Olefin polymerization behavior of bis(phenoxy-imine) Zr, Ti, and V complexes with MgCl2-based cocatalysts

Abstract This contribution reports on the olefin polymerization behavior of phenoxy-imine ligated Zr, Ti, and V complexes 1 – 10 with MgCl 2 /R m Al(OR) n systems. Zr complexes 1 – 4 combined with MgCl 2 /R m Al(OR) n display strikingly high ethylene polymerization activities; indeed, they are some of the highest reported activities for methylalumoxane (MAO)- and borate-free olefin polymerization catalysts (max. 1819 kg-PE/(mmol-cat h), 0.9 MPa ethylene pressure, 50 °C). In addition, when Ti complexes 5 – 7 are combined with MgCl 2 /R m Al(OR) n they exhibit high ethylene polymerization activities (max. 36.3 kg-PE/(mmol-cat h), 0.9 MPa ethylene pressure, 50 °C) and produce polyethylenes with narrow molecular weight distributions ( M w / M n ) and ethylene–propylene copolymers with homogeneous structures, representing the first examples of MAO- and borate-free, highly active single-site catalyst systems. The activities exhibited by the Zr and Ti complexes with MgCl 2 /R m Al(OR) n are superior or comparable to those obtained with MAO cocatalyst systems. Moreover, V complexes 9 and 10 in association with MgCl 2 /R m Al(OR) n demonstrate high activities at elevated temperatures ( 9 : 75 °C, 65.1 kg-PE/(mmol-cat h), atmospheric ethylene pressure) and are the first reported examples of highly active, thermally robust single-site V-based olefin polymerization catalysts. All of the polyethylenes formed from the MgCl 2 /R m Al(OR) n systems display good polymer morphology, indicating that complexes 1 – 10 are heterogenized on the surface of the MgCl 2 /R m Al(OR) n . These results suggest that MgCl 2 /R m Al(OR) n not only works as an excellent cocatalyst, but is also a good support for phenoxy-imine ligated Zr, Ti, and V complexes.