Structural and spectroscopic characterization of ClC(O)SNSO. A theoretical and experimental study

Abstract

N-(Sulfinylimine)chlorocarbonylsulfane, ClC(O)SNSO, was prepared by the reaction of ClC(O)SCl with Hg(NSO)₂. The crystal structure of ClC(O)SNSO was determined by X-ray diffraction analysis from crystals obtained at low temperature using a miniature zone melting procedure. The molecule exhibits only one form with C_s symmetry: the CO double bond syn with respect to the S–N single bond, the C–S single bond anti to the NS double bond and the S–N single bond syn with respect to the SO double bond. The following skeletal parameters were determined (distances in Å, angles in degrees, errors between parentheses expressed as sigma): Cl–C=1.771(2), CO=1.184(3), C–S=1.750(2), S–N=1.666(2), NS=1.534(2), SO=1.455(2), ClCO=122.9(2), ClCS=107.1(1), OCS=130.0(2), CSN=97.4(1), SNS=122.3(1). NSO=118.0(1), OCSN=-1.9, ClCSN=178.0, CSNS=-178.0, SNSO=-1.2. These experimental parameters compare satisfactorily with those obtained by abinitio and DFT calculations. The best agreement was found with the B3PW91/6–31+G* calculation. These quantum chemical methods were also employed to predict the vibrational spectra providing a good agreement with the experimental Raman spectra measured from the liquid sample. It is shown that the analysis of the vibrational spectra provides a sound basis for the determination of the conformation and configuration of R–NSO compounds. Raman excitation profiles were determined in the range from 514 to 413 nm. Most of the modes are predominantly enhanced via the π→π* transition at 296 nm but additional intensity is derived from low-electronic transitions at ca. 450 and 430 nm which are too weak to be detectable in the UV/VIS absorption spectra.