NOVEL POLYMERIZATIONS OF GERMYLENES AND THEIR REACTION-MECHANISMS

Novel copolymerizations for the synthesis of germanium-containing polymers using a divalent germanium species, germylene, have been developed. The copolymerization involves a redox process between a germylene (M(red)) and an oxidant monomer (M(ox)) such as p-benzoquinones, cyclic alpha,beta-unsaturated ketones, and substituted acetylenes. A new germanium-containing polymer having a germanium-sulfur bond unit in the main chain has been synthesized by the oxidative addition of a poly(dithioalkylene) toward the germylene. A ligand exchange polymerization has been developed as a new polymerization reaction affording a polygermane. The reaction mechanism of the copolymerization between germylene and p-benzoquinone derivatives has definitely been established as a biradical polymerization system involving a germyl radical and a semiquinone radical, providing the first clear-cut evidence for a biradical mechanism in the polymerization chemistry.