Comparison of spectroscopic, structural, and molecular docking studies of 5-nitro-2-fluoroaniline and 2-nitro-5-fluoroaniline: An attempt on fluoroaniline isomers

Abstract

Density Functional Theory (DFT) and Hartree-Fock (HF) approaches were used to study the spectroscopic, pharmacological and other molecular properties of structural isomers of fluoroaniline such as 5-nitro-2-fluoroaniline (5N2FA) and 2-nitro-5-fluoroaniline (2N5FA). The geometrical properties, vibrational properties, electronic properties, and chemical shifts of fluoroaniline isomers have been thoroughly investigated. In the gas phase, the energy gap between the highest occupied molecular orbital (HOMO) and lowest unoccupied molecular orbital (LUMO) of fluoroaniline isomers is found to be 3.874 / 8.248 eV (DFT/HF) for 5N2FA and 3.979 / 8.176 eV (DFT/HF) for 2N5FA. The current study reveals that the dipole moment values for 5N2FA and 2N5FA were computed (using DFT / HF) to be approximately 4.5318 / 4.2777 D and 3.6551 / 3.5440 D, respectively. Absorption, distribution, metabolism, and excretion (ADME) properties have been predicted to evaluate the toxicity and pharmacokinetic profile of fluoroaniline isomers. Moreover, the Natural Bond Orbital (NBO), Mulliken population, and Molecular Electrostatic Potential Surface (MESP) analyses have been performed to get a crystal clear insight into the bonding characters, and reactive sites of structural isomers of fluoroaniline. Molecular docking simulation is used to investigate the biological activities of fluoroaniline isomers by forming a stable complex with inducible Nitric Oxide Synthase (iNOS) with a binding affinity of -5.6 kcal/mol (5N2FA), and -5.3 kcal/mol (2N5FA), which shows that of an enzyme inhibitor.