Solvation spectra. Part 41.—Absolute proton magnetic resonance shifts for water protons induced by cations and anions in aqueous solutions

Abstract

Nuclear magnetic resonance salt shifts have been determined for a wide range of electrolytes in water at 273 and 298 K. Salt shifts for alkali metal chlorides have also been determined at 313, 333 and 353 K. Two independent methods are discussed for assigning an absolute shift to the chloride ion. The absolute values so derived are used to set up scales of absolute ionic shifts, which are discussed in terms of ion-solvent interactions. Although we do not discount the possibility of long-range effects, we can explain our results by reference only to the primary solvation layers. The anion shifts were mainly dependent on the basicity of the anion, but various anomalous cases are discussed.