Hydralazine based Schiff Base ligand and its Ni(II), Cu(II) and Zn(II) complexes: Synthesis, Antibacterial effect and Molecular docking Studies

Hydrazones are strong electron-donating ligands capable of coordinating through nitrogen donor atoms. Hydrazones and their transition metal complexes have been extensively investigated due to their wide-ranging applications in pharmaceuticals, analytical reagents, and agrochemicals. In this study, a new Schiff base ligand (HAG) was synthesized from 2-hydroxy-4-(prop-2-yn-1-yloxy)benzaldehyde and hydralazine. The antibacterial activities of the ligand and its Cu(II), Ni(II), and Zn(II) complexes were evaluated. The synthesized compounds were characterized by elemental analysis, IR, ¹H NMR, and UV–Vis spectroscopy. Analytical data confirmed the formation of 1:2 (M:L) complexes, where M represents Cu(II), Ni(II), or Zn(II) ions and L represents the deprotonated hydrazone ligand. IR spectral data revealed that HAG coordinates in a tridentate manner via phthalazine nitrogen, azomethine nitrogen, and phenolic oxygen atoms. Antimicrobial studies showed that [Zn(AG)₂] exhibited the strongest activity against Staphylococcus aureus, with a MIC value of 250 µg/mL, while [Cu(AG)₂] and [Ni(AG)₂] showed MIC values of 1000 µg/mL against the same strain