Amphiphilic Oxo-Bridged Ruthenium "Green Dimer" for Water Oxidation

Qing-Qing Yang; Xin Jiang; Bing Yang; Yang Wang; Chen-Ho Tung; Li-Zhu Wu

doi:10.1016/j.isci.2020.100969

Amphiphilic Oxo-Bridged Ruthenium "Green Dimer" for Water Oxidation

iScience. 2020 Mar 27;23(3):100969. doi: 10.1016/j.isci.2020.100969. Epub 2020 Mar 8.

Authors

Qing-Qing Yang¹, Xin Jiang¹, Bing Yang¹, Yang Wang¹, Chen-Ho Tung¹, Li-Zhu Wu²

Affiliations

¹ Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, P. R. China; School of Future Technology, University of Chinese Academy of Sciences, Beijing 100190, P. R. China.
² Key Laboratory of Photochemical Conversion and Optoelectronic Materials, Technical Institute of Physics and Chemistry, The Chinese Academy of Sciences, Beijing 100190, P. R. China; School of Future Technology, University of Chinese Academy of Sciences, Beijing 100190, P. R. China. Electronic address: lzwu@mail.ipc.ac.cn.

Abstract

In 1982, an oxo-bridged dinuclear ruthenium(III) complex, known as "blue dimer," was discovered to be active for water oxidation. In this work, a new amphiphilic ruthenium "green dimer" 2, obtained from an amphiphilic mononuclear Ru(bda) (N-OTEG) (L1) (1; N-OTEG = 4-(2-(2-(2-methoxyethoxy)ethoxy)ethoxy)-pyridine; L1 = vinylpyridine) is reported. An array of mechanistic studies identifies "green dimer" 2 as a mixed valence of Ru^II-O-Ru^III oxo-bridged structure. Bearing the same bda^2- and amphiphilic axial ligands, monomer 1 and green dimer 2 can be reversibly converted by ascorbic acid and oxygen, respectively, in aqueous solution. More importantly, the oxo-bridged "green dimer" 2 was found to take water nucleophilic attack for oxygen evolution, in contrast to monomer 1 via radical coupling pathway for O-O bond formation. This is the first report of an amphiphilic oxo-bridged catalyst, which possesses a new oxygen evolution pathway of Ru-bda catalysts.

Keywords: Catalysis; Inorganic Chemistry; Materials Chemistry.