Polythiophene 3,4-dibromo

The related polythiophene 64 has been produced in 63% yield by a Stille coupling from 2-(tributylstannyl)-3,4-(ethylenedioxy)thiophene and 2,6-dibromo-4f/-cyclopenta[2,l- 3,4- ]dithiophen-4-one catalyzed by PdCl2(PPh3)2 or Pd(PPh3)4 in refluxing toluene <2004CM3667>. 

Stable polythiophene semiconductors 237 incorporating the thieno[2,3-fc]thiophene ring system were synthesized by Stille coupling of 5,5 -dibromo-4,4 -dialkyl-2,2 -bithiophene 235 with thieno[2,3-fc]thiophene-2,5-diylbis(trimethystannane) 236 (Scheme 48). The polymers 237 described showed both good charge carrier mobility and stability to ambient air and light [62],... 

Anodic coupling consists of the oxidation of the monomer to a polymer with proton elimination whereas cathodic coupling is based on the reduction of the suitable dihalogen-substituted (usually dibromo-substi-tuted) monomer to a polymer with halogenide release. Anodic coupling is preferred because (1) it uses the unmodified monomer and (2) the formed polymer, being more easily oxidized (doped), is produced in the conductive state and therefore allows the continuous deposition of the material up to considerable thicknesses (even some millimeters). The method is used for the most investigated polymers polypyrrole and polythiophene. 

Soon after the publication of the spontaneous polymerization reaction of 2,5-dibromo EDOT to PEDOT by Wudl and colleagues, - this kind of polythiophene formation was transferred to EDIT and similar compounds by Skabara and coworkers. Three dibromothiophenes—DBMDTT, DBEDTT and DBPTT— were prepared from thieno[3,4-d][l,3]dithiol-2-one (see Figure 13.19). 

All three pale yellow, crystalline dibromo compounds tend to darken during standing over several da). This process, indicating the polymerization to oligo-or polythiophenes, could be accelerated by heating up to temperatures about 10°C below the melting point. In all cases, coupling of the thiophene moieties is accompanied by the concomitant release of elemental bromine, which dopes... 

Other 5-membered Heterocyclic Derivatives. Several other classes of 5-membered heterocyclic derivatives exist Most are polymerized via a step-growth mechanism. A dibenzo fused derivative of polythiophene (figure 15), which is also partially formed upon doping of poly(phenylene sulfide), can also be synthesized by reaction of dibromo benzothiophene and sodium sulfide. Carbazoles have beoi polymerized by in situ coupling of their Grignards as well by as coupling of diiodocarbazole in molten iodine Thin films of carbazole polymers have been prepared by... 

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