Siloxyaluminum Alkyl Cations: Syntheses, Structures, and Reactions Related to Activation of Zirconocene Catalysts on Silica Gel Surfaces

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• 作者：Olaf Wrobel ; Frank Schaper ; Ulrich Wieser ; Heike Gregorius ; and Hans H. Brintzinger
• 刊名：Organometallics
• 出版年：2003
• 出版时间：March 17, 2003
• 年：2003
• 卷：22
• 期：6
• 页码：1320 - 1325
• 全文大小：140K
• 年卷期：v.22,no.6(March 17, 2003)
• ISSN：1520-6041

文摘

Binuclear siloxyaluminum methyl complexes of the type Me₂Al(mages/entities/mgr.gif">-OSiR₃)₂AlMe₂ react withprotonated N,N-dimethylanilinium tetrakis(pentafluorophenyl)borate, with release of CH₄,to form the dimethylaniline (DMA)-stabilized siloxyaluminum methyl cations Me₂Al(mages/entities/mgr.gif">-OSiR₃)₂AlMe(NMe₂(C₆H₅)⁺. These cations abstract a Cl^- ligand from (C₅H₅)₂ZrCl₂, to givethe dinuclear cation {(C₅H₅)₂ZrCl}₂(mages/entities/mgr.gif">-Cl)⁺, and a CH₃^- ligand from (C₅H₅)₂Zr(CH₃)₂, to giveby way of the DMA-stabilized cation (C₅H₅)₂Zr(CH₃)NMe₂(C₆H₅)⁺ the CH-activation product(C₅H₅)₂ZrCH₂NMe(C₆H₅)⁺; reaction with Me₂Si(ind)₂ZrMe₂ in toluene solution yields amoderately active catalyst for ethene polymerization. This reactivity of siloxyaluminummethyl cations is qualitatively similar to, although substantially lower than, that of a silicagel surface treated with trimethylaluminum and a cationizing agent.