The Electronic Structure of β-Thioxoketones. A Photoelectron Spectroscopic Study of the Enol-Enethiol Tautomerism of Thioacetylacetone and Related Compounds

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Flemming S. Jorgensen, Lars Carlsen, Fritz Duus

The He I photoelectron spectra of thioacetylacetone, 2-acetylcyclohexanethione, 2-thioacetylcyclohexanone, and the S-methyl derivative of thioacetylacetone has been recorded and interpreted by comparison with PE data on related compounds. The interpretation has been supported by semiempirical molecular orbital calculations based on the CNDO/B, CNDO/S, and MNDO methods on the enol and enethiol forms of monothiomalondialdehyde. The three lowest ionization energies were determined as ns ͌π32 for the enol form and as π3 πn02 for the enethiol form. The influence of hydrogen bonding on the electronic structure is discussed. Attention is called to the possibility of distinguishing generally by means of PE spectroscopy between the enol and enethiol forms of a tautomeric equilibrium system under consideration.

Original languageEnglish
JournalJournal of the American Chemical Society
Volume103
Issue number6
Pages (from-to)1350-1353
Number of pages4
ISSN0002-7863
DOIs
Publication statusPublished - 1 Jan 1981

ID: 218715147