Synthesis, characterization and application of organolanthanide complexes (CH2CHCH2CH2C5H4)2LnCl·2THF (Ln=Sm, Y, Dy, Er) as methyl methacrylate (MMA) polymerization catalysts

The title complexes (CH2CHCH2CH2C5H4)2LnCl·2THF (Ln=Sm, Y, Dy, Er) were synthesized as air and moisture sensitive free-flowing oils that have been fully characterized by MS, EA and IR. The EA and IR results indicate the presence of coordinated THF molecules. No evidence of intra-molecular coordination of the butenyl side-chain was observed. In association with Al(i-Bu)3, the complexes have shown high activity for the bulk polymerization of MMA. At a MMA/catalyst (MMA/cat) molar ratio of 2000, temperature of 80 °C and polymerization time of 30 h, the catalyst system produced at a 70% conversion a syndiorich polymer (rr=62%), Mη=1.65×106. Effects of temperature, time and molar ratios of MMA/catalyst and catalyst/cocatalyst on the polymerization have been studied. The result showed that higher temperature, longer time and Al/catalyst molar ratio=10 are conditions suitable for polymerization.