Sulfur K-shell photoabsorption spectroscopy of the sulfanes R-Sn-R, n=2-4

X-ray absorption near edge structure (XANES) measurements were carried out at the sulfur K-edge of nine sulfanes with the structure R-S-n-R, n = 2-4. The discrete part of the XANES spectra of these sulfanes is expected to be quite similar under the change of the hydrocarbon substituents R. However, significant differences were observed in the energy splitting of the pre-edge resonances as well as in the relative intensities of these features. A linear correlation is observed between the splitting of the sulfur 1s --> sigma*(S-C) and 1s --> sigma*(S-S) transitions and the S-C bond length. Similar correlations are expected for the energy splitting and the S-C bond enthalpy and the difference in electronegativity between the sulfur atom and the substituent R. We have carried out MS-X alpha calculations on the C-S-S fragment to support the proposed assignment and the parameter dependence of the resonances mentioned above. (C) 1997 Elsevier Science B.V.