DFT calculations on aromatic character of juglone and its derivatives

Publish Year: 1389
نوع سند: مقاله کنفرانسی
زبان: English
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شناسه ملی سند علمی:

MIAUCHEMISTRY01_159

تاریخ نمایه سازی: 18 اسفند 1397

Abstract:

1,4-naphthoquinones are widely distributed in plants, fungi and some animals and many are found to exhibit an interesting range of pharmacological properties including antibacterial antimicrobial antiviral, trypanocidal, anticancer, antimalarial, and antifungal activities, especially when a hydroxyl group is present at the C5 position [1-4]. Juglone is a quinone produced in the roots, leaves and bark of walnut trees which contains an intramolecular hydrogen bond (IAHB) between hydroxyl and keto groups. The IAHB can be formed between donor and acceptor groups of the same molecule when the molecular configuration and conformation bring them within hydrogen bond geometry. Studies on IAHB became increasingly popular in the and hydrogen bonding complexes have been extensively studied with a wide range of experimental techniques and calculations. At the present work, first, intramolecular proton transfer (IPT) process of juglone and its derivatives were theoretically investigated in the gas phase and the effect of electron withdrawing and electron-releasing substituents in different positions of phenyl and benzoquinone rings of juglone on the IPT process was studied in which geometries, energies and thermodynamic functions of compounds were obtained using DFT calculations at the B3LYP/6-31+G(2d,p) level. Next, the influence of IPT on changing the aromaticity phenyl and benzoquinone rings was investigated. To determine the aromaticity of rings, NICS values were calculated for the ground state and transition state structures (GS1,TS,GS2) using continues set of gauge transformations (CSGT) procedure at the B3LYP/6- 311+G(2d,p) level. The results will be presented and discussed.

Authors

E. Vessally

Islamic Azad University, Miyaneh Branch, Miyaneh, Iran