Enthalpic contributions to solvent-solute and solvent-ion interactions: Electronic perturbation as key to the understanding of molecular attraction

We present a theoretical and numerical framework for the study of molecular attraction mechanisms between species in solution. The respective approach provides detailed insight into the enthalpic contributions of solvation and relies on molecular exchange reactions in combination with electronic perturbations. Associated values for chemical reactivity indices such as the electronegativity, the chemical hardness, and the electrophilicity are obtained from straightforward conceptual density functional theory calculations. Further analysis of corresponding reaction energies allows us to estimate the enthalpic stability of solvent-solute, solvent-ion, and ion-ion complexes. The validity of our approach is demonstrated by the calculation of donor numbers for distinct solvents. Our results reveal a reasonable agreement between calculated and experimental outcomes which highlights the applicability of our combined theoretical and computational approach.