Charge transfer band of N-alkyl pyridinium iodides in mixed binary solvents containing acetone: Existence of preferential salvation

Abstract

The longest wavelength charge transfer band of N-ethyl-4-cyanopyridinium iodide has been studied in mixed binary solvents like acetone + ethyl acetate, acetone + dichloroethane, acetone + carbontetrachloride, acetone + chlorobenzene and acetone + benzene. The nonlinear variation of the charge transfer absorption energy with mole fraction has been explained as due to preferential salvation of the solute by acetone, the more polar solvent component. Different mechanisms of solute-solvent interaction have been discussed in relation to the phenomenon of preferential solvation.