Characterization and Catalytic Activity of Covalently Linked Bipyridyl Ruthenium OXO Dimers

Petach, Helen H.; Elliott, C. Michael

doi:10.1149/1.2221205

Cited by 33 publications

(38 citation statements)

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“…The slow step in this process is the oxidation of A number of blue-dimer analogues have been reported based on the RuÀOÀRu framework and using different polypyridylic type of ligands. [23] Their redox and catalytic properties are described in a recent Review [24] and thus will not be further discussed herein.…”

Section: The Blue Dimermentioning

confidence: 99%

Molecular Catalysts that Oxidize Water to Dioxygen

et al. 2009

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During the past four years we have witnessed a revolution in the field of water-oxidation catalysis, in which well-defined molecules are opening up entirely new possibilities for the design of more rugged and efficient catalysts. This revolution has been stimulated by two factors: the urgent need for clean and renewable fuel and the intrinsic human desire to mimic nature's reactions, in this case the oxygen-evolving complex (OEC) of the photosystem II (PSII). Herein we give a short general overview of the established basis for the oxidation of water to dioxygen as well as presenting the new developments in the field. Furthermore, we describe the new avenues these developments are opening up with regard to catalyst design and performance, together with the new questions they pose, especially from a mechanistic perspective. Finally the challenges the field is facing are also discussed.

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Section: The Blue Dimermentioning

confidence: 99%

Molecular Catalysts that Oxidize Water to Dioxygen

et al. 2009

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“…Only a few reports describe molecular catalysts that are oxidized by direct electron transfer at an electrode surface and then go on to catalyze water oxidation in homogeneous solution. 49 Catalysis in these systems is limited by diffusion of the catalyst to the electrode and the efficiency of the electron transfer between the catalysts and the electrode. To overcome these limitations, and optimize the catalytic effect, one therefore needs to immobilize the catalyst at the electrode surface.…”

Section: Molecular Catalysts For Photoelectrochemical Cellsmentioning

confidence: 99%

Molecular water-oxidation catalysts for photoelectrochemical cells

et al. 2009

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Photoelectrochemical cells that efficiently split water into oxygen and hydrogen, "the fuel of the future", need to combine robust water oxidation catalysts at the anode (2H(2)O -> O-2 + 4H(+) + 4e(-)) with hydrogen reduction catalysts at the cathode (2H(+) + 2e(-) -> H-2). Both sets of catalysts will, ideally, operate at low overpotentials and employ light-driven or light-assisted processes. In this Perspective article, we focus on significant efforts to develop solid state materials and molecular coordination complexes as catalyst for water oxidation. We briefly review the field with emphasis on the various molecular catalysts that have been developed and then examine the activity of molecular catalysts in water oxidation following their attachment to conducting electrodes. For such molecular species to be useful in a solar water-splitting device it is preferable that they are securely and durably affixed to an electrode surface. We also consider recent developments aimed at combining the action of molecular catalysts with light absorption so that light driven water oxidation may be achieved. Photoelectrochemical cells that efficiently split water into oxygen and hydrogen, "the fuel of the future", need to combine robust water oxidation catalysts at the anode (2H 2 O → O 2 + 4H + + 4e -) with hydrogen reduction catalysts at the cathode (2H + + 2e -→ H 2 ). Both sets of catalysts will, ideally, operate at low overpotentials and employ light-driven or light-assisted processes. In this Perspective article, we focus on significant efforts to develop solid state materials and molecular coordination complexes as catalyst for water oxidation. We briefly review the field with emphasis on the various molecular catalysts that have been developed and then examine the activity of molecular catalysts in water oxidation following their attachment to conducting electrodes. For such molecular species to be useful in a solar water-splitting device it is preferable that they are securely and durably affixed to an electrode surface. We also consider recent developments aimed at combining the action of molecular catalysts with light absorption so that light driven water oxidation may be achieved.

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“…5 An elegant attempt was made to stabilize the complex by using two bipyridines linked at the 4 position with a polymethylene bridge. 6 It was expected that if the oxo bridge broke during the water oxidation process, the remaining bridge between the bpy moieties would entropically favor re-formation of the critical oxo linkage. No remarkable improvement in the activity was observed for this linked catalyst.…”

Section: Introductionmentioning

confidence: 99%

“…The addition of NH 4 PF 6 (105 mg, 0.64 mmol) to the aqueous solution produced a precipitate, which was collected, washed with H 2 O, and dried. Chromatography on alumina, eluting with acetone, followed by a mixture of saturated aqueous KPF 6 and acetone (2:100), gave [Ru(23)(pic) 2 (H 2 O)](PF 6 ) 2 as a solid (71 mg, 55%). 1 H NMR (acetone-d 6 ): δ 9.89 (s, 1 H), 9.14 (d, J ) 8.…”

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confidence: 99%

Mononuclear Ruthenium(II) Complexes That Catalyze Water Oxidation

et al. 2008

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Two series of mononuclear ruthenium(II) complexes involving polypyridine-type ligands have been prepared, and their ability to act as catalysts for water oxidation has been examined. One series is of the type [Ru(tpy)(NN)Cl](PF(6)) (tpy = 2,2'; 6,2''-terpyridine), where NN is one of 12 different bidentate ligands, and the other series includes various combinations of 4-picoline, 2,2'-bipyridine (bpy), and tpy as well as the tetradentate 2,9-dipyrid-2'-yl-1,10-phenanthroline (dpp). The electronic absorption and redox data for these compounds have been measured and reported. The long-wavelength metal-to-ligand charge-transfer absorption and the first oxidation and reduction potentials are found to be consistent with the structure of the complex. Of the 23 complexes, 14 catalyze water oxidation and all of these contain a tpy or dpp. Kinetic measurements indicate a first-order reaction and together with a catalyst recovery experiment argue against the involvement of RuO(2). A tentative mechanism is proposed that involves a seven-coordinate Ru(VI)=O species that is attacked by water to form the critical O-O bond. Density functional theory calculations, which support the proposed mechanism, are performed.

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Characterization and Catalytic Activity of Covalently Linked Bipyridyl Ruthenium OXO Dimers

Cited by 33 publications

References 1 publication

Molecular Catalysts that Oxidize Water to Dioxygen

Molecular Catalysts that Oxidize Water to Dioxygen

Molecular water-oxidation catalysts for photoelectrochemical cells

Mononuclear Ruthenium(II) Complexes That Catalyze Water Oxidation

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