Nanotheoretical studies on evaluation of Antioxidant potential in Naphthoquinones from the Malvaceae

In this study, quantum chemical calculations using density functional theory at B3LYP level by 6-31G* basis set have been applied to analyze the substituent effect on the electronic structural properties including thermochemical parameters as well as anticancer characteristics of 2-methyl-3-methoxy-5,6-dihydroxy-1,4-naphthoquinone and 2-methyl -3,6-dihydroxy-5-methoxy -1,4- naphthoquinone. This study involves substitution of the functional groups of methyl in the active site of this molecule with electronegative atoms of F, Cl and Br and calculations by keywords opt ,NMR and freq for optimization and chemical shift calculations, respectively. The quantum mechanics (QM) calculations were carried out with the GAUSSIAN 98 program at NMR by using B3LYP methods. Optimization electronic effects, such as stability energy, thermodynamic properties and magnetic tensors, atomic charge, band gap between LUMO and HOMO and total dipole moment of naphthoquinone and replacement of halogen atoms have been calculated.

Keywords:

Quantum mechanic , Dipole moment , HOMO , NMR , Freq