New multinuclear metal catalysts for the light-driven activation of water and reduction of CO2

首先，合成了水和一氧化碳活化型杂寡核金属有机化合物。研究了它们的(光)催化性能，并优化了反应条件。在已有经验的基础上，将合成用于生产氢气和氧气(氢燃料电池燃料)以及CO或HCOOH的新型优化催化剂。在这些体系中，光活性单元与催化活性单元的连接起着主要作用。良好的定向光电子转移(PET)能够在这些光催化剂上提供所需的电子当量或空穴。氧化离子氧化为O2及其返回反应(O2为H2O或H2O2)将分别被研究，特别是对于Hangman和Pacman类型的化合物。取代基和催化金属中心的具体引入将决定反应的方向。一方面采用Ru多吡啶化合物作为催化活性单元，另一方面采用高价锰和铁卟啉作为催化活性单元。对还原过程的研究，特别是对二氧化碳的光激活还原的研究，将使用超分子化合物进行。扩展的卟啉大环起到桥联配体的作用，其排列方式是将捕捉光能的光活性中心与催化活性金属中心连接在一起。通过研究光、pH值、取代基和其他参数对计划中的有机转化的可控性，可以得到精确的产物选择性。此外，应通过对活性中间体的分离和表征来提供对流逝过程和机理的新见解。

First hetero-oligonuclear metal-organic compounds for the activation of water and carbon monoxide have been prepared. Their (photo)catalytic properties are currently investigated and reaction conditions are optimized. With the experiences gained new optimized catalysts for the production of hydrogen and oxygen (hydrogen fuel cell fuels) as well as CO or HCOOH as C1 building blocks shall be synthesized. In those systems, the connection of a photoactive unit with a catalytic active unit plays a major role. A well-directed photo-electron-transfer (PET) enables the provision of the required electron equivalents or holes in these photo-catalysts.The oxidation of oxid-ions to O2 and its backreaction (O2 to H2O or H2O2), respectively, are to be investigated especially with compounds of the Hangman- and Pacman-type. The specific introduction of substituents and catalytic metal center will determine the direction of the reaction. On the one hand, ruthenium polypyridyl compounds and on the other hand high-valent manganese and iron porphyrinoids shall be employed as catalytic active unit. Studies on reduction processes, especially the light-activated reduction of CO2, are to happen using supramolecular compounds. Extended porphyrinic macrocycles function as a bridging ligand and are arranged in a way to connect a photoactive center capturing light energy with a catalytic active metal center.The investigation of the controllability of the planned organic transformations by light, pH value, substituents and other parameters is supposed to lead to a precise product selectivity. Additionally, new insights into the elapsing processes and mechanisms shall be provided by isolation and characterization of reactive intermediates.