Design and Synthesis of Ni(II), Zn(II), and VO(IV) Heteroleptic Complexes Incorporating a Benzohydrazide Schiff Base and 1,10-Phenanthroline: Biological Activities, DNA Interaction, Catalysis, and Theoretical Insights

The present study reports the synthesis and characterization of novel heteroleptic Ni(II), Zn(II), and VO(IV) complexes derived from the tridentate Schiff base ligand Acetylpyridine benzoyl hydrazone(APBH) and 1,10-phenanthroline as a co-ligand. The complexes were characterized using elemental analysis, FT-IR, NMR, mass spectrometry, UV–Vis spectroscopy, magnetic measurements, thermogravimetric analysis, and DFT calculations. Spectroscopic and magnetic data suggested octahedral geometries for Ni(II) and Zn(II) complexes and a square pyramidal structure for the VO(IV) complex. Biological evaluation revealed promising antimicrobial, antioxidant, and anticancer activities against MCF-7 and HepG2 cell lines. DNA-binding studies using UV–Vis spectroscopy and gel electrophoresis indicated possible intercalative and/or groove binding interactions with CT-DNA. Molecular docking studies further supported the experimental findings by predicting favorable binding affinities of the complexes toward selected biological targets involved in antimicrobial and anticancer activity. Additionally, the complexes were examined as homogeneous catalysts in the oxidation of 1,2-cyclooctene under aerobic conditions. The VO(IV) complex exhibited superior catalytic performance compared to its Ni(II) and Zn(II) analogues. These findings highlight the multifunctional potential of the synthesized heteroleptic complexes in medicinal and catalytic applications.