基于拓展大环卟啉的分子设计、合成及催化性能研究

Porphyrins are one class of the tetrapyrrolic multifunctional complexes which have unique photochemical, electrochemical, photophysical and photobiological properties, and they have wide potential applications in the fields of biopharmaceuticals, catalysts and novel functional materials. Modification or extending of porphyrin macrocycle may efficiently tune and controll properties of the compound. Therefore, the benzo-extended porphyrin complexes are able to have more significant substitution effects and larger conjugate systems, and lead to stronger pi-pi interactions between the conjugated macrocycles. The catalytic activity could be efficiently increased if they are utilized as catalysts for the electrocatalytic reduction of oxygen. This project is going to design and synthesize three series of novel porphyrins which contain benzo-groups on the beta-positions and have iron, cobalt and manganese as central metal ions of the compound. The structure of the novel porphyrins will be characterized and the properties will be studied using various spectral and electrochemical techniques. The effect of extended benzo-structure, the substituent and the central metal ion of the porphyrin on the catalytic activity for reduction of molecular oxygen will be examined systematically. The properties of the porphyrins for catalyzing oxygen reduction will be examined emphatically and the catalytic mechanism will also be proposed. The relationship between the structure and electrocatalytic efficiency will be revealed, which could provide a theoretical basis for practical application of the porphyrins.

卟啉是一类具有独特的光化学、电化学、光物理和光生物性质，在生物制药、催化剂、新型功能材料等领域都有着广泛应用前景的四吡咯多功能大环配合物。对卟啉大环进行修饰或拓展能够有效地调控配合物的性质，因此苯并拓展卟啉可能具有更强的取代基效应和更大的共轭体系，并使其共轭大环分子间存在更强的pi-pi相互作用,若利用它们作为氧气还原的催化剂将可能更有效地提高催化效率。本项目拟设计合成三个系列创新的在分子大环的beta-位上具有苯并拓展结构、分别含有铁、钴或锰为中心金属离子的卟啉配合物,用多种光谱及电化学技术对它们进行结构表征和性质研究；系统研究苯并拓展大环结构对卟啉配合物的光谱和电化学性质以及电催化还原氧气性能的影响；着重研究探讨创新卟啉配合物用于电催化还原氧气的特性以及相应机理，揭示该类卟啉配合物的结构与催化效能的相关性，为该类配合物的实际应用提供理论基础。

苯并拓展卟啉是一类在卟啉beta-位上具有苯并结构，因而具有更强的取代基效应又具有更大的拓展共轭体系的新型卟啉配合物。本课题围绕项目的研究目标，开展了苯并拓展卟啉配合物的合成、光谱、电化学及电催化性质表征的研究工作。首先，根据特定的目标产物优化合成路线，分离提纯得到了两个系列创新的分子大环beta-位上具有环己烷并和苯并拓展结构、分别含有锌、铁、钴或锰的中心金属离子的拓展卟啉配合物；采用电化学、光谱电化学等方法测定了该类配合物在多种非水溶剂中的氧化还原性质，发现中心金属离子种类、取代基种类、溶剂效应和大环结构对拓展卟啉氧化还原能力有显著影响；最后，采用旋转盘电极和旋转环盘电极技术测定了部分卟啉配合物催化还原氧气性质，探讨配合物的催化机理及结构与催化性能的关系，研究证实，苯并卟啉配合物因其更大的共轭体系比非拓展卟啉配合物有更优良的催化性能，该研究为苯并拓展卟啉的合成和应用提供了重要理论基础。