Titanium(IV) complexes with monocyclopentadienyl and phenoxy-alkoxo ligands: Synthesis, structures and catalytic properties for ethylene polymerization

Abstract

Three monochlorotitanium complexes Cp′Ti(2,4- t Bu 2-6-(CPh 2O)C 6H 2O)Cl [Cp′ = η 5-C 5H 5 ( 2), η 5-C 5(CH 3) 5 ( 3), η 5-C 5H 2Ph 2CH 3 ( 4)] have been synthesized in high yields (>90%) by the reaction of corresponding Cp′TiCl 3 with the dilithium salt of ligand 2,4- t Bu 2-6-(CPh 2OH)C 6H 2OH ( 1). When activated by [Ph 3C] +[B(C 6F 5) 4] − and Al i Bu 3, complexes 2– 4 exhibit reasonable catalytic activity for ethylene polymerization, producing polyethylenes with moderate molecular weights and melting points. Addition of excess water to complex 2 gave the oxo-bridged complex [Ti(η 5-C 5H 5)(2,4- t Bu 2-6-(CPh 2O)C 6H 2O)] 2O ( 5). Complexes 4 and 5 were characterized by single crystal X-ray diffraction.