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

Abstract

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 {[R_nGa]⁺[Cl_xAlCl_4–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.