, so that HBr in the polymerization can be completely eliminated without any problems, while a complete elimination of HCl during the polymerization reactions of the chloride monomers is difficult to achieve. This results in both the formation of by-products and a residual content of Cl substituents in the polymers obtained as by-products. On the other hand, such a residual content can lead to the elimination and release of HCl in the later use of the polymers, which, for example when used in organic electronics, can lead to problems due to corrosion. The only partial reaction which has not undergone optimization according to the invention is the reaction of (1 a) to (1 b), which also in preferred embodiments of the present invention is based on the literature (Sevez and Pozzo, Dyes Pigments 89, 246). 253 (2011)), although it is disclosed there exclusively for R = CFI3.

This means that the reaction of 1,4-diiodobenzene (1a) to the corresponding 4- (alkylthio) iodobenzene (1b) is preferably carried out with 1 mol of alkyl iodide of the formula R1 in the cold using n-butyllithium (n-Buu) and elemental sulfur (Se) in a solvent, preferably in diethyl ether:

 However, according to Sevez and Pozzo, supra, the product (1 b) is subsequently reacted not with a thiol as in the present invention, but with a bromothiophene.

The reaction of 1,4-diiodobenzene (1a) with 2 mol of thiol of the formula R-SFI to give the respective 1,4-di (alkylthio) benzene (2) is therefore carried out according to the present invention using copper (I) iodide ( Cul) as catalyst and potassium phosphate (K3PO4) as base at temperatures> 160 ° C, and the literature unknown reaction of 4- (alkylthio) iodobenzene (1 b) with 1 mol of thiol of the formula R'-SFI for 1, 4-di (alkylthio) benzene (2) is carried out in preferred embodiments of the invention in an analogous manner under the same conditions:

 (1 b)

In this case, the reaction mixture is particularly preferably heated to a high temperature of 160-200 ° C., more preferably about 180 ° C., which drastically reduces the reaction time to the literature, namely to 2 to 3 hours instead of 12 or 24 or 48 hours. shortened, which will be discussed in more detail below. In particular, the heating according to the present invention is carried out by means of microwave radiation, where the reaction can be completed within 2 hours and the products can be obtained in yields of up to 90%. A similar reaction for the first case, ie the reaction of (1 a) to (2), as previously mentioned, by Hubijar et al. for 2-ethylhexylthiol and described in US 7,112,697 B1 for n-butylthiol. However, first, according to Hubijar et al. obtained 1, 4-di (2-ethylhexylthio) benzene directly para-dibromination to 1, 4-dibromo-2,5-di (2-ethylhexylthio) benzene and no para-Dibrommethylierung and according to US 7.112. 697 B1 obtained 1, 4-di (butylthio) benzene no further reaction. Secondly, it is imperative to disclose the use of neocuproin or other bidentate ligand for complexing the Cu (I) ions, DMF as the solvent, and choosing a reaction temperature of 115 ° C and 110 ° C, respectively Reaction time of 48 h or 24 h resulted. Thomas et al., Tetrahedron Lett. 56, 6560-6564 (2015) disclose a temperature of 80% for the reaction of 4-iodoanisole with thiophenol Cul as catalyst. 120 ° C for 12 h and thus similar reaction conditions as in Hubijar et al. and US 7.112,697 B1, and also there, the presence of a Cu-complexing ligand is disclosed as indispensable, but with the study of four different ligands and with variation of the solvent, the base and the reaction temperature. The cost-effective DABCO, diazabicyclo [2.2.2] octane, gave the best results as a ligand.

Surprisingly, however, upon closer examination of the reac tion of (1 a) or (1 b) to (2), the inventors have found that at higher reaction temperatures than described in the literature, namely at temperatures> 160 ° C, preferably 160-200 ° C, in particular about 180 ° C, the presence of the complex-forming ligand is not required at all: With and without DABCO virtually identical conversions were achieved, as the later examples prove. The preferred use of a microwave oven to rapidly heat the reaction mixture also reduced the reaction time to 2 hours. The solvent used in the present invention is preferably dimethoxyethane (DME) (ethylene glycol dimethyl ether), which is also preferred according to Thomas et al., Supra, while US Pat. No. 7,112,697 B1 discloses toluene and Hubijar et al. DMF, just like the others of Thomas et al. investigated solvent (acetonitrile, water, toluene, THF, DMSO, t-BuOH) is also generally applicable according to the present invention. However, the high boiling water-miscible DME is preferred as the solvent herein. As base, Thomas et al. K2CO3 and according to US 7.1 12,697 B1, t-BuONa is used, whereas according to the present invention K3PO4, as also in Hubijar et al., Is used to avoid excessive pressure increases due to the release of CO2 at the preferred high temperatures.

The final reaction of 1,4-di (alkylthio) benzene (2) to the corresponding 2,5-di (alkylthio) -a, a'-dibromo-p-xylene (3) according to the present invention is preferably not with formalin, but using the powdery and therefore easy-to-handle paraformaldehyde (PFA) in acidic solution to cause its decomposition to formaldehyde even at room temperature, as before mentioned, either in formic acid (FICOOFI) or a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) as a reaction medium and introduction or addition of a solution of hydrogen bromide (FHBr), more preferably carried out with heating:

 As mentioned above, EP 567 429 A1 discloses an analogous synthesis of 2,5-di (alkylthio) -α, α'-dichloro-p-xylenes from corresponding 1,4-di (alkylthio) benzenes using ( preferably para) formaldehyde in acetic acid (CFI3COOFI) and concentrated hydrochloric acid (FICI). However, the inventors have found that when analogously using acetic acid as the reaction medium for the above reaction of (2) to (3), not only was no precipitation of the products, but also mainly a variety of by-products and the desired product formed only in traces was. The mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) is preferably used according to the present invention when both radicals R and R 'contain very long alkyl chains, especially when R = R' and both of alkyl radicals having more than 10 carbon atoms are selected. In other cases, according to previous experience of the inventors, formic acid (FICOOFI) will be the reaction medium of choice.

The hydrogen bromide can, as mentioned, introduced as gas or in the form of a solution, for example in the same acid, which is preferably used as a reaction medium, or - regardless of whether the reaction medium FICOOFI or TFA / TFAA is used - readily available added to cheaper acetic acid become. In preferred embodiments, the hydrogen bromide is used as a solution in glacial acetic acid, which is commercially available.

To accelerate the course of the reaction and to ensure complete decomposition of paraformaldehyde to formaldehyde, the reaction is preferably carried out with heating, more preferably at a temperature of 70 ° C to 80 ° C, Runaway.

In preferred embodiments of the process according to the invention, R and R 'are selected from linear or branched C 1 -C 12 -alkyl radicals, more preferably C 1 -C 10 -alkyl radicals. On the one hand, because cyclic residues, for which the skilled artisan may almost certainly assume that they can be prepared in an analogous manner, may not have the same positive effects on the optoelectronic properties, such as steric effects in the later S-PPV molecule. the HOMO and LUMO energy levels (see Cui and Wong, supra) having polymers. And on the other hand, with a larger chain length or number of carbon atoms of the radicals no further increase of the positive effect of the substituents on the optoelectronic properties is expected more, but the production is difficult. This has already been shown, for example, at Kettenlän conditions of 12 carbon atoms, as has already been indicated and as evidenced by the later examples. R and R 'are more preferably of methyl, 2-ethylhexyl,

3.7-dimethyloctyl, n-hexyl and n-dodecyl, in particular from methyl, 2-ethylhexyl,

3.7-Dimethyloctyl and n-hexyl selected, with which good results have already been achieved.

In further aspects, the invention relates to the 2,5-di (alkylthio) -a, a'-dibromo-p-xylenes of the formula (3) prepared by the process according to the first aspect, in particular the following, by the inventors in the Examples of prepared compounds:

2,5-di (2-ethylhexylthio) -α, α'-dibromo-p-xylene (3a),

 2,5-di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene (3b),

 2,5-di (hexylthio) -a, a'-dibromo-p-xylene (3c),

2,5-di (dodecylthio) -a, a'-dibromo-p-xylene (3d), 2- (2-ethylhexylthio) -5-methylthio-a, a'-dibromo-p-xylene (3e),

2- (3,7-Dimethyloctylthio) -5-methylthio-a, a'-dibromo-p-xylene (3f),

2-hexylthio-5-methylthio-a, a'-dibromo-p-xylene (3g) and

2-dodecylthio-5-methylthio-a, a'-dibromo-p-xylene (3h),

and their use as monomers in polymerization reactions for the preparation of alkylthio-substituted poly (p-phenylene-vinylene) polymers (S-PPVs) (4) with elimination of hydrogen bromide in the presence of a base (analogous to the Gilch reaction):

 (3) (4)

For this purpose, according to the present invention, the respective 2,5-di (alkylthio) - a, a'-dibromo-p-xylene in a dry solvent, preferably THF, in the presence of potassium t-butoxide as a base at low temperatures from about -60 ° C to about -50 ° C, since the inventors were able to show that this reaction gives the best conversion in the preparation of S-PPVs (4).

