Aluminium-27 and 71Ga NMR studies of the solution chemistry of Ga[AlCl4] and related compounds

The non-aqueous solution chemistry of GaAlCl4 has been investigated by 27Al and 71Ga NMR spectroscopy. In dilute solution in benzene, the solute species are of the form {[RnGa]+[ClxAlCl4–x]–}m (R = arene; x = 1–3, n, m undetermined), while in concentrated solutions the dominant interactions involve aggregates of ion pairs. Dilute solutions of the salt in n-heptane have also been studied, together with n-heptane–benzene mixtures, solutions of GaAlCl4 and Ga2Cl6 in n-heptane, solutions of GaAlBr4 and GaAlI4 in benzene, and mixed GaAlCl4–GaAlBr4 systems. The hydrolysis of GaAlCl4 in benzene is shown to involve reaction at both Ga and Al centres.