Synthesis, Characterization, Antimicrobial and Antiproliferative Activity Evaluation of Cu(II), Co(II), Zn(II), Ni(II) and Pt(II) Complexes with Isoniazid-Derived Compound

Hydrazone complexes of Cu(II), Co(II), Zn(II), Ni(II) and Pt(II) with <i>N</i>-isonicotinoyl-<i>N</i>'-(3-metoxy-2 hydroxybenzaldehyde)-hydrazone (<b>HL</b>) were synthesized and characterized by different physico-chemical techniques including elemental and thermal analysis, magnetic susceptibility measurements, molar electric conductivity, as well as IR (infrared), ¹H-NMR and ¹³C-NMR (hydrogen and carbon nuclear magnetic resonance, UV-Vis (ultraviolet-visible), FAB (fast atom bombardment), EPR (electron paramagnetic resonance), and mass spectroscopies. The crystal structure of ligand was determined by single crystal X-ray diffraction studies. Spectral data showed that hydrazone behaves as an ONO tridentate ligand through the azomethine nitrogen, phenolate and keto oxygen atoms. For the copper(II) complexes, metal-ligand bonding parameters were evaluated from the EPR spectra. These parameters indicate the presence of in-plane π bonding. In addition, the f values of complexes <b>1</b>-<b>4</b> indicate small distortion from planarity. The effect of these complexes on proliferation of human breast cancer (MCF-7 and SKBR-3), human melanoma (A375), lung adenocarcinoma cells (NCI-H1573) and their antibacterial activity against <i>Escherichia coli</i>, <i>Klebsiella pneumoniae</i>, <i>Staphylococcus aureus</i> and <i>Candida albicans</i> strains were studied and compared with those of free ligand. The ligand and complexes <b>1</b>-<b>3</b> showed significant antimicrobial activity against the Gram-positive bacteria <i>Staphylococcus aureus</i> and <i>Candida albicans</i> in comparison to the control drugs. The complexes <b>2</b>-<b>4</b> could be potential antitumor agents, leading to a significant improvement of the cytotoxic activity when compared with <b>HL</b>.