This study aimed to prepare three imine derivatives (1, 2, and 3) via a condensation reaction of phenyl hydrazine, 2-hydrazino pyridine, and 4-methoxy aniline with 4-formyl pyridine. Electron impact mass spectrometry (EIMS), proton nuclear magnetic resonance (1H-NMR), ultraviolet-visible (UV-Vis) and Fourier transform infrared (FTIR) spectroscopy were utilized for the characterization. The chemosensing properties of [4((2-phenyl hydrazono)methyl) pyridine] (1), [2-(2-(pyridin-4-ylmethylene)hydrazinyl) pyridine] (2), and [4-methoxy-N-yl methylene) aniline] (3) imino bases have been explored for the first time in aqueous media. The photophysical properties of chemosensors (1, 2, and 3) were examined by various cations (Na+, NH4+, Ba+2, Ni+2, Ca+2, Hg+2, Cu+2, Mg+2, Mn+2, and Pd+2). The chemosensor (1) showed very selective binding capability with copper ions at low concentrations (20 µM) without the influence of any other mentioned ions. The maximum complexation was noted with Cu+2 and 1 at pH between 7 to 7.5. The stoichiometry binding ratio between chemosensor (1) and Cu+2 was determined by Job’s plot and it was found to be 1:2. The current study explored the use of these Schiff bases for the first time as heterocyclic chemosensors. DPPH radical scavenging, urease enzyme inhibition activities, molecular docking simulation, and density functional theory (DFT) analysis of compounds 1, 2, and 3 were also conducted.

The treatment of chemical and biological contaminants in water through biofabricated metal nanoparticles is one of the promising sustainable methods.Herein, an efficient synthesis of novel chromium oxide nanorods is introduced by Illicium verum fruit extract as a bio-reducing, capping, and stabilizing agent.The morphological, optical, catalytic, and bactericidal properties of nanorods are investigated by various techniques. The UV-visible spectra displayed strong absorption peak in the region of 309.8 nm, whereas Fourier transform infrared presented the characteristic vibrations at 605.65 and 651.94 cm À1 attributed to Cr O binding mode. Scanning electron microscopy results showed that chromium oxide nanoparticles are well-dispersed with small rodshaped morphology. The average size of nanorods was found to be ~15 to 20 nm in length. Due to their ultra-large surface area and strong π-π interaction, the plant-coated nanorods were tested for the catalytic removal of methyl orange (MO), a common water-soluble textile dye. Adsorption potential of Cr 2 O 3 nanoparticles was monitored by UV-visible spectrophotometer, which showed 90-95% successive decrease in the absorption maxima of aqueous MO (1 μM). The elimination rate of MO was drastically improved from 45 to 30 min, while a combination of Cr 2 O 3 nanorods and sodium borohydride NaBH 4 was used. Bactericidal activities of these nanorods were tested against vast number of Gram-positive and Gram-negative bacteria. The significant results were obtained with 27 mm zone of inhibition against Klebsiella. oxytoca and Serratia. marcescens. This quick and simple procedure can be scaled up for commercial applications of new, eco-friendly, and cost-effective water treatment process.

The present research describes a rapid, green, and convenient method for bio-stimulated preparation of silver and iron oxide nanoparticles using the aqueous leaf extract of Psidium guajava Linn (PG). The physicochemical properties of bio-synthesized nanoparticles were determined through UV/Visible, SEM, EDX, and FTIR spectroscopic techniques. The wavelength maxima (nm) at 435 and 300 depict silver and iron oxide nanoparticles' formation, respectively. Scanning electron microscopic analysis infers the spherically shaped silver (81.4-102 nm) and iron oxide (80.3-99.1 nm) particles. The energy dispersive X-ray technique accomplished elemental mapping. The in vitro antioxidant properties of silver and iron oxide nanoparticles were assessed using the DPPH (1,1-diphenyl-2-picryl-hydrazil) method with IC50 values of 85.39±0.28 and 78.6±0.63, respectively. The antimicrobial potential was evaluated against selected Gram-positive and Gram-negative bacterial and fungal strains by the agar well diffusion method. The significant zone of inhibition against microbial pathogens reveals the potential industrial and biomedical applications of obtained nanoparticles. The antimicrobial prospective of guava extract-coated iron oxide nanoparticles has been studied for the first time against Bacillus pumilus, Streptococcus faecalis, Streptococcus pneumoniae, and Candida albican. The current report envisions the comparative evaluation of these nanoparticles' antimicrobial and antioxidant characteristics for the first time from this plant.