Liu Tianqi, Zhan Shaoqi, Zhang Biaobiao, Wang Linqin, Shen Nannan, Ahlquist Mårten S G, Fan Xiaolei, Sun Licheng
Department of Chemistry, School of Engineering Sciences in Chemistry Biotechnology and Health, KTH Royal Institute of Technology, 10044 Stockholm, Sweden.
Institute of Wenzhou, Zhejiang University, 325006 Wenzhou, China.
Inorg Chem. 2024 Sep 2;63(35):16161-16166. doi: 10.1021/acs.inorgchem.4c01560. Epub 2024 Aug 18.
Despite extensive research on water oxidation catalysts over the past few decades, the relationship between high-valent metal-oxo intermediates and the O-O bond formation pathway has not been well clarified. Our previous study showed that the high spin density on O in Ru=O is pivotal for the interaction of two metal-oxyl radical (I2M) pathways. In this study, we found that introducing an axially coordinating ligand, which is favorable for bimolecular coupling, into the Ru-pda catalyst can rearrange its geometry. The shifts in geometric orientation altered its O-O bond formation pathway from water nucleophilic attack (WNA) to I2M, resulting in a 70-fold increase in water oxidation activity. This implies that the I2M pathway is concurrently influenced by the spin density on oxo and the geometry organization of the catalysts. The observed mechanistic switch and theoretical studies provide insights into controlling reaction pathways for homogeneous water oxidation catalysis.
尽管在过去几十年里对水氧化催化剂进行了广泛研究，但高价金属-氧中间体与O-O键形成途径之间的关系尚未得到很好的阐明。我们之前的研究表明，Ru=O中O上的高自旋密度对于两条金属-氧自由基（I2M）途径的相互作用至关重要。在本研究中，我们发现将有利于双分子偶联的轴向配位配体引入Ru-pda催化剂中可以重新排列其几何结构。几何取向的改变使其O-O键形成途径从水亲核攻击（WNA）转变为I2M，导致水氧化活性提高了70倍。这意味着I2M途径同时受到氧上自旋密度和催化剂几何结构的影响。观察到的机理转变和理论研究为控制均相水氧化催化的反应途径提供了见解。
