Separation of chlorocyclohexane's axial and equatorial conformer infrared spectrum by isothermal relaxation in the glass→liquid transition region

Abstract

A new low-temperature method enables separation of the infrared spectrum of a mixture of conformers into the distinct spectra of its constituents, and its merits are demonstrated here for chlorocyclohexane (Cl–CH). Nonequilibrium population of Cl–CH's axial (a) and equatorial (e) conformers was generated by rapid quenching of their vapours into the glassy state. Interconversion of conformers was accomplished by isothermal relaxation in the glass→liquid transition, and was followed by Fourier-transform infrared spectroscopy. These spectra were separated into the distinct spectra of the a and e-conformer. Assignment of infrared bands of the separated spectra to the normal vibrations of the conformers is consistent with those reported in the literature with two exceptions.