Organoaluminum Hydroxides Supported by β-Diketiminato Ligands: Synthesis, Structural Characterization, and Reactions

Three β-diketiminato ligands (L1 = HC[C(Me)N(Ar)]2, Ar = 2,4,6-Me3C6H2; L2 = HC[C(Me)N(Ar)]2, Ar = 2,6-iPr2C6H3; L3 = HC[C(tBu)N(Ar)]2, Ar = 2,6-iPr2C6H3) were employed to prepare the organoaluminum hydroxides LAlR(OH) (R = Me, Et, Ph, OEt, OSiMe3) by hydrolysis of the corresponding chlorides in the presence of a N-heterocyclic carbene as HCl scavenger. Reaction of the organoaluminum hydroxide with Cp2ZrMe2 in toluene afforded the heterobimetallic oxide LAlR(μ-O)ZrMeCp2 under evolution of methane. All compounds were characterized by multinuclear NMR, IR, mass spectrometry, and elemental analysis. The structures of L1AlPh(OH) (10), L2AlPh(OH) (11), L2AlOEt(OH) (12), L2AlOSiMe3(OH) (13), and L2AlPh(μ-O)ZrMeCp2 (17) were determined by single-crystal X-ray diffraction studies. The polymerization of ethylene was studied with compound 17, which exhibits moderate catalytic activity.