GA-71 NMR-STUDIES OF MIXTURES OF GALLIUM TRICHLORIDE AND TRIMETHYLGALLIUM

Ga-71 NMR spectra of solutions of GaCl3 and Me3Ga, and of binary mixtu res of GaCl3-Me3Ga, in n-heptane have been recorded. The resonance sig nals for both Me3Ga and GaCl3 are unchanged on dilution over the tempe rature range 20-100-degrees-C. Mixtures of GaCl3 and Me3Ga show only o ne resonance signal, whose chemical shift is determined predominantly by the nature of the coordination at gallium, indicating rapid chemica l exchange of the species involved. The results of studies of methanol ysis -and hydrolysis, and of adduct formation, are also discussed. The Ga-71 resonances of several possible external standards in the temper ature range 20-100-degrees-C are also reported. The Ga-71 NMR signal o f a solution of GaCl4- in 6 M aqueous hydrochloric acid. for which del ta(Ga-71) = 250 +/- 0.5 ppm downfield from the signal of a 1 M solutio n of [Ga(H2O)6]3+[ClO4]3- in 1 M HClO4, is recommended as a temperatur e-independent external standard for gallium NMR studies.