Conducting copolymers of pyridine with thiophene, N-methylpyrrole, and selenophene

A series of three-ring heteroaromatic compounds consisting of a pyridine central ring and thiophene, selenophene, or N-methylpyrrole outer rings, and their polymers have been investigated. Differences in redox potentials and electronic absorbance spectra of the three-ring monomers have been interpreted with the aid of HOMO and LUMO energies from ab initio calculations. Both p- and n-doping of the polymers were investigated electrochemically in acetonitrile. In all cases, the p-doped states were not stable, and measured conductivities were well below intrinsic values. In most cases, the n-doped states were more stable, but conductivities were very low.