Structural, spectroscopic and theoretical studies on dixanthogens: (ROC(S)S)2, with R = n-propyl and isopropyl

LUCIANA C. JUNCAL; YENY A. TOBON; ROSANA M. ROMANO; OSCAR E. PIRO; CARLOS O. DELLA VÉDOVA

NEW JOURNAL OF CHEMISTRY

ROYAL SOC CHEMISTRY

Lugar: CAMBRIDGE; Año: 2014 vol. 38 p. 3708 - 3716

1144-0546

Structural and conformational properties of two dixanthogen molecules, [CH3(CH2)2OC(S)S]2 and [(CH3)2CHOC(S)S]2, have been analyzed using a combined experimental and theoretical approach, with data obtained from structural X-ray diffraction methods, IR, Raman and UV-visible spectroscopies, and DFT calculations. [(CH3)2CHOC(S)S]2 crystallizes in the monoclinic P21/c space group with a=9.735(1), b= 12.588(3), c= 12.131(2) Å, β= 112.65(1)°, and Z=4 molecules per unit cell. The interactions in the crystal were modelled and interpreted by NBO analysis. [CH3(CH2)2OC(S)S]2 is liquid at room temperature, and the vibrational spectra were satisfactorily explained in terms of the equilibrium between three conformers, originated from the rotation of the two terminal CH3 groups, in agreement with the DFT predictions. The electronic spectra of both dixanthogens were assigned with the assistance of the TD-DFT calculations.