A model based QSPR analysis of the unified non-specific solvent polarity scale

Abstract

A Model Based QSPR approach, MQSPR, has been employed to estimate the S′ parameters of the Unified Solvent Polarity Scale. MQSPR selects descriptors, a priori to the correlation analysis, that have potential meaning in the context of the measured property. A successful two-parameter correlation (R² = 0.9587) is developed from 48 diverse molecules using two orthogonal descriptors, the dipolar density (given by the total dipole moment of the molecule divided by the molecular volume) and the reciprocal of the HOMO–LUMO energy gap. The correlation equation allows confident estimations of S′ from quantum mechanical calculations, assists in the interpretation of non-specific solvation and enables one to analyse solvent conformational-dependent solvation influences.