Homopolymerizations of alpha-olefins with diastereomeric metallocene/MAO catalysts

1-Butene and l-pentene were polymerized with three different metallocenes: dimethylsilyl-bis(2-methyl-4,5-benzoindenyl)zirconium dichloride [Me2Si(2-M e-4,5-BzoInd)(2)ZrCl2] (1), dimethylsilylbis(2-methyl-4-phenylindenyl)zirco nium dichloride [Me2Si(2-Me-4-PhInd)(2)ZrCl2] (2), and dimethylsilylbis(ind enyl)zirconium dichloride [Me2Si(Ind)(2)ZrCl2] (3). The polymerizations wer e conducted with the rac-isomers of the metallocenes and mixtures of the ra c- and meso-systems far 1 and 2 and with the meso-form of catalyst 3 combin ed with MAO. It was shown that the activities in the polymerization of the alpha-olefins of the meso-isomers of 1 and 2 were much higher than those of the rac-metallocenes, while a vice versa behavior is observed for catalyst 3. Additionally, reaction profiles of 1 and 2 were recorded which underlin e that the stability of their meso-compounds is much higher than that of th e rac-systems for the polymerization of the investigated monomers.