Polymorphism in Chloride Salt of m-Nitroaniline: Structural, Spectroscopic, Thermal, Molecular Docking, Biological, and Quantum Chemical Computational Investigation

The crystal structure of the compound 3-nitroanilinium chloride (3NAC) has been successfully obtained using the solvent evaporation solution growth method. The structural confirmations studied by using single crystal XRD using good quality crystal and it revealed that molecular arrangements in polymorphism nature. The Hartree-Fock (HF) and density functional theory (DFT) methods have been employed to get the molecular structure and geometrical parameters of 3NAC using B3LYP level of theory and validated the results with a 6–311++G(d,p) basis set. The computed vibrational spectra compared with experimental spectra and confirmed the appreciable agreement between the spectra. The physio-chemical properties, such as chemical potential, chemical hardness, electrophilicity, and electronegativity of the title compound have been calculated using the highest energy occupied molecular orbital– lowest energy unoccupied molecular orbital (HOMO–LUMO) plots. The probable pharmaceutical activity of 3NAC has predicted by the lower band gap value achieved in frontier molecular orbital (FMO) analysis. Grown crystal has been used against some specific potentially threatening microbes for antimicrobial activity investigation. Molecular docking has been performed with suitable protein. The melting point of the title compound was calculated at 246°C and its thermal stability was calculated using TG/DTA.