Cooperative effects in binuclear zirconocenes: Their synthesis and use as catalyst in propene polymerization
摘要:
The mono- and bis-cyclopentadienyl compounds 1-(Cp'')-4-(CH3)C6H4 (1) and 1, 4-(Cp'')(2)C6H4 (2) (Cp'' = 3,4-dimethylcyclopenta-1,3-diene-1-yl) have been synthesized. The reactions of the lithium salts of 1 and 2 with CpZrCl(3).dme (dme = dimethoxyethane) and Cp(*)ZrCl(3)(Cp(*) = C-5(CH3)(5)) yielded the mono- and bi-nuclear bridged zirconocenes 1-(Cp''ZrCpCl(2) )-4-(CH3)C6H4 (3), 1,4-(Cp''ZrCpCl(2))(2)C6H4 (4) and 1,4-(Cp''ZrCp(*)Cl(2))(2)C6H4 (5). When activated with methylaluminoxane (MAO), the mono- and bi-nuclear zirconocenes 3 and 4 catalyse the polymerization of propene. The influence of the catalyst composition on the polymerization kinetics and molecular weight is discussed.