Analyses on the reactivity, topology and bioactivity of Fluazinam using density functional theory

Abstract

Quantum chemical computations were initiated to perform geometry optimization of Fluazinam by B3LYP/6–311 ++ G (d, p) basis set employing the DFT approach. Sample of Fluazinam dissolved in dichloromethane yielded single crystals for analysis through slow evaporation technique. For the objective of characterizing the title molecule, spectroscopic methods such as FT-IR, FT-Raman, NMR, and UV-Vis studies were used. The carbon atoms coupled to nitrogen atoms exhibit the strongest de-shielded signals, according to the NMR spectra. The observed UV-Vis spectrum is correlated with the computed spectrum. Natural Bond Orbital analysis interprets the charge delocalization within the molecule. Frontier molecular orbital (FMO), Molecular electrostatic potential (MEP) and Fukui function analyses were conducted to identify the chemical reactivity and hence the stability of the compound is evinced. Frontier molecular orbital study endorses a band gap of 3.66 eV which facilitates intra-molecular charge transfer. MEP study infers that the electronegative atoms behave as an electrophile while the hydrogen and carbon atoms take the nucleophilic reactivity. Weak covalent interactions as well as N-H…O intra-molecular hydrogen bonding were understood from the topology analyses. Molecular docking confirmed good binding affinity of -8.1 and – 7.6 Kcal/mol with the target proteins which were then ratified from the experimental activity assay showing a larger inhibition zone than the compared standard Nystatin.