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Chen G, Chen ZW, Wang YM, He P, Liu C, Tong HX, Yi XY. Efficient Electrochemical Water Oxidation Mediated by Pyridylpyrrole-Carboxylate Ruthenium Complexes. Inorg Chem 2021; 60:15627-15634. [PMID: 34613720 DOI: 10.1021/acs.inorgchem.1c02251] [Citation(s) in RCA: 2] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/28/2022]
Abstract
Spurred by the rapid growth of Ru-based complexes as molecular water oxidation catalysts (WOCs), we propose novel ruthenium(II) complexes bearing pyridylpyrrole-carboxylate (H2ppc) ligands as members of the WOC family. The structure of these complexes has 4-picoline (pic)/dimethyl sulfoxide (DMSO) in [Ru(ppc)(pic)2(dmso)] and pic/pic in [Ru(ppc)(pic)3] as axial ligands. Another ppc2- ligand and one pic ligand are located at the equatorial positions. [Ru(ppc)(pic)2(dmso)] behaves as a WOC as determined by electrochemical measurement and has an ultrahigh electrocatalytic current density of 8.17 mA cm-2 at 1.55 V (vs NHE) with a low onset potential of 0.352 V (vs NHE), a turnover number of 241, a turnover frequency of 203.39 s-1, and kcat of 16.34 s-1 under neutral conditions. The H2O/pic exchange of the complexes accompanied by oxidation of a ruthenium center is the initial step in the catalytic cycle. The cyclic voltametric measurements of [Ru(ppc)(pic)2(dmso)] at various scan rates, Pourbaix diagrams (plots of E vs pH), and kinetic studies suggested a water nucleophilic attack mechanism. HPO42- in a phosphate buffer solution is invoked in water oxidation as the proton acceptor.
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Affiliation(s)
- Guo Chen
- College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Chemical Power Sources, Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, Central South University, Changsha, Hunan 410083, P. R. China
| | - Ze-Wen Chen
- College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Chemical Power Sources, Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, Central South University, Changsha, Hunan 410083, P. R. China
| | - Yuan-Mei Wang
- College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Chemical Power Sources, Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, Central South University, Changsha, Hunan 410083, P. R. China
| | - Piao He
- College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Chemical Power Sources, Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, Central South University, Changsha, Hunan 410083, P. R. China
| | - Chao Liu
- College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Chemical Power Sources, Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, Central South University, Changsha, Hunan 410083, P. R. China
| | - Hai-Xia Tong
- School of Chemistry and Food Engineering, Changsha University of Science and Technology, Changsha, Hunan 410114, P. R. China
| | - Xiao-Yi Yi
- College of Chemistry and Chemical Engineering, Hunan Provincial Key Laboratory of Chemical Power Sources, Hunan Provincial Key Laboratory of Efficient and Clean Utilization of Manganese Resources, Central South University, Changsha, Hunan 410083, P. R. China
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