Unusual Reactivity of Tris(pyrazolyl)borate Zirconium Benzyl Complexes

摘要

MAO activation of group 4 Tp'MCl_3 complexes that contain sterically bulky tris(pyrazolyl)borate ligands (Tp') generates highly active ethylene polymerization catalysts with interesting properties,including the production of ultrahigh molecular weight polyethylene (PE) and high 1-hexene incorporation in ethylene/hexene copo-lymerization.These systems differ from metallocene catalysts in several ways.First,Tp'M complexes can undergo a variety of rearrangements,suggesting that Tp' ligands may not be innocent in olefin polymerization.