Comparative spectral (FT-IR, FT-Raman, UV) investigations, HOMO–LUMO, NBO and in-silico docking analysis of Nikethamide, niazid and 2-Mercaptonicotinic acid

Abstract

The FT-IR and FT-Raman spectra of N, N-Diethylnicotinamide (ENA), Nicotinic Hydrazide (NHD) and 2-Mercaptonicotinic acid (MNA) were recorded and analyzed experimentally and theoretically. The complete vibrational assignments for all the vibrational modes have been supported by normal coordinate analysis and potential energy distributions. The equilibrium geometry, natural bond orbital calculations and vibrational assignments have been carried out using density functional B3LYP method with the 6–311G++(d,p) basis set. In addition, TD-DFT calculation is initiated to simulate the UV–Vis absorption spectrum and to determine several important electronic properties like HOMO-LUMO gap energy and electronic transitions. In-silico studies have been used to analyze the drug likeness and de-addiction property of the title compounds. The antibacterial activities of the title compounds have been studied via molecular docking and QSAR analysis. Moreover, the title compounds ENA (18.2, 161.9 μm) and NHD (75.11, 54.02 μm) showed a greater inhibiting ability than MNA (80.5, 122.08 μm) when docked against the proteins (PDB ID: 2H29 and 3NM8) and the QSAR analysis proved that the studied compounds have an inhibitor effect against bacterial diseases.