The determination of the parameters of conformational equilibria by infrared absorption spectra

Abstract

New methods of determining the entropy difference of two conformations, the activation energy of the conformational transitions, of free enthalpy difference and the ratio of integral absorption coefficients of two conformations by i.r. absorption spectra are proposed. The basis of the method of ΔSo determination is the study of the i.r. spectra of compounds both in the temperature range where there are conformational transitions and at the temperatures were they do not occur. For the determination of E≠ ΔGo and αA/αB it is proposed to investigate the kinetics of the conformational transitions in liquid solutions. The methods have been applied to chloro-, bromo- and trans-dichlorocyclohexanes. © 1985