The structure of sulfathiazole-4-nitrobenzoic acid (STZBA) was characterized by X-ray diffraction (XRD). The crystal was stabilized by C–H…O, N–H…O, and S–O…S intermolecular interaction along with C–H…π and π…π interactions. The experimental FT-IR, FT-Raman, and UV-Vis spectra of STZBA were recorded and the results were compared with quantum chemical computation using the DFT method. Molecular electron density, topology, and natural bond orbital (NBO) analysis were used to explain the strength of the interaction. The molecular electrostatic potential and Fukui function of STZBA was determined to give a visual representation of charge distribution and provide information about the electrophilic and nucleophilic site of the molecule. Hirshfeld surface analysis was carried out to analyze the stability of the crystal structure. The antimicrobial activity of STZBA was determined against anticancer, bacterial strain E. coli and fungal stain Candida albicans and Sars-cov. Molecular docking analysis was performed with antimicrobial proteins to confirm the bioactivity of the molecule and drug likeness factors were calculated to comprehend the biological assets of STZBA. The molecular dynamic (MD) simulation result explains the protein stability, ligand properties, and protein-ligand interactions. The compounds were assessed for their structural, physic-chemical, pharmacokinetic, and toxicological properties.

Piperazin-1-ium 4-aminobenzoate monohydrate (PPAB) single crystals were grown by slow evaporation method. The grown crystal PPAB has been characterized by single-crystal X-ray diffraction, FTIR, FT-Raman, and UV-visible analysis. The B3LYP method and 6-311G (d, p) basis set were used to optimize the structure. The title compound was investigated theoretically and experimentally by FT-IR, FT-Raman, and UV-Vis spectral analysis. The presence of various functional groups in the structure was elucidated by FTIR and FT-Raman spectral studies. The intermolecular interactions within the crystal structure were investigated using Hirshfeld surface analysis. The crystal packing diagram reveals interesting non-covalent interactions involving C–H···O, N–H···O, and N–H···N hydrogen bonds, leading to the generation of 3D supramolecular architecture. The charge transfer within the molecule was deeply analyzed by using the NBO approach. The molecular electrostatic potential (MEP) and the local reactivity descriptors, such as Fukui function (fk+, fk−) analyses were performed to determine the reactive sites within the molecule. The HOMO and LUMO analysis was used to determine the chemical reactivity and bioactivity of the molecule. Hole-electron analysis was performed to analyze the charge transfer in an excited state. Based on the hole-electron analysis, the inter-fragment charge transfer (IFCT) analysis establishes the amount of charge transfer among different fragments. Topological analyses, such as AIM, RDG, and ELF were carried out to identify the non-covalent interaction within the molecule. The molecular docking studies of the molecule are performed to investigate the binding affinity of the ligand with the protein receptor. Drug-likeness properties, such as Lipinski’s rule of five, adsorption, distribution, metabolism, excretion, and toxicity (ADMET) have been investigated by in silico web-based tools like SwissADME and ADMETlab.

The prospective antimicrobial molecule N-(2-Hydroxyphenyl)-4-methylbenzene sulfonamide has been synthesized and characterized by single crystal XRD, FT-IR, FT-Raman, UV-Vis spectra and antimicrobial analysis. The quantum chemical computations of energies, geometrical structure, charge transfer and vibrational wavenumbers were carried out using density functional method (DFT/B3LYP) with 6-311 G (d, p) basis set. The complete vibrational assignment for the vibrational modes were performed with vibrational energy distribution analysis (VEDA4) and these assignments were compared with the experimental FT-IR and FT-Raman spectrum. In FT-IR spectrum, strong intense absorption bands are observed at 3408 and 3273 cm(-1) corresponding to OH and NH group, which is involved in N-H horizontal ellipsis O and C-H horizontal ellipsis O intermolecular interaction. Hirshfeld surface analysis determines the stability of crystal packing within the crystal packing ensured by C-H horizontal ellipsis O and O-H horizontal ellipsis O intermolecular interactions. The 2 D fingerprint plot shows that H horizontal ellipsis H, C horizontal ellipsis H and O horizontal ellipsis H interaction exhibit the most significant contribution. Natural bond orbital (NBO) analysis suggests that the electronic transitions are mainly attributed to pi ->pi* transitions. The strength of N-H horizontal ellipsis O and C-H horizontal ellipsis O intermolecular interactions were analyzed using reduced density gradient (RDG) analysis and atom in molecule (AIM) analysis. The frontier molecular orbital analysis reveals the possibility of charge transfer within the molecule. Electrophilic and nucleophilic sites were found by molecular electrostatic potential (MEP) analysis and Fukui analysis. Molecular docking shows that sulfonamide and hydroxyl groups are biologically active through their hydrogen bonding interaction with amino acids, which reveals the antimicrobial activity of the compound. Antimicrobial activity of the compound was confirmed by the Kirby Bauer disk diffusion method. The band gap energy and antimicrobial evaluation of the title molecule were compared with the reported relative compounds, which reveals the significant antimicrobial activity. Besides, drug likeness and ADMET (absorption, distribution, metabolism, excretion and toxicity) prediction analysis suggest that the title compound can be used as an antimicrobial drug.

The structural and packing feature of novel Metachlorphenprop-p-anisidine (MCPA) single crystal was grown by refluxing stoichiometric amount of Metachlorphenprop (MCP) and p-anisidine (PAS) in ethanol, was investigated by single crystal X-ray diffraction. The title compound was investigated theoretically and experimentally by FTIR, FT-Raman, TG-DTA and UV-Vis spectra. The theoretical optimized geometrical parameters and vibrational analysis were performed by density functional theory (DFT) with the B3LYP method at 6-311 G (d,p) basis set. The optimized geometrical parameters obtained by DFT calculations were in good agreement with the experimental data. Various intermolecular interactions involved in MCPA were analysed using different topological analysis atoms-in-molecule (AIM), reduced density gradient (RDG), electron localization function (ELF) and natural bond orbital (NBO) analysis. The stability of the molecule arising from intermolecular interaction and charge delocalization have been analysed using NBO analysis. Molecular electrostatic potentials (MEP) was performed to analyse the reactive area of the title molecule, local chemical reactivity was studied by population analysis and Fukui function analysis. The thermal behaviour of the MCPA crystal was analysed by TG-DTA analysis. Hole-electron interaction study divulge that S1-S4 undergo charge transfer excitation. The mechanical strength of the grown material proves that it is a soft material. Molecular docking was performed to confirm the stability of the protein-ligand complex. The results shows that the title compound has antibacterial properties as well as antifungal activities against Escherichia coli and Aspergillus niger organisms. The pharmacokinetics and drug likeness were also performed on titled molecule for the confirmation of drug-like character of title molecule.

Abstract The present study aims to provide deeper knowledge about the structural, vibrational, chemical, antimicrobial activity, molecular dynamic simulation and drug likeness of synthesized compound 4-Methoxy-N-(nitrobenzylidene)-aniline. The FT-IR and FT-Raman spectra of 4-Methoxy-N-(nitrobenzylidene)-aniline have been recorded in the powder form in the region 4000–500 cm−1 and 3500–50 cm−1. The vibrational analysis were carried out with the help of normal coordinate analysis (NCA). The molecular geometry, hydrogen bonding interaction and vibrational frequencies have been calculated using the density functional method (DFT/B3LYP) with 6-311 G (D) basis set. The natural bond orbital (NBO), atoms in molecule (AIM), and Hirshfeld surface analysis and RDG were applied to evaluate the relative strength of hydrogen bond interactions and represent their effect on the stabilities of molecular arrangements. Related molecules were compared by computation in order to understand the effect of non-bonded interactions (i.e. intermolecular and intramolecular hydrogen bonding). The HOMO and LUMO analysis was used to determine the charge transfer within the molecule. Furthermore, the in vitro antimicrobial study was carried out for the title compound against Aspergillus niger and Staphylococcus aureus. The antimicrobial activity was confirmed on the compounds with molecular docking (A.niger, S.aureus, Homosapians, Sars-Cov-19 and anticancer) studies and molecular dynamic simulation. The non-linear optical (NLO) properties were also analyzed for the molecules.