Jr. Durig et al., INFRARED AND RAMAN-SPECTRA, CONFORMATIONAL STABILITY, VIBRATIONAL ASSIGNMENT, AND AB-INITIO CALCULATIONS OF CHLOROMETHYL ISOCYANATE, Journal of molecular structure, 375(1-2), 1996, pp. 83-94
The infrared (3200 to 400 cm(-1)) and Raman (3200 to 20 cm(-1)) spectr
a of gaseous and solid chloromethyl isocyanate, ClCH2NCO, have been re
corded. Also, the Raman spectrum of the liquid and qualitative depolar
ization values have been obtained. Additionally, infrared spectra have
been recorded at various temperatures with the sample dissolved in li
quid xenon. An assignment of the fundamental vibrations based on the i
nfrared band contours, depolarization values and group frequencies is
given and discussed. This assignment is supported by a normal coordina
te analysis utilizing a force field obtained from ab initio calculatio
ns with the RHF/6-31G basis set as well as with electron correlation,
MP2/6-31G. A complete equilibrium geometry has been determined by ab
initio gradient calculations employing the RHF/3-21G, RHF/6-31G* and
MP2/6-31G basis sets, The potential surface governing internal rotat
ion about the C-N bond is calculated to be consistent with a single mi
nimum corresponding to a structure having the chlorine atom cis or nea
r-cis to the NCO moiety. These results are compared with the correspon
ding quantities for ethyl isocyanate, CH3CH2NCO, and related compounds
.