A THEORETICAL-STUDY OF SOLVENT A Theoretical-Study Of Solvent Effects on The Relative Thermodynamic Stabilities of The Allyl+/F- and Allyl-/Li+ Ion-Pairs in Polar Media

Abstract

The relative thermodynamic stabilities of several ion-pair structures, including intimate and solvent-separated forms, in solution have been studied for the allyl +/F- and allyl- /Li + model systems. The electrostatic part of the solvent effects was modelled through the self-consistent reaction field (SCRF) theory and an extension of it including desolvation effects (SCRF ID theory). Specific solvent effects were also analysed by explicitly incorporating a solvent molecule, vía the supermolecule (SM) approach. It is shown that a more complete thermodynamic description of these systems is attained by using mixed continuum-SM schemes. This last approach allows qualitative separation of the individual contributions of the electrostatic and hydrogen-bonding effects, which are particularly relevant to a discussion of the relative stabilities of intimate and solvent-separated ion pairs in these systems.