Synthesis of double silylene-bridged binuclear metallocenes and their cooperation effect during ethylene polymerization and ethylene/1-hexene copolymerization

Novel double silylene‐bridged binuclear Group 4 metallocene complexes [(η5‐C5H5)MCl2]2[μ, μ‐(SiMe2)2 (η5‐RC5H2)2] [R = Me, M = Zr (1); R = allyl, M = Ti (2); R = allyl, M = Zr (3); R = nBu, M = Ti (5); R = Me3Si, M = Zr (6)] and [(η5‐CH3C5H4)ZrCl2]2[μ, μ‐(SiMe2)2 (η5‐allyl‐C5H2)2, (4)] were synthesized by the reaction of CpMCl3 (M = Ti, Zr) with [μ, μ‐(SiMe2)2 (η5‐RC5H2)2]2‐ (L2‐) in THF, and they were all well characterized by 1H‐NMR, MS, and EA. When activated with methylaluminoxane (MAO), this series complexes are active catalysts for Ethylene polymerization (Complex 3, 3.86 × 106 g‐PE/mol‐M h, Al/Zr = 500) and copolymerization of ethylene with 1‐hexene (Complex 3,30.87 × 105 g‐polymer/mol‐M h, 1‐hexene content in polymer 2.34 mol %, Al/Zr = 1000). The result of polymerization implies that there is a cooperative effect between the two metals in the double‐bridged binuclear molecules. © 2011 Wiley Periodicals, Inc. J Appl Polym Sci, 2011