Preparation and properties of ((trimethylsilyl)methyl)gallium(III) compounds

Article abstract of DOI:10.1021/ic50206a046

A series of neutral organogallium(III) compounds which incorporate the (trimethylsilyl)methyl ligand, Ga(CH₂SiMe₃)_nX_3-n (n = 3, 2, 1; X = Cl, Br), have been prepared and fully characterized by elemental analyses, ¹H NMR and infrared spectroscopy, molecular weight data, solubility properties, and Lewis acid-base chemistry. The parent compound Ga(CH₂SiMe₃)₃ was prepared from GaCl₃ by a standard Grignard reaction in diethyl ether. The halogen derivatives were prepared from Ga(CH₂SiMe₃)₃ by elimination reactions with HCl or HBr and exchange reactions with GaCl₃ or GaBr₃. The following molecular formulas are supported by all available data: Ga(CH₂SiMe₃)₃, [Ga(CH₂SiMe₃)₂Cl]_x, [Ga(CH₂SiMe₃)₂Br]₂, [Ga(CH₂SiMe₃)Cl₂]₂, and [Ga(CH₂SiMe₃)Br₂]₂. It is noteworthy that the (trimethylsilyl)methyl ligand significantly influences the chemistry of only Ga(CH₂SiMe₃)₃ and [Ga(CH₂SiMe₃)₂Cl]_x. The Lewis acidity of Ga(CH₂SiMe₃)₃ has been greatly diminished as diethyl ether can be readily removed by simple vacuum distillation. The chemical and physical properties of Ga(CH₂SiMe₃)₂Cl, which could only be prepared in low yield by the elimination reaction, suggest that the compound might have an unusual structure. A ladder polymer or a linear polymer with one bridging chlorine atom per gallium atom is proposed. All other ((trimethylsilyl)methyl)gallium-halogen compounds have properties analogous to those of other known organogallium-halogen compounds.