Gallium Hydrides with a Radical-Anionic Ligand

The reaction of Cl2GaH with a sodium salt of the dpp-Bian radical-anion (dpp-Bian(.-))Na (dpp-Bian = 1,2-bis[(2,6-diisopropylphenyl)imino]acenaphthene) affords paramagnetic gallane (dpp-Bian(.))Ga(Cl)H (1). Oxidation of (dpp-Bian(2-))Ga-Ga(dpp-Bian(2-)) (2) with N2O results in the dimeric oxide (dpp-Bian(.-))Ga(mu(2)-O)(2)Ga(dpp-Bian(.-)) (3). A treatment of the oxide 3 with phenylsilane affords paramagnetic gallium hydrides (dpp-Bian(.-))GaH2 (4) and (dpp-Bian(.-))Ga{OSi(Ph)H-2} H (5) depending on the reagent's stoichiometry. The reaction of digallane 2 with benzaldehyde produces pinacolate (dpp-Bian(.-))Ga(O2C2H2Ph2) (6). In the presence of PhSiH3, the reaction between digallane 2 and benzaldehyde (2: PhSiH3: PhC(H)O = 1:4:4) affords compound 4. The newly prepared complexes 1, 3-6 consist of a spin-labeled diimine ligand-dpp-Bian radical-anion. The presence of the ligand-localized unpaired electron allows the use of the ESR spectroscopy for characterization of the gallium hydrides reported. The molecular structures of compounds 1, 3-6 have been determined by the single-crystal X-ray analysis.