A three Schiff bases; Lhy, Lme, and Lph, as well as their CuLhy, CuLme, and CuLph complexes, were synthesized, and their physicochemical properties were investigated. Vibrational spectra proposed that the hydrazone ligands reacted as neutral tridentate chelator with NNO chelating centers to the Cu(II) ion via azomethine-N, Isatin-carbonyl, and pyridine-N forming the general formulae [Cu(L)2]Cl2 nH2O, where L = neutral tridentate Isatin-hydrazone ligand (L = Lhy, (CuLhy); L = Lme, (CuLme); L = Lph, (CuLph)). TG/DTA analyses have shown that there is at least one water molecule in each of the complexes. The spectrophotometric method was used to calculate the stoichiometry and thermodynamic characteristics of the metal complexes. By using density functional theory (DFT) techniques, the 3D structure of the produced complexes was verified. Based on an investigation of the electronic structural configurations of the complexes, calculations verified the predicted structure and clarified the nature of the chemical reactivity. Cu(II) adsorption from aqueous solutions onto ligands was investigated in a number of different settings. The influence of the initial metal concentration (10–100 ppm), the weight of the hydrazone ligands (0.1–1.0 gm), and the contact period (1–2 h) were all investigated as potential moderators of the uptake behavior. In just three hours, equilibrium had been reached thanks to the speedy adsorption process. An initial pH of ≈ 6–8 with a metal ion concentration of 80 ppm was found to be optimal. Iodine (I2) uptake behavior of hydrazone ligands was also studied using spectroscopy. In the first 8 h, hydrazone ligands exhibited high adsorption efficiency (E, %), which gradually declined until equilibrium was achieved after 25 h.
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