A Non-Bornian Approach to the Standard Gibbs Energy of Ion Transfer at the Oil | Water Interface

Abstract

A voltammetric study on the transfer of polyoxometalate anions at the oil½water interface highlighted the utmost importance of short-range ion–solvent interactions in the transfer or resolvation energy. Based on these findings the author proposed a non-Bornian solvation model, in which the Born-type long-range electrostatic interaction was daringly ignored and the ion solvation energy (scaled by the surface area) was simply expressed as a quadratic function of the ion's surface field strength. This model was successfully used to calculate the hydration energy and the transfer energy at the oil½water interface, for a variety of inorganic and organic ions. In the analysis for an organic ion, the local surface field strengths on the minute surfaces of the ion were evaluated through DFT calculation. A few applications of the present solvation model are also described, featuring its higher usefulness.