Synthesis, structural, and electrocatalytic properties of copper (II) complex of ONO donor acylhydrazone and 2-methylimidazole

A novel mixed-ligand complex [CuL(2-MeIm)(H₂O)] was synthesized and characterized by elemental analysis, IR, and single-crystal X-ray diffraction. In the structure, Cu (II) was five-coordinated by three O atoms and two N atoms. L acted as a tridentate ligand, which formed two stable five-numbered chelating rings sharing one edge in the keto form. The coordination polyhedron around Cu (II) was described as a square-pyramidal. The electrocatalytic properties for oxygen reduction reaction (ORR) were investigated by cyclic voltammetry (CV) and chronocoulometry (CC) in oxygen-saturated 0.1 mol· L^-1 KOH. The results showed that complex had pronounced electrocatalytic activity for ORR with a four-electron transfer mechanism.