Mononuclear Aluminum Hydroxide for the Design of Well-Defined Homogeneous Catalysts

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• 作者：Guangcai Bai ; Sanjay Singh ; Herbert W. Roesky ; Mathias Noltemeyer ; and Hans-Georg Schmidt
• 刊名：Journal of the American Chemical Society
• 出版年：2005
• 出版时间：March 16, 2005
• 年：2005
• 卷：127
• 期：10
• 页码：3449 - 3455
• 全文大小：179K
• 年卷期：v.127,no.10(March 16, 2005)
• ISSN：1520-5126

文摘

An unprecedented aluminum hydroxide LAlMe(OH) (5; L = HC[(CMe)(2,6-iPr₂C₆H₃N)]₂) has beenprepared by the hydrolysis of LAlMeCl (4). For the preparation of 5, the reagents of KOH, water, and KH,as well as the two-phase ammonia/toluene system, were used. Further reactions of 5 with Cp₂ZrMe₂ (8)and Cp₂ZrHCl in toluene lead to the intermolecular elimination of CH₄ and H₂ and the formation of -O-bridged dinuclear aluminum and zirconium complexes [LAlMe(-O)ZrMeCp₂] (6) and [LAlMe(-O)ZrClCp₂](7), respectively, in high yields. The crystal structure reveals that 5 is a monomer with terminal OH and Megroups. The X-ray structure analysis shows that 6 and 7 contain a bent Al-(-O)-Zr core with terminalAl-Me and Zr-Me or Zr-Cl arrangements. The methylalumoxane (MAO)-activated compounds 6 and 7exhibit high catalytic activity for the polymerization of ethylene. Under comparable polymerization conditions,the MAO/6 and MAO/7 catalyst systems show considerably higher activity and much lower MAO:catalystratios than that of MAO/8.