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 x 10 g-PE/ mol-M h, Al/Zr = 500) and copolymerization of ethylene with 1-hexene (Complex 3,30.87 x 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.