Optically active, regioregular, head-to-head/tail-to-tail poly(3-alkyl)thiophene by inherently regiospecific oxidative synthesis from 3,3′-dialkyl 2,2′-bithiophene monomer

A fully regioregular poly(3-alkylthiophene) displaying only head-to-head/tail-to-tail connections between thiophene rings has been prepared by oxidative chemical or electrochemical polymerization starting from a symmetrical bithiophene monomer bearing at the b positions the optically active S-(+)-2- methylbutyl group. The polymeric product has been fully characterized as far as its spectroscopic, solvatochromic, chiroptical, thermal, electrochemical and morphological properties are concerned. In particular, the solvatochromic, chiroptical and thermal properties have been compared to those of the related, well known, head-to-tail regioregular polymeric derivative possessing the same side-chain substituent in order to elucidate the structural features characterizing the head-to-head regioregular derivative.