Towards the absolute determination of the conformation in thioester compounds through the first pre-resonance Raman study in X-NSO molecules. Preparation and properties of S( N-sulphinylimine) chlorocarbonylsulphane, ClC(O)SNSO: IR, pre-resonant Raman, 13C NMR, mass and UV spectroscopic and conformational study

Abstract

Starting from chlorocarbonylsulphenyl chloride, ClC(O)SCl, and N-trimethylsilylsulphinylimine, (CH 3) 3SiNSO, the compound S( N-sulphinylimine)-chlorocarbonylsulphane, ClC(O)SNSO, has been prepared. The IR, pre-resonant Raman, 13C NMR, mass and UV spectra have been obtained and interpreted. The two bands appearing in the C  O stretching fundamental mode region were investigated in order to determine the existence of conformational isomerism in the molecule. Both Raman studies at different temperatures and those using different excitations revealed the existence of the molecule in only one conformation. From these studies, a pre-resonant effect has been determined for the first time for XNSO compounds. Its extension is associated with the planarity of the molecule. The study of the C  O envelope in the IR spectrum of the vapour phase reveals the syn conformation (with respect to the C  O and SN bonds) as the only structure for the molecule in appreciable concentration at room temperature.