A proton NMR method for the study of the solvation of alkaline earth cations with methanol (MeOH), ethanol (EtOH) and propanol (PrOH) in nitromethane (NM) as diluent is described. The method is based on monitoring the resonance frequency of alchohols protons as a function of solvent to metal ion mole ratio at constant metal ion concentration. The average solvation number of cation, , at any alchohol/methal ion mole ratio was calculated from the NMR chemical shift-mole ratio data and was plotted against the mole ratio values. The solvation numbers of alkaline earth cations were obtained from the limiting values of the corresponding vs. mole ratio plots. With regard to the results presented, there are increases in the solvation number from Mg2+ to Sr2+ about every alcohols, but decreases in solvation number from methanol to propanol as concerns every metal ion.

Keywords: Ionic solvation, Solvation number, Methanol, Ethanol, Propanol, Alkaline earth cations, Nitromethane, NMR

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