Binuclear Transition‐Metal Complexes of an Oxaloyl Dihydrazone Ligand: DNA Binding and Catalytic Oxidation of Cyclohexene

ABSTRACT A polydentate oxaloyl dihydrazone ligand (H 2 L) was synthesized using 2‐hydroxy‐1‐naphthaldehyde and oxaloyl dihydrazide, and its transition metal complexes with Cu(II), Co(II), Ni(II) and Fe(II) were prepared. The structures of the ligand and complexes were characterized by FT‐IR, UV–vis, LC–MS/MS, TGA/DTA, and NMR spectroscopy (for the ligand), while their magnetic, conductivity, and geometric properties were also evaluated. The electrochemical behavior of the ligand and its complexes was investigated by cyclic voltammetry, revealing quasi‐reversible redox processes. DNA‐binding studies performed using voltammetric methods indicated significant interaction between the complexes and calf thymus DNA, with the Cu(II) complex exhibiting the highest intrinsic binding constant, suggesting strong affinity toward DNA. Furthermore, the catalytic performance of the complexes was evaluated in the H 2 O 2 ‐mediated oxidation of cyclohexene under reflux in acetonitrile. Among the studied catalysts, the Co(II) complex demonstrated superior activity, achieving 99.0% ± 1.5% conversion and 81.4% ± 1.0% selectivity toward oxidation products in 2 h. These findings highlight the potential of oxaloyl dihydrazone‐based binuclear metal complexes as efficient oxidation catalysts and promising DNA‐interacting agents.