For the production of PPVs and O-PPVs 2 ^nd Ed., Zhigang Rick Li (eds.), CRC Press, for example, in "Organic Light-Emitting Materials and Devices" (2015), for various types of Gilch Reaction temperatures disclosed between about 60 ° C and about 220 ° C in order to achieve the highest possible turnovers. In diametrical contrast, the present inventors have found that the preparation of S-PPVs should be carried out at low temperatures between about -60 ° C and about -50 ° C with subsequent heating to room temperature. In this way, yields of S-PPVs of more than 50% and over 90% could be achieved after only 5 h reaction time. In addition, the inventors have surprisingly been able to show that almost no polymers are obtained at even lower temperatures could be, as described in the later experimental part under "General procedure wise C".

This reaction temperature thus also constitutes a selection from the range disclosed in US Pat. No. 5,817,430 A between -78.degree. C. and 150.degree. C., as mentioned at the outset, wherein the practical examples for the preparation of O-PPVs were operated exclusively at room temperature and polymerized only in the single comparative example without addition of a regulator. However, the result of this no-controller polymerization at room temperature was a polymer that was "insoluble in typical organic solvents." In contrast, the inventors obtained in their poly merisationsreaktionen between about -60 ° C and -55 ° C or -50 ° C S-PPV polymers, all of which were soluble in common organic solvents.

In particularly preferred embodiments of the inventive use of the 2,5-di (alkylthio) -a, a'-dibromo-p-xylenes (3) prepared by the process according to the first aspect for the preparation of polymers, the alkylthio-substituted S PPVs (4) subsequently oxidized to alkylsulfone-substituted polymers (SO2-PPVS) (5):

 (4) (5)

The inventors are thus the first to whom an oxidation of S-PPVs to SO 2 PPVS, ie an oxidation of the first by polymerization of 2,5-di (alkylthio) -a, a'-di-bromo-p-xylenes (3 ) obtained S-PPVs (4) to SO2-PPVS (5), succeeded. The only SO2 PPV disclosed to date is the one mentioned in the beginning, by Hubijar et al. prepared Poly [2,5-di (2-ethylhexylsulfonyl) phenylene-vinylene] (referred to as SO2-EH-PPV, herein referred to as polymer (4a)) but obtained from a monomer already oxidized prior to polymerization, its subsequent polymerization , as mentioned, by means of Stille coupling under palladium catalysis over 24 h.

The oxidation of the present invention, however, takes place only after the polymerization using a conventional oxidizing agent, such as. H2O2, but preferably using dimethyldioxirane (DMDO), since the working group of the inventors had already had good experience with this oxidizing agent in the oxidation of other alkylthio-substituted polymers in the past (see Glöcklhofer et al., J. New J. Chem. 38, 2229-2232 (2014); Glöcklhofer et al., J. React., Funct Polym., 86, 16-26 (2015)). More preferably, the oxidation reaction is carried out by simply stirring a DMDO-added solution of the S-PPV (4) in a suitable solvent, e.g. Chloroform, carried out at room temperature.

In a further aspect, the present invention also relates to the products of the above polymerization reaction, i. Alkylthio-substituted poly (p-phenylene-vinylene) polymers (S-PPVs) of the formula (4) prepared according to the invention, in particular one of the following polymers:

 Poly [2,5-di (2-ethylhexylthio) phenylene-vinylene] (4a),

Poly [2,5-di (3,7-dimethyloctylthio) phenylene-vinylene] (4b),

Poly [2,5-di (hexylthio) phenylene-vinylene] (4c),

 Poly [2,5-di (dodecylthio) phenylene-vinylene] (4d),

Poly [2- (2-ethylhexylthio) -5-methylthiophenylenevinylene] (4e),

 Poly [2- (3,7-dimethyloctylthio) -5-methylthiophenylenevinylene] (4f),

Poly [2-hexylthio-5-methylthiophenylenevinylene] (4g) and

Poly [2-dodecylthio-5-methylthiophenylenevinylene] (4h). In a still further aspect, the present invention also relates to the products of the above oxidation reaction, ie alkylsulfonyl-substituted poly (p-phenylene-vinylene) -polymers (SO 2 -PSVS) of the formula (5) prepared according to the invention. In particular, the invention relates to one of the following polymers:

Poly [2,5-di (2-ethylhexylsulfonyl) phenylene-vinylene] (5a) having a number-average molecular weight M _n > 30,000 Da,

 Poly [2,5-di (3,7-dimethyloctylsulfonyl) phenylene-vinylene] (5b),

Poly [2,5-di (hexylsulfonyl) phenylene-vinylene] (5c),

Poly [2,5-di (dodecylsulfonyl) phenylene-vinylene] (5d),

Poly [2- (2-ethylhexylsulfonyl) -5-methylsulfonylphenylene-vinylene] (5e),

 Poly [2- (3,7-dimethyloctylsulfonyl) -5-methylsulfonylphenylene-vinylene] (5f),

Poly [2-hexylsulfonyl-5-methylsulfonylphenylene-vinylene] (5g) and

Poly [2-dodecylsulfonyl-5-methylsulfonylphenylene-vinylene] (5h). And in a final aspect, the invention relates to a number of novel 2,5-di (alkylthio) -a, a'-dibromo-p-xylene monomers of the formula (3) prepared and characterized by the inventors for the first time, namely those wherein R and R 'are each independently selected from saturated, linear, branched or cyclic C 1 -C 20 -alkyl radicals to give the following chemical compound:

2,5-di (2-ethylhexylthio) -a, α'-dibromo-p-xylene (3a):

; oder ,5-Di(3,7-dimethyloctylthio)-a,a'-dibrom-p-xylol (3b):

; or , 5-Di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene (3b):

, 5-Di (hexylthio) -a, a'-dibromo-p-xylene (3c):

, 5-Di (dodecylthio) -a, a'-dibromo-p-xylene (3d)

; oder -(2-Ethylhexylthio)-5-methylthio-a,a'-dibrom-p-xylol (3e):

; or - (2-ethylhexylthio) -5-methylthio-a, a'-dibromo-p-xylene (3e):

 (3e); or (3,7-Dimethyloctylthio) -5-methylthio-a, a'-dibromo-p-xylene (3f):

-Hexylthio-5-methylthio-a, a'-dibromo-p-xylene (3g):

2-Dodecylthio-5-methylthio-a,a'-dibrom-p-xylol (3h):

2-Dodecylthio-5-methylthio-a, a'-dibromo-p-xylene (3h):

EXAMPLES

The present invention will now be further described by way of illustrative examples, which, however, are to be considered as exemplary only and not as limiting the scope of protection as defined in the appended claims.

All starting materials and reagents were obtained from commercial sources and used directly without further purification, unless otherwise specified. The chemical names and abbreviations have the usual meanings commonly known to average professionals.

Examples 1 to 4, stage 1

 Preparation of 1, 4-di (alkylthio) benzenes (2a) to (2d) with identical alkyl radicals

Allgemeine Vorgangsweise zur Herstellung der Verbindungen (2a) bis (2d)

General procedure for the preparation of the compounds (2a) to (2d)

1,4-diiodobenzene (990 mg, 3.0 mmol, 1.0 equiv.), Cul (57 mg, 0.3 mmol, 0.1 equiv.) And K 3 PO 4 (2.61 g, 12.3 mmol, 4.1 equiv) were weighed into a 20 ml reaction vial and purged with argon. The respective alkyl thiol (6.6 mmol, 2.2 equiv) and 1, 2-dimethoxyethane (DME) as solvent (15 ml, 0.2 M) were charged into the vial in an argon stream, which was then sealed and stirred was heated to 180 ° C in a microwave oven. When 180 ° C was reached, which usually took about 15-20 minutes, this temperature was maintained for 2 hours. The reaction mixture was then poured onto 100 ml of water and extracted three times with CH 2 Cl 2 (2 × 100 ml, 1 × 50 ml). The combined organic phases were dried over Na 2 SO 4 and evaporated in vacuo. The residue was applied dry to a 40 g silica gel column (the respective compound was first dissolved in CH 2 Cl 2, 8 g of silica gel were added and the solvent was removed in vacuo) and using petroleum ether (PE) as the eluent by means of flash chromatography. Purified by chromatography.

