Ligand effects on olefin polymerizations with multinuclear zirconocene catalysts having dimethylsilylferrocene as a cyclopentadienyl substituent

Abstract

Abstract Olefin polymerizations were conducted with novel multimetallic zirconocene catalyst systems: RCpCpZrCl 2 ( 1 ) (R = dimethylsilylferrocene; Cp = cyclopentadienyl) and (RCp) 2 ZrCl 2 ( 2 ) in combination with methylaluminoxane or tetrakis(pentafluorophenyl) borates. In ethylene polymerization, the maximum catalyst activity was observed at a lower temperature (30–45°C) when using complex 1 or 2 , compared with Cp 2 ZrCl 2 . It was also revealed that complex 1 is a more effective catalyst than Cp 2 ZrCl 2 for copolymerization of ethylene and propene.