Organoaluminum hydroxides supported by β-diketiminato ligands:: Synthesis, structural characterization, and reactions

Three beta-diketiminato ligands (L-1 = HC[C(Me)N(Ar)](2), Ar = 2,4,6-Me3C6H2;L-2 = HC[C(Me)N(Ar)](2), Ar = 2,6-iPr(2)C(6)H(3); L-3 = HC[C(tBu)N(Ar)](2), Ar = 2,6-iPr(2)C(6)H(3)) 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(mu-O)ZrMeCp2 under evolution of methane. All compounds were characterized by multinuclear NMR, IR, mass spectrometry, and elemental analysis. The structures of (LAlPh)-Al-1(OH) (10), L-2 AlPh(OH) (11), L-2 AlOEt(OH) (12), L-2 AlOSiMe3(OH) (13), and L-2 AlPh(mu-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.