Ethylene polymerization with cycloalkylidene-bridged cyclopentadienyl metallocene catalysts

Communication: Ethylene was polymerized with cycloalkylidene-bridged cyclop entadienyl metallocene catalysts 1-9 in the presence of methyl aluminoxane (MAO) as the cocatalyst. Unlike the normal titanocene catalysts, the cycloa lkylidene-bridged cyclopentadienyl titanocene catalysts show much higher ac tivities than the corresponding zirconacene and halfocene catalysts and sho w the highest activities at higher temperature. This indicates that the cyc loalkylidene-bridged cyclopentadienyl titanocene system is very thermally s table and maybe a very promising catalyst system for industrial application .