Reactions of dimethyl[tris(trimethylsilyl)methyl]metalanes of aluminum andgallium with H2S and elemental chalcogens - Crystal structures of [RAl(mu-S)](2)center dot 2THF, [RGa(mu(3)-S)](4), [{RAl(mu(3)-S)}(3)MeAl(mu(3)-S)],[RAlMe(mu-SeMe)](2), and [RGaMe(mu-TeMe)](2) [R = C(SiMe3)(3)]

The reaction of the trialkylalane (Me3Si)(3)CAIMe(2) x THF (1) with H2S in toluene at room temperature results in the formation of the dimeric sulfide compound [(Me3Si)(3)CAl(mu-S)](2) x 2 THF (3), while the reaction of the h omologous gallane (Me3Si)(3)CGaMe2 (2) with H2S under similar conditions af fords the heterocubane [(Me3Si)(3)CGa(mu(3)-S)](4) (4). Heating of compound 3 in vacuo gives a mixture of the symmetrically substituted [(Me3Si)(3)CAl (mu(3)-S)](4) (5) and the unsymmetrically substituted heterocubane [{(Me3Si )(3)CAl(mu(3)-S)}(3)MeAl(mu(3)-S)] (6). Reaction of the trialkylmetalanes 1 and 2 with elemental selenium in refluxing toluene results in the formatio n of the corresponding selenolates [(Me3Si)(3)CMMe-(mu-SeMe)](2) (7, M = Al ; 8, M = Ga). The compounds exhibit a high thermal stability and can not be converted to the corresponding selenides [(Me3Si)(3)CM(mu(3)-Se)](n) (M = Al, Ga) upon heating. In contrast, the trialkylalane 1 does not react with tellurium metal in refluxing toluene at all, while the trialkylgallane 2 af fords the tellurolate [(Me3Si)(3)CGaMe(mu-TeMe)](2) (9) under similar condi tions. Compounds 3-9 have been characterized by H-1- and Si-29-NMR, mass, a nd IR spectroscopy. Furthermore, the molecular structures of compounds 3.C6 H6, 4.1.5 C6H6, 6, 7.C6H6 and 9 have been determined by X-ray crystallograp hy.