Mechanism of H+ dissociation–induced O–O bond formation via intramolecular coupling of vicinal hydroxo ligands on low-valent Ru(III) centers

2021 ◽  
Vol 118 (52) ◽  
pp. e2113910118
Author(s):  
Yuki Tanahashi ◽  
Kosuke Takahashi ◽  
Yuta Tsubonouchi ◽  
Shunsuke Nozawa ◽  
Shin-ichi Adachi ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Water Oxidation ◽  
Artificial Photosynthesis ◽  
Bond Formation ◽  
Chemical Oxidation ◽  
Intersystem Crossing ◽  
The Core ◽  
Mechanistic Insight ◽  
Low Valent ◽  
Insight Into

The understanding of O–O bond formation is of great importance for revealing the mechanism of water oxidation in photosynthesis and for developing efficient catalysts for water oxidation in artificial photosynthesis. The chemical oxidation of the RuII2(OH)(OH2) core with the vicinal OH and OH2 ligands was spectroscopically and theoretically investigated to provide a mechanistic insight into the O–O bond formation in the core. We demonstrate O–O bond formation at the low-valent RuIII2(OH) core with the vicinal OH ligands to form the RuII2(μ-OOH) core with a μ-OOH bridge. The O–O bond formation is induced by deprotonation of one of the OH ligands of RuIII2(OH)2 via intramolecular coupling of the OH and deprotonated O− ligands, conjugated with two-electron transfer from two RuIII centers to their ligands. The intersystem crossing between singlet and triple states of RuII2(μ-OOH) is easily switched by exchange of H+ between the μ-OOH bridge and the auxiliary backbone ligand.

scholarly journals Mediator-assisted water oxidation by the ruthenium “blue dimer” cis,cis-[(bpy)2(H2O)RuORu(OH2)(bpy)2]4+

2008 ◽  
Vol 105 (46) ◽  
pp. 17632-17635 ◽  
Author(s):  
Javier J. Concepcion ◽  
Jonah W. Jurss ◽  
Joseph L. Templeton ◽  
Thomas J. Meyer
Keyword(s):  
Carbon Dioxide ◽  
Electron Transfer ◽  
Renewable Energy ◽  
Photosystem Ii ◽  
Water Splitting ◽  
Water Oxidation ◽  
Oxygenic Photosynthesis ◽  
Reduced Water ◽  
Insight Into ◽  
Recent Insight

Light-driven water oxidation occurs in oxygenic photosynthesis in photosystem II and provides redox equivalents directed to photosystem I, in which carbon dioxide is reduced. Water oxidation is also essential in artificial photosynthesis and solar fuel-forming reactions, such as water splitting into hydrogen and oxygen (2 H2O + 4 hν → O2 + 2 H2) or water reduction of CO2 to methanol (2 H2O + CO2 + 6 hν → CH3OH + 3/2 O2), or hydrocarbons, which could provide clean, renewable energy. The “blue ruthenium dimer,” cis,cis-[(bpy)2(H2O)RuIIIORuIII(OH2)(bpy)2]4+, was the first well characterized molecule to catalyze water oxidation. On the basis of recent insight into the mechanism, we have devised a strategy for enhancing catalytic rates by using kinetically facile electron-transfer mediators. Rate enhancements by factors of up to ≈30 have been obtained, and preliminary electrochemical experiments have demonstrated that mediator-assisted electrocatalytic water oxidation is also attainable.

A Mechanistic Insight into a Simple C−N Bond Formation via SN2 Displacement: A Synergistic Kinetics and Design of Experiment Approach

2010 ◽  
Vol 14 (6) ◽  
pp. 1364-1372 ◽  
Author(s):  
Luca Massari ◽  
Laura Panelli ◽  
Mark Hughes ◽  
Federica Stazi ◽  
William Maton ◽  
...  
Keyword(s):  
Design Of Experiment ◽  
Bond Formation ◽  
Mechanistic Insight ◽  
Insight Into

scholarly journals Mechanistic insight into proton-coupled mixed valency

2016 ◽  
Vol 52 (1) ◽  
pp. 100-103 ◽  
Author(s):  
Luke A. Wilkinson ◽  
Kevin B. Vincent ◽  
Anthony J. H. M. Meijer ◽  
Nathan J. Patmore
Keyword(s):  
Electron Transfer ◽  
Valence State ◽  
Mixed Valence ◽  
Bridging Ligands ◽  
Mixed Valency ◽  
Mixed Valence State ◽  
Mechanistic Insight ◽  
Insight Into

Stabilisation of the mixed-valence state in [Mo2(TiPB)3(HDOP)]2+ (HTiPB = 2,4,6-triisopropylbenzoic acid, H2DOP = 3,6-dihydroxypyridazine) by electron transfer (ET) is related to the proton coordinate of the bridging ligands.

Molecular ruthenium water oxidation catalysts carrying non-innocent ligands: mechanistic insight through structure–activity relationships and quantum chemical calculations

2016 ◽  
Vol 6 (5) ◽  
pp. 1306-1319 ◽  
Author(s):  
Markus D. Kärkäs ◽  
Rong-Zhen Liao ◽  
Tanja M. Laine ◽  
Torbjörn Åkermark ◽  
Shams Ghanem ◽  
...  
Keyword(s):  
Quantum Chemical Calculations ◽  
Water Oxidation ◽  
Quantum Chemical ◽  
Oxidation Catalysis ◽  
Oxidation Catalysts ◽  
Structure Activity Relationships ◽  
Structure Activity ◽  
Mechanistic Insight ◽  
Insight Into

Herein is highlighted how structure–activity relationships can be used to provide mechanistic insight into H2O oxidation catalysis.

scholarly journals Mechanisms of Photoisomerization and Water Oxidation Catalysis of Ruthenium(II) Aquo Complexes

2021 ◽  
Author(s):  
Yuta Tsubonouchi ◽  
Eman A. Mohamed ◽  
Zaki N. Zahran ◽  
Masayuki Yagi
Keyword(s):  
Physicochemical Properties ◽  
Water Oxidation ◽  
Recent Progress ◽  
Artificial Photosynthesis ◽  
Ruthenium Complexes ◽  
Oxidation Catalysis ◽  
Oxidation Catalysts ◽  
Water Oxidation Catalysis ◽  
Molecular Catalysts ◽  
Insight Into

Polypyridyl ruthenium(II) complexes have been widely researched as promising functional molecules. We have found unique photoisomerization reactions of polypyridyl ruthenium(II) aquo complexes. Recently we have attempted to provide insight into the mechanism of the photoisomerization of the complexes and distinguish between the distal−/proximal-isomers in their physicochemical properties and functions. Moreover, polypyridyl ruthenium(II) aquo complexes have been intensively studied as active water oxidation catalysts (WOCs) which are indispensable for artificial photosynthesis. The catalytic aspect and mechanism of water oxidation by the distal-/proximal-isomers of polypyridyl ruthenium(II) aquo complexes have been investigated to provide the guided thought to develop more efficient molecular catalysts for water oxidation. The recent progress on the photoisomerization and water oxidation of polypyridyl ruthenium(II) aquo complexes in our group are reviewed to understand the properties and functions of ruthenium complexes.

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