Scale-up for the compounds (2a) and (2b):

In each case four batches were carried out in the microwave oven as described above, poured together onto 250 ml of water and extracted three times with CH 2 Cl 2 (2 × 200 ml, 1 × 100 ml). The combined organic phases were dried over Na 2 SO 4 and evaporated in vacuo. The residue was applied dry to a 90 g silica gel column (each compound first being dissolved in CH 2 Cl 2, 30 g of silica gel added and the solvent removed in vacuo) and using petroleum ether (PE) as eluent by flash Purified by chromatography.

Example 1, Step 1: Preparation of 1,4-di (2-ethylhexylthio) benzene (2a)

 (1a) (2a)

The synthesis was carried out according to the general procedure above using 2-ethylhexanethiol (966 mg, 1.15 ml, 6.6 mmol, 2.2 equiv.). Column chromatography revealed 838 mg (2.29 mmol, 76%) (2a) as a yellowish liquid. Scale-up: 3.96 g (10.8 mmol, 90%). ¹ H-NMR (600 MHz, CDCl 3): d = 7.23 (s, 4H), 2.87 (d, J = 6.4 Hz, 4H), 1.58-1.52 (m, 2H) , 1.51-1.33 (m, 8H), 1.32-1.22 (m, 8H), 0.91-0.85 (m, 12H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCl3): d = 135.0 (C), 129.7 (CH), 39.0 (CH / CH's), 38.6 (CH _2), 32.4 (CH ₂ ), 28.9 (CH ₂ ), 25.6 (CH ₂ ), 23.1 (CH ₂ ), 14.2 (CH / CHs), 10.9 (CH / CHs) ppm.

Example 2, Step 1: Preparation of 1,4-di (3.7-dimethyloctylthio) benzene (2b)

The synthesis was carried out according to the general procedure above using 3,7-dimethyloctanethiol (1.15 g, 6.6 mmol, 2.2 equiv.). Column chromatography gave 914 mg (2.16 mmol, 72%) (2b) as a yellowish liquid. Scale-up: 4.45 g (10.5 mmol, 88%). ¹ H-NMR (600 MHz, CDCl 3): d = 7.23 (s, 4H), 2.95-2.83 (m, 4H), 1.67-1.42 (m, 8H), 1, 32-1.19 (m, 6H), 1.16-1.08 (m, 6H), 0.89 (d, J = 6.6 Hz, 6H), 0.86 (d, J = 6, 7 Hz, 12H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCl3): d = 134.5 (C), 129.7 (CH), 39.3 (CH ₂ ), 37.0 (CH ₂ ), 36.3 (CH ₂ ), 32.4 (CH / CHs), 31, 9 (CH ₂ ), 28.1 (CH / CHs), 24.8 (CH ₂ ), 22.8 (CH / CHs), 22.7 (CH / CHs), 19.5 (CH / CHs) ppm.

Example 3, Step 1: Preparation of 1,4-di (hexylthio) benzene (2c)

 (1a) (2c)

The synthesis was carried out according to the general procedure above using 1-hexanethiol (780 mg, 0.94 ml, 6.6 mmol, 2.2 equiv.). Column chromatography afforded 661 mg (2.13 mmol, 71%) (2c) as a white solid. ¹ H-NMR (600 MHz, CDCls): d = 7.23 (s, 4H), 2.88 (t, J = 7.4 Hz, 4H), 1.62 (quint, J = 7.5 Hz , 4H), 1, 41 (quint, J = 7.4Hz, 4H), 1, 33-1, 24 (m, 8H), 0.88 (t, J = 6.9Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCls): d = 134.5 (C), 129.8 (CH), 34.1 (CH ₂ ), 31, 5 (CH ₂ ), 29.2 ( CH ₂ ), 28.6 (CH ₂ ), 22.7 (CH ₂ ), 14.2 (CHs) ppm.

Example 4, Step 1: Preparation of 1,4-di (dodecylthio) benzene (2d)

The synthesis was carried out according to the general procedure above using 1-dodecanethiol (1, 34 g, 1, 58 ml, 6.6 mmol, 2.2 equiv.). Column chromatography revealed 1.15 g (2.37 mmol, 79%) (2d) as a white solid. ¹ H-NMR (600 MHz, CDCls): d = 7.23 (s, 4H), 2.88 (t, J = 7.4 Hz, 4H), 1.62 (quint, J = 7.5 Hz , 4H), 1, 40 (quint, J = 7.4Hz, 4H), 1, 32-1, 21 (m, 32H), 0.88 (t, J = 7.0Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCls): d = 134.5 (C), 129.7 (CH), 34.1 (CH ₂ ), 32.1 (CH ₂ ), 29.80 (CH ₂ ), 29.78 (CH ₂ ), 29.73 (CH ₂ ), 29.65 (CH ₂ ), 29.5 (CH ₂ ), 29.31 (CH ₂ ), 29.27 (CH ₂ ), 29.0 (CH ₂ ), 22.8 (CH ₂ ), 14.3 (CHs) ppm.

Examples 5 to 8, step 1

Preparation of 1-ald-4- (methylthio) benzene (1 b)

 (1 a) (1 b)

1,4-Diiodobenzene (4.95 g, 15.0 mmol, 1.0 equiv.) Was weighed into a 250 ml three-necked round bottom flask equipped with a septum, thermometer and argon balloon. The flask was purged with argon and 150 mL of dry dimethyl ether (Et ₂ O) was added to dissolve the starting material. The reaction mixture was stirred and cooled to -80 ° C using a cooling bath of acetone and liquid N ₂ . Subsequently, 6.6 ml of n-BuLi (2.5 M in hexane, 16.5 mmol, 1.1 equiv.) Was added slowly and the reaction mixture was stirred for 40 minutes while allowing to warm slowly to -65 ° C. Thereafter, the reaction mixture was cooled to -70 ° C, and elemental sulfur (553 mg, 17.25 mmol, 1.15 equiv.) Was added all at once. The reaction mixture was stirred again for 40 minutes after which time methyl iodide (4.26 g, 1.87 mL, 30.0 mmol, 2.0 equiv.) Was added. The reaction mixture was then left in the cooling bath and allowed to warm slowly to room temperature overnight. Thereafter, 90 ml of a saturated aqueous NH ₄ Cl solution was added and the mixture into a

Transfer separating funnel. After phase separation, the aqueous phase was extracted three times with Et ₂ O (2 × 100 ml, 1 × 50 ml). The combined organic phases were washed with water and brine, dried over Na ₂ SO ₄ and evaporated in vacuo to give 3.31 g (13.2 mmol, 88%) of the crude compound (1 b), which was then allowed to crystallize slowly. ¹ H-NMR (400 MHz, CDCl 3): d = 7.57 (d, J = 8.5 Hz, 2H), 6.99 (d, J = 8.6 Hz, 2H), 2.45 (s, 3H ) ppm (without impurity signals). ¹³ C-NMR (APT) (100 MHz, CDCl 3): d = 138.7 (C), 137.7 (CH), 128.3 (CH), 89.3 (C), 15.8 (CH 3) ppm (without impurity signals).

Examples 5 to 8, stage 2

Preparation of 1, 4-di (alkylthio) benzenes (2e) to (2h) with different alkyl radicals

General Procedure for Preparing Compounds (2e) to (2h)

Crude 1-ald-4- (methylthio) benzene (1b) (750mg, 3.0mmol, 1.0 equiv.), Cul (57mg, 0.3mmol, 0.1 equiv.) And K3PO4 ( 2.61 g, 12.3 mmol, 4.1 equiv) were weighed into a 20 ml reaction vial and purged with argon. The respective alkylthiol (3.6 mmol, 1.2 equiv) and 1,2-dimethoxyethane (DME) as solvent (15 ml, 0.2 M) were purged with argon and filled into the vial, after which it was sealed and heated to 180 ° C with stirring in a microwave oven. When 180 ° C was reached, which usually took about 15-20 minutes, this temperature was maintained for 2 hours. The reaction mixture was then poured into 100 ml of water and extracted three times with CH 2 Cl 2 (2 × 100 ml, 1 × 50 ml). The combined organic phases were dried over Na 2 SO 4 and evaporated in vacuo. The residue was applied dry to a 40 g silica gel column (first dissolving the respective compound in CH 2 Cl 2, adding 6 g of silica gel and removing the solvent in vacuo) and using petroleum ether (PE) as eluent by flash Purified by chromatography. Example 5, Step 2: Preparation of 1- (2-ethylhexylthio) -4-methylthiobenzene (2e)

 (1 b) (2e)

The synthesis was carried out according to the general procedure above using 2-ethylhexanethiol (527 mg, 0.62 ml, 3.6 mmol, 1.2 equiv.). Column chromatography revealed 643 mg (2.39 mmol, 80%) (2e) as a yellowish liquid. ¹ H-NMR

(600 MHz, CDCls): d = 7.26 (d, J = 8.5 Hz, 2H), 7.17 (d, J = 8.5 Hz, 2H), 2.86 (d, J =

6.4 H, 2H), 2.47 (s, 3H), 1.54 (sept, J = 6.3 Hz, 1H), 1, 51-1, 33 (m, 4H), 1, 32 -1, 21 (m, 4H), 0.91-0.85 (m, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCl3): d = 135.9 (C), 134.3 (C), 130.0 (CH), 127.5 (CH), 39.0 (CH / CHs), 38.8 (CH 2), 32.4 (CH 2), 28.9 (CH 2), 25.6 (CH 2), 23.1 (CH 2), 16.3 (CH / CHs), 14.2 (CH / CHs), 10.9 (CH / CHs) ppm.

