A Catalytic System for Ethylene Polymerisation Based on Group III and Lanthnnide Complexes of Tris(pyrazolyl)borate Ligands

摘要

There has been recent interest in the use of soluble transition metal- and lanthanide-based catalysts for polymerization of ethylene and a-olefins. For lanthanides, a variety of bis-(substituted cyclopentadienyl) alkyl and hydride complexes of lanthanide metals have been shown to be active for olefin hydrogenation, oligomerization, isomerization, cyclization, methane transmetalation, and ethylene and butadiene polymerization. Some lanthanide catalytic systems display advantages over analogous transition metal-based catalysts such as high stereo-selectivity, activity over wide temperature ranges, simplicity of polymerization mechanisms, relative lack of decomposition reactions, and extremely high activity.