| Some metal complexes used as anticancer drugs are significantly investigated, which have aroused wide interest from more and more investigators. The main purpose of this article is to study the interaction among polypyridyl complexes, purine drugs including 6-Mercaptopurine (6-MP), 6-thiolguanine(6-TG), 6-Hypoxanthine (HX), 2-Mercaptobenzothiazole (MBTH) , Adenine(A) and 2,5-Dimercapto-1,3,4--thiadiazole (DMcT) and DNA using electrochemical methods(cyclic voltammetry, differential pulse voltammetry, ac impedance and its data fitting), spectral techniques and viscosity measurements based on the interaction of polypyridyl complexes with 6-MP.In chapter 1, we describe the structure of DNA and the modes of interaction between some anticancer drugs and DNA. At the same time, we also summarize the methods used in field of investigating the interaction of anticancer drugs with DNA, which is widely used by many investigators, give some advice on the future research. With these described above as basis, the purposes of this article are suggested.In chapter 2, electrochemical behavior of 6-MP self-assembled monolayers on the gold electrode has been investigated using cyclic voltammetry, differential pulse voltammetry, coulometry and surface-enhanced Raman spectroscopy (SERS). The results indicate that self-assembled monolayers of 6-MP can be obtained on the goldelectrode. In the solution containing K3Fe(CN)6, the redox peak current of K3Fe(CN)6 on the gold electrode modified by 6-MP increases with the increase of the assembled time, but the formal potential shifts negatively. In the solution containing 0.2 mol/L KC1, the double layers capacity decreases with the increase of the assembled time. After the assembled time is over 120 min, the self-assembled monolayers obtained by 6-MP are completely formed.In chapter 3, the interaction between polypyridyl cobalt complexes and 6-MP has been studied using electrochemical methods (cyclic voltammetry, differential pulse voltammetry, ac impedance and its data fitting), UV-spectroscopy, voltage titration and SERS. The results indicate that there is obvious interaction between polypyridyl cobalt complexes and 6-MP. A Au electrode modified by polypyridyl cobalt complexes and 6-MP is obtained in the solution containing polypyridyl cobalt complexes through their interaction. In the presence of 6-MP, the redox peak current of polypyridyl complexes for the central cobalt ion from voltammograms is significantly reduced compared with that in the absence of 6-MP and the current of a new quasi-reversible redox wave shown at lower potential gradually increases with 6-MP addition. At the same time, UV-spectra of polypyridyl complexes are regularly changed in the presence of 6-MP, which show that a new complex is formed through obvious interaction of polypyridyl cobalt complexes with 6-MP. And the bond constant of Co(phen)33+ and Co(bpy)33+ with 6-MP is 7.7 X 104L/mol and 3.7 X 104 L/mol, respectively. In the same condition, the interaction of polypyridyl cobalt complexes with the other compounds including 6-TG, HX, MBTH, A and DMcT has been studied using electrochemical methods and UV-spectroscopy. The results show that the interaction of 6-TG and MBTH containing conjugated heterocycle and -SH groups with polypyridyl cobalt complexes is similar to the properties of 6-MP. However, there are no obvious interaction of A and HX only including conjugated heterocycle groups with polypyridyl cobalt complexes. Meantime, interaction of DMcT only containing -SH groups with polypyridyl cobalt complexes is also proved to no exit.In chapter 4, the interaction between Co(L)33+-6-MP complex (L=phen, bpy) and calf thymus DNA has been investigated using electrochemical methods(cyclic voltammetry, differential pulse voltammetry, ac impedance and its data fitting) and UV-spectroscopy and viscosity measurements. There is obvious interaction between Co(L)33+-6-MP complex and DNA. Meantime, there is an obvious interaction equilibrium among Co(L)33+, 6-MP and DNA. When DNA is added to the sol...
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