【作者】 许娟；

【导师】 李红；

【作者基本信息】 华南师范大学 ， 物理化学， 2007， 硕士

【摘要】 钌最外层具有4d⁷5s¹结构，其离子常见价态为Ru（Ⅰ）、Ru（Ⅱ）和Ru（Ⅲ），并易于形成六配位的八面体结构配合物。钌中心离子与配体结合后，中心钌离子的氧化还原电位会受到配体共轭程度以及配体的空间结构的影响。多吡啶钌配合物与DNA相互作用的强度也受配体结构的影响。本论文选择了具有不同共轭程度或空间结构配体的多吡啶钌配合物：A[Ru（bpy）₂tatp（ClO₄）₂]，B [Ru（bpy）₂dmt（ClO₄）₂]，C[Ru（phen）₂dmt（ClO₄）₂]，D [Ru（dmp）₂dmt（ClO₄）₂]，E [Ru（bpy）₃Cl₂]（bpy=2，2′-联吡啶，tatp=1，4，8，9-四氮三苯，dmt=2，3-二甲基-1，4，8，-四氮三联苯，phen=邻菲咯啉，dmp=2，9-二甲基邻菲咯啉）作为研究的对象，深入地研究了配体的变化对于多吡啶钌配合物电子吸收光谱、荧光光谱、电化学性质、电致化学发光性质及其与DNA的相互作用，并在此基础上研究了钉配合物在ITO电极上的电化学组装及DNA对组装的促进作用。在第一章中，介绍了DNA以及多吡啶钌配合物的基本性质，并综述了DNA组装的发展现状，同时也介绍了多吡啶钌配合物组装的研究概况，DNA和多吡啶钌配合物的组装一般都是通过吸附作用、自组装、电化学方法、LB膜、共价键合作用和生物素-亲和素法等。在第二章中，介绍了本论文实验过程中所用的仪器、试剂、实验方法和相关的理论分析。在第三章中，研究了五种配合物的电子吸收光谱，并讨论了DNA的存在对四种多吡啶钌配合物A、B、C、D的电子吸收光谱的影响，发现DNA会使配合物的吸收峰发生减色和红移。计算了DNA与多吡啶钌配合物相互作用的键合常数，发现键合常数大小顺序为A＞C＞B＞D，其中配合物A、B、C与DNA的相互作用主要为插入作用。离子强度对DNA-配合物相互作用也存在明显的影响，0.22 mol L^-1为转折点，NaCl浓度高于转折点时，DNA与配合物的相互作用变得非常弱。在第四章中，考察了DNA浓度及离子强度对了四种多吡啶钉配合物A、B、C、D荧光光谱的影响，发现配合物A、B、C在450 nm激发光下可以发射强的荧光，配合物D的荧光强度较弱。DNA的存在可以增强配合物在Tris-NaCl缓冲溶液中的荧光强度，并且在较低离子强度范围内(0～0.25 mol L^-1)，DNA浓度越高，对配合物荧光的增强作用越强，NaCl对单纯配合物的荧光强度影响不大；但是NaCl浓度不利于DNA对配合物荧光的增强，高的NaCl浓度不利于DNA与配合物的相互作用。第五章中采用了循环伏安法、微分脉冲伏安法等电化学方法以及荧光显微镜方法研究了多吡啶钌配合物A、B、C、D的电化学行为，进而讨论了配合物在ITO电极上的组装。结果表明：四种配合物在pH=7.2的缓冲溶液中，电位范围是0.2～13.5 V时，在ITO电极上可以观察到一对扩散控制氧化还原峰，这对氧化还原峰归属于Ru（Ⅱ）氧化为Ru（Ⅲ），四种配合物的条件电位E^o′高低顺序为A＞C≈D＞B＞E，这与相应物质的配体共轭程度相呼应。重复的伏安扫描可以获得一个新的前置峰，表示Ru（Ⅱ）的氧化产物形成了一层Ru（Ⅲ／Ⅱ）强吸附层吸附在ITO电极上。通过荧光显微镜观察电极上的组装层，发现配合物在490 nm波长激发光下发出橙红色的光。离子强度会影响配合物的电化学性质，并且影响配合物在电极上的组装。高的离子强度阻碍配合物在电极上的组装。第六章中，研究了缓冲溶液中存在0.224 mmol L^-1DNA时配合物A、B、C、D分别在ITO电极上的电化学行为及DNA-多吡啶钉配合物在ITO电极上的组装，发现DNA／多吡啶钌配合物混合溶液在电极上发生准可逆反应，其速度控制步骤主要为扩散控制；DNA的存在影响多吡啶钌配合物中心离子在电极上的反应：比较离子强度对多吡啶钌配合物／DNA混合体系和钌配合物电化学性质的影响。采用重复的伏安扫描可以形成和控制DNA促进多吡啶钉配合物在ITO电极上的组装；DNA分子促进多吡啶钌配合物在ITO电极上的组装，并且可以增强组装层的荧光性质。低的离子强度可以促进DNA-配合物在ITO电极上的组装，但是更高的离子强度将阻碍组装的进行。在本章中还初步探讨了组装体的应用，认为在0.2 mmol L^-1[Ru（bpy）₂tatp]²⁺／0.224mmol L^-1DNA体系中获得的修饰电极对检测[Ru（bpy）₂L]²⁺（L：tatp，bpy,dmt）与DNA间的相互作用有良好的效果，为进一步发展DNA-多吡啶钌配合物修饰电极提供了新的思路。第七章着重讨论了五种多吡啶钌配合物A、B、C、D、E的电致化学发光性能，并研究了DNA、NaCl浓度对配合物A、B、C、D电致化学发光性能的影响，多吡啶钌配合物A：[Ru（bpy）₂tatp]²⁺，B：[Ru（bpy）₂dmt]²⁺，C：[Ru（phen）₂dmt]²⁺在缓冲溶液中有无DNA存在时都有良好的电致化学发光性能，配合物D[Ru（dmp）₂dmt]²⁺在无DNA存在时，在缓冲溶液中呈现出较弱的电致化学发光。当多吡啶钌配合物溶液中没有DNA存在时，NaCl浓度对配合物A、B、C的ECL强度影响不大；而DNA存在在较大程度上影响多吡啶钌配合物的ECL性能。更多还原

