scholarly journals A Force Field for a Manganese-Vanadium Water Oxidation Catalyst: Redox Potentials in Solution as Showcase

Catalysts ◽  
2021 ◽  
Vol 11 (4) ◽  
pp. 493
Author(s):  
Gustavo Cárdenas ◽  
Philipp Marquetand ◽  
Sebastian Mai ◽  
Leticia González
Keyword(s):  
Force Field ◽  
Molecular Mechanics ◽  
Water Oxidation ◽  
Mixed Valence ◽  
Oxidation Catalyst ◽  
Synthetic Analogue ◽  
Oxygen Evolving Complex ◽  
Redox Potentials ◽  
Jahn Teller ◽  
Oxygen Evolving

We present a molecular mechanics force field in AMBER format for the mixed-valence manganese vanadium oxide cluster [Mn4V4O17(OAc)3]3−—a synthetic analogue of the oxygen-evolving complex that catalyzes the water oxidation reaction in photosystem II—with parameter sets for two different oxidation states. Most force field parameters involving metal atoms have been newly parametrized and the harmonic terms refined using hybrid quantum mechanics/molecular mechanics reference simulations, although some parameters were adapted from pre-existing force fields of vanadate cages and manganese oxo dimers. The characteristic Jahn–Teller distortions of d4 MnIII ions in octahedral environments are recovered by the force field. As an application, the developed parameters have been used to calculate the redox potential of the [MnIIIMn3IV] ⇌ [Mn4IV]+e− half-reaction in acetonitrile by means of Marcus theory.

scholarly journals Simulation of the isotropic EXAFS spectra for the S2 and S3 structures of the oxygen evolving complex in photosystem II

2015 ◽  
Vol 112 (13) ◽  
pp. 3979-3984 ◽  
Author(s):  
Xichen Li ◽  
Per E. M. Siegbahn ◽  
Ulf Ryde
Keyword(s):  
Photosystem Ii ◽  
Water Oxidation ◽  
Density Functional ◽  
Structural Changes ◽  
Complete Agreement ◽  
Oxygen Evolving Complex ◽  
Chemical Modeling ◽  
Oxygen Evolving ◽  
High Degree ◽  
Exafs Spectra

Most of the main features of water oxidation in photosystem II are now well understood, including the mechanism for O–O bond formation. For the intermediate S2 and S3 structures there is also nearly complete agreement between quantum chemical modeling and experiments. Given