10.1021/jo701543g.s007 Sonia Torrico Vallejos Sonia Torrico Vallejos Mauricio F. Erben Mauricio F. Erben Helge Willner Helge Willner Roland Boese Roland Boese Carlos O. Della Védova Carlos O. Della Védova Preparation and Properties of Methoxycarbonylsulfenyl Isocyanate, CH<sub>3</sub>OC(O)SNCO American Chemical Society 2007 vibrational spectroscopy novel species metathesis reaction OC form C S symmetry isocyanate group synperiplanar conformation Methoxycarbonylsulfenyl Isocyanate UV quantum chemical calculations FTIR MP 2 methods CO IR spectrum 1 H CS bond synperiplanar CH compound exhibits 13 C NMR B 3LYP molecule room temperature 2007-11-23 00:00:00 Dataset https://acs.figshare.com/articles/dataset/Preparation_and_Properties_of_Methoxycarbonylsulfenyl_Isocyanate_CH_sub_3_sub_OC_O_SNCO/2972824 Pure methoxycarbonylsulfenyl isocyanate, CH<sub>3</sub>OC(O)SNCO, is quantitatively prepared by the metathesis reaction between CH<sub>3</sub>OC(O)SCl and AgNCO. This novel species has been obtained in its pure form and characterized by <sup>1</sup>H and <sup>13</sup>C 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 <i>C</i><i><sub>S</sub></i> symmetry with the CO 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 NC double bond of the isocyanate group. The structure of a single crystal of CH<sub>3</sub>OC(O)SNCO was determined by X-ray diffraction analysis at low temperature using a miniature zone melting procedure. The crystalline solid (triclinic, <i>P</i>1̄, <i>a</i> = 8.292(6) Å, <i>b</i> = 9.839(7) Å, <i>c</i> = 11.865(8) Å, α = 67.290(2)°, β = 71.5570(10)°, γ = 83.4850(10)° and <i>Z</i> = 6) shows the presence of molecules having exclusively a synperiplanar conformation with respect to the three φ(CO−CO), φ(OC−SN), and φ(CS−NC) dihedral angles.