Syntheses and properties of conjugated polymers with cumulenic bond in the main chain

Syntheses of novel π-conjugated polymers with a cumulene unit such as allene and butatriene in the main chain were attempted in order to investigate properties of cumulene moiety in the conjugated polymer chain. Electroreductive polycondensation of tetraiodoallene afforded an ill-characterized transparent dark filmy product. Polymerization of 1,4-bis(4-bromophenyl)-1,4-diphenylbutatriene by dehydrohalogenative polymerization with Ni(cod)2 gave a soluble red polymer having a semiconducting property was obtained without decomposition of the cumulenic bond, which was characterized by IR, Raman, and UV-Vis spectroscopy. Oxidative polycondensation of 1,4-bis(4-ethynylphenyl)-1,4-diphenylbutatriene with a Cu-TMEDA catalyst gave a conjugated polymer with butatriene and butadiyne segments.