Synthesis and application of pendant phenyl cyclopentadienyl lanthanide chlorides as catalyst precursors for methyl methacrylate polymerization

The synthesis and characterization of a series of new pendant phenyl substituted cyclopentadienyl lanthanide chlorides are reported. The analytical data of 3a-3e point to the formation of monomeric and unsolvated complexes, (PhCMe2C5H4)(2)LnCl (Ln = Er (3a), Sm (3b), Gd (3c), Y (3d), Nd (3e)); and the analytical data of 4a-4d point to the formation of the dimeric and unsolvated complexes, I(PhCH2CMe2C5H4)(2)LnCl](2) (Ln = Gd (4a), Y (4b), Sm (4c), Er (4d)). The X-ray crystallographic structure of 4d indicates that the pendant phenyl substituent is not coordinated to the central metal. The nine complexes are efficient catalysts for the polymerization of methyl methacrylate in conjunction with AI(Et)(3) or NaH. As NaH was used as a new co-catalyst, the catalytic systems show highly catalytic activity at room temperature. In the [(PhCH2CMe2C5H4)(2)ErCl2/Al(Et)(3) catalyst system, the effects of the concentration of catalyst, and the temperature and time of polymerization were studied. Copyright (C) 2004 John Wiley Sons, Ltd.