Cation template assisted electrosynthesis of a highly piconjugated polythiophene containing oligooxyethylene segments

A polythiophene precursor involving two bithiophene groups linked by an oligooxyethylene chain has been synthesized. Electropolymerizations performed in the presence of tetrabutylammonium, lithium, sodium and barium perchlorate show that the nature of the electrolyte cation strongly affects the polymerization process. The electrochemical and spectroelectrochemical properties of the resulting polymers show that the presence of barium cation in the electrosynthesis medium leads to a 300 mV decrease in the oxidation potential of the polymer, together with a significant red shift in the absorption maximum providing conclusive evidence for a metal template effect during electropolymerization.