CEQUINOR   05415
CENTRO DE QUIMICA INORGANICA "DR. PEDRO J. AYMONINO"
Unidad Ejecutora - UE
congresos y reuniones científicas
Título:
Photoionization dynamic of O-methyl dithiocarbonate (dimethyl xanthate), CH3OC(S)SCH3, on the sulfur 2p absorption edge
Autor/es:
MAURICIO ERBEN; ANTONELA CANNEVA; RODRIGUEZ PIRANI, LUCAS SEBASTIÁN; CAVASSO-FILHO REYNALDO; CARLOS OMAR DELLA VEDOVA
Lugar:
Campinas
Reunión:
Encuentro; 25th Annual Users? Meeting (RAU); 2015
Institución organizadora:
LNLS, CNPEM
Resumen:
Xanthates are the esters of xanthic acid, with general formulaROC(S)SR´. These are important organosulfur compounds used in the production ofcellophane and as flotation agents for extraction of metals from many ores. As an example,sodium ethyl xanthate is added as a collector in the selective flotation of PbS (galena) toseparate it from ZnS (sphalerite). A series of xanthate and xanthogen derivatives are beingthe subject of investigation in our group, including synthetic aspects together with theelucidation of structural, conformational and vibrational properties.1 Following our generalproject aimed at elucidating the shallow and inner shell core electronic properties andphotoionization dynamics of sulfur-containing derivatives,2,3 we became now interested inthe simplest xanthate compound, with R=R´=CH3. Here we report a study of the photonimpact excitation and dissociation dynamics of CH3OC(S)SCH3 exited at the S 2p level byusing synchrotron radiation. Interestingly, the photoelectron spectrum of CH3OC(S)SCH3 inthe valence region (7.5-13 eV energy range) was reported by Guimon et al. in 1974 andinterpreted in terms of ionization of non-bonded orbital mostly localized on the sulfur atoms.4 The S 2p core XPS and KLL Auger spectra of CH3OC(S)SCH3 were early reported bySuoninen et al. 5 showing that the ionization energies of the =S and S atoms within thexanthate group differ from each other by 1.5 eV, this difference assigned to the initial-statecharge distribution rather than to final-state relaxation. In this presentation, the TIY spectra of CH3OC(S)SCH3 following S 2p excitations is reported and compared with the previous data.The dissociative photoionizaiton is discussed in term of PEPICO and PEPIPICO spectra andpossible fragmentations mechanisms are deduced from the interpretation of the PEPIPICOspectra. Thus, the advantage of energy tunability offered by synchrotron radiation allowed usfor a clear understanding of the resonant electronic processes occurring after excitation ofeach of the sulfur atoms present in this molecule and how the ionic dissociation is affected.Juncal, L. C.; Tobon, Y. A.; Piro, O. E.; Della Vedova, C. O.; Romano, R. M. New J. Chem. 2015, 38, 3708.Berrueta Martínez, Y.; Bava, Y. B.; Erben, M. F.; Cavasso Filho, R. L.; Romano, R. M.; Della Védova, C. O. The Journal of PhysicalChemistry A 2015, 119, 1894.Bava, Y. B.; Berrueta Martínez, Y.; Moreno Betancourt, A.; Erben, M. F.; Cavasso Filho, R. L.; Della Védova, C. O.; Romano, R. M.ChemPhysChem 2015, 16, 322.Guimon, C.; Gonbeau, D.; Pfister-Guillouzo, G.; Åsbrink, L.; Sandström, J. J. Electron Spectrosc. Rel. Phenom. 1974, 4, 49.Suoninen, E. J.; Thomas, T. D.; Anderson, S. E.; Runyan, M. T.; Ungier, L. J. Electron Spectrosc. Rel. Phenom. 1985, 35, 259.
rds']