Multinuclear transition metal compounds

本论文的主要工作包括两个方面：（1）光系统II（PSII）中放氧中心（OEC）的模拟研究;（2）多功能小分子催化剂的开发。(1)OEC建模：大自然利用太阳能在绿色植物和藻类中将水转化为氧气，供应全世界。这种光化学水氧化过程发生在PSII的OEC。最近的PSII的晶体结构测定揭示了OEC的结构作为一个不对称的锰簇与钙离子作为辅助因子。我们正在寻找合成模型化合物，在结构和功能上都非常相似的OEC，以探索氧气释放过程的机制。从这项研究中获得的信息将有助于设计高效的光化学水分解系统，为世界提供清洁，轻质和高能量的燃料-氢气。(2)多功能催化剂：由于开发用于有效利用烃资源的方法的重要性，烷烃活化和官能化继续是现代化学中的重要领域。小分子如双氧、双氮、一氧化碳和二氧化碳的受控活化是一个激烈的研究领域，其最终目标是受控的基于双氧的氧化、碳循环和固氮。自然界已经开发出酶，在相对温和的条件下有效地完成这些工作，这是由于酶活性位点上多组分之间的协同作用。我们的目标是向大自然学习，设计多功能化合物，通过每个亚基的协同作用，结合烷烃功能化催化小分子活化。这项研究可能会导致新的催化系统，比传统的单功能系统更有效。

The proposed work consists of two aspects: (1) modeling of the oxygen evolving center (OEC) in photosystemII (PSII), and (2) developing multifunctional catalysts for small molecule activation. (1) OEC Modeling: Nature uses solar energy to convert water into oxygen gas in green plants and algae to supply the whole world. This photochemical water oxidation process occurs at the OEC in PSII. A recent crystal structure determination of PSII revealed the structure of the OEC as a asymmetric manganese cluster with a calcium ion as a cofactor. We are looking to synthesize model compounds that closely resemble the OEC both structurally and functionally, in order to probe the mechanism of the oxygen evolving process. Information gained from this research will help design efficient photochemical water-splitting system to support the world with a clean, light and high energy fuel --hydrogen gas. (2) Multifunctional Catalyst: Due to the importance of developing processes for the efficient utilization of hydrocarbon resources, alkane activation and functionalization continue to be an important area in modern chemistry. The controlled activation of small molecules, such as dioxygen, dinitrogen, carbon monoxide, and carbon dioxide, is an intense area of study with the ultimate goals of controlled dioxygen-based oxidation, carbon recycling, and nitrogen fixation. Again nature has developed enzymes to do these jobs efficiently under relatively mild conditions, owning to the cooperative actions between multi-components at the active sites of enzymes. Our goal is to learn from Nature and design multi-functional compounds to catalyze small molecule activation in combination with alkane functionalization through the cooperative action of each subunit. This research may lead to new catalytic systems that are more efficient than the conventional mono-functional systems.