From solvation thermodynamics to polarity scales and universalities

Reliable information on intermolecular interactions is crucial for molecular thermodynamic modeling and in a vast range of practical applications, including solvent screening. A wealth of such information may be extracted from experimental data on solvation quantities by consistent use of Solvation Thermodynamics. This is facilitated when a holistic approach is adopted involving large number of systems of diverse character and their specific and non-specific interactions are treated on a common basis. The present work combines quantum chemical information on over 1400 solute molecules and experimental information on solvation enthalpy and free energy in common solvents in order to extract information on dispersion, (di)polar, and hydrogen-bonding (HB) interactions from over 190,000 solute – solvent systems. The widely used Abraham's LSER (linear solvation energy relationship) model has been restructured for handling this information and for the development of new polarity scales as well as acidity (HB donor capacity) and basicity (HB acceptor capacity) scales. The number of solvent systems with known LSER-type solvent-specific parameters has been increased significantly along with its predictive capacity. Self-solvation quantities over a broad range of external conditions have been explored as well and their universalities at the boiling point and the (vapor – liquid) critical point have been identified. Solvation parameters facilitating the exchange of thermodynamic information between diverse polarity scales have been developed. The significance and perspectives of these developments are discussed. • New polarity, acidity and basicity scales for solutes and solvent systems. • Restructure of LSER model facilitates molecular characterization of solvents. • Quantum-chemical account of polar contribution to solvation properties.