On the quest for new mixed-metal mu-oxo-bridged complexes: synthesis of compounds containing transition metal-oxygen-main group metal motifs M-O-M1 (M = Ti, Zr; M1 = Al, Ga) without cyclopentadienyl ligands.

The reaction of TiBz4 (Bz = benzyl) with LAlMe(OH), L = (2,6-iPr2C6H3NC(Me))2CH, afforded LAlMe(mu-O)TiBz3 (1) and [LAlMe(mu-O)]2TiBz2 (2), whereas the corresponding reaction with ZrBz4 resulted only in the formation of the trinuclear species [LAlMe(mu-O)]2ZrBz2 (3). The reaction of (Mes 2Ga(OH))2 x THF (Mes = 2,4,6-Me3C6H2) with Ti(NEt2)4 yielded the cluster compound TiGa6O7(NEt2)2(Mes)6 (4). All compounds have been characterized by elemental analysis, NMR spectroscopy, and mass spectrometry. Additionally, single crystal X-ray structure data of 1, 3, and 4 are reported. Compounds 1-4 show low catalytic activities in the polymerization of ethylene. Revisiting known mu-oxo-bridged complexes containing the M-O-M(1) (M = Ti, Zr, Hf; M(1) = Al, Ga) skeleton revealed that the application of polynuclear group 13 hydroxides and oxo bridged complexes possesses a potential for the preparation of new polyoxometal clusters.