Example 6, Step 2: Preparation of 1- (3,7-dimethyloctylthio) -4-methylthiobenzene (20

The synthesis was carried out according to the general procedure above using 3,7-dimethyloctanethiol (628 mg, 3.6 mmol, 1.2 equiv.). Column chromatography revealed 704 mg (2.37 mmol, 79%) (2f) as a yellowish liquid. ¹ H-NMR (600 MHz, CDCl 3): d = 7.26 (d, J = 8.5 Hz, 2H), 7.18 (d, J = 8.5 Hz, 2H), 2.95-2 , 82 (m, 2H), 2.47 (s, 3H), 1, 66-1, 40 (m, 4H), 1, 32-1, 18 (m, 3H), 1, 16-1, 07 (m, 3H), 0.88 (d, J = 6.6Hz, 3H), 0.86 (d, J = 6.6Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCl3): d = 136.2 (C), 133.6 (C), 130.1 (CH), 127.4 (CH), 39.3 (CH2) , 37.0 (CH 2), 36.4 (CH 2), 32.3 (CH / CHs), 32.2 (CH 2), 28.1 (CH / CHs), 24.8 (CH 2), 22.8 (CH / CHs), 22.7 (CH / CHs), 19.5 (CH / CHs), 16.3 (CH / CHs) ppm.

Example 7, Step 2: Preparation of 1-hexylthio-4-methylthiobenzene (2q)

 (1 b) (2g)

The synthesis was carried out according to the general procedure above using 1-hexanethiol (426 mg, 0.51 ml, 3.6 mmol, 1.2 equiv.). Column chromatography gave 568 mg (2.36 mmol, 79%) (2 g) as a white solid. ¹ H-NMR (600 MHz,

CDCls): d = 7.26 (d, J = 8.5 Hz, 2H), 7.18 (d, J = 8.5 Hz, 2H), 2.87 (t, J = 7.3 Hz, 2H),

2.47 (s, 3H), 1, 61 (quint, J = 7.5Hz, 2H), 1.40 (quint, J = 7.4Hz, 2H), 1, 33-1, 24 (m , 4H), 0.88 (t, J = 7.0 Hz, 3H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCl3): d = 136.2 (C), 133.6 (C), 130.2 (CH), 127.4 (CH), 34.3 (CH2) , 31, 5 (CH2), 29.3 (CH2), 28.6 (CH2), 22.7 (CH2), 16.3 (CHs), 14.2 (CHs) ppm. Example 8, Step 2: Preparation of 1-dodecylthio-4-methylthiobenzene (2h)

The synthesis was carried out according to the general procedure above using 1-dodecanethiol (729 mg, 0.86 ml, 3.6 mmol, 1.2 equiv.). Column chromatography revealed 759 mg (2.34 mmol, 78%) (2 h) as a white solid. ¹ H-NMR (600 MHz, CDCl 3): d = 7.26 (d, J = 8.5 Hz, 2H), 7.18 (d, J = 8.5 Hz, 2H), 2.87 (t , J = 7.4 Hz, 2H), 2.47 (s, 3H), 1, 61 (quint, J = 7.5Hz, 2H), 1, 39 (quint, J = 7.3Hz, 2H), 1, 32-1, 21 (m, 16H), 0.88 (t, J = 7.2 Hz, 3H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCls): d = 136.2 (C), 133.6 (C), 130.2 (CH), 127.4 (CH), 34.3 (CH ₂ ), 32.1 (CH ₂ ), 29.79 (CH ₂ ), 29.78 (CH ₂ ), 29.73 (CH ₂ ), 29.65 (CH ₂ ), 29.5 (CH ₂ ), 29.31 (CH ₂ ), 29.30 (CH ₂ ), 28.9 (CH ₂ ), 22.8 (CH ₂ ), 16.3 (CHs), 14.3 (CHs) ppm.

Examples 1 to 4, step 2; Examples 5 to 8, step 3

 Preparation of 2,5-di (alkylthio) -a, a'-dibromo-p-xylenes (3a) to (3h)

General Procedure for Preparing Compounds (3a) to (3c) and (3e) to (3h)

The respective 1,4-di (alkylthio) benzene (2) (2.0 mmol, 1.0 equiv.) And paraformaldehyde (PFA) (240 mg, 8.0 mmol, 4.0 equiv.) Were added to a Weighed out a 25 ml three-necked round-bottomed flask with a thermometer and a reflux condenser with drying tube (CaCl ₂ ). Thereafter, 10 ml of formic acid and 2.8 ml of HBr (30% in acetic acid) were added, and the reaction mixture was heated to 70 ° C. After 1 h, 2 h and 3 h of reaction time, each additional PFA (240 mg, 8.0 mmol, 4.0 equiv.) And 2.8 ml of HBr (30% in acetic acid) were added. The reaction mixture was stirred at 70 ° C overnight and then allowed to cool to room temperature to provide complete precipitation of the product. The precipitate was filtered off, washed with a small amount of methanol and dried in vacuo. The resulting solid was recrystallized from acetonitrile (with stirring to facilitate crystallization), filtered off and washed with a small amount of acetonitrile. Scale-up for the compounds (3a) and (3b):

 The reactions were carried out as described above, but with 10.0 mmol of 1, 4-di (alkylthio) benzene (2) and correspondingly larger amounts of reagents and Lösungsmit stuff done.

Example 1, Step 2: Preparation of 1,4-di (2-ethylhexylthio) -a, a'-dibromoxylol (3a)

 (2a) (3a)

The synthesis was carried out according to the general procedure above using 1, 4-di (2-ethylhexylthio) benzene (2a) (733 mg, 2.0 mmol, 1 equiv.). as a starting product. Recrystallization gave 780 mg (1.41 mmol, 71%) (3a) as a cream solid. Scale-up: 3.89 g (7.04 mmol, 70%). ¹ H-NMR (600 MHz, CDC): d = 7.36 (s, 2H), 4.64 (s, 4H), 2.93 (d, J = 6.2 Hz, 4H), 1.59 (sept, J = 6.3Hz, 2H), 1, 54-1, 36 (m, 8H), 1, 34-1, 24 (m, 8H), 0.92-0.88 (m, 12H ) ppm. ¹³ C-NMR (APT) (150 MHz, CDCl3): d = 138.3 (C), 135.7 (C), 131, 9 (CH), 39.1 (CH / CHs), 38.9 ( CH ₂ ), 32.5 (CH ₂ ), 31, 4 (CH ₂ ), 28.9 (CH ₂ ), 25.8 (CH ₂ ), 23.1 (CH ₂ ), 14.3 (CH / CHs), 11, 0 (CH / CHs) ppm.

Example 2, Step 2: Preparation of 1,4-di (3.7-dimethyloctylthio) -a, a'-dibromoxylol (3b)

 (2b) (3b)

The synthesis was carried out according to the general procedure above using 1, 4-di (3,7-dimethyloctylthio) benzene (2b) (846 mg, 2.0 mmol, 1 equiv.). as starting product. Recrystallization gave 793 mg (1.30 mmol, 65%) (3b) as an off-white solid. Scale-up: 4.75 g (7.81 mmol, 78%). ¹ H-NMR (600 MHz, CDCls): d = 7.36 (s, 2H), 4.63 (s, 4H), 3.02-2.90 (m, 4H), 1, 71-1, 56 (m, 4H), 1, 54-1, 45 (m, 4H), 1, 33-1, 20 (m, 6H), 1, 18-1, 09 (m, 6H), 0.91 ( d, J = 6.5 Hz, 6H), 0.86 (d, J = 6.6 Hz, 12H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCl 3): d = 138.3 (C), 135.2 (C), 131, 8 (CH), 39.3 (CH ₂ ), 37.0 (CH ₂ ), 36.2 (CH ₂ ), 32.4 (CH / CHs), 32.2 (CH ₂ ), 31, 3 (CH ₂ ), 28.1

(CH / CHs), 24.8 (CH ₂ ), 22.9 (CH / CHs), 22.8 (CH / CHs), 19.5 (CH / CHs) ppm.

