The introduction of pyrrolotetrathiafulvalene into conjugated architectures: synthesis and electronic properties

A series of new conjugated copolymers incorporating the redox-active pyrrolo-TTF unit has been synthesised. The properties of the polymers have been investigated by cyclic voltammetry and electronic absorption spectroscopy, revealing that the pyrrolo-TTF behaves very differently to its thieno-TTF variant. In comparison to thieno analogues, the band gaps of the new polymers are wider than expected due to a decrease in the polarizability of the heteratom (nitrogen vs. sulfur) and steric interactions between repeat units. Whilst the pyrrolo-TTF units are stronger electron donors than thieno-TTFs in related structures, the two redox active elements of the new polymers (TTF and conjugated chain) function independently under oxidative conditions.