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 EtAlCl 2 and Bu 2 Mg, in various stoichiometric proportions. The components of these solutions are identified by multinuclear NMR ( 1 H, 13 C, 27 Al, and 25 Mg) and conductivity measurements for the closely related system where the organomagnesium species is Et 2 Mg. 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 EtAlCl 2 and Et 2 Mg and is shown to be composed of a chloride-bridged species, Et 2 ClAl−Cl−AlClEt 2 -, and of MgCl +, the result of transmetalation reactions.