Electrochemical behavior and DNA-binding properties of binuclear copper(II) complex containing mixed ligands of N-hydroxyethylaminoethyl oxamido and 2,2′-bipyridine

Abstract

The electrochemical property of dinuclear copper(II) complex containing mixed ligands of N-hydroxyethylaminoethyl oxamido and 2,2′-bipyridine [Cu2(bpy)2(HAO) 2 2+ ] was studied with cyclic voltammetry. Cu2(bpy)2(HAO) 2 2+ had irreversible oxidation peaks in 0.1 mol/L NaCl solution at the stearic acid-modified carbon paste electrode. Cyclic voltammetry and absorption spectra measurements were used to study the interaction between Cu2(bpy)2(HAO) 2 2+ and herring fish sperm DNA. All the experimental results showed that Cu2(bpy)2(HAO) 2 2+ interacted with DNA mainly through electrostatic affinity to make tiny difference between Cu2(bpy)2(HAO) 2 2+ –ssDNA and Cu2(bpy)2(HAO) 2 2+ –dsDNA. The binding ratio and the binding constant of DNA–Cu2(bpy)2(HAO) 2 2+ were calculated as 1:1 and 6.41 × 104, respectively. The redox peak current of Cu2(bpy)2(HAO) 2 2+ decreased markedly after its interaction with DNA. This was used to detect the concentration of DNA quantitatively.