THE EFFECT OF SOLVENT-SOLUTE INTERACTIONS ON THE INFRARED CARBONYL STRETCHING VIBRATION

Abstract

The effect of solvent-solute interactions on the carbonyl stretching vibration of several ketones, amides and esters has been studied. The compounds examined include acetone, cyclohexanone, n-acetyl pyrrolidine, ethyl acetate, ethyl trichloroacetate and ethyl trifuloroacetate. Changes in the frequency and shape of the carbonyl band were produced by varying the composition of two-component solvent systems and/or by varying the temperature of the solutions. The results clearly suggest that the observed variations in frequency and intensity are due to specific interactions between solvent and solute rather than to bulk dielectric effects. Moreover, these interactions can result in the formation of a number of solvent-solute complexes which are in equilibrium with each other.