Broken pi-conjugated thiophene systems: 3. Synthesis and polymerization of2,2-di(alkylthien-2-yl) propanes

A series of 2,2-di(alkylthien-2-yl)propanes has been synthesized by chloroa lkylation of the thiophene ring in the presence of zinc chloride. The produ cts were obtaines as mixtures of regio isomers which were not separated. Th ese monomers were oxidatively polymerized with iron(III) chloride to yield the respective broken pi-conjugated poly(2,2-di(alkylthien-2-yl)propane)s. The new polymers are broken pi-conjugated due to the blocking of the bridge carbon with two methyl groups. Due to the limited conjugated segments, the se polymers show conductivity on the order of 10(-7) S/cm. (C) 2000 Elsevie r Science S.A. All rights reserved.