Preferential solvation in mixed binary solvents by ultraviolet–visible spectroscopy: N-ethyl-4-cyanopyridinium iodide in alcohol–acetone mixtures

Preferential solvation of N-ethyl-4-cyanopyridinium iodide has been studied by monitoring its solvatochromic charge-transfer band in an alcohol–acetone binary mixture. Solvation by alcohols is found to be preferred over acetone over the entire range of composition. The role of (i) self-association in alcohols, (ii) the size effect of the solvents and (iii) solvent–solvent interaction in determining the preferential solvation in the binary mixture has also been discussed.