Investigation of compounds containing SiS and SSiS bonds by ultraviolet spectrophotometry

Abstract

Five- and six-membered ring and open chain compounds containing SSi and SSiS bonds were examined by UV spectrospcopy and the ɳO * transition found to show a blue shift compared with that in the analogous carbon compounds. This is a consequence of the ( d p interaction between the lone electron pair of sulfur and the d orbitals of silicon, at the same time through-conjugation over silicon is not unambigously proved. The results are in accordance with conclusions based on PES data. Interaction between the sulfur atoms and the aromatic system can be deduced from the spectra and the extent of this effect is similar to that for chlorine in the corresponding derivatives. On the other hand the bathochromic shift of the α and p bands for the silicon compounds indicates that the lone electron pairs of the sulfur atom can form a conjugative connection with the aromatic ring. A new transition appearing between the α and p bands can be attributed to charge transfer (CT) interaction; the intensity of the CT band depends on the distance between the sulfur atom and the phenyl group.