Development of New Anionic Polymerization Initiators Based on Metal Ate Complexes

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We have succeeded in demonstrating that ate complexes of various metals are effective as polymerization initiators.1.Transition metal ate complexes as initiators for anionic polymerization of methyl methacrylate (MMA).We have found that transition metal ate complexes generated by the reaction of transition metal halide with organolithium can initiate the anionic polymerization of MMA. Living polymerization of MMA was achieved by using ate complex of Fe in conjunction with an organoaluminum as an additive or by the polymerization at -78℃ using ate complexes of V and Cr. Ate complexes of Nb, Mo, and W bearing secondary amide ligands afforded highly isotactic PMMA at -78℃. Y-ate complexes with secondary amide ligands initiated the living polymerization of MMA, giving PMMAs with narrow molecular weight distributions and amino groups at chain ends.2.Living polymerization of t-butyl acrylate (tBA) initiated with an ate complex of Al.The Al-ate complex generated by the reaction of iBu_3Al with tBuOK initiated living polymerization of tBA. Block copolymerization of tBA with MMA was also successful using the initiating system.3.Cationic polymerization of isobutyl vinyl ether (IBVE) initiated with ate complexes of NbThe ate complex of Nb with trityl cation was found to be effective for the cationic polymerization of IBVE. The ate complex bearing a secondary amide ligand afforded poly(IBVE)s with narrow molecular weight distributions.