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, (Me 3 Si) 3 CAlH 2 ·THF ( 1 ), has been prepared by the reaction of RLi·2THF (R = (Me 3 Si) 3 C) with H 3 Al·NMe 3 . The reaction of 1 with elemental Se or Te in toluene afforded the novel organoaluminum chalcogenide heterocubane [RAl(μ 3 -E)] 4 (E = Se ( 2 ), Te ( 3 )) in good yield. [R‘GaH(μ-H)] 2 ( 4 ) (R‘ = (Me 3 Si) 2 C(Ph)C(Me 3 Si)N) was obtained by the reaction of R‘Li·THF with H 3 Ga·NMe 3 and compounds 5 − 7 by the reaction of [R‘GaH(μ-H)] 2 with S ( 5 ) and RGaCl 2 with (Me 3 Si) 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 Ga 2 E 2 core. On the basis of 1 H and 29 Si NMR data of 6 and 7, the trans and cis isomers could not be confirmed due to the formation of several species in solution.