Example 3, Step 2: Preparation of 1,4-di (hexylthio) -a, a'-dibromoxylol (3c)

(2c) (3c)

The synthesis was carried out according to the general procedure above using 1, 4-di (hexylthio) benzene (2c) (621 mg, 2.0 mmol, 1 equiv.). as a starting product. Recrystallization gave 618 mg (1.24 mmol, 62%) (3c) as a white solid. ¹ H-NMR (600 MHz, CDCls): d = 7.35 (s, 2H), 4.63 (s, 4H), 2.95 (t, J = 7.4 Hz, 4H), 1.66 (quint, J = 7.5Hz, 4H), 1.44 (quint, J = 7.4Hz, 4H), 1.35-1.26 (m, 8H), 0.89 (t, J = 7.0 Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCls): d = 138.3 (C), 135.2 (C), 131, 9 (CH), 34.4 (CH ₂ ), 31.5 (CH ₂ ), 31, 3 (CH ₂ ), 29.1 (CH ₂ ), 28.7 (CH ₂ ), 22.7 (CH ₂ ), 14.2 (CH 3) ppm.

Example 4, Step 2: Preparation of 1, 4-di (dodecylthio) -a.g'-dibromoxylol (3cl)

1,4-Di (dodecylthio) benzene (2d) (1.20 g, 2.5 mmol, 1.0 equiv.) And paraformaldehyde (PFA) (450 mg, 15.0 mmol, 6.0 equiv weighed in a 20 ml reaction vial. Trifluoroacetic acid (2.5ml, 0.1M), trifluoroacetic anhydride (0.5ml) and 1.75ml HBr (30% in acetic acid) were added, the vial was sealed, the contents stirred and on for 24 hours Heated to 80 ° C. The reaction mixture was then allowed to cool to room temperature, forming a precipitate which was filtered off and washed with water and methanol. The resulting solid was purified by recrystallization from acetonitrile to give 838 mg (1.26 mmol, 50%) (3d) as a white solid. ¹ H-NMR (600 MHz, CDCl 3): d = 7.35 (s, 2H), 4.63 (s, 4H), 2.95 (t, J = 7.4 Hz, 4H), 1.66 (quint, J = 7.5Hz, 4H), 1, 43 (quint, J = 7.3Hz, 4H), 1, 33-1, 22 (m, 32H), 0.88 (t, J = 7.0 Hz, 6H) ppm. ¹³ C-NMR

(APT) (150 MHz, CDCl 3): d = 138.3 (C), 135.2 (C), 131, 9 (CH), 34.4 (CH 2), 32.1 (CH 2), 31, 3 (CH 2), 29.80 (CH 2), 29.79 (CH 2), 29.7 (CH 2), 29.6 (CH 2), 29.5 (CH 2), 29.3 (CH 2), 29.1 ( CH2), 29.0 (CH2), 22.8 (CH2), 14.3 (CHs) ppm. Example 5, Step 3: Preparation of 1- (2-ethylhexylthio) -4-methylthio-a, a'-dibromoxylol

(2e) (3e)

The synthesis was carried out according to the general procedure above using 1 - (2-ethylhexylthio) -4-methylthiobenzene (2e) (537 mg, 2.0 mmol, 1 equiv.). as starting product. Recrystallization gave 498 mg (1.10 mmol, 55%) (3e) as a cream solid. ¹ H-NMR (600 MHz, CDCls): d = 7.36 (s, 1H), 7.27 (s, 1H), 4.66 (s, 2H), 4.59 (s, 2H) , 2.92 (d, J = 6.2 Hz, 2H), 2.52 (s, 3H), 1, 61-1, 36 (m, 5H), 1, 34-1, 24 (m, 4H ), 0.90 (t, J = 7.4 Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCls): d = 138.7 (C), 136.75 (C), 136.66 (C), 135.0 (C), 132.1 (CH) , 129.2 (CH), 39.12 (CH / CHs), 39.11 (CH ₂ ), 32.5 (CH ₂ ), 31, 5 (CH ₂ ), 31, 0 (CH ₂ ), 28 , 9 (CH ₂ ), 25.7 (CH ₂ ), 23.1 (CH ₂ ), 16.5 (CH / CHs), 14.2 (CH / CHs), 10.9 (CH / CHs) ppm ,

Example 6, Step 3: Preparation of 1- (3.7-dimethyloctylthio) -4-methylthio-a, a'-dibromo-xylene (30

 (2f) (30

The synthesis was carried out according to the general procedure above using 1 - (3,7-dimethyloctylthio) -4-methylthiobenzene (2f) (593 mg, 2.0 mmol, 1.0 equiv.). as starting product. Recrystallization gave 578 mg (1.20 mmol, 60%) (3f) as a cream solid. ¹ H NMR (600 MHz, CDC): d = 7.35 (s, 1H), 7.27 (s, 1H), 4.66 (s, 2H), 4.59 (s, 2H) , 3.01-2.89 (m, 2H), 2.53 (s, 3H), 1, 70-1, 44 (m, 4H), 1, 33-1, 19 (m, 3H), 1 , 17-1, 09 (m, 3H), 0.91 (d, J = 6.6 Hz, 3H), 0.86 (d, J = 6.6 Hz, 6H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCl3): d = 138.8 (C), 136.9 (C), 136.7 (C), 134.3 (C), 132.1 (CH) , 129.2 (CH), 39.3 (CH 2), 37.0 (CH 2), 36.2 (CH 2), 32.43 (CH 2), 32.39 (CH / CHs), 31, 4 (CH 2 ), 31, 0 (CH2), 28.1 (CH / CHs), 24.8 (CH2), 22.9 (CH / CHs), 22.8 (CH / CHs), 19.5 (CH / CHs ), 16.5 (CH / CHs) ppm.

Example 7, Step 3: Preparation of 1-Hexylthio-4-methylthio-a.q'-dibromoxylol (3q)

 (2g) (3g)

The synthesis was carried out according to the general procedure above using 1-hexylthio-4-methylthiobenzene (2g) (481 mg, 2.0 mmol, 1.0 equiv.). as a starting product. Recrystallization gave 538 mg (1.26 mmol, 63%) (3 g) as a cream solid. ¹ H NMR (600 MHz, CDCls): d = 7.35 (s, 1H), 7.27 (s, 1H), 4.66 (s, 2H), 4.59 (s, 2H) , 2.94 (t, J = 7.5Hz, 2H), 2.53 (s, 3H), 1.65 (quint, J = 7.5Hz, 2H), 1.44 (quint, J = 7.4Hz, 2H), 1, 34-1, 26 (m, 4H), 0.89 (t, J = 7.0, 3H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCls): d = 138.8 (C), 136.9 (C), 136.7 (C), 134.3 (C), 132.2 (CH) , 129.2 (CH), 34.6 (CH ₂ ), 31, 5 (CH ₂ ), 31, 4 (CH ₂ ), 31, 0 (CH ₂ ), 29.1 (CH ₂ ), 28, 6 (CH ₂ ),

22.7 (CH ₂ ), 16.5 (CHs), 14.2 (CHs) ppm.

Example 8, Step 3: Preparation of 1-dodecylthio-4-methylthio-a.q'-dibromoxylol (3h)

Die Synthese erfolgte gemäß der obigen allgemeinen Vorgangsweise unter Verwen dung von 1 -Hexylthio-4-methylthiobenzol (2g) (481 mg, 2,0 mmol, 1 ,0 Äquiv.). als Aus gangsmaterial, wobei in diesem Fall jedoch statt auf 70 °C auf 80 °C erhitzt wurde. Die Umkristallisation ergab 721 mg (1 ,41 mmol, 71 %) (3h) als cremefarbenen Feststoff. ¹H-NMR (600 MHz, CDCls): d = 7,35 (s, 1 H), 7,27 (s, 1 H), 4,66 (s, 2H), 4,59 (s, 2H), 2,94 (t, J = 7,4 Hz, 2H), 2,53 (s, 3H), 1 ,65 (quint, J = 7,5 Hz, 2H), 1 ,43 (quint, J = 7,5 Hz, 2H), 1 ,33-1 ,22 (m, 16H), 0,88 (t, J = 7,0 Hz, 3H) ppm. ¹³C-NMR (APT) (150 MHz, CDCls): d = 138,8 (C), 136,9 (C), 136,7 (C), 134,3 (C), 132,2 (CH), 129,2 (CH), 34,6 (CH₂), 32,1 (CH₂), 31 ,4 (CH₂), 31 ,0 (CH₂), 29,80 (CH₂), 29,78 (CH₂), 29,7 (CH₂), 29,6 (CH₂), 29,5 (CH₂), 29,3 (CH₂), 29,1 (CH₂), 29,0 (CH₂), 22,8 (CH₂), 16,5 (CHs), 14.3

