Preparation of titanocene and zirconocene dichlorides bearing bulky 1,4-dimethyl-2,3-diphenylcyclopentadienyl ligand and their behavior in polymerization of ethylene

Abstract New metallocene dichlorides [η 5 -(1,4-Me 2 -2,3-Ph 2 -C 5 H) 2 TiCl 2 ] ( 2 ), [η 5 -(1,4-Me 2 -2,3-Ph 2 -C 5 H) 2 ZrCl 2 ] ( 3 ) and [η 5 -(1,4-Me 2 -2,3-Ph 2 -C 5 H)η 5 -(C 5 H 5 )ZrCl 2 ] ( 4 ) were prepared from lithium salt of 1,4-dimethyl-2,3-diphenylcyclopentadiene ( 1 ) and [TiCl 3 (THF) 3 ], [ZrCl 4 ] and [η 5 -(C 5 H 5 )ZrCl 3 (DME)], respectively. Compounds 2–4 were characterized by NMR spectroscopy, EI-MS and IR spectroscopy, and the solid state structure of 3 was determined by single crystal X-ray crystallography. The catalytic systems 3 /MAO and 4 /MAO were almost inactive in polymerization of ethylene at 30–50 °C, however, they exhibited high activity at temperature…