The compound exists a priori in two conformers, equatorial (e) and axial (a), and the experimental results suggest an equilibrium in which the a-conformer has 1.2 kJ mol鈭? lower enthalpy than the e-conformer in the liquid, leading to 60%a-conformer at ambient temperature.
B3LYP calculations with various basis sets and the G3 model chemistry gave conformational enthalpy difference 螖H(e 鈭?#xA0;a) in the range 0.6 and 1.8 kJ mol鈭?. Infrared and Raman intensities, polarization ratios and vibrational frequencies for the e and a conformers were calculated. The wavenumbers of the vibrational modes were derived in the anharmonic approximation in B3LYP/cc-pVTZ calculations. An average relative deviation of ca. 1%between the observed and calculated wavenumbers for the 48 modes of the e and a conformers was found.