VIBRATIONAL-SPECTRA OF ACETYL ISOCYANATE AND MONOCHLOROACETYL, DICHLOROACETYL AND TRICHLOROACETYL ISOCYANATES

The gas-phase infrared and liquid-phase Raman spectra of R-CO-NCO, whe re R = CH3, CH2Cl, CHCl2 and CCl3, have been recorded. For each molecu le an assignment of the observed bands has been proposed in terms of t he two planar conformers derived from rotation about the C-N bond. The observations indicate that the cisoid conformation is the preferred o ne in the gas phase while substantial amounts of both cisoid and trans oid conformers are present in the liquid.