Asymmetric silicon-bridged metallocenes useful as catalysts in the polymerization of Alpha-olefins, process for their preparation and use of said metallocenes for the polymerization of Alpha-olefins

摘要

Novel asymmetric silicon-bridged metallocenes useful as catalysts in the polymerization of olefins and process for preparing said metallocenes. The novel metallocenes are represented by the general formula (I): (SiR'R")(Cp)(Cp')MXX' wherein Cp is a partially or fully hydrogenated fluorenyl moiety selected from those of formula (II) and (III) Cp' is an indenyl group selected from those of formula (IV) M represents a transition metal selected from Ti, Zr and Hf, X and X' represent, same or different from each other, a halogen atom, R<1>,R<2> and R<3> are, same or different from each other, an alkyl group containing 1 or 2 carbon atoms, an aryl group containing from 6 to 10 carbon atoms or a hydrogen atom, (SiR'R") is a divalent group which bridges the two groups Cp and Cp' repectively on position 9 and 1, R' and R" are, same or different from each other, an alkyl or aryl group containing from 1 to 10 carbon atoms. Process for producing said metallocenes and process for the polymerization of alpha -olefins such as ethylene and propylene by means of said metallocenes.