【作者】 刘平；

【导师】 张爱东； 涂海洋；

【作者基本信息】 华中师范大学 ， 有机化学， 2007， 硕士

【摘要】 超氧化物歧化酶（superoxide dismutase，SOD）是生物体内普遍存在的一种金属酶，能有效调控和维持生物体内正常的超氧阴离子（O₂^-）浓度。设计合成具有SOD功能的超氧化物歧化酶模型化合物（Model compound of Superoxide dismutase，MSOD），具有稳定性高、毒性小、成本低、分子量小等特点，在医药及临床应用上具有重要意义。设计合成具有SOD活性的手性大环多胺金属配合物，替代天然SOD进行界面分子组装，制备成SOD拟酶生物传感器，实现超氧阴离子自由基的检测，将具有寿命长、制作重复性高等显著优点，在临床上实现与超氧阴离子浓度相关的疾病诊断检测方面，具有重要的应用价值。本文设计并合成了一系列新的手性大环多胺锰（Ⅱ）配合物，在金电极界面构建了SOD模拟酶的分子组装体系，用电化学方法和X-射线光电子能谱（XPS）对其结构和性质进行了研究，测定了它对超氧阴离子的歧化作用。主要研究内容如下：1．合成了一系列以[15]-ane-N₅为基本骨架的手性大环多胺锰（Ⅱ）配合物、以及具有界面组装和金属离子配位功能的咪唑衍生物硫辛酰组胺（imid-2S）。这些目标化合物和部分中间体的分子结构用¹HNMR、GC-MS、ESI-MS、IR和UV等进行了确认：（?）2．尝试了在imid-2S自组装膜界面通过其咪唑基与Mn-01的轴向Cl^-1配体进行交换来进行界面固定大环多胺金属配合物。采用电化学交流阻抗谱及循环伏安法研究了大环多胺锰（Ⅱ）配合物Mn-01的轴向Cl^-1配体与imid-2S自组装膜在电极界面上的轴向配体交换行为，实验结果表明通过轴向配体交换将大环多胺金属配合物在自组装膜上固定是可以实现的，且得到Mn-01的表面浓度为1.45×10^-11mol·cm^-2。而溶液中配合物Mn-01的轴向Cl^-1配体与imid-2S进行配体交换前后，紫外可见吸收光谱无明显变化，可能因为这类大环多胺金属配合物的轴向配位是弱配位，配体的交换对金属离子配位场的改变影响很小。3．通过自组装技术制备了含有α-硫辛酸头基的大环多胺配合物Mn-07/Au修饰电极。电化学交流阻抗谱及循环伏安法实验结果表明，该自组装膜的覆盖度达到99.65％，表面浓度为1.32×10^-10mol·cm^-2。当改变循环伏安检测的扫描速率时，Mn-07/Au修饰电极的氧化还原峰电位基本保持不变，氧化还原峰电流随着扫描速率的增加而增大并呈很好的线性关系，表明Mn-07在金电极表面形成了致密的自组装膜。这一结论可以通过X-射线光电子能谱（XPS）对Mn-07/Au修饰电极表征的结果得到进一步证实。4．采用黄嘌呤-黄嘌呤氧化酶系统产生O₂^-，研究了含有α-硫辛酸头基的大环多胺配合物Mn-07/Au分子组装体系与O₂^-的相互作用，结果表明这类拟酶分子组装体系对超氧阴离子自由基的歧化具有明显的催化作用，并提出了该催化歧化过程可能的反应机理。对无法直接在金电极表面组装的大环多胺配合物，选择Mn-02，Mn-04，Mn-06为代表，用经典的邻苯三酚自氧化法分别测定了它们的SOD样活性，得到它们的抑制率分别为14.75％，9.01％，0.82％。更多还原

【Abstract】 Superoxide dismutase （SOD） is a common metalloenzyme in organism for the effective mediation and maintaniance of biological superoxide concentration. Superoxide dismutase mimics （MSOD） by rational design and synthesis are expected to have the advantages of high stability, low toxicity, low cost for production and small molecular weight, etc., over natural SODs, and it is significant for these MSOD to be used in clinic. Design and synthesis of chiral macrocyclic polyamine-metal complexes with SOD-like activity will be very useful for their immobilization on electrodes for the detectation of superoxide in vivo and in vitro. It is expected that this kind biosensors with SOD mimics modified electrodes will possess long lifetime in use and high reproducibility in production, etc., and have impotant application in clinic diagnosis for the diseases related to superoxide.In this thesis, we designed and synthesized a new group of chiral macrocyclic polyamine-Mn（Ⅱ） complexes as superoxide dismutase mimics, and constructed them on the surface of gold substrates for the application of superoxide detection. The main contents are listed as the following:1. A group of chiral macrocyclic polyamine-Mn（Ⅱ） complexes based on the substituted [15]-ane-N₅ backbone and a axial ligand N-（2-（1H-imidazol-5-yl）ethyl）-5-（1,2-dithiolan-3-yl） pentanamide （imid-2S） were synthesized. The molecular structures of the target compounds and some intermediates were confirmed by ¹HNMR、GC-MS、ESI-MS、IR、UV, etc.2. Macrocyclic polyamine-metal complexes were attempted to immobilize on a self-assembled monolayer （SAM） of imid-2S on gold electrode by exchange of axial ligand Cl^-1 of Mn-01 with the terminal imidazolyl of imid-2S SAM and the exchang procedure was investigated by the electrochemical cyclic voltammetry and electrochemical impendence spectra. The result showed that immobilization of macrocyclic polyamine-metal complexes on a self-assembled monolayer via axial ligand exchange had been achieved, and the surface concentration of Mn-01 reached 1.45×10^-11mol·cm^-2. However, the UV-Vis spectra was not obvious for the axial ligand exchange and maybe it can be attributed to the week coordination ability of Cl^-1 and imidazole group to Mn²⁺, for the change of the coordination field of the metal ion via ligand exchange. 3. Macrocyclic polyamine manganese（Ⅱ） complex linked withα-lipoic acid as headgroup （Mn-07） had been constructed on gold electrodes by self-assembly technology. The surface coverage of the SAMs is up to 99.65%, and the surface concentration of Mn-07 is 1.32×10^-10 mol·cm^-2. Upon the change of potential scan rate, the redox potential position of Mn-07/Au modified electrodes remained unchanged and the anodic peak currents augmented linearly with potential scan rate, implifying Mn-07 has formed well packed SAM on gold electrodes. This conclusion could been further confirmed by the X-ray photoelectron spectra（XPS） of Mn-07/Au modified electrodes.4. Xanthine and xanthine oxidase system was used to generate O₂^.- and its dimutation on Mn-07/Au were investigated. The result demonstrated that these MSOD molecular self-assembly systems promoted the disproportionation of superoxide obviously, and the plausible mechanism was established. For those Macrocyclic polyamine manganese（Ⅱ） complex without the self-assembly ability on gold electrodes directly, Mn-02, Mn-04 and Mn-06 were tested their SOD-like activity by the method of pyrogallol autoxidation, and afforded the inhibition rate 14.75%, 9.01%, 0.82% respectively.更多还原