- Chemistry of methylgallium(III) compounds in protic solvents
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The chemical properties of as well as routes to the formation of methylgallium(III) compounds in aqueous acidic solutions and in other protic solvents have been investigated. Aqueous perchloric acid solutions of Me2GaClO4 at room temperature are surprisingly resistant to hydrolytic cleavage of the gallium-carbon bond. Only 14% of the available methyl groups of Me2GaClO4 when dissolved in 0.0171 M HClO4 are converted to CH4 after a 3-month time period. In contrast, Me2GaClO4 undergoes a significantly faster methyl-transfer reaction with Ga(ClO4)3 in aqueous HClO4 solution to form MeGa2+(aq) which in turn hydrolyzes to form Ga3+(aq) and methane. Approximately 36% of the initially available methyl groups form CH4 in 3 months. The dimethylgallium cation also methylates Hg2+(aq) to form MeGa2+(aq) and MeHg+(aq) in aqueous solution, but Me2Ga+(aq) does not react with Al3+(aq), Zn2+(aq), or Na+(aq). In a second series of experiments the methylation of gallium(III) by Me2Co(BDM1,3pn) (BDM1,3pn = {N,N′-propane-1,3-diyl[bis(biacetyl monooxime imino)]}) was investigated in ethanol and acetone solutions by using UV titration and 1H NMR data. The observed stoichiometry of the reaction requires 1 mol of Ga(ClO4)3 for every 2 mol of Me2Co(BDM1,3pn). The identified products are Me2Ga+ and MeCo-(BDM1,3pn)+. In contrast, gallium(III) is not methylated by methylcobalamin in aqueous solution.
- Beachley Jr.,Kirss,Bianchini,Royster
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p. 724 - 727
(2008/10/08)
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