Furfuryl alcohol—III. Infrared, matrix infrared and Raman spectra and ab initio and normal coordinate calculations

The i.r. spectra of furfuryl alcohol have been recorded for gaseous and liquid states and in argon and nitrogen matrices, and the i.r. spectrum of the OD deuterated analogue has been recorded in an argon matrix. The Raman spectra of the compounds in the liquid state were also recorded. In particular the modes related to the OH and OD vibrations were studied and the results are discussed. Ab initio STO-3G optimizations were carried out on five conformations of furfuryl alcohol. The rotation of the side group around the CC bond seems to be almost free: an ‘orthogonal’ conformer being the most stable form. Normal coordinate calculations were carried out on the most stable C s conformer, using the general valence force field, and a vibrational assignment is presented. Force constants taken from the literature were employed for the in-plane vibrations of the furane ring, but for its out-of-plane modes a new force field was developed. This also gave good results for furane.