THERMODYNAMICS OF HYDROGEN BONDING OF PHENOL TO VINYL DERIVATIVES AND TO THEIR CORRESPONDING SATURATED DERIVATIVES

The thermodynamics of hydrogen bonding of phenol with both vinyl derivatives and the corresponding saturated compounds have been investigated by measuring the hydroxyl stretching vibration in carbon tetrachloride. In the case of the vinyl derivatives (CH2CHX) the hydroxyl proton does not interact with the π electrons delocalized over both the vinyl group and the substituent (X) but with a n electron of the substituent. The enthalpy of association (-ΔH°) decreases in the order oxygen-containing bases > nitrile derivatives > olefins > aromatic hydrocarbons. For hydrogen bonding with π-bases the entropy (ΔS°) contribution to the free energy change is the largest. © 1968.