The synthesis was carried out according to the general procedure above using 1-hexylthio-4-methylthiobenzene (2g) (481 mg, 2.0 mmol, 1.0 equiv.). as starting material, in which case, however, was heated to 80 ° C instead of 70 ° C. Recrystallization gave 721 mg (1.41 mmol, 71%) (3 h) as a cream solid. ¹ H NMR (600 MHz, CDCls): d = 7.35 (s, 1H), 7.27 (s, 1H), 4.66 (s, 2H), 4.59 (s, 2H) , 2.94 (t, J = 7.4 Hz, 2H), 2.53 (s, 3H), 1.65 (quint, J = 7.5 Hz, 2H), 1.43 (quint, J = 7.5 Hz, 2H), 1, 33-1, 22 (m, 16H), 0.88 (t, J = 7.0 Hz, 3H) ppm. ¹³ C-NMR (APT) (150 MHz, CDCls): d = 138.8 (C), 136.9 (C), 136.7 (C), 134.3 (C), 132.2 (CH) , 129.2 (CH), 34.6 (CH ₂ ), 32.1 (CH ₂ ), 31, 4 (CH ₂ ), 31, 0 (CH ₂ ), 29.80 (CH ₂ ), 29, 78 (CH ₂ ), 29.7 (CH ₂ ), 29.6 (CH ₂ ), 29.5 (CH ₂ ), 29.3 (CH ₂ ), 29.1 (CH ₂ ), 29.0 ( CH ₂ ), 22.8 (CH ₂ ), 16.5 (CHs), 14.3

(CH3) ppm.

Examples 1 to 4, Step 3: Examples 5 to 8, Step 4

 Preparation of poly [2,5-di (alkylthio) phenylene-vinylene] polymers (4a) to (4h)

 (3) (4)

General procedure for the preparation of the S-PPV polymers

A) At room temperature:

The respective 2,5-di (alkylthio) -a, a'-dibromo-p-xylene (3) (0.30 mmol, 1 equiv) was added to a 100 ml three-necked flask equipped with a septum and an argon balloon. Weighed in a round bottom flask. The flask was purged with argon and 30 ml of degassed, dry THF was added. The resulting solution was sparged with argon for 15 minutes. In the meantime, 1.5 mL of potassium tert-butoxide (KO / Bu) (1.0 M in THF, 1.50 mmol, 5.0 equiv.) Was diluted with 3 mL of dry THF (to precipitate) Prevent) bubbled with argon for 2 min and then added all at once into the flask. The reaction mixture was stirred for 5 hours at room temperature and then slowly poured into 150 ml of methanol to precipitate the product. The resulting solid was filtered off and dried in vacuo to determine the crude yield. For purification, the solid was treated in a Soxhlet extractor first with methanol (1 h) and then with flexan (1 h) to remove impurities. Finally, the soluble fraction was extracted with CFICI3 and evaporated to leave the respective pure polymer as a red solid.

B) At -60 ° C:

 The above procedure was repeated except that the solution of monomer (3) and THF was cooled to -60 ° C by means of a cooling bath of CHCl 3 and liquid N 2 before the KO / Bu solution was added to allow polymerization and the reaction mixture for 3 hours at -60 ° C to -55 ° C, then heated to room temperature within 1 h and then stirred for a further 1 h at room temperature. The workup and purification were analogous to above.

C) At -70 ° C:

 The above procedure B) was repeated except that the solution of monomer (3) and THF was cooled to -70 ° C and the reaction mixture was kept at -70 ° C for 3 hours. After analogous work-up and purification as above wur only the smallest amounts of red solid with yields in the range of 1% to 2% d. Th. Received.

Scale-up for the compounds (4a) and (4b):

The reactions were carried out in accordance with procedure B) above, but in a 250 ml three-necked round-bottom flask and using 1.0 mmol of the monomers (3) as starting material and correspondingly larger amounts of KO / Bu solution and solvents , The monomer solution was bubbled with argon for 30 minutes, the Ko / Bu solution for 4 minutes. Example 1, Step 3: Preparation of Polv [2,5-di (2-ethylhexylthio) phenylene-vinylene 1 (4a)

 (3a) (4a)

 The synthesis was carried out according to the general procedure above using 2,5-di (2-ethylhexylthio) -α, α'-dibromo-p-xylene (3a) (166 mg, 0.30 mmol, 1 equiv.). as starting product. The yields were as follows:

 A) at room temperature: crude yield 71 mg (61%) and pure yield 65 mg (55%)

B) at -60 ° C: crude yield 85 mg (73%) and pure yield 79 mg (68%), in the scale-up: crude yield 352 mg (90%), pure yield 346 mg (89%), each on red solid (4a);

C) at -70 ° C: Crude yield 1, 1 mg (1%) of red solid, which was not further purified or characterized.

Example 2, Step 3: Preparation of Polv di (3,7-dimethyloctylthio) phenylene-vinylene1,44bl

 The synthesis was carried out according to the general procedure above using 2,5-di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene (3b) (183 mg, 0.30 mmol, 1 equiv .). as starting product. The yields were as follows:

 A) at room temperature: crude yield 70 mg (52%) and pure yield 63 mg (47%)

B) at -60 ° C. Crude yield 86 mg (64%) and pure yield 75 mg (56%), in scale-up: crude yield 342 mg (77%), pure yield 299 mg (67%), in each case on red solid. Cloth (4b);

C) at -70 ° C: crude yield 2.7 mg (2%) of red solid which has not been further purified or characterized.

Example 3, Step 3: Preparation of Polv di (hexylthio) phenylene-vinylene1 (4c)

 The synthesis was carried out according to the above general procedure B) at -60 ° C using 2,5-di (hexylthio) -a, a'-dibromo-p-xylene (3c) as starting material in yields of 62% (crude) or 19% (in).

Example 4, Step 3: Preparation of Polv [2,5-di (dodecylthio) phenylene-vinylene 1 (4d)

Die Synthese erfolgte gemäß der obigen allgemeinen Vorgangsweise B) bei -60 °C unter Verwendung von 2,5-Di(dodecylthio)-a,a'-dibrom-p-xylol (3d) als Ausgangspro dukt mit Ausbeuten von 60 % (roh) bzw. 17 % (rein). Beispiel 5, Stufe 4: Herstellung von Poly[2-(2-ethylhexylthio)-5-methylthiophenylen- vinylenl (4e)

The synthesis was carried out according to the above general procedure B) at -60 ° C using 2,5-di (dodecylthio) -a, a'-dibromo-p-xylene (3d) as starting product with yields of 60% (crude ) or 17% (in). Example 5, Step 4: Preparation of poly [2- (2-ethylhexylthio) -5-methylthiophenylenevinylene (4e)

 (3e) (4e)

 The synthesis was carried out according to the above general procedure B) at -60 ° C using 2- (2-ethylhexylthio) -5-methylthio-a, a'-dibromo-p-xylene (3e) as starting material in yields of 67% (raw) or 4% (pure).

Example 6, Step 4: Preparation of Polyr2- (3,7-dimethyloctylthio) -5-methylthiophenylene-vinylene (4f)

Die Synthese erfolgte gemäß der obigen allgemeinen Vorgangsweise B) bei -60 °C unter Verwendung von 2-(3,7-Dimethyloctylthio)-5-methylthio-a,a'-dibrom-p-xylol (3f) als Ausgangsprodukt mit Ausbeuten von 49 % (roh) bzw. 6 % (rein). Beispiel 7, Stufe 4: Herstellung von Poly[2-hexylthio-5-methylthiophenylen-vinylen1 (4q)

The synthesis was carried out according to the above general procedure B) at -60 ° C using 2- (3,7-dimethyloctylthio) -5-methylthio-a, a'-dibromo-p-xylene (3f) as starting material in yields of 49% (raw) and 6% (pure). Example 7, Step 4: Preparation of poly [2-hexylthio-5-methylthiophenylene-vinylene 1 (4q)

 (3g) (4g)

The synthesis was carried out according to the above general procedure B) at -60 ° C using 2-hexylthio-5-methylthio-a, a'-dibromo-p-xylene (3g) as starting product in yields of 41% (crude ) or 8% (pure).

