Then, the bimetal element - metallocenes isotactische polypropylene - polymerization catalyst system for

摘要

A metallocene compound having general formula: CpAXMQ1Q2Cp'A'X'M'Q1'Q2' wherein Cp and Cp' are each independently a substituted or unsubstituted cyclopentadienyl moiety; M and M' are each independently a metal chosen from Group IV B transition metals and vanadium, and coordinate to Cp and Cp' respectively; X and X' are each independently a substituted or unsubstituted Group VA or VIA heteroatom and coordinate to M and M' respectively; A and A' are bridging groups between Cp and X and between Cp' and X' respectively and are independently chosen from -SiR'2-O-SiR'2-, -SinR'm-, -CnR'm- and -CR'2-SiR'2-CR'2-SiR'2-, in which each R' is independently H or hydrocarbyl having 1 to 20 carbon atoms, n is an integer in the range 1 to 4 and m = 2n; each Q1, Q2 and Q1' and Q2' is independently a coordinating group which is hydrogen, halogen or hydrocarbyl having 1 to 20 carbon atoms and each of Q1 and Q1' is coordinated to both M and M'.