71Ga NMR studies of mixtures of gallium trichloride and trimethylgallium

Article abstract of DOI:10.1016/0022-328X(93)83311-I

71Ga NMR spectra of solutions of GaCl3 and Me3Ga, and of binary mixtures of GaCl3-Me3Ga, in n-heptane have been recorded.The resonance signals for both Me3Ga and GaCl3 are unchanged on dilution over the temperature range 20-100 deg C.Mixtures of GaCl3 and Me3Ga show only one resonance signal, whose chemical shift is determined predominantly by the nature of the coordination at gallium, indicating rapid chemical exchange of the species involved.The results of studies of methanolysis and hydrolysis, and of adduct formation, are also discussed.The 71Ga resonances of several possible external standards in the temperature range 20-100 deg C are also reported.The 71Ga NMR signal of a solution of GaCl4^- in 6 M aqueous hydrochloric acid, for which δ(71Ga) = 250 +/- 0.5 ppm downfield from the signal of a 1 M solution of ³⁺3^- in 1 M HClO4, is recommended as a temperature-independent external standard for gallium NMR studies.