PREPARATION AND OXIDATIVE DOPING OF ALPHA,OMEGA-DITHIENYL POLYENES

alpha,omega-Dithienyl polyenes can be prepared from appropriately substituted 2-thienyl or 3-thienyl carbaldehydes or propenals by condensation with either bis-Wittig reagents or bis-phosphonate esters (Horner-Emmons-Wadsworth modifications) containing one or two double bonds. These polyenes, containing either 3, 4, 5 or 6 conjugated double bonds, can be oxidatively doped with SbCl5, in solution, forming polaronic (radical cation) and bipolaronic (dication) charge states by successive one-electron transfers. In all cases, the bipolaron is the more stable charge state.