Ethylene Polymerization with Half-Sandwich Allyl Imido Complexes of Tantalum

Abstract

The imido-based half-sandwich complex Cp*Ta(N(2,6-diisopropylphenyl))(η1-C3H5)(η3-C3H5) (3) polymerizes ethylene in the presence of [(C6H5)3C]+[(C6F5)4B]- or B(C6F5)3, while chloride and alkyl derivatives are inactive in the presence of MAO or alkyl abstraction reagents. In contrast, however, Cp*Ta(NSi(tert-butyl)3)Cl2 (5) polymerizes ethylene in the presence of MAO while Cp*Ta(NSi(tert-butyl)3)(η1-C3H5)(η3-C3H5) (6) and Cp*Ta(NSi(tert-butyl)3)Me2 (4) are essentially inactive in the presence of alkyl abstractors.