Abstract: In this paper, the interaction of Cu(phen)22+ (phen=1,10-phenanthroline) with 6-mercaptopurine(6-MP) in Tris-NaCl buffer solution(pH=7.2) has been investigated by electrochemical techniques including cyclic voltammetry, differential pulse voltammetry, rotating disk electrode measurements, AC(alternative current) impedance and its data fitting. The results show that the interaction of Cu(phen)22+ with 6-MP is proved to exist under diffusion control or electrochemistry control. The cyclic voltammograms assume a couple of redox peaks and the electrochemical impedance spectra for Cu(phen)22+ on the platinum disk electrode show two obvious capacitance arches in the absence or presence of 6-MP.However,peak potentials shifted negatively, peak currents decreased significantly, and both the charge transfer resistance and the electrochemical absorption-desorption resistance increased in the presence of 6-MP compared with those in the absence of 6-MP. On the other hand, with the increase of the rotating rate, the values of the charge transfer resistance and the electrochemical absorption-desorption resistance decreased, while the double-layer capacitance and the absorption-desorption capacitance showed an enhanced and a reduced tendences in the absence or presence of 6-MP, respectively.

Key words: Copper complex, 6-mercaptopurine(6-MP), AC(alternative current) impedance, Rotating disk electrode