【Abstract】 Ruthenium possesses 4d⁷5s¹ electronic structure and its ions haveforms of Ru（Ⅰ）, Ru（Ⅱ） and Ru（Ⅲ）. Ru（Ⅱ） can form easily octahedralruthenium （Ⅱ） complex with chelating atoms. The redox potentials ofruthenium center ion and DNA binding of the complexes are affected byconjugated intensity and spacial structure of ligands. We choose fourpolypyridine ruthenium （Ⅱ） complexes with different ligands such as A[Ru（bpy）₂tatp（ClO₄）₂], B [Ru（bpy）₂dmt（ClO₄）₂], C [Ru（phen）₂dmt（ClO₄）₂],D [Ru（dmp）₂dmt（ClO₄）₂], and E [Ru（bpy）₃Cl₂] （where bpy=2,2′-bi-pyridine, tatp=1,4,8,9-tetra-aza-triphenylene, dmt=2,3-dimethyl-1,4,8,9-tetraazatriphenylene, phen=1,10-phenanthroline and dmp= 2,9-di-methyl-1,10-phenanthroline） as our researchful object. The effects of theligands on the electronic absorption spectra, fluorescence spectra,electrochemical behavior, electrochemiluminescence properties of thesecomplexes have been investigated. Based on these results, the interactionof these compounds with DNA and their electrochemical assembly in theabsence and presence of DNA are also been studied.In chapter 1, the basic properties of DNA and polypyridyl rutheniumcomplexes are first introduced. Then, the progresses on assembly of DNAand/or polypyridyl ruthenium complexes are also reviewed. Theimmobilization for them on the substrates is fulfilled by using the methodsincluding chemical adsorption, self-assembly monolayer, electrochemicalmethod, Langmuir-Biodgett technique, Biotin-Avidin system, and covalentbinding. In chapter 2, all chemicals, instruments and experimental methodsused in this thesis are briefly described.In chapter 3, the electronic absorption spectra of polypyridylruthenium complexes A, B, C, D and E have been studied in thc absenceand presence of DNA. The results show that the presence of DNA canresult in obvious hypochromism, red shift. According to the hypochromism,bathochromism phenomena, and the binding constants, the interactivestrength of these complexes with DNA conforms the order A＞C＞B＞D. TheDNA binding of the complexes A, B and C is suggested to be intercalativemodes. Furthermore, the effects of ion strength on the interaction of thesecomplexes with DNA have been studied. NaCl concentration of 0.22 molL^-1 is a turning point. When the concentration of NaCl is higher than theturning point, the interaction of complex with DNA becomes extremelyweak.In chapter 4, the fluorescence properties of these complexes A, B, Cand D in buffer solution have been studied. The complexes A, B, C exhibitstrong fluorescence properties at about 590 nm, but D indicates weakfluorescence. The results show that the presence of DNA can enhance thefluorescence strength of these ruthenium complexes at 450 nm excitedlight. At the low ion strength (＜0.25 mol L^-1), fluorescence strengthbecomes stronger with the increasing concentration of DNA. Theconcentration of NaC1 is proved to have an obvious effect on theDNA-binding of these complexes.In chapter 5, the electrochemical properties of