Synthesis and characterization of titanium(IV) complexes bearing end functionalized biphenyl: Efficient catalysts for synthesizing high molecular weight polyethylene

Abstract

Two phenoxy-imine complexes 1d and 2d bearing bulky substituents were synthesized by introducing ethyl or vinyl substituted phenyl to the para position of N-aryl group and characterized by 1H NMR, 13C NMR, and elemental analysis. The X-ray crystallographic analysis revealed a distorted octahedral geometry of complex 2d. When activated by dried MAO, two titanium complexes exhibited good to high activity (up to 4.5×106gmol−1(Ti)h−1) for ethylene polymerization. Using these two complexes, ultra-high molecular weight polyethylene (UHMWPE, Mw>1,000,000) can be prepared only by changing polymerization time in mild conditions.