Synthesis and characterization of tris(trimethylsilyl)methylaluminum chalcogenides [RAl(μ3-E)]4 (R = (Me3Si)3C; E = Se, Te) and 1-azaallylgallium chalcogenides [R′Ga(μ2-E)]2 (R′ = (Me3Si)2C(Ph)C(Me3Si)N; E = S, Se, Te)

Tris(trimethylsilyl)methylaluminum dihydride, (Me3Si)(3)CAlH2. THF (1), has been prepared by the reaction of RLi . 2THF (R = (Me3Si)(3)C) with H3Al . NMe3. The reaction of 1 with elemental Se or Te in toluene afforded the novel organoaluminum chalcogenide heterocubane [RAl-(mu3-E)](4) (E = Se (2), Te (3)) in good yield. [R ' GaH(mu -H)](2) (4) (R ' = (Me3Si)(2)C(Ph)C( Me3Si)N) was obtained by the reaction of R ' Li . THF with H3Ga . NMe3 and compounds 5-7 by the reaction of [R ' GaH(mu -H)](2) with S (5) and RGaCl2 with (Me3Si)(2)E (E = Se (6), Te (7)). The structures of 6 and 7 have been established by X-ray crystallography. Compounds 6 and 7 have a dimeric structure featuring fused planar four-membered ring systems with a central Ga2E2 core. On the basis of H-1 and Si-29 NMR data of 6 and 7, the trans and cis isomers could not be confirmed due to the formation of several species in solution.