Regioregular Poly(3-alkoxythiophene)s: Toward Soluble, Chiral Conjugated Polymers with a Stable Oxidized State

Chiral poly(3-(3,7-dimethyloctyloxy)thiophene)s were prepared using three different methodologies, rendering polymers with different degrees of regioregularity. In a first attempt, 3-alkoxythiophene was polymerized using FeCl3, resulting in a highly regioirregular poly(3-alkoxythiophene). Second, the GRIM methodology was applied, which yielded poly(3-alkoxythiophene)s with relatively high, but not perfect, degrees of regioregularity. Finally, an alternative methodology was used, which consisted of the exclusive formation and subsequent polymerization of 2-bromomagnesio-3-(3,7-dimethyloctyloxy)-5-bromothiophene) and which resulted in poly(3-alkoxythiophene)s with (almost) perfect regioregularity. The degrees of regioregularity were evaluated with 1H NMR, UV−vis, and CD spectroscopy and cyclic voltammetry. These (regioregular) poly(3-alkoxythiophene)s show a very high λmax, indicating very high conjugation lengths. Moreover, the polymers could easily be oxidized and they were stable in both neutral as well ...