Synthesis, spectroscopic studies and evaluation of biological activity of some Subsistuded 1,2,4-triazoles and their complexes with Co(II), Ni(II) and Zn(II) ions

The present work describes the synthesis and characterization of new Schiff base of (E)-6-(4-(5-mercapto-4-((1-(4-methoxyphenyl)ethylidene)amino)-4H-1,2,4-triazol-3-yl)phenyl)-5H-pyrrolo[3,4-b]pyridine-5, 7(6H)-dione(L2) by condensation reaction of 6-(4-(4-amino-5-mercapto-4H-1,2,4-triazol-3-yl)phenyl)-5H-pyrrolo[3,4-b]pyridine-5,7(6H)-dione (5)(L1) with p- methoxy benzaldehyde. Using a 1:2 (metal : ligand) ratio, the ligands L1 and L2 were utilized to create a novel complex containing cobalt(II), nickel(II), and zinc(II) metal ions . Fourier transform infrared (FT-IR), ultraviolet-visible (UV-Visible), nuclear magnetic resonance (1H-NMR, 13C-NMR), micro elemental analysis (CHNS), thermal analysis, atomic absorption, molar conductance , and magnetic moment measurements have been used to examine and confirm new ligands (L1, L2) and their complexes. The observed data indicated the octahedral geometry around the Co(II), Ni(II )and Zn(II) complexes. Furthermore, the biological activity of ligands and its metal complexes in DMSO as control have also studied against four types of bacteria. The obtained results from inhibition zone values investigated that most metal complexes exhibited greater inhibition against all kinds of bacteria zone. KEY WORDS: Triazole ligand, Transition metals, Benzohydrazide, 1,2,4-triazole complexes, Microbial activity Bull. Chem. Soc. Ethiop. 2025, 39(6), 1119-1136. DOI: https://dx.doi.org/10.4314/bcse.v39i6.8