Control of symmetry in active cationic ansa-zirconocene species: catalyst preparation, characterization and ethylene–norbornene copolymerization

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• 作者：Lee ; Hyosun ; Hong ; Sung-Don ; Park ; Young-Whan ; Jeong ; Boong-Goon ; Nam ; Dae-Woo ; Jung ; Hye Young ; et. al.
• 关键词：ansa-Zirconocene ; Bent metallocene ; Borane ; Borate ; Copolymerization ; Ethylene ; Ion pair ; Norbornene ; Zwitterion
• 刊名：Journal of Organometallic Chemistry
• 出版年：2004
• 出版时间：October 15, 2004
• 年：2004
• 卷：689
• 期：21
• 页码：3402-3411
• 全文大小：384 K

文摘

New bis-hydrocarbyl complexes of methylene bridged ansa-metallocenes [H₂C(C₅Me₂H₂)₂]ZrR₂ {R=Me (1), CH₂Ph (2), CH₂SiMe₃ (3), Ph (4)} have been prepared. They form catalytically active intermediates with borane or borate depending on solvent and ZraaaR group. Specifically, [H₂C(Me₂C₅H₂)₂]Zr(CH₂Ph)₂ (2) produced an ion pair upon treatment with B(C₆F₅)₃ whereas [H₂C(Me₂C₅H₂)₂]Zr(CH₂SiMe₃)₂ (3) produced a zwitterionic species, identified by ¹H, ¹³C, and ¹⁹F NMR spectroscopy. Copolymerization of ethylene and norbornene for the metallocene dichloride/MAO and bis-hydrocarbyl complex/borate systems was compared.