Unexpected formation of gallium-gallium single bonds by irradiation of thehydride [(Me3C)(2)GaH](3)

Di(tert-butyl)gallium hydride I dismutates partially in solution forming tr i(tert-butyl)gallium 2 and the sesquihydride [(Me3C)(2)GaH](2)[H2GaCMe3](2) (3). The loss of tert-butyl radicals upon irradiation of this mixture with day light or an UV lamp gave the hexagallium compound (Me3CGaGaCMe3)(2)(mu -H)(2)[mu -H2Ga(CMe3)(2)](2) (4), which possesses two Ga-Ga single bonds. These Ga-2 groups are bridged by two hydrogen atoms to give a six-membered Ga4H2 heterocycle. Couples of opposite gallium atoms of this heterocycle ar e bridged via Ga-H-Ga 3c-2e bonds by two H2Ga(CMe3)(2) ligands, which are s ituated above and below the molecular plane. Compound 4 may be described as a hypho-hexagallane(14) cluster compound.