Polymer-end mimetic organotellurium and organostibine compounds mediate highly controlled living radical polymerizations that allow the molecular weight to be controlled accurately and give well-defined end-groups. A variety of both conjugated (including styrene, acrylate and methacrylate derivatives) and unconjugated monomers (including 1-vinyl-2-pyrrolidinone and vinyl acetate) have been successfully polymerized in a controlled manner. The higher controllability of organotellurium- and organostibine-mediated polymerization compared to organoiodine-mediated polymerization is due to the faster degenerative transfer of organotellanyl and organostibino groups compared to iodine atom. AB-diblock, ABA-triblock and ABC-triblock copolymers have also been synthesized by the successive addition of different families of monomers. Transformations of the end-groups via radical and ionic reactions yielded polymers with a range of different functional groups and well-defined structures.


(Communicated by Hitosi NOZAKI, M.J.A.)