1005391-39-8Relevant articles and documents
Twofold hydrogallation of C≡C triple bonds by H-GaCl2 - Synthesis of chelating Lewis acids and their application in adduct formation
Uhl, Werner,Claesener, Michael
, p. 729 - 735 (2008/10/09)
The twofold addition of Ga-H to C≡C triple bonds (hydrogallation) did not succeed by treatment of alkynes with an excess of dialkylgallium hydrides. In contrast, double hydrogallation was easily achieved by the reactions of H-GaCl2 with trimethylsilyl-substituted alkynes [trimethylsilylphenylethyne and 1,4-bis(trimethylsilylethynyl)benzene] in appropriate stoichiometric ratios. The monoalkyne yielded the compound [H 5C6-CH2-C(SiMe3)(GaCl 2)2]2, 1, which was only sparingly soluble in n-hexane. Crystal structure determination revealed a dimeric formula unit possessing two parallel Ga2Cl2 heterocycles in the solid state. Treatment of the dialkyne with four equivalents of the hydride gave a colorless precipitate, which was completely insoluble in hydrocarbons. Addition of diethyl ether to both products afforded soluble and monomelic etherates 1(OEt2)2 and 2 in which the two or four gallium atoms, respectively, were coordinated by ether molecules. Preliminary experiments with simple Lewis bases showed the principle capability of 1 to act as an effective chelating Lewis acid. Adducts of the type [H5C6-CH 2-C(SiMe3)(GaCl2)(GaClX)(μ-Cl)]- (4-6) resulted upon treatment with halide ions (X = Cl, Br, I).