these complexes havebeen studied by using the methods such as cyclic voltammetry, differentialpulse voltammetry, the fluorescence microscope imaging. Moreover, theassembly mechanism of these complexes on ITO electrode is explored. Inthe potential range from 0.2 to 1.5 V, a couple of well-defined redox wavesare observed in pH=7.2 buffer solution, the oxidize wave is ascribedRu（Ⅲ）] from Ru（Ⅱ）. The formal E^o′ of these complexes conforms thefollowing A＞C≈D＞B＞E. The order matches with the conjugated intensity of ligands. When continuous voltammetric sweeping is carriedout in the potential range from 0.2 V to 1.5 V a new wave appears,representing the oxidation of dissolved reactant Ru（Ⅱ）to form a layer ofproduct Ru（Ⅲ）adsorbed strongly on the ITO clectrode. Through thefluorescence microscope observation assembled layer on ITO electrode,the orange-red light is discovered at 490 nm excited wavelength. Theelectrochemical properties and assembly of these complexes on theelectrode are affected by the ion strength. High ion strength is discoveredto influence the assembly of these complexes on the electrode.In chapter 6, the electrochemical properties and assembly of thesecomplexes A, B, C, and D on the ITO electrode in the buffer solutioncontaining 0.224 mmol L^-1 DNA have been investigated. The resultsindicate that the redox reaction at more positive potential exhibits a quasi-reversible process. The effects of ion strength on the electrochemicalproperties of the interactive products between these complexes and DNAare discovered. Compared with the in absence of DNA, DNA can promotethe assembly of the complexes on the ITO electrode. The fluorescencestrength of the assembly layer is stronger than the complexes themselves.The electrochemical assembly of these complexes on the electrode isaffected by the ion strength. The high ion strength may be hindered theassembly of the complexes in the presence of DNA. The of the assembledlayer is applied in the determination of the DNA-binding for thesecomplexes. The assembled layer obtained from 0.2 mmol L^-1[Ru（bpy）₂tatp]²⁺/0.224 mmol L^-1DNA in buffer solution is used as theprobe of DNA-binding mode for [Ru（bpy）₂L]²⁺ （L: tatp, bpy, dmt）.In chapter 7, the Electrochemiluminescence （ECL） properties of five kinds ofruthenium complexes A, B, C, D and E have been studied. The results show that thesecomplexes exhibit an excellence ECL signals in the absence and presence of DNA,but complexes D has weak ECL intensity. The influence of ion strength on ECLproperties of the ruthenium complexes in buffer solution containing DNA is largercompared with that in absence of DNA.更多还原