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1、西北师范大学 硕士学位论文 卟啉自组装膜电化学表征及其应用研究 姓名：智福鹏 申请学位级别：硕士 专业：分析化学 指导教师：卢小泉 2009-06 西北师范大学硕士学位论文 研究生：智福鹏 专业：分析化学 导 师：卢小泉 教授 研究方向：电分析化学 摘 要 摘 要 自组装膜 (Self-assembled monolayers，SAMs) 是研究表面及界面现象的理 想模型，在电子及光学器件、化学传感器、生物传感器、催化等方面都有着广 阔的应用前景，是近年来国内外普遍关注的一个前沿热点。卟啉及其金属配合 物具有优异的光电特性，它们与生命活动密切相关，在生命体的电子转移过程 中发挥着重要的作用，被
2、称为“生命的颜料” 。 因此，本论文将卟啉与自组装 技术相结合，构建了功能化的卟啉单、多层自组装膜，利用多种电化学表征方 法，较系统地考察了卟啉类化合物的物理化学特性，卟啉自组装膜对 H2PO4- 的 识别。 有关阴离子识别的研究报道比较多，合成的大多数阴离子识别主体是在有 机溶剂中对特定阴离子的识别，但是以卟啉自组装膜为阴离子识别主体的研究 非常少，特别是在水溶液中进行对 H2PO4- 的识别，H2PO4- 离子在环境化学、 临床医学、生物化学、药物化学及其他领域中起着非常重要的作用。卟啉组装 膜在化学传感、生物传感和生物界面活性研究方面有着巨大的潜力。通过自组 装技术将巯基卟啉修饰在金电极
3、表面，研究了 SH-TPP 和 TCA-ATP 自组装膜 在水体系中对 H2PO4- 离子的识别。通过电化学交流阻抗技术、电化学扫描显微 镜实验研究了卟啉自组装膜对 H2PO4- 的识别现象。 卟啉自组装膜可以有选择性 的识别 H2PO4- 离子，并且加入10倍的其它阴离子不会产生干扰。 采用5，15-二-4-(6-巯基己氧基)-苯基-10，20-二苯基卟啉 (trans-PPS2) 为研究对象，通过 S-Au 键相互作用，将双巯基卟啉化合物组装在金电极表面， 然后再通过 S-Au 键作用组装一层纳米金，继续组装卟啉分子，成功的实现了 层层组装，构筑了卟啉分子金属卟啉分子的夹心式结构，应用 S
4、ECM 技术 结合常规电化学方法表征了金电极上的巯基卟啉自组装分子膜，清晰直观地检 测到不同膜层状态的表面形貌，并通过交流阻抗技术计算得到了相应的电子转 移速率。 在无氧化还原探针的电解液中，采用电化学交流阻抗技术对铜离子介入的 硫辛酸自组装膜进行离子渗入研究。 在 1000-0.2 Hz 的低频区域考察了电解液离 子的渗入，并用阻抗谱等效电路的阻抗 (RSAM) 进行了量化。探索了电极电势和 西北师范大学硕士学位论文 电解液浓度对离子渗入的影响。实验结果表明：电解液中加入铜离子时，RSAM 减小近 70%；电解液浓度减小 10 倍时，RSAM增大约 2-3 倍。 关键词关键词：卟啉，自组装膜
5、，阴离子识别，层层自组装膜，硫辛酸自组装膜 研究生：智福鹏 专业：分析化学 导 师：卢小泉 教授 研究方向：电分析化学 西北师范大学硕士学位论文 研究生：智福鹏 专业：分析化学 导 师：卢小泉 教授 研究方向：电分析化学 Abstract Self-assembled monolayers (SAMs) is the ideal model to study the surface and interfacial phenomena, which has been widely applied in the electronic and optical devices, chemical se
6、nsors, biological sensors, catalysis, and other research fields and has been the focus of considerable research activity. Owning to porphyrins favorable optoelectronic properties and biologically activity, the porphyrin and their metal complexes play an important role in the biological electron tran
7、sport in biomembranes and other investigations, known as the “life of pigment.“ In this paper, porphyrins are effectively combined with self-assembled monolayer technique to construct functional ordered ultrathin filmsmonolayer and multiplayer films. The physical and chemical characteristics of porp
8、hyrin SAMs, the sensing properties of H2PO4- on porphyrin SAMs have been investigated by a variety of electrochemical methods, such as electrochemical impedance spectroscopy (EIS) and scanning electrochemical microscopy (SECM). Most anion recognition and sensing phenomena reported thus far have been
9、 investigated in bulk solution, especially in organic media. However, most anions exist in aqueous medium, such as pollutants, organisms, and so on. Specially, it is of particular significance to detect the dihydrogenphosphate anion in aqueous solution due to its biological importance, such as biolo
10、gical systems, chemical processes, medicine, food chemistry, material sciences and environmental sciences. In order to make anion sensing possible in aqueous solution, the directed assembly of organized arrays of molecules covalently bound to substrate surfaces offers an attractive, versatile method
11、 to design and construct a wide range of thin films by controlling the structure and material properties. SAMs of thiol-derivatized tetraphenylporphyrin on gold are able to bind anions reversible from aqueous solutions. Electrochemical impedance spectroscopy (EIS) and scanning electrochemical micros
12、copy (SECM) were employed to investigate the binding of anions by porphyrin SAMs and proved to 西北师范大学硕士学位论文 be efficient and convenient techniques for detecting anions in aqueous solutions using the redox couple Fe(CN)63-/4- as “reporter ion”. SAMs of porphyrins were shown to bind dihydrogenphosphat
13、e selectively over various other anions, including Cl-, Br-, NO2- or NO3-. Gold electrodes modified with porphyrins can detect H2PO4- even in the presence of a 10-fold excess of other anions studied. We have studied the electrochemical response of the organic-inorganic multilayers film using CV, SEC
14、M, and EIS, and have determined the electrochemical parameters. Multilayers film of nanostructured gold particles (AuNPs) has been fabricated based on the layer-by-layer (LBL) technique using a self-assembled monolayer of 5,15-di-p-(6-mercaptohexyl)-phenyl -10,20-diphenyl porphyrin (trans-PPS2). AuN
15、Ps act as physical cross-link points in the multilayers. Using the high sensitivity of the electron transfer of ferricyanide to the modification of the gold surface with multilayers film, we selected this reaction as a probe to study the different modification stages at this modified electrode. SECM
16、 images obtained from bare and the different modification stages showed very good resolution with different topographies. Based on a comparison with the results of the experiments, a reasonable agreement can be obtained, which means a conjunction of these techniques. Electrochemical impedance spectroscopy (EIS) was employed to explore the permeation of electrolyte io
