Vapor-phase infrared and Raman spectra and ab-initio calculations of the axial and equatorial forms of cyclohexane-d1 and d11

Abstract

The vapor-phase infrared and Raman spectra of cyclohexane-d11 in the C–H stretching region show two bands at 2891 and 2921cm−1 corresponding to the axial and equatorial C–H stretching modes respectively. Similarly, cyclohexane-d1 has two C–D stretching modes at 2145 and 2164cm−1 (Mátrai and Gal, 1984) corresponding to the two forms. Force constants were calculated for these vibrations and these confirm the theoretical calculations, which show the equatorial bonds to be shorter and stronger. The force constant for the equatorial C–H stretching is 2% higher than for the axial.