title: Mononuclear aluminum hydroxide for the design of well-defined homogeneous catalysts.
abstract: An unprecedented aluminum hydroxide LAlMe(OH) (5; L = HC[(CMe)(2,6-iPr2C6H3N)]2) has been prepared 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 mu-O-bridged dinuclear aluminum and zirconium complexes [LAlMe(mu-O)ZrMeCp2] (6) and [LAlMe(mu-O)ZrClCp2] (7), respectively, in high yields. The crystal structure reveals that 5 is a monomer with terminal OH and Me groups. The X-ray structure analysis shows that 6 and 7 contain a bent Al-(mu-O)-Zr core with terminal Al-Me and Zr-Me or Zr-Cl arrangements. The methylalumoxane (MAO)-activated compounds 6 and 7 exhibit 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:catalyst ratios than that of MAO/8.
authors.affiliation: Institut für Anorganische Chemie der Universität, Göttingen, D-37077 Göttingen, Germany.
authors.forename: Guangcai
authors.initials: G
authors.lastname: Bai
authors.forename: Sanjay
authors.initials: S
authors.lastname: Singh
authors.forename: Herbert W
authors.initials: HW
authors.lastname: Roesky
authors.forename: Mathias
authors.initials: M
authors.lastname: Noltemeyer
authors.forename: Hans-Georg
authors.initials: HG
authors.lastname: Schmidt