Polyethylene with extremely narrow polydispersity obtained from the new catalyst systems Nb(η5-C5Me5)(η4-diene)Cl2–MAO and Nb(η5-C5Me5)(η4-diene)2–MAO

Abstract

Niobium complexes Nb(η⁵-C₅Me₅)(η⁴-diene)Cl₂(diene = buta-1,3-diene 1a, isoprene 1b, or 2,3-dimethylbuta-1,3-diene 1c) and Nb(η⁵-C₅Me₅)(η⁴–2,3-dimethylbuta-1,3-diene)₂3 in the presence of a large excess of methylaluminoxane (MAO)were found to be active catalysts for the polymerization of ethylene to give polyethylen with narrow polydispersities (M_w/M_n as low as 1.05).