Photolysis, tautomerism and conformational analysis of dehydroacetic acid and a comparison with 2-hydroxyacetophenone and 2-acetyl-1,3-cyclohexanodione.
Heliyon
; 6(7): e04457, 2020 Jul.
Article
em En
| MEDLINE
| ID: mdl-32728640
The purpose of this work was to determine the tautomerism, the conformational analysis and photoreactivity of dehydroacetic acid (DHAA, 1). For that reason, the photolysis of DHAA (1) was performed at 254 nm and compared with two structurally similar compounds: 2-hydroxyacetophenone (HAP, 2) and 2-acetyl-1,3-cyclohexanodione (ACH, 3). We confirmed the degradation of 1 to acetic acid and we propose a mechanism on the assumption that a [2+2] cyclodimerization occurs (after UV light absorption) followed by some consecutive Norrish Type I cleavages, affording ketenes that end-up in acetic acid. The UV absorption study was conducted for all three compounds to gain insight about their electronic transitions, both experimentally and with computational simulations using TDDFT (B3LYP/6-31+G(d,p)) methods. A detailed analysis of the different tautomers and isomers that can be present in solution and the MOs involved in the electronic transitions was also achieved. The HOMOâLUMO transition was the least energetic optically active transition for 1 and 2, whereas 3 was recognized to have a HOMO-1âLUMO transition. These transitions were all of nâπ∗ character.
Texto completo:
1
Coleções:
01-internacional
Base de dados:
MEDLINE
Idioma:
En
Revista:
Heliyon
Ano de publicação:
2020
Tipo de documento:
Article
País de afiliação:
Argentina
País de publicação:
Reino Unido