Tetrakis[tris(trimethylsilyl)silylaluminum(I)], a silicon-rich compound with a central tetrahedral Al-4 nucleus

The first neutral aluminium(I) compound Al4Cp4* [Angew. Chem. 103 (1991) 59 4; Angew. Chem. Int. Ed. Engl. 30 (1991) 564] was published in 1991. Until now other neutral aluminum polyhedra, e.g. Al-4[Si(t-Bu)(3)](4) [Organometa llics 17 (1998) 1894], Al-4[C(SiMe3)(3)](4) [Angew. Chem. 110 (1998) 2059; Angew. Chem. Int. Ed. Engl. 37 (1998) 1952] and Al4Cp3*[N(SiMe3)(2)] [J. Or ganomet. Chem. 561 (1998) 203], could be synthesized and structurally chara cterized. All of them form Al, tetrahedra-obviously a preferred structural unit of aluminium(I) compounds. The reaction of [AlBr.NE3](4) [Angew. Chem. 106 (1994) 1860; Angew. Chem. Int. Ed. Engl. 33 (1994) 1754] with [(Me3Si) (3)SiLi.3THF] leads, in a yield of 25%, to tetrakis[tris(trimethylsilyl)sil ylaluminium(I)] Al-4[Si(SiMe3)(3)](4) 1, another compound of this type cont aining an Al, tetrahedron in an environment of four distorted tetrahedral S i-4 units: Al-4(Si-4)(4)(CH3)(36).