SYNTHESIS OF POLY(9-HEXYL-3,6-CARBAZOLYLENEETHYNYLENE) AND ITS MODEL COMPOUNDS

The novel conjugated polymer poly(9-hexyl-3,6-carbazoylyleneethylene) (16) was prepared by palladium-catalyzed polycondensation of 3,6-diiodo-9-hexylcarbazole and 3,6-diethynyl-9-hexylcarbazole. The polymer has a number-average molecular weight (M(n)BAR) of 3 100. By fractionation a polymer with M(n)BAR of 6400 was obtained. Besides polycondensation, a palladium-catalyzed bond-opening polymerization of the triple bonds occurs as a side reaction which can be partially suppressed by lowering the reaction temperature to 60-degrees-C. Two well-defined model compounds of the title polymer, a dimer and a trimer, were synthesized by stepwise reaction. The mass spectra of both model compounds demonstrate the remarkably high stability of the radical cations of the dimer and trimer. Since the trimer forms a stable glass it is ideally suited for the investigation of its photoconductive properties. First experiments carried out by the Time-of-Flight technique showed remarkably high carrier mobilities up to 2 . 10(-4) cm2/(V . s) for the trimer.