Hydrogen bonds between cholesterol and oxygen bases: a thermodynamic study

Abstract

Using calorimetric and IR spectroscopic methods, the values of thermodynamic functions of (1 : 1) hydrogen-bond complex formation between cholesterol and some proton acceptors in CCl₄ have been determined. The self-association of cholesterol in the solvent used was taken into account in calculations. The proton acceptors used are oxygen bases containing CO, —O—, PO and SO groups. The values of Δ_fH were compared with those previously obtained for the pure bases. The enthalpy of hydrogen-bond complex formation of cholesterol is a linear function of Gutmann's donor number for all the proton acceptor compounds examined. Badger–Bauer's relation {Δ_fH=f[Δv(OH)]} is not satisfied as well as Δ_fH=f(DN) but it allows the prediction of values of enthalpy of complex formation between cholesterol and proton acceptors within ± 1.5 kJ mol^–1 limits.