Transition Metal Compounds in Combination with Alkylaluminoxanes as Catalysts for Olefin and Diene Polymerization

Catalytic systems based on Zr, Co, Ti, V, and Nd in combination with –(–RAlO–)– _n alkylaluminoxanes, where R = Me or iso-Bu, were used for the polymerization of olefins and dienes. The structure of methylaluminoxane (MAO) was studied with the use of theoretical calculations and experimentally by vibrational spectroscopy. It was found that only cis and trans conformations of linear MAO oligomers actually occurred at the active centers of olefin polymerization. The stereospecificity of catalytic systems for diene polymerization depends on the nature of the substituent at aluminum, as well as on the nature of the transition metal and its ligand environment.