Monomer reactivity vs regioregularity in polythiophene derivatives: A joint synthetic and theoretical investigation.

Over the past decade, conducting polymers have gained a large interest. From the factors influencing their conductivity, the regioregularity of the chains is one of the greatest importance. A joint experimental and theoretical study on various alkyl-, alkylthio- and alkoxy-substituted thiophenes and bithiophenes shows that the reactivity of the monomer, i.e. the distribution of the unpaired electron pi-spin density on the different positions of the oxidized monomer, has a significant influence on the regioregularity of the resulting polymers. From all these results, it is clear that INDO calculations can be useful as a pre-synthetic tool for the rational design by oxidative polymerization (chemically or electrochemically) of novel regioregular and non-regioregular aromatic polymers.