Preparation and oxidative doping studies of α,ω-dithienyl polyenes stabilized by long chain alkylthio substituents
Polyenes containing mesomerically interactive substituent groups can be oxidatively doped with SbCl5 in solution to yield stabilized bipolaron-like charge states. However, in both α,ω-diphenyl and α,ω-dithienyl polyene series, lack of solubility has precluded studies of bipolaron formation for polyenes containing more than six double bonds in the polyene segment. In the present study, the use of long-chain alkylthio substituents to stabilize the bipolaronic charge states has allowed the synthesis of dithienyl polyenes containing up to ten double bonds, and observation of bipolaron formation in the octaene. Models for copolymers containing these bipolaronic repeat units have also been synthesized, and oxidatively doped.