| Abstract
| - Pure methoxycarbonylsulfenyl isocyanate, CH3OC(O)SNCO, is quantitatively prepared by the metathesisreaction between CH3OC(O)SCl and AgNCO. This novel species has been obtained in its pure form andcharacterized by 1H and 13C NMR, UV−vis, FTIR, and FT-Raman spectroscopy. The conformationalproperties of the gaseous molecule have been studied by vibrational spectroscopy and quantum chemicalcalculations (B3LYP and MP2 methods). The compound exhibits a conformational equilibrium at roomtemperature having the most stable form CS symmetry with the CO double bond synperiplanar withrespect to the S−N single bond. A second form was observed in the IR spectrum and corresponds to aconformer possessing the C−S bond antiperiplanar with respect to the NC double bond of the isocyanategroup. The structure of a single crystal of CH3OC(O)SNCO was determined by X-ray diffraction analysisat low temperature using a miniature zone melting procedure. The crystalline solid (triclinic, P1̄, a =8.292(6) Å, b = 9.839(7) Å, c = 11.865(8) Å, α = 67.290(2)°, β = 71.5570(10)°, γ = 83.4850(10)° andZ = 6) shows the presence of molecules having exclusively a synperiplanar conformation with respectto the three φ(CO−CO), φ(OC−SN), and φ(CS−NC) dihedral angles.
|
