Synthesis of the Novel species Methoxycarbonyl Perfluoromethane Disulfide, CH3OC(O)SSCF3: Structure in Solid State and Conformational Properties

TORRICO VALLEJOS, SONIA; ERBEN, MAURICIO FEDERICO; BOESE, ROLAND; DELLA VÉDOVA, CARLOS OMAR

NEW JOURNAL OF CHEMISTRY

ROYAL SOC CHEMISTRY

Año: 2010 vol. 34 p. 1365 - 1372

1144-0546

Pure methoxycarbonyl trifluoromethyl disulfide, CH3OC(O)SSCF3, has been prepared  quantitatively by the reaction of CH3OC(O)SCl and Hg(SCF3)2. The conformational properties of  the novel molecule have been studied by vibrational spectroscopy [IR(gas) and Raman(liquid)]  and quantum chemical calculations (B3LYP and MP2 methods). The gaseous compound exhibits  a conformational equilibrium at room temperature where the most stable form has C1 symmetry  with a synperiplanar (syn) orientation of the CO double bond with respect to the S-S disulfide  bond. A second form is observed in the gaseous IR spectra corresponding to a conformer with the carbonyl bond CO in antiperiplanar (anti) position with respect to the SS single bond (ap). The structure of a single crystal of CH3OC(O)SSCF3 has been determined by X-ray diffraction analysis at low temperature using a miniature zone melting procedure. The crystalline solid (triclinic, a= 6.4698(5) Å, b= 9.0499(8) Å, c= 12.5700(11), alfa= 97.219(6), beta= 93.131(5), gamma= 96.888(5) degrees and Z= 4) consists exclusively of molecules with the synperiplanar conformation and the usual gauche orientation around the disulfide bond  is adopted. The geometrical parameters agree with those obtained from quantum chemical calculations.