Synthesis, Characterization, DPPH Radical Scavenging, Urease Enzyme Inhibition, Molecular Docking Simulation, and DFT Analysis of Imine Derivatives of 4-formylpyridine with Selective Detection of Cu⁺² Ions

>Background: Three imine derivatives (1, 2 & 3) have been prepared via condensation reaction of phenyl hydrazine, 2-hydrazino pyridine and 4-methoxy aniline with 4-formyl pyridine. Materials and Methods: Electron impact mass spectrometry (EIMS), proton nuclear magnetic resonance (1H-NMR), ultra violet- visible (UV-Vis) and fourier transform infrared (FTIR) spectroscopy have been utilized for the characterization. The chemosensing properties of [4((2-phenyl hydrazono)methyl) pyridine] (1), [2-(2-(pyridin-4-ylmethylene)hydrazinyl) pyridine] (2) & [4-methoxy-N-yl methylene) aniline] (3) imino bases are 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). Results and Discussion: The chemosensor (1) has shown very selective binding capability with copper ions at low concentration (20 μM) without influence of any other mentioned ions. The maximum complexation was noted with Cu⁺² and 1 at pH (7-7.5). The stoichiometry binding ratio between chemosensor (1) and Cu⁺² was determined by Job’s plot and it is found to be (1:2). Conclusion: Current study explores the use of these Schiff bases for the first time as heterocyclic chemosensors. DPPH radical scavenging, urease enzyme inhibition activities along with molecular docking simulation and density functional theory (DFT) analysis of compounds 1, 2 and 3 were also explored.