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

The electrochemical property of dinuclear copper(II) complex containing mixed ligands of N-hydroxyethylaminoethyl oxamido and 2,2'-bipyridine [Cu-2(bpy)(2)(HAO) (2) (2+) ] was studied with cyclic voltammetry. Cu-2(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 Cu-2(bpy)(2)(HAO) (2) (2+) and herring fish sperm DNA. All the experimental results showed that Cu-2(bpy)(2)(HAO) (2) (2+) interacted with DNA mainly through electrostatic affinity to make tiny difference between Cu-2(bpy)(2)(HAO) (2) (2+) -ssDNA and Cu-2(bpy)(2)(HAO) (2) (2+) -dsDNA. The binding ratio and the binding constant of DNA-Cu-2(bpy)(2)(HAO) (2) (2+) were calculated as 1:1 and 6.41 x 10(4), respectively. The redox peak current of Cu-2(bpy)(2)(HAO) (2) (2+) decreased markedly after its interaction with DNA. This was used to detect the concentration of DNA quantitatively.