Example 8, Step 4: Preparation of poly [2-dodecylthio-5-methylthiophenylene-vinylene1 i

 The synthesis was carried out according to the above general procedure B) at -60 ° C using 2-dodecylthio-5-methylthio-a, a'-dibromo-p-xylene (3h) as a starting product with yields of 37% (crude) or 5% (in).

The optimization of the polymerization conditions for the preparation of the S-PPVs, in particular with regard to the selection of the solvent, since in some cases precipitation of the product during the polymerization, has been the subject of much research.

Examples 1 to 4, step 4; Examples 5 to 8, step 5

 Preparation of poly [2,5-di (alkylsulfonyl) phenylene-vinylene] polymers (5a) to (5h)

 (4) (5)

General procedure for the preparation of the SÖ ₂ -PPV polymers

The respective poly [2,5-di (alkylthio) phenylene-vinylene-1 polymer (4) obtained according to procedure B) was dissolved in 30 ml of CHCl 3 and 8.8 ml of dimethyl dioxirane (DMDO) (0.077 M in acetone, 0.68 mmol, 4.5 equiv.) Were added and the reaction mixture was stirred for 10 minutes at room temperature, after which the solvent and excess DMDO were distilled off to leave the respective oxidized polymer as a yellow solid.

Example 1, Step 4: Preparation of Polv [2,5-di (2-ethylhexylsulfonyl) phenylene-vinylene] 1al

 (4a) (5a)

The synthesis was carried out according to the above general procedure using poly [2,5-di (2-ethylhexylthio) phenylene-vinylene] (4a) as the starting material, wherein the polymer (5a) was obtained as a pale yellow solid in quantitative yield. Polymer (5a) proved to be insoluble in all common solvents.

Example 2, Step 4: Preparation of Polv [2,5-di (3.7-dimethyloctylsulfonyl) phenylene-vinylene (5b)

The synthesis was carried out according to the general procedure above using poly [2,5-di (3,7-dimethyloctylthio) phenylene-vinylene] (4b) as the starting product, wherein the polymer (5b) as an orange-yellow solid in quantitative Yield was obtained. Polymer (5b) proved to be insoluble in all common solvents.

Example 3, Step 4: Preparation of Polv [2,5-di (hexylsulfonyl) phenylene-vinylene 1 (5c)

 (4c) (5c)

The synthesis was carried out according to the above general procedure using poly [2,5-di (hexylthio) phenylene-vinylene] (4c) as the starting material, the polymer (5c) was obtained as a yellow solid in quantitative yield. Polymer (5c) proved to be insoluble in all common solvents.

Example 4, Step 4: Preparation of Polv [2,5-di (dodecylsulfonyl) phenylene-vinylene1 (5d)

Die Synthese erfolgte gemäß der obigen allgemeinen Vorgangsweise unter Verwen dung von Poly[2,5-di(dodecylthio)phenylen-vinylen] (4d) als Ausgangsprodukt, wobei das Polymer (5d) als gelber Feststoff in quantitativer Ausbeute erhalten wurde. Poly mer (5d) erwies sich als in allen gängigen Lösungsmitteln unlöslich.

The synthesis was carried out according to the general procedure above using poly [2,5-di (dodecylthio) phenylene-vinylene] (4d) as the starting material, the polymer (5d) being obtained as a yellow solid in quantitative yield. Polymer (5d) was found to be insoluble in all common solvents.

Example 5, Step 5: Preparation of poly [2- (2-ethylhexylsulfonyl) -5-methylsulfonyl-phenylene-vinylene (5e)

The synthesis was carried out according to the general procedure above using poly [2- (2-ethylhexylthio) -5-methylthiophenylenevinylene] (4e) as starting product, the polymer (5e) being obtained as a yellow solid in quantitative yield , Polymer (5e) proved to be insoluble in all common solvents.

Example 6, Step 5: Preparation of Polv [2- (3,7-dimethyloctylsulphonyl) -5-methylsulphonylphenylene-vinylene (50

 The synthesis was carried out according to the general procedure above using poly [2- (3,7-dimethyloctylthio) -5-methylthiophenylenevinylene] (4f) as starting material, the polymer (5f) as a yellow solid in quantitative yield was obtained. Polymer (5f) proved to be insoluble in all common solvents. Example 7, Step 5: Preparation of poly [2-hexylsulfonyl-5-methylsulfonylphenylene-vinylene (5q)

Die Synthese erfolgte gemäß der obigen allgemeinen Vorgangsweise unter Verwen dung von Poly[2-hexylthio-5-methylthiophenylen-vinylen] (4g) als Ausgangsprodukt, wobei das Polymer (5g) als gelber Feststoff in quantitativer Ausbeute erhalten wurde. Polymer (5g) erwies sich als in allen gängigen Lösungsmitteln unlöslich.

The synthesis was carried out according to the above general procedure using poly [2-hexylthio-5-methylthiophenylen-vinylene] (4g) as the starting material, wherein the polymer (5g) was obtained as a yellow solid in quantitative yield. Polymer (5g) proved to be insoluble in all common solvents.

Example 8, Step 5: Preparation of poly [2-dodecylsulfonyl-5-methylsulfonylphenylenevinylene (5h)

 The synthesis was carried out according to the general procedure above using poly [2-dodecylthio-5-methylthiophenylenevinylene] (4h) as starting product, the polymer (5h) being obtained as a yellow solid in quantitative yield. Polymer (5h) proved to be insoluble in all common solvents.

Molar masses of the SÖ2-PPV polymers:

Due to the insolubility of the oxidized polymers in all common solvents a direct molecular weight determination was impossible. Based on first results of GPC molecular weight determinations of the precursors, ie the S-PPVs (4a) to (4h), and assuming that the degree of polymerization does not change appreciably during the oxidation reaction to the sulfonyl-substituted polymers, However, it can be determined with almost certain probability that at least the two oxidized polymers of Examples 1 and 2, ie poly [2,5-di (2-ethylhexylsulfonyl) phenylene-vinylene] (5a) and poly [2,5-di (3,7-dimethyloctylsulfonyl) phenylene-vinylene] (5b) have a number average molecular weight M _n of at least 30,000 Da and a weight average molecular weight M _w of at least 90,000 Da.

This corresponds in each case to approximately three times those values given for the hitherto only poly [2,5-di (alkylsulfonyl) phenylene-vinylene] polymer sufficiently characterized in the literature, namely the polymer designated as SO2EH-PPV according to Hubijar et al ., for which a M _n of 10,600 Da and a M _w of 27,800 Da are cited.

Although this literature known SO2-PPV formally corresponds to the poly [2,5-di (2-ethyl-hexylsulfonyl) phenylene-vinylene] (5a) according to the present invention, but it was in completely different ways, namely as mentioned above by polymerization tion of a already oxidized monomer. The latter was also not a di (alkylsulfonyl) dibromoxylol, which is converted by homopolymerization to SO2-PPV, but a di (alkylsulfonyl) dibromobenzene, with trans-1, 2-bis (tri-n-butylstannyl) - ethylene under palladium catalyzed Stille coupling was copolymerized, which is a logical explanation for the skilled person that Hubijar et al. could obtain a polymer of relatively low molecular weight.

As a consequence, the SO2 PPV has, according to Hubijar et al. but also properties which differ significantly from those of poly [2,5-di (2-ethylhexylsulfonyl) phenylene-vinylene] (5a) according to the present invention - especially good solubility in gän gigen organic solvents ("soluble in common organic solvents, such as THF, chloroform and toluene "). This good solubility is described by Hubijar et al. attributed to the two alkylsulfonyl side chains, which, in view of the insolubility of the two inventive SO2-PPVS (5a) and (5b) in all common solvents seems to be inaccurate. Because of these enormous differences, there is no doubt that the product of Hubijar et al. is a substance other than the high molecular weight poly [2,5-di (2-ethylhexylsulfonyl) phenylene-vinylene] (5a) of the present invention, therefore the SO 2-PPV (5a) having a number average molecular weight M _n > 30,000 Da is also in the Scope of the present invention should lie.

