Living radical polymerization of hydrophobic monomers catalyzed by cyclometalated ruthenium(II) complexes: Improved control and formation of block co-polymers

Abstract

Living radical polymerizations of three representative monomers, styrene (St), methyl methacrylate (MMA) and n-butyl acrylate (BA) catalyzed by cyclometalated ruthenium(II) complex, cis-[Ru(o-C6H4-2-py)(phen)(MeCN)2]PF6, has been investigated. It has been shown, that the control over all three homo-polymerizations may be significantly improved in the presence of small amounts of another ruthenium(II) complex, Ru(o-C6H4-2-py)(phen)2]PF6, bearing strongly bound bidentate ligands. Although the mechanism of the phenomenon is rather different in the case of St and in the case of MMA and BA polymerizations. The best control was achieved in polymerization of St, while BA polymerization remained the worst controlled. The possibility of formation of sequential di- and tri-block copolymers from these monomers has been demonstrated.