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A molecular ruthenium catalyst with water-oxidation activity comparable to that of photosystem II



Across chemical disciplines, an interest in developing artificial water splitting to O2 and H2, driven by sunlight, has been motivated by the need for practical and environmentally friendly power generation without the consumption of fossil fuels. The central issue in light-driven water splitting is the efficiency of the water oxidation, which in the best-known catalysts falls short of the desired level by approximately two orders of magnitude. Here, we show that it is possible to close that ‘two orders of magnitude’ gap with a rationally designed molecular catalyst [Ru(bda)(isoq)2] (H2bda = 2,2′-bipyridine-6,6′-dicarboxylic acid; isoq = isoquinoline). This speeds up the water oxidation to an unprecedentedly high reaction rate with a turnover frequency of >300 s−1. This value is, for the first time, moderately comparable with the reaction rate of 100–400 s−1 of the oxygen-evolving complex of photosystem II in vivo.

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Figure 1: Catalytic performances of complexes 1 and 2 .
Figure 2: Kinetic and spectral data for complex 2 .
Figure 3
Figure 4: Calculated encounter complex EC(isoq) ([O1 · · · O2] = 3.22 Å).
Figure 5: Calculated potential energy profile of O–O bond formation combined with the reactions steps of the liberation of O2 from the RuIV-peroxo dimer.
Figure 6: Calculated transition state (TSoo(isoq); [O1−O2] = 2.038 Å) according to the potential energy scan from Fig. 5.


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This work was supported by the Swedish Research Council, K & A Wallenberg Foundation, the Swedish Energy Agency, the China Scholarship Council (CSC), the China Natural Science Foundation (21120102036), the National Basic Research Program of China (2009CB220009), MICINN (CTQ2010-21497 and Consolider Ingenio 2010 CSD2006-0003) Spain and the WCU Program (R31-10010) Korea.

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L.S. and A.L. supervised the project. T.P. supervised the theoretical part of the project. L.D. synthesized all the complexes and carried out the characterization, catalysis and electrochemistry. S.M. carried out the electrochemistry and mass measurements. F.B. performed stopped-flow UV–vis measurements. B.S. and T.P. performed DFT calculations. L.S., A.L., L.D. and T.P. wrote the paper.

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Correspondence to Timofei Privalov, Antoni Llobet or Licheng Sun.

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The authors declare no competing financial interests.

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Duan, L., Bozoglian, F., Mandal, S. et al. A molecular ruthenium catalyst with water-oxidation activity comparable to that of photosystem II. Nature Chem 4, 418–423 (2012).

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