Alkyl group transmetalation reactions in electrolytic solutions studied by multinuclear NMR

Advantageous electrolytic solutions for rechargeable magnesium batteries are obtained by dissolving in THF the reaction products of EtAlCl2 and Bu2Mg, in various stoichiometric proportions. The components of these solutions are identified by multinuclear NMR (H-1, C-13, Al-27, and Mg-25) and conductivity measurements for the closely related system where the organomagnesium species is Et2Mg. The system with the highest electrochemical stability and relatively high ionic conductivity, denoted as a 2:1 complex, is obtained from a 2:1 ratio of EtAlCl2 and Et2Mg and is shown to be composed of a chloride-bridged species, Et2ClAl-Cl-AlClEt2-, and of MgCl+, the result of transmetalation reactions.