Synthesis, structures, and catalytic properties for ethylene polymerization of bridged [η 5,η 1-C 5H 4CHPhArO]TiCl 2 complexes

Abstract

A number of bridged half-sandwich titanium complexes [η 5:η 1-2-C 5H 4CHPh-4-R 1-6-R 2C 6H 2O]TiCl 2 [R 1 = H ( 5), Me ( 6), t Bu ( 7, 8); R 2 = H ( 6, 7), t Bu ( 5, 8)] were synthesized from the reaction of their corresponding trimethylsilyl substituted ligand precursors 2-Me 3SiC 5H 4CHPh-4-R 1-6-R 2C 6H 2OSiMe 3 [R 1 = H ( 1), Me ( 2), t Bu ( 3, 4); R 2 = H ( 2, 3), t Bu ( 1, 4)] with TiCl 4 in hexane. All new complexes were characterized by 1H and 13C NMR spectroscopy. Molecular structures of complexes 5 and 8 were determined by single crystal X-ray diffraction analysis. Upon activation with Al i Bu 3/Ph 3CB (C 6F 5) 4, complexes 5– 8 exhibit reasonable catalytic activity for ethylene polymerization and copolymerization with 1-hexene, producing polyethylene and poly(ethylene-co-1-hexene) with moderate molecular weights.