Molecular gallosilicates and their group 4 multimetallic derivatives.

Reaction between the silanediol (HO)2Si(OtBu)2 and gallium amides, LGaCl(NHtBu) and LGa(NHEt)2 (L = [HC{C(Me)N(Ar)}2]−, Ar = 2,6-iPr2C6H3), respectively, resulted in the facile isolation of molecular gallosilicates LGaCl(μ-O)Si(OH)(OtBu)2 (1) and LGa(NHEt)(μ-O)Si(OH)(OtBu)2 (2). Compound 2 easily reacts with 1 equiv of water to form the unique gallosilicate-hydroxide LGa(OH·THF)(μ-O)Si(OH)(OtBu)2 (3). Compounds 1–3 contain the simple Ga–O–SiO3 framework and are the first structurally authenticated molecular gallosilicates. These compounds may be used not only as models for gallosilicate-based materials but also as further reagents because of the presence of reactive functional groups attached to both gallium and silicon atoms. Accordingly, seven molecular heterometallic compounds were obtained from the reactions between compound 3 and group 4 amides M(NMe2)4 (M = Ti, Zr) or M(NEt2)4 (M = Ti, Zr, Hf). Hence, by tuning the reactions conditions and stoichiometries, it was possible to isolate and structurally...