Switching O—O bond formation mechanism between WNA and I2M pathways by modifying the Ru-bda backbone ligands of water-oxidation catalysts

• 作者: Biaobiao Zhang Shaoqi Zhan Tianqi Liu Linqin Wang A.Ken Inge Lele Duan Brian J.J.Timmer Oleksandr Kravchenko Fei Li M?rten S.G.Ahlquist Licheng Sun
• 来源期刊: 能源化学
• 年，卷（期）: 2021,（3）
• 页码范围: 815-821
• 页数: 7页
• 语种: 英文

摘要

Understanding the seven coordination and 0—O coupling pathway of the distinguished Ru-bda catalysts is essential for the development of next generation efficient water-oxidation catalysts based on earth-abundant metals.This work reports the synthesis,characterization and catalytic properties of a mono-meric ruthenium catalyst Ru-bnda(H2bnda = 2,2'-bi(nicotinic acid)-6,6'-dicarboxylic acid)featuring steric hindrance and enhanced hydrophilicity on the backbone.Combining experimental evidence with systematic density functional theory calculations on the Ru-bnda and related catalysts Ru-bda(H2bda = 2,2'-bipyridine-6,6'-dicarboxylic acid),Ru-pda(H2pda = 1,10-phenanthroline-2,9-dicarboxylic acid),and Ru-biqa(H2biqa =(1,1'-biisoquinoline)-3,3'-dicarboxylic acid),we emphasized that seven coor-dination clearly determines presence of Ruv=O with high spin density on the ORuV=o atom,i.e.oxo with radical properties,which is one of the necessary conditions for reacting through the O—O coupling path-way.However,an additional factor to make the condition sufficient is the favorable intermolecular face-to-face interaction for the generation of the pre-reactive[Ruv=O…O=Ruv],which may be significantly influenced by the secondary coordination environments.This work provides a new understanding of the structure-activity relationship of water-oxidation catalysts and their potential to adopt I2M pathway for O—O bond formation.