scholarly journals Chemical Probes for Water-Oxidation: Synthetic Manganese Complexes in Photoactivation of Water Splitting Complex and as Exogenous Electron Donors to Photosystem II

ENERGYO ◽  
2018 ◽  
Author(s):  
Gábor Bernát ◽  
Subhash Padhye ◽  
Csilla Barta ◽  
László Kovács ◽  
Sándor Demeter
Keyword(s):  
Photosystem Ii ◽  
Water Splitting ◽  
Water Oxidation ◽  
Electron Donors ◽  
Manganese Complexes ◽  
Chemical Probes

Chemical Probes for Water-Oxidation: Synthetic Manganese Complexes in Photoactivation of Water Splitting Complex and as Exogenous Electron Donors to Photosystem II

2001 ◽  
Vol 56 (9-10) ◽  
pp. 755-766 ◽  
Author(s):  
Gábor Bernát ◽  
Subhash Padhye ◽  
Csilla Barta ◽  
László Kovács ◽  
Sándor Demeter
Keyword(s):  
Water Splitting ◽  
Water Oxidation ◽  
Fluorescence Induction ◽  
Chlorophyll Fluorescence Induction ◽  
Manganese Complexes ◽  
Manganese Ions ◽  
Chemical Probes ◽  
Induction Kinetics ◽  
Fluorescence Induction Kinetics ◽  
Chlorophyll Fluorescence Induction Kinetics

AbstractPhotoactivation of the water splitting enzyme was performed with 13 different synthetic manganese complexes and characterized by oxygen evolution yield, thermoluminescence and chlorophyll fluorescence induction kinetics. The efficiency of different compounds in photoactivation correlated with the rate of linear electron transport in the presence of these com pounds. The organic ligands, associated with the manganese ions, do not prevent the photoactivation of the water splitting complex (WOC). Photoactivation with different manganese complexes depended on the number of the Mn-ions in the complex, their valence state and the nature of their donor atoms. The most efficient restorations were achieved by using tetram eric complexes having a dimer+dimer structure, complexes containing Mn(II) ions, and having 4-6 oxygen and 0-2 nitrogen atoms as donor atoms. Further, the effectiveness of photoactivation depended largely on the structure of the complexes. Our data support the notion that WOC in intact thylakoids requires the cooperation and well determined arrangement of all four manganese ions, and argue against the hypothesis that two manganese ions are sufficient for water splitting. Photoactivation by some complexes led to anomalous flashoxygen patterns, which are explained by a modified/perturbed water splitting complex.

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.

scholarly journals Towards Hydrogen Energy: Progress on Catalysts for Water Splitting

2012 ◽  
Vol 65 (6) ◽  
pp. 577 ◽  
Author(s):  
Gerhard F. Swiegers ◽  
Douglas R. MacFarlane ◽  
David L. Officer ◽  
Amy Ballantyne ◽  
Danijel Boskovic ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Water Splitting ◽  
Water Oxidation ◽  
Research Council ◽  
Hydrogen Energy ◽  
Energy Technology ◽  
Production Of Hydrogen ◽  
Centre Of Excellence ◽  
The University ◽  
Reduction Catalysts

This article reviews some of the recent work by fellows and associates of the Australian Research Council Centre of Excellence for Electromaterials Science (ACES) at Monash University and the University of Wollongong, as well as their collaborators, in the field of water oxidation and reduction catalysts. This work is focussed on the production of hydrogen for a hydrogen-based energy technology. Topics include: (1) the role and apparent relevance of the cubane-like structure of the Photosystem II Water Oxidation Complex (PSII-WOC) in non-biological homogeneous and heterogeneous water oxidation catalysts, (2) light-activated conducting polymer catalysts for both water oxidation and reduction, and (3) porphyrin-based light harvesters and catalysts.

Pivotal role of the redox-active tyrosine in driving the water splitting catalyzed by photosystem II

2020 ◽  
Vol 22 (1) ◽  
pp. 273-285 ◽  
Author(s):  
Shin Nakamura ◽  
Matteo Capone ◽  
Daniele Narzi ◽  
Leonardo Guidoni
Keyword(s):  
Hydrogen Bond ◽  
Photosystem Ii ◽  
Water Splitting ◽  
Oxidation State ◽  
Water Oxidation ◽  
Oxidation Catalysis ◽  
Pivotal Role ◽  
Redox Active ◽  
Water Oxidation Catalysis

TyrZ oxidation state triggers hydrogen bond modification in the water oxidation catalysis.

Defective ZnFe2O4 nanorods with oxygen vacancy for photoelectrochemical water splitting

Nanoscale ◽  
2015 ◽  
Vol 7 (45) ◽  
pp. 19144-19151 ◽  
Author(s):  
Ju Hun Kim ◽  
Youn Jeong Jang ◽  
Jin Hyun Kim ◽  
Ji-Wook Jang ◽  
Sun Hee Choi ◽  
...  
Keyword(s):  
Charge Transfer ◽  
Oxygen Vacancy ◽  
Water Splitting ◽  
Water Oxidation ◽  
Oxygen Vacancies ◽  
Electron Donors ◽  
Surface Trap ◽  
Oxidation Activity ◽  
Vacuum Atmosphere ◽  
Photoelectrochemical Water Oxidation

A 1D ZnFe2O4 photoanode is treated under a hydrogen or vacuum atmosphere to improve the photoelectrochemical water oxidation activity up to 20 times. This post-treatment creates oxygen vacancies in the ZnFe2O4 lattice that serve as a source of electron donors and passivates surface trap sites, and as a result improves charge transfer.

scholarly journals Binuclear Manganese(III) Complexes as Electron Donors in D1/D2/Cytochrome b 559 Preparations Isolated from Spinach Photosystem II Membrane Fragments

1994 ◽  
Vol 49 (9-10) ◽  
pp. 587-592 ◽  
Author(s):  
S. I. Allakhverdiev ◽  
M. S. Karacan ◽  
G. Somer ◽  
N. Karacan ◽  
E. M. Khan ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Cytochrome B ◽  
Turnover Rate ◽  
Electron Donors ◽  
Manganese Complexes ◽  
Anaerobic Conditions ◽  
Cytochrome B559 ◽  
Ps Ii ◽  
Actinic Light ◽  
Donor Capacity

Abstract The capability of different manganese complexes to act as PS II electron donors in D1/D2/ cytochrome b 559 complexes has been analyzed by measuring actinic light-induced absorption changes at 680 nm (650 nm) and 340 nm, reflecting the photoaccumulation of Pheophytin- (Pheo-) and the reduction of NADP+ respectively. The data obtained reveal: a) the donor capacity of synthetic binuclear Mn(III)2 complexes containing aromatic ligands significantly exceeds that for MnCl2 in both cases, i.e. Pheo- photoaccumulation and NADP+ reduction; b) manganese complexes can serve as suitable electron donors for light-induced NADP+ reduction catalyzed by D1/D2/cytochrome b559 complexes and ferredoxin plus ferredoxin- NADP+ reductase under anaerobic conditions and c) the specific turnover rate of the system leading to NADP+ reduction is extremely small.The implications of these findings are briefly discussed.

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