六元卟啉的电化学和光谱电化学研究

发布时间：2018-10-23 17:35

【摘要】：卟啉是一类具有四个吡咯通过次甲基桥相连的共轭大环化合物,它们在医学和材料化学等领域都有着广泛的应用前景。六元卟啉则是具有六个吡咯相连的拓展大环化合物,它们具有更为独特的光化学和电化学性质,因此对这些化合物进行研究具有重要的学术意义和潜在的应用价值。本论文第一章综述了卟啉及拓展卟啉的结构特性、在医学和材料等方面的应用以及采用的研究方法。第二章研究了三种无金属卟啉在不同溶剂中的电化学性质,讨论了溶剂对氧化还原反应的影响。每一种化合物在给定溶剂中的氧化还原反应均为卟啉大环上的电子转移过程,第一级还原反应的产物为卟啉阴离子自由基,而第一级氧化反应的产物为卟啉阳离子自由基。另外,还研究了HexaPyH_2在二氯甲烷中的质子化反应,与三氟乙酸反应时,HexaPyH_2可以一步得到两个质子生成[HexaPyH_4]~(2+)。第三章研究了两种常规铜、锌卟啉以及两种六元铜、锌卟啉在非水溶剂中的电化学和光谱电化学性质。结果表明,常规的铜、锌卟啉在给定的溶剂中均可以发生两级一电子还原反应,生成负一价阴离子[T2,6-diFPPM]~-和负二价阴离子[T2,6-diFPPM]~(2-)。但是在相同的溶剂中,六元卟啉铜、锌均能发生四级可逆的一电子还原反应,生成负一到负四价的卟啉阴离子,即:[HexaPyM_2]~-,[HexaPyM_2]~(2-),[HexaPyM_2]~(3-)和[HexaPyM_2]~(4-)。第四章研究了T2,6-diFPPCo和HexaPyCo_2在非水溶剂中的电化学和光谱电化学性质。在二氯甲烷或苯腈中,T2,6-diFPPCo的第一级还原和第一级氧化反应均为金属中心的电子转移过程,其中还原反应的产物为Co(Ⅰ)卟啉,而氧化反应产物为Co(Ⅲ)卟啉。对于含有两个钴中心离子的六元卟啉HexaPyCo_2来说,在同样的溶剂中可以观察到三级还原反应,其中第一、二两级还原为分子中两个Co(Ⅱ)离子分别得到一个电子被还原为Co(Ⅰ)卟啉。六元钴卟啉的前两级氧化反应也都是金属中心的电子转移过程,分子中两个Co(Ⅱ)离子分别失去一个电子最终生成含有两个三价钴中心离子的正二价卟啉阳离子,[HexaPyCo_2~Ⅲ]~(2+)。在吡啶中,六元卟啉钴能够与吡啶发生轴向配位反应生成五配位的化合物,每一个钴离子会配位一个吡啶而生成[HexaPyCo_2(py)_2]。[HexaPyCo_2(py)_2]在吡啶中可以观察到三级还原反应,其中第一级是两个重迭的一电子还原过程,生成的产物为含有两个Co(Ⅰ)的六元卟啉。在第四章中还研究了T2,6-diFPPCo和HexaPyCo_2与咪唑、甲基咪唑、吡啶、甲基吡啶在二氯甲烷中的轴向配位反应,测定了相应的配位反应平衡常数。另外,采用旋转盘电极技术研究了六元卟啉钴在水溶液中催化还原氧气的性能,结果表明,在1.0 M HClO_4中,HexaPyCo_2可以用作氧气还原的电催化剂,在给定的实验条件下,氧气的还原反应为两电子过程,产物主要是过氧化氢。
[Abstract]:Porphyrins are a class of conjugated macrocyclic compounds with four pyrrole linked by methylene bridge. They have been widely used in medicine and material chemistry. Hexagonal porphyrins are extended macrocyclic compounds with six pyrrole links, which have more unique photochemical and electrochemical properties. Therefore, the study of these compounds has important academic significance and potential application value. In the first chapter of this paper, the structural properties of porphyrins and their applications in medicine and materials, as well as their research methods are reviewed. In chapter 2, the electrochemical properties of three metalloporphyrins in different solvents were studied, and the effects of solvents on the redox reaction were discussed. The redox reaction of each compound in a given solvent is an electron transfer process over a porphyrin macroring. The product of the first order reduction reaction is a porphyrin anion radical, while the first order oxidation reaction product is a porphyrin cationic radical. In addition, the proton reaction of HexaPyH_2 in dichloromethane was studied. In the reaction of HexaPyH_2 with trifluoroacetic acid, two protons [HexaPyH_4] ~ (2) were obtained in one step. In chapter 3, the electrochemical and spectral electrochemical properties of two kinds of conventional copper, zinc porphyrin and two kinds of hexagonal copper and zinc porphyrin in non-aqueous solvent were studied. The results show that conventional copper and zinc porphyrins can undergo two-stage one-order electron reduction reaction in a given solvent to produce negative monovalent anions [T2O6-diFPPM] ~-and negative divalent anions [T2O6-diFPPM] ~ (2-). However, in the same solvent, hexagonal porphyrin copper and zinc can undergo a fourth order reversible electron reduction reaction to form negative 1 to negative tetravalent porphyrin anions, that is, [HexaPyM_2] ~ -, [HexaPyM_2] ~ (2-), [HexaPyM_2] ~ (3-) and [HexaPyM_2] ~ (4-). In chapter 4, the electrochemical and spectral electrochemical properties of T2O6-diFPPCo and HexaPyCo_2 in non-aqueous solvents were studied. In dichloromethane or benzonitrile, the first stage reduction and the first order oxidation of T2N 6-diFPPCo are electron transfer processes of the metal center, in which the product of reduction reaction is Co (鈪，

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