A density functional theory study of a series of symmetric dibenzylideneacetone analogues as potential chemical UV-filters.

Autor: Magaji B; School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban, 4000, South Africa., Singh P; School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban, 4000, South Africa., Skelton AA; School of Pharmacy and Pharmacology, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban, 4001, South Africa., Martincigh BS; School of Chemistry and Physics, University of KwaZulu-Natal, Westville Campus, Private Bag X54001, Durban, 4000, South Africa.
Jazyk: angličtina
Zdroj: Heliyon [Heliyon] 2024 Oct 29; Vol. 10 (21), pp. e39910. Date of Electronic Publication: 2024 Oct 29 (Print Publication: 2024).
DOI: 10.1016/j.heliyon.2024.e39910
Abstrakt: The aim of this research was to provide valuable insights on symmetrical α,β-unsaturated ketones as potential chemical ultraviolet (UV) filters from experimental data and theoretical aspects. Towards this end, density functional theory (DFT/B3LYP) calculations on a series of symmetrical α,β-unsaturated ketones, ( 1E,4E )-1,5-bis[4-(R)phenyl]penta-1,4-diene-3-one (R = methylthio, 1 ; R = dimethylamino, 2 ; R = ethyl, 3 ), were performed to determine the effect of different electron-donating substituents on their stability when exposed to solar UV radiation. Their molecular structures, and UV-visible, infrared (IR) and NMR ( 1 H and 13 C) spectra were theoretically obtained from their optimized geometries with the B3LYP/6-311++ G (d, p) basis set and were compared with the experimental results. Conformational analysis was performed and the most stable conformer of each compound was identified as the trans-trans conformer, which was further supported by experimental NMR data. The UV spectra and effect of solvent polarity and proticity were studied by the time-dependent-DFT (TD-DFT) approach with the B3LYP/6-311++G (d, p) level of theory. Furthermore, various molecular parameters like dipole moment, frontier molecular orbital (FMO) energies, ΔE HOMO-LUMO gap, lifetime of the first excited state (τ), global chemical reactivity descriptors, and natural bond orbital analysis were predicted at the same level of theory and compared with the experimental data. Inspection of the active FMOs revealed the photoinstability trends of 1 and 3 under UV irradiation. However, introducing a -N(CH 3 ) 2 substituent to 2  at the para -position improves its photostability towards simulated solar UV radiation. Thus, compound 2 has the potential to provide efficient broad-spectrum protection against UV radiation. This work has shown that molecular modelling strategies can assist to rationalize experimental findings and also support the identification of photoproducts of 1 and 3 .
Competing Interests: The authors declare that they have no known competing financial interests or personal relationships that could have appeared to influence the work reported in this paper.
(© 2024 The Authors.)
Databáze: MEDLINE
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