Synthesis, spectroscopic characterization, and stability study of Co(II), Ni(II), AND Cu(II) complexes derived from a 1,2,4-triazole-based azo dye ligand

Abstract

This work describes the synthesis of new metallic complexes with azo-based ligand 5-(2-(1H-1,2,4-triazol-3-yl)hydrazinyl)-2-hydroxy-4-methoxybenzaldehyde. The new ligand was prepared by the condensation reaction of 4-amino-1,2,4-triazole with 2-hydroxy-4-methoxybenzaldehyde in 10% (v/v) hydrochloric acid. The new ligand, L, was characterized on the basis of elemental analysis, FT-IR, ¹H-NMR, and ¹³C-NMR spectra. In addition, the mass spectrum revealed the chemical structure of the free azo ligand. The metal complexes were prepared in their solid state after adjusting to the reaction conditions, including the reaction time, mole ratios (M: L), and pH of the reaction medium. The prepared complexes were characterized based on elemental analyses (C, H, N, and S), IR, UV-visible spectra, molar conductivity, and magnetic susceptibility measurements. Spectroscopic and magnetic data were consistent with an octahedral geometry around the metal(II) ions. The spectroscopic study of metal complexes formation involved the effect of time, mole-ligand ratio, and the adjustments of PH degree, which investigated the Maintenance of regions (6.5-7.5) for precipitation of the colored complexes in ethanol medium after (30-45) minutes of refluxing reactions. As well as the calculations of formation constants K_f by spectroscopic technique, it was found that the cobalt (II) complex showed a value equal to 3.738 x 10⁸ L.mole^-1 compared with the other complexes.

KEY WORDS: Metal complexes of 1,2,4-triazole, Azo ligands of triazole, Spectroscopic study of triazole complexes

Bull. Chem. Soc. Ethiop. 2026, 40(11), 2433-2441                                            

DOI: https://dx.doi.org/10.4314/bcse.v40i11.11