旋转铂盘电极上Cu(phen)_2~(2 )与6-巯基嘌呤的相互作用

在Tris-NaC1*(pH=7.2)缓冲溶液中,应用循环伏安法,微分脉冲伏安法、旋转圆盘电极实验、交流阻抗法及其数据模拟等技术研究了Cu(phen)2 25(phcn=1.10-邻菲咯啉)与6-巯基嘌呤(6-MP)的相互作用.结果显示.Cu(phen)2 2MP与6-MP无论在扩散控制过程或电化学控制过程都发生了相互作用.Cu(phen)2 2及其与6-MP的作用产物于铂电极上均呈现一对氧化还原峰,但后者呈现的氧化还原峰负移.峰电流减小.交流阻抗结果显示,无论6-MP存在与否,Cu(phen)2 2在交流阻抗谱上均呈现两个清晰的电容弧,但当6-MP存在时,电化学反应电阻和电化学吸脱附电阻均增大.Cu(phen)2 2在不同转速下的阻抗拟合结果显示.随转速增大.电化学反应电阻和电化学吸脱附电阻均减小.双电层电容呈增大趋势,而吸脱附电容呈减小趋势:当6-MP存在时.仍然呈现此变化规律.

The Interaction of Cu(phen)~(2 )_2 with 6-mercaptopurine on a Rotating Platinum Disk Electrode

In this paper, the interaction of Cu(phen)2 2 (phen = 1, 10-phenanthroline) with 6-mercaptopurine (6-MP) in Tris-NaC1 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)2 2 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)2 2 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.