Poly(3′,4′-dibutyl-α-terthiophene-phenylene-vinylene), and poly(3′,4′-dibutyl-α-terthiophene-phenylene-imine): synthesis and properties of two new isoelectronic soluble conjugated polymers

A new soluble and dopable copolymer consisting of 3′,4′-dibutyl-2,2′:5′,2″-terthiophene and phenylene vinylene units has been designed and prepared via a Wittig reaction. This copolymer is soluble in common organic solvents such as THF and CHCl₃, and can be doped with various oxidants increasing its electrical conductivity by several orders of magnitude. Its films are electrochromic and turn reversibly and rapidly from red to green-blue upon doping and undoping electrochemically. If the phenylene vinylene units are replaced with phenylene imine units, another interesting new polymer forms which is not readily dopable with the same oxidants but is dopable with acids. The new material exhibits strong chemochromism with dramatic shifts in its optical absorption spectra. In the undoped state both copolymers show strong photoluminescence.