Claims

1. A process for the preparation of 2,5-di (alkylthio) -α, α'-dibromo-p-xylenes of the formula (3),

wherein R and R 'are each independently selected from saturated, linear, branched or cyclic C 1 -C 20 -alkyl radicals, comprising the reaction of 1,4-diiodobenzene (1 a) to 1,4-di (alkylthio) benzenes (2) and their para-bromomethylation by reaction with formaldehyde (CH 2 O) in the presence of hydrogen bromide (HBr) to give the corresponding 2 , 5-di (alkylthio) -a, a'-dibromo-p-xylenes (3), where either  i) when R = R ', 1, 4-diiodobenzene (1 a) directly with 2 moles of thiol of the formula R-SFI using copper (I) iodide (Cul) as catalyst and of potassium phosphate (K3PO4) as base at temperatures> 160 ° C to the corresponding 1, 4-di (alkylthio) - benzene (2) and then by reaction with formaldehyde in formic acid (FICOOFI) or a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) as the reaction medium and adding a Reacted solution of hydrogen bromide (FIBr) to the corresponding 2,5-di (alkylthio) -a, a'-dibromo-p-xylene (3):

or ii) when RFR 'is 1, 4-diiodobenzene (1 a) first with 1 mol of alkyl iodide of the formula Rl to the corresponding 4- (alkylthio) iodobenzene (1 b), then with 1 mol of thiol of the formula R'-SH to the mixed 1, 4-di (alkylthio) benzene (2) and finally in analogous Wei as above with formaldehyde (CH2O) in formic acid (HCOOH) or a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) as Reaktionsme medium and addition a solution of hydrogen bromide (HBr) to the mixed 2,5-di- (alkylthio) -a, a'-dibromo-p-xylene (3) is reacted:

2. The method according to claim 1, characterized in that the reaction of 1, 4-diiodobenzene (1 a) with 1 mol of alkyl iodide of formula Rl to the corresponding 4- (alkylthio) iodobenzene (1 b) in the cold using n-butyllithium (n-BuLi) and elem tarem sulfur (Ss ), z. In diethyl ether (Et 2 O) as solvent, is carried out:

3. The method according to claim 1 or 2, characterized in that both the reaction of 1, 4-diiodobenzene (1 a) with 2 mol of thiol of the formula R-SH and the reac tion of 4- (alkylthio) iodobenzene (1 b ) with 1 mol of thiol of the formula R'-SH to the respective 1, 4-di (alkylthio) benzene (2) using copper (I) iodide (Cul) as catalyst and potassium phosphate (K3PO4) as the base in dimethoxyethane (DME) at temperatures of 160-200 ° C are carried out: 2 R-SH [R = R ']  Cul, K3PO4 DME T = 160-200 ° C

 1 R'-SH [R F R ']  Cul, K3PO4 DME, T = 160-200 ° C

4. The method according to claim 3, characterized in that the reaction mixture is heated to a temperature of about 180 ° C. 5. The method according to claim 3 or 4, characterized in that the heating is effected by means of microwave radiation. 6. The method according to any one of claims 1 to 5, characterized in that the reaction of 1, 4-di (alkylthio) benzene (2) to the corresponding 2,5-di (alkylthio) - a, a'-dibromo-p- xylene (3) using paraformaldehyde (PFA) in formic acid (HCOOH) or a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) as the reaction medium and adding a solution of hydrogen bromide (HBr) is carried out:

7. The method according to claim 6, characterized in that the 1, 4-di (alkylthio) - benzenes (2) with paraformaldehyde (PFA) in the presence of a solution of Bromwasser- substance (HBr) in acetic acid (AcOFI) reacted in the flitze to obtain the corresponding 2,5-di (alkylthio) -a, a'-dibromo-p-xylenes of the formula (3):

 8. The method according to claim 7, characterized in that the reaction is carried out at a temperature of 70 ° C to 80 ° C. 9. The method according to any one of claims 6 to 8, characterized in that when R and R 'are selected from alkyl radicals having more than 10 carbon atoms, a mixture of trifluoroacetic acid (TFA) and trifluoroacetic anhydride (TFAA) is used as the reaction medium. 10. The method according to any one of claims 1 to 9, characterized in that R and R 'are selected from linear or branched Ci-Ci2-alkyl radicals. 1 1. A process according to claim 10, characterized in that R and R 'are selected from the following radicals: methyl, 2-ethylhexyl, 3,7-dimethyloctyl, n-hexyl and n-dodecyl. 12. 2,5-di (alkylthio) -a, a'-dibromo-p-xylene of the formula (3), prepared by a procedural ren any one of claims 1 to 1 1st 13. 2,5-di (alkylthio) -a, a'-dibromo-p-xylene according to claim 12, characterized in that it is selected from the following compounds: 2,5-di (2-ethylhexylthio) -a, a'-dibromo-p-xylene (3a),  2,5-di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene (3b),  2,5-di (hexylthio) -a, a'-dibromo-p-xylene (3c),  2,5-di (dodecylthio) -a, a'-dibromo-p-xylene (3d), 2- (2-ethylhexylthio) -5-methylthio-a, a'-dibromo-p-xylene (3e), 2- (3,7-Dimethyloctylthio) -5-methylthio-a, a'-dibromo-p-xylene (3f), 2-hexylthio-5-methylthio-a, a'-dibromo-p-xylene (3g) and 2-Dodecylthio-5-methylthio-a, a'-dibromo-p-xylene (3h). 14. Use of 2,5-di (alkylthio) -α, α'-dibromo-p-xylenes of the formula (3) as monomers in polymerization reactions for the position of alkylthio-substituted poly (p-phenylene-vinylene) polymers (S -PPVs) (4) with elimination of hydrogen bromide in the presence of a base:

(3) (4) wherein the polymerization is carried out in each case in a dry solvent in the presence of potassium tert-butoxide as the base at a temperature of about -60 ° C to -50 ° C. 15. Use according to claim 14, characterized in that the obtained Alkylthio-substituted poly (p-phenylene-vinylene) -polymers (S-PPVs) (4) are subsequently oxidized to give alkylsulfone-substituted polymers (SO2-PPVS) (5):

 (4) (5) 16. Use according to claim 15, characterized in that the oxidation takes place with Dimethyldioxiran. 17. An alkylthio-substituted poly (p-phenylene-vinylene) polymer (S-PPV) of the formula (4), prepared according to claim 14. 18. Alkylthio-substituted poly (p-phenylene-vinylene) polymer (S-PPV) according to claim 17, characterized in that it is selected from the following polymers:  Poly [2,5-di (2-ethylhexylthio) phenylene-vinylene] (4a), Poly [2,5-di (3,7-dimethyloctylthio) phenylene-vinylene] (4b), Poly [2,5-di (hexylthio) phenylene-vinylene] (4c),  Poly [2,5-di (dodecylthio) phenylene-vinylene] (4d), Poly [2- (2-ethylhexylthio) -5-methylthiophenylenevinylene] (4e), Poly [2- (3,7-dimethyloctylthio) -5-methylthiophenylenevinylene] (4f), Poly [2-hexylthio-5-methylthiophenylenevinylene] (4g) and Poly [2-dodecylthio-5-methylthiophenylenevinylene] (4h). 19. An alkylsulfonyl-substituted poly (p-phenylene-vinylene) polymer (SO2-PPV) of the formula (5), prepared according to claim 16 or 17. 20. Alkylsulfonyl-substituted poly (p-phenylene-vinylene) polymer (S-PPV) according to claim 19, characterized in that it is selected from the following polymers: Poly [2,5-di (2-ethylhexylsulfonyl) phenylene-vinylene] (5a) having a number-average molecular weight M _n > 30,000 Da,  Poly [2,5-di (3,7-dimethyloctylsulfonyl) phenylene-vinylene] (4b), Poly [2,5-di (hexylsulfonyl) phenylene-vinylene] (4c), Poly [2,5-di (dodecylsulfonyl) phenylene-vinylene] (4d), Poly [2- (2-ethylhexylsulfonyl) -5-methylsulfonylphenylene-vinylene] (4e), Poly [2- (3,7-dimethyloctylsulfonyl) -5-methylsulfonylphenylene-vinylene] (4f), Poly [2-hexylsulfonyl-5-methylsulfonylphenylene-vinylene] (4g) and Poly [2-dodecylsulfonyl-5-methylsulfonylphenylene-vinylene] (4h). 21. 2,5-Di (alkylthio) -α, α'-dibromo-p-xylene of the following formula (3),

wherein R and R 'are each independently selected from saturated, linear, branched or cyclic C 1 -C 20 -alkyl radicals to give the following chemical compound: 2,5-di (2-ethylhexylthio) -a, α'-dibromo-p-xylene (3a):

 (3a); or 2,5-di (3,7-dimethyloctylthio) -a, a'-dibromo-p-xylene (3b):

; or 2,5-di (hexylthio) -a, a'-dibromo-p-xylene (3c):

 2,5-di (dodecylthio) -a, a'-dibromo-p-xylene (3d)

2- (2-Ethylhexylthio) -5-methylthio-a, a'-dibromo-p-xylene (3e):

 (3e); or 2- (3,7-Dimethyloctylthio) -5-methylthio-a, a'-dibromo-p-xylene (3f):

2-Hexylthio-5-methylthio-a, a'-dibromo-p-xylene (3g):

 2-Dodecylthio-5-methylthio-a, a'-dibromo-p-xylene (3h):