Theoretical and Experimental Studies of the Electronic Structure, Spectra, and Biological Activity of some α-and γ-Pyrone Derivatives".

Abstract

The present work presents a detailed and thorough investigation of the electronic structure, spectra and biological activity of some α-and γ-Pyrone derivatives. Full geometry optimizations were performed at the Density Functional Theory (DFT) level of theory. The B3LYP method has been adopted using 6-311G** basis set. The effect of substituent’s of different electron-donating (accepting) strengths on the geometry and the electronic structural features of α-and γ-Pyrone derivatives was examined. The nucleophalic substitutions in the α- and γ-Pyrone were studied using proton detachment energy calculations (PDE) at the level of B3LYP/6-311G**. The electronic absorption spectra in the UV region were measured using polar (methanol) and non-polar (dioxane) solvents. Comparison between the experimentally observed and theoretically computed spectra Time Dependant - Density Functional Theory (TD-DFT) in addition to a quantitative assignment of all transitions observed, were given. The α -and γ-Pyrone compounds were tested as antimicrobial agents against Gram-positive and Gram-negative bacteria and as antifungal agents. The α -and γ-Pyrone derivatives showed antimicrobial activity against the Gram-positive bacteria and the Gram-negative bacteria and antifungal except compounds 10 and 8.

Keywords: α-and γ-Pyrone derivative, UV spectra, DFT calculations, proton detachment energy (PDE) and biological activity.