Preparation of (CH3)2CHOC(S)SC(O)OCH3: A comprehensive study of its nature using matrix isolation technique, FTIR, FTRaman, X-Ray diffraction, NMR, mass spectrometry and theoretical calculations

YENY A. TOBÓN; ROSANA M. ROMANO; EVAMARIE HEY-HAWKINS; ROLAND BOESE; CARLOS O. DELLA VÉDOVA

JOURNAL OF PHYSICAL ORGANIC CHEMISTRY

Año: 2009 vol. 22 p. 815 - 822

0894-3230

Potassium isopropyl xanthate, (CH3)2CHOC(S)SK, reacts with methyl chloroformiate ClC(O)OCH3 to yield (methoxycarbonyl) (2-propoxythiocarbonyl) sulfide, (CH3)2CHOC(S)SC(O)OCH3. This novel xanthogen formate was characterized by 1H and 13C{1H} NMR spectroscopy, mass spectrometry and IR and Raman spectroscopy. The structure of a single crystal of (CH3)2CHOC(S)SC(O)OCH3 was determined by X-ray diffraction analysis at 173 K. The conformational properties have been studied by liquid IR and Raman spectroscopy, matrix isolation spectroscopy together with photochemical studies and quantum chemical calculations (HF and B3LYP methods with the 6-31RG* basis set). The analysis of the IR spectrum of liquid (CH3)2CHOC(S)SC(O)OCH3 suggests the presence of two conformers in equilibrium at room temperature. However, in the photochemical matrix study, an equilibrium of three conformers was detected. These forms were further characterized by theoretical calculations. Different photolysis products, such as CH3OC(O)SCH(CH3)2, OCS, CO, CO2 and CS2, were identified by matrix spectroscopy. The IR absorptions of CH3OC(O)SCH(CH3)2, for which literature data are scarce, were analysed in the light of the results of appropriate theoretical calculations.