Quantifying Solvophobic Effects in Non-polar Cohesive Interactions

The hydrophobic effect plays a central role in determining the structure, activity and properties of biomolecules and materials. In contrast, the general manifestation of this phenomenon in other solvents -the solvophobic effect- although widely invoked, is currently poorly defined due to the lack of a universally accepted descriptor. Here we have used synthetic molecular balances to measure solvent effects on aromatic, aliphatic and fluorous non-polar interactions. Our solvent screening data combined with independent experimental measurements of supramolecular association, single-molecule folding and bulk phase transfer energies were all found to correlate well with the cohesive energy density of the solvent. Meanwhile, other measures of solvent cohesion, such as surface tension and internal pressure, gave inferior correlations. Thus, we establish cohesive energy density as a readily accessible, quantitative descriptor of solvophobic association in a range of chemical contexts.