He I and He II photoelectron spectra of thiophenones

Abstract

He II photoelectron spectra of tetrahydrothiophen-2-one, tetrahydrothiophen-3-one and 2(5H)-thiophenone have been recorded along with the corresponding He I spectra. The relative He I/He II band intensities provide clear evidence for the assignment of the first few bands, which are also assigned on the basis of bandshape and SCF MO calculations. Correlations with IPs of tetrahydrothiophene, 2,5-dihydrothiophene and formaldehyde show that the interaction of the carbonyl group and the ring heteroatom is primarily inductive in nature in these thiophenones, though there may be a small degree of conjugative interaction between the carbonyl group and the ethylenic moiety in 2(5H)-thiophenone. © 1998 Elsevier Science B.V.