1,2-Ethylidene bridged bis-(benzimidazolyl, benzothiazolyl, and benzoxazolyl) transition metal complexes as catalysts for ethylene polymerization

A series of 1,2-ethylidene bridged bis-(benzimidazolyl, benzothiazolyl, and benzoxazolyl) complexes with the transition metals titanium, zirconium and vanadium were synthesized and characterized. The activation with methylalumoxane (MAO) gave ethylene polymerization catalysts with good activities. Structure-property-relationship studies were performed in order to investigate the influence of the hetero atoms of the ligand and to optimize the catalyst design with suitable substituents at the ligand. The best activity (385.8 kg PE/molcat.h) was achieved with the titanium bis-(oxazolyl) complex 23/MAO containing a methyl substituent meta to nitrogen in the six-membered ring.