A New Dinuclear Ruthenium Complex as Efficient Catalyst for Electrochemical and Chemical Water-oxidation

  • Mr Yunhua Xu, Department of Organic Chemistry, Royal Institute of Technology, 100 44 Stockholm, Sweden, Sweden
  • Miss Rong Zhang, State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116012, China, China
  • Prof Björn Åkermark, Department of Organic Chemistry, Arrhenius Laboratory, Stockholm University, 106 91 Stockholm, Sweden, Sweden
  • Prof Licheng Sun, Department of Organic Chemistry, Royal Institute of Technology, 100 44 Stockholm, Sweden, Sweden

    • A new dinuclear ruthenium complex as a bioinspired molecular catalyst for water oxidation has been synthesized and characterized. The complex was prepared by the reaction of Ru(DMSO)4Cl2 and the bis-tridentate ligand 3,6-bis(4,4´-dimethyl-2,2´-bipyridine-6-yl)pyridazine, and characterized by 1H and 13C NMR and high-resolution mass spectrometry (HRMS). Its electronic and electrochemical properties were studied by UV-Vis spectroscopy and cyclic voltammetry. The catalytic activity of this complex toward water oxidation was investigated by chemical and electrochemical methods, and the turnover number of this catalyst for water oxidation with Ce(IV) as chemical oxidant was found to be of the order of 103. In comparison with the one reported by Thummel et al.,[1] this new complex is structurally simpler but exhibits similar catalytic features. Moreover, the methyl groups in the bipyridine ligands offer possibilities to introduce other functional groups to the dinuclear ruthenium catalyst, for immobilization of the catalyst on electrode surface or coupling to a photosensitizer. Synthesis of new type ligands for dinuclear ruthenium complexes that can catalytically oxidize water at lower oxidation potential is in progress.
    [1] R. Zong and R. P. Thummel, J. Am. Chem. Soc. 2005, 127, 12802-12803.