Infrared Spectra of Cyclohexanoxime and Cyclohexanoxime-d

Abstract

The infrared absorption bands due to the functional group of cyclohexanoxime and cyclohexanoxime-d were reasonably assigned by taking into account the concentration dependence of these bands in solutions. Cyclohexanoxime having no conjugate system showed a spectral feature different in many respects from that of diacetyl monoxime or isonitrosoacetone already studied. The type of hydrogen bonding is −OH…N=C< both in solutions and in the solid state. Consequently, the stretching frequency of bonded OH groups of cyclohexanoxime is different from those of diacetyl monoxime and isonitosoacetone. The doubling of absorption bands was observed for both the OH in-plane bending vibration and the NO stretching vibration of free molecules. This suggests the presence of rotational isomers. The wave numbers of the C=N stretching vibration is higher, while that of the NO stretching vibration is lower than those of the corresponding vibrations of diacetyl monoxime and isonitrosoacetone. This indicates that the double bond character of the C=N bond in cyclohexanoxime is greater than that in oximes having a conjugate system.