Unusaual Enhancement of Ethylene Polymerization Activity of Benzyl Zirconium Complexes by Benzylation of the Imino Moiety of 2-(N-Aryliminomethyl)pyrrolyl Ligand

摘要

Reaction of Zr(CH_2Ph)_4 (1) with one equiv.of 2-(N-arylimi-nomethyl)pyrrolyl ligands (2a-e) in toluene afforded two types of products,depending upon the bulkiness of the aryl moiety.The reactions of 1 with two equiv.of the most sterically bulky 2e afforded complex 5e,whose pseudo octahedral geometry around the zirconium atom and totally dissymmetric cis-dibenzyl structure were elucidated.The high catalytic activity for ethylene polymerization was obtained by using complexes 3a and 3b.