Synthesis, structure characterization and catalytic activity of lanthanide complexes containing an ansa carbonous-bridged cyclopentadienyl-thienyl ligand

A kind of new lanthanocene complex with an ansa carbonous-bridged cyclopentadienyl/aromatic heterocycle ligand was prepared and characterized. Based on the data of elemental analyses, MS and IR, they were presumed to be solvent-free complexes (cyclo-C4H3SCMe2C5H4)(2)LnCl [Ln=Er(1), Dd (2), Y(3), Sm (4)]. These complexes were effective for the polymerization of methyl methacrylate in the presence of co-catalyst. When AlEt3 and NaH (nanometric) were used as different co-catalysts, the lanthanocene complexes 1-4 showed different catalytic behavior. These differences resulted from the formation of different active species. The catalyst system (cyclo-C4H3SCMe2C5H4)(2)LnCl/NaH (nanometric) showed high catalytic activity (yield >= 95% and M eta > 10(5)) in a short time at the ambient temperature. Copyright (C) 2008 John Wiley & Sons, Ltd.