Binuclear neutral nickel complexes bearing bis(bidentate) salicylaldiminato ligands:Synthesis,structure and ethylene polymerization behavior

摘要

Reaction of sodium salts of the bridging [O,N,N,O]-type bisalylaldimine ligands [O,N,N,O = [3-phenyl-2-OH-(CH=N)]_2-L(L = CH_2CH_2CH_2 3a,1,4-C_6H_4 3b)] with trans-bis(triphenylphosphane)phenylnickel(II)chloride result in neutral bis(bidentate)binu-clear nickel(II)complexes 4a and 4b.The structure of 4b has been confirmed by X-ray crystallography.4a shows moderate activity for polymerization of ethylene in the presence of methylaluminoxane(MAO).Catalytic activities,molecular weights and molecular weight distribution of polyethylene have been investigated under the various reaction conditions.