The synthesis of regio-regular poly(3-alkyl-2,5-thienylene vinylene) derivatives using lithium bis(trimethylsilyl)amide (LHMDS) in the dithiocarbamate precursor

Poly(2,5-thienylene vinylene) derivatives (ptvs) present a specific class of low band gap conjugated polymers of which the synthesis seems to be problematic. Recently, the dithiocarbamate route was introduced as a synthetic route towards ptv. However, the synthesis of alkyl-ptv derivatives failed on using lithium diisopropyl amide (lda) as the base in the polymerisation reaction. We demonstrate that the use of lithium bis(trimethylsilyl)amide (lhmds) instead of lda allows for an efficient synthesis of alkyl-ptv derivatives. Indications are presented for the formation of an ordered structure in case of the 3-alkyl derivative, pointing to a regio-regular polymerisation process.