Preferential solvation of organic species in binary solvent mixtures probed by intermolecular H-1 NOESY NMR spectroscopy

The preferential solvation of neutral and ionic organic species (phenol, ni troanilines, N-methylbutyramide, 1,4-dioxane, acetate and tetraalkylammoniu m ions) in binary solvent mixtures (aqueous CH3CN, DMSO, EtOH, 1-PrOH, CH3C ON(CH3)(2); CH2Cl2/Et2O; 1,4-dioxane/benzene; cyclohexane/THF) has been inv estigated through the analysis of the relative intensities of intermolecula r H-1 NOESY cross-peaks according to Macura-Ernst theory. Observed preferen tial solvation is discussed in terms of the strength of individual solute-s olvent interactions, hydrophobic interactions in water-rich mixtures, and m icroheterogeneity in the mixed medium.