scholarly journals New insights in Mn–Ca chemistry from the use of oximate-based ligands: {MnII/III22Ca2} and {MnIV2Ca2} complexes with relevance to both low- and high-valent states of the oxygen-evolving complex

Polyhedron ◽  
2018 ◽  
Vol 149 ◽  
pp. 39-44 ◽  
Author(s):  
Alysha A. Alaimo ◽  
Dimitris I. Alexandropoulos ◽  
Christos Lampropoulos ◽  
Theocharis C. Stamatatos
Keyword(s):  
Oxygen Evolving Complex ◽  
High Valent ◽  
Oxygen Evolving

New Linear High-Valent Tetranuclear Manganese-Oxo Cluster Relevant to the Oxygen-Evolving Complex of Photosystem II with Oxo, Hydroxo, and Aqua Coordinated to a Single Mn(IV)

2005 ◽  
Vol 44 (25) ◽  
pp. 9567-9573 ◽  
Author(s):  
Chen ◽  
Marie-Noëlle Collomb ◽  
Carole Duboc ◽  
Geneviève Blondin ◽  
Eric Rivière ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Oxygen Evolving Complex ◽  
High Valent ◽  
Oxygen Evolving

scholarly journals Preparation and properties of an MnIV–hydroxide complex: proton and electron transfer at a mononuclear manganese site and its relationship to the oxygen evolving complex within photosystem II

2014 ◽  
Vol 5 (8) ◽  
pp. 3064-3071 ◽  
Author(s):  
Taketo Taguchi ◽  
Kari L. Stone ◽  
Rupal Gupta ◽  
Benedikt Kaiser-Lassalle ◽  
Junko Yano ◽  
...  
Keyword(s):  
Electron Transfer ◽  
Photosystem Ii ◽  
Oxygen Evolving Complex ◽  
High Valent ◽  
Oxygen Evolving

Preparation of new MnIV–OH complex leads to insights into the steps needed to produce high valent Mn–ox species.

scholarly journals A ligand field chemistry of oxygen generation by the oxygen-evolving complex and synthetic active sites

2007 ◽  
Vol 363 (1494) ◽  
pp. 1293-1303 ◽  
Author(s):  
Theodore A Betley ◽  
Yogesh Surendranath ◽  
Montana V Childress ◽  
Glen E Alliger ◽  
Ross Fu ◽  
...  
Keyword(s):  
Water Oxidation ◽  
Active Sites ◽  
Ligand Field ◽  
Oxygen Evolving Complex ◽  
Oxygen Generation ◽  
Bond Forming ◽  
Oxygen Oxygen ◽  
Functional Models ◽  
High Valent ◽  
Oxygen Evolving

Oxygen–oxygen bond formation and O 2 generation occur from the S 4 state of the oxygen-evolving complex (OEC). Several mechanistic possibilities have been proposed for water oxidation, depending on the formal oxidation state of the Mn atoms. All fall under two general classifications: the AB mechanism in which nucleophilic oxygen (base, B) attacks electrophilic oxygen (acid, A) of the Mn 4 Ca cluster or the RC mechanism in which radical-like oxygen species couple within OEC. The critical intermediate in either mechanism involves a metal oxo, though the nature of this oxo for AB and RC mechanisms is disparate. In the case of the AB mechanism, assembly of an even-electron count, high-valent metal-oxo proximate to a hydroxide is needed whereas, in an RC mechanism, two odd-electron count, high-valent metal oxos are required. Thus the two mechanisms give rise to very different design criteria for functional models of the OEC active site. This discussion presents the electron counts and ligand geometries that support metal oxos for AB and RC O–O bond-forming reactions. The construction of architectures that bring two oxygen functionalities together under the purview of the AB and RC scenarios are described.

scholarly journals Structural Changes in the Acceptor Site of Photosystem II upon Ca2+/Sr2+ Exchange in the Mn4CaO5 Cluster Site and the Possible Long-Range Interactions

Biomolecules ◽  
2019 ◽  
Vol 9 (8) ◽  
pp. 371
Author(s):  
Koua
Keyword(s):  
Crystal Structure ◽  
Photosystem Ii ◽  
Long Range ◽  
Electron Acceptor ◽  
Structural Changes ◽  
Acceptor Site ◽  
Oxygen Evolving Complex ◽  
Long Range Interactions ◽  
Structural Perturbations ◽  
Oxygen Evolving

The Mn4CaO5 cluster site in the oxygen-evolving complex (OEC) of photosystem II (PSII) undergoes structural perturbations, such as those induced by Ca2+/Sr2+ exchanges or Ca/Mn removal. These changes have been known to induce long-range positive shifts (between +30 and +150 mV) in the redox potential of the primary quinone electron acceptor plastoquinone A (QA), which is located 40 Å from the OEC. To further investigate these effects, we reanalyzed the crystal structure of Sr-PSII resolved at 2.1 Å and compared it with the native Ca-PSII resolved at 1.9 Å. Here, we focus on the acceptor site and report the possible long-range interactions between the donor, Mn4Ca(Sr)O5 cluster, and acceptor sites.

scholarly journals CaMn3IVO4 Cubane Models of the Oxygen Evolving Complex: Spin Ground States S < 9/2 and the Effect of Oxo Protonation

2021 ◽  
Author(s):  
Heui Beom Lee ◽  
Angela A Shiau ◽  
David Marchiori ◽  
Paul H Oyala ◽  
BYUNG-KUK Yoo ◽  
...  
Keyword(s):  
Ground States ◽  
Oxygen Evolving Complex ◽  
Complex Spin ◽  
Oxygen Evolving
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