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 [(η 5 ‐C 5 H 5 )MCl 2 ] 2 [μ, μ‐(SiMe 2 ) 2 (η 5 ‐RC 5 H 2 ) 2 ] [R = Me, M = Zr (1); R = allyl, M = Ti (2); R = allyl, M = Zr (3); R = n Bu, M = Ti (5); R = Me 3 Si, M = Zr (6)] and [(η 5 ‐CH 3 C 5 H 4 )ZrCl 2 ] 2 [μ, μ‐(SiMe 2 ) 2 (η 5 ‐allyl‐C 5 H 2 ) 2 , (4)] were synthesized by the reaction of CpMCl 3 (M = Ti, Zr) with [μ, μ‐(SiMe 2 ) 2 (η 5 ‐RC 5 H 2 ) 2 ] 2‐ ( L 2‐ ) in THF, and they were all well characterized by 1 H‐NMR, MS, and EA. When activated with methylaluminoxane (MAO), this series complexes are active catalysts for Ethylene polymerization (Complex 3 , 3.86 × 10 6 g‐PE/mol‐M h, Al/Zr = 500) and copolymerization of ethylene with 1‐hexene (Complex 3 ,30.87 × 10 5 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