He(I)/He(II) ultraviolet photoelectron spectroscopic studies on organosulfur compounds with emphasis on the sulfur-oxygen interaction

The electronic structure of compounds having the possibility of exhibiting intramolecular sulfur-oxygen non-bonded interaction of the S(II, IV or VI). .. O(carbonyl or nitro) type and a hypervalent sulfur atom of the O-S-O typ e - i.e, R-S-Me, RSO-Me, R-SO2-Me (R = 2-nitrophenyl; 2, 7 and 12), R-S-R, R-SO-R, R-SO2-R (R = 2-methoxycarbonylphenyl; 5, 10 and 15) and spirosulfur ane (16) - have been investigated by the He(I) and He(II) ultraviolet photo electron spectroscopic method. Reference compounds with R = phenyl or 4-nit rophenyl group (1, 3, 4, 6, 8, 9, 11, 13 and 14) were also studied for the sake of completeness and uniformity. On the basis of the photoelectron spec tra and ab initio Hartree-Fock calculations, the sulfur-oxygen non-bonded i nteraction in compounds 2, 7, 12 and 5, 10, 15 can be attributed to electro static interaction. The sulfur-oxygen bond in the sulfoxides and sulfones, which is usually considered as a polarized double bond, seems to be a singl e bond with zwitterionic character. The photoelectron spectra of spirosulfu rane (16) show no similarity to those of the symmetrical disubstituted sulf ide, sulfoxide and sulfone (5, 10 and 15). (C) 1998 Elsevier Science B.V. A ll rights reserved.