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(μ²-O)₂Ga­(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)­H₂}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.