Mixed ligand complexes of Mn[II], Co[II] and Cd[II] with a novel Schiff base ligand 4-(2-((1E,2E)-1-(2-(p-tolyl)hydrazineylidene)propan-2-ylidene)hydrazineyl) as principal ligand (L1) and Methionine (L2) as an ancillary ligand were successfully synthesized and thoroughly characterized by employing various analytical methods, including Elemental analysis, FT-IR, UV-Visible, Mass spectra, and conductometric measurements. Density functional theory (DFT) computations have being executed employing LANL2DZ basis sets, conjoined with the B3LYP correlation functional, to elucidate the stable electronic configuration, (HOMO–LUMO) energy gap, dipole moment, and chemical hardness of the hybrid ligand complexes. The proposed geometry for the complexes is a distorted octahedral structure. Additionally, the structural parameters and (MEP) Molecular Electrostatic Potential of these compounds were calculated using a DFT level basis set and allied with the experimental records. The antimicrobial potential of these compounds were assessed in contradiction of a diverse range of bacterial and fungal strains, encompassing Gram(+ve) bacteria such as Streptococcus mutans and Staphylococcus aureus, Gram(-ve) bacteria like Klebsiella Pneumonia and Escherichia coli, and the fungus Candida albicans. Significantly, these complexes demonstrated noteworthy antimicrobial activities, with the Cd (II) complex exhibiting the greatest efficacy against all the checked organisms. In the pursuit of exploring their broader medical potential, these compounds were also investigated for their antibiotic properties against H. pylori, showing substantial potential as effective antibiotics against this bacterium. Furthermore, the synthesized complexes were considered for their antitumor properties against MCF-7 [Breast carcinoma] cells. Among them, the [(L1) (L2) Co (Cl)].3H2O complex displayed the most potent activity, with the lowest IC50 value of 17 μg/ml compared to cisplatin. Moreover, it exhibited reduced cytotoxicity towards normal cells (VERO cells) in comparison to cisplatin, establishing it as the supreme potent compound in the study. Moreover, molecular docking studies were conducted using DFT-optimized structures of the Schiff base ligand (L1) and its Cd (II) complex to elucidate their interactions with selected protein structures involving (3AHU, 1GHP, 2ZIC, 4N74, 5JPE, 3HB5, and 6W41), providing insights into their preferred modes of interaction. This comprehensive study underscores the multifaceted applications and promising bioactive properties of these synthesized compounds.

Arsenic is a toxic metalloid that occurs naturally in the Earth's crust. Its widespread distribution and mobility have led to extensive environmental contamination and adverse human health effects across numerous regions worldwide. Monitoring arsenic concentrations in ecosystems is crucial for mitigating potential hazards and minimizing human exposure. This research outlines the synthesis, characterization, and application of an innovative Schiff base Quinazoline ligand and its corresponding ternaryMn(II) complex for arsenic sensing. A manganese (II) coordination compound featuring a principal ligand denoted (WMS) and an auxiliary ligand Glycine (GLY) was synthesized and comprehensively characterized using analytical techniques such as FT-IR, UV-Vis, mass spectrometry, elemental analysis, and electrical conductance measurements. Thermal analysis (TGA) of the Manganese(II) complex corroborated well with the proposed formula derived from the analytical data. The molecular formula of the complex was determined to be [Mn(WMS)(GLY)H2O].Cl.H2O, with the (WMS) ligand exhibiting tridentate chelation behavior by coordinating with the central Mn(II) ion through its two azomethine nitrogen atoms and one pyridine nitrogen. The (Gly) ligand bound to Mn (II) via deprotonated carboxylate oxygen and the (NH2) nitrogen, resulting in a distorted Octahedral geometry. In addition, Density Functional Theory (DFT) calculations are performed to determine the optimal structure of the Schiff base (WMS) and its Mn (II) complex. The HOMO-LUMO energy gaps, chemical hardness, and dipole moments of the (WMS) and its Manganese complex were also investigated. The study examined the biological roles of the (WMS) and its Mn (II) complex, specifically focusing on its antibacterial, antifungal, and anticancer properties. To understand the molecular interactions, we conducted molecular docking simulations to determine the potential binding orientations of the (WMS) and its Mn (II) complex with active sites on the receptor (3HB5). The docking analyses were conducted meticulously utilizing the MOE program, renowned for its robust, stiff molecular docking capabilities. Extensive characterization of the nano-sized Quinazoline Manganese complex involved dynamic light scattering (DLS), zeta potential analysis, x-ray diffraction (XRD), atomic force microscopy (AFM), BET surface area determination, and pore size analysis. The possible application of this nano-complex as a quartz crystal microbalance (QCM) sensor for detecting arsenic contamination in water was investigated. The sensor exhibited rapid response times (less than 2 minutes), excellent mechanical stability (confirmed by contact angle measurements), and consistent performance across varying pH and temperature conditions. This research highlights the synthesis of new arsenic-sensing material and its promising application in continuous environmental monitoring. Given the widespread prevalence of arsenic contamination, particularly in groundwater sources used for drinking and irrigation, developing sensitive and selective arsenic sensors is paramount for safeguarding public health and ecosystem integrity.

Pyruvate:ferredoxin oxidoreductase (PFOR) is a key Achilles’ heel in anaerobic pathogens. We integrate electronic-structure calculations (DFT), cheminformatic QSAR metrics, and residue-resolved docking to distill a concise “recognition code” and translate it into practical design rules. Using nitazoxanide (Nita; ΔG_(bind) ≈ −10.0 kcal·mol⁻¹) as a well-established reference, productive binding requires a conserved triad: a hydrogen-bond donor addressing Thr-997 and Cys-840, a π–π stack with Phe-869, and a recurrent π–σ contact to Thr-997 that orients the scaffold. Deacetylation to tizoxanide unmasks the phenolic donor and raises local electrophilicity, yet it also slightly loosens pocket packing (−9.6 kcal·mol⁻¹). Strategic halogenation introduces a σ-hole interaction near Pro-29, tightening pose geometry without disrupting the donor network; the lead analogue yields −10.1 kcal·mol⁻¹, and two others match the reference by preserving the triad and hydrophobic belt. The result is a minimal, testable recipe—retain the phenolic donor, enforce Thr-997/Cys-840 and Phe-869, and add a calibrated halogen σ-hole—offering falsifiable predictions to surpass nitazoxanide and guiding synthesis and biophysical validation in targeted PFOR inhibition.