Correlation between empirical solvent polarity scales and computed quantities derived from molecular surface electrostatic potentials

Abstract

Analysis of five empirical solvent polarity scales E_T ^N, π*, Py, S′ and SPP is carried out by correlating them with Π and σ² _tot, two computed quantities derived from molecular surface electrostatic potentials. Our results indicate (i) that the S′ scale should be a good global solvent polarity scale, (ii) that it would be inappropriate to use the E_T ^N and Py scales to describe non-specific solute–solvent interactions for protic solvents, and (iii) that the π* and SPP scales are probably contaminated with charge-transfer effects for aromatic and polychlorinated solvents. The differences between our results and those obtained by the correlation of empirical scales with a theoretical thermodynamic analysis result (E_PNA) are discussed in the context of intermolecular interactions between the probe solutes and the solvent considered.