Preparation and Properties of Methoxycarbonylsulfenyl Isocyanate, CH3OC(O)SNCO

TORRICO VALLEJOS, SONIA; ERBEN, MAURICIO FEDERICO; DELLA VÉDOVA, CARLOS OMAR; WILLNER, HELGE; BOESE, RONALD

JOURNAL OF ORGANIC CHEMISTRY

American Chemical Society

Año: 2007 vol. 72 p. 9074 - 9080

0022-3263

Pure methoxycarbonylsulfenyl isocyanate, CH3OC(O)SNCO, is quantitatively prepared by the metathesis reaction between CH3OC(O)SCl and AgNCO. This novel species has been obtained in its pure form and characterized by 1H and 13C NMR, UV-vis, FTIR, and FT-Raman spectroscopy. The conformational properties of the gaseous molecule have been studied by vibrational spectroscopy and quantum chemical calculations (B3LYP and MP2 methods). The compound exhibits a conformational equilibrium at room temperature having the most stable form CS symmetry with the CdO double bond synperiplanar with respect to the S-N single bond. A second form was observed in the IR spectrum and corresponds to a conformer possessing the C-S bond antiperiplanar with respect to the NdC double bond of the isocyanate group. The structure of a single crystal of CH3OC(O)SNCO was determined by X-ray diffraction analysis at low temperature using a miniature zone melting procedure. The crystalline solid (triclinic, P1h, a= 8.292(6) Å, b= 9.839(7) Å, c= 11.865(8) Å, "alfa"= 67.290(2)°, "beta"= 71.5570(10)°, "gamma"= 83.4850(10)° and Z = 6) shows the presence of molecules having exclusively a synperiplanar conformation with respect to the three (CO-C=O), (O=C-SN), and (CS-N=C) dihedral angles.