Far Infrared Group Frequencies. V. Oximes and Aldoximes

Abstract

The low frequency infrared spectra from 450 to 75 cm⁻¹ of seven oximes and five aldoximes have been recorded for pure samples and for dilute solutions in cyclohexane. An intense characteristic band is present in the solution spectra at 367 ± 10 cm⁻¹. This characteristic band shifts to 275 ± 10 cm⁻¹ in the spectra of the OD compounds. The 367 ± 10 cm⁻¹ and 275 ± 10 cm⁻¹ bands are assigned to OH and OD torsional vibrations. A comparison of the solution spectra with spectra of the solid samples indicated that the OH … N hydrogen bond stretch of oximes and aldoximes occurs in 300 to 200 cm⁻¹ region. Strong bands also are present in 140 to 100 cm⁻¹ region which are due to OH … N bending modes or perhaps lattice vibrations.