Solvation spectra. Part 36.—Solvent-shared ion-pairs in methanolic electrolyte solutions—a nuclear magnetic resonance study

Abstract

For solutions of MgBr₂, Mg(NO₃)₂ and Mg(ClO₄)₂, the hydroxyl proton resonance from methanol molecules bonded to Mg²⁺ shifts with concentration in a manner which closely resembles the OH proton shift for the bulk solvent. This is interpreted in terms of a purely statistical interaction between the protons of Mg(MeOH)²⁺₆ and the anions. In contrast, the concentration shift for Mg(AcO)₂, is more rapid than that for the bulk OH protons, the difference becoming less with increasing concentration. This is interpreted in terms of preferential formation of solvent-shared ion-pairs, [graphic ommitted], which are favoured because of the relatively high basicity of of the acetate ion.