Structural activity (monomer and dimer), spectroscopic analysis, chemical reactivity, fungicidal activity and molecular dynamics simulation of phenyl benzamide fungicides: A combined experimental and theoretical approach

Abstract

The present study aims to provide deeper knowledge of the structural activity, spectroscopic analysis, chemical reactivity and fungicidal activity of phenyl benzamide fungicides: flutolanil and mepronil based on monomer and dimer model with the aid of experimental and computational methods. The distribution of the vibrational bands are carried out with the help of normal coordinate analysis (NCA). The resulting harmonic wavenumbers are scaled by using Wavenumber Linear Scaling method (WLS). The nature of the hydrogen bonds are characterized by NBO analysis. The evaluated HOMO and LUMO energies indicate the chemical stability of the molecules. The time dependent density functional theory is used to find the various electronic transitions and their nature within the molecule. The molecular orbital contributions are studied by using TDOS spectral analysis. The molecular electrostatic potential (MESP) and global reactivity descriptor parameters are also performed. The 1H and 13C NMR spectra are recorded. The stable conformers of flutolanil and mepronil have been identified by potential energy surface scan analysis. The binding affinity and hydrogen bond interaction between the selected compounds and the target protein are evaluated using molecular docking studies. The pose with highest interaction energy and hydrogen bond interaction is further analyzed using molecular dynamics studies to understand the effect of ligands on conformational changes of protein and the stability of protein ligand complex. The invitro analysis has been performed against two fungal pathogens, Aspergillus niger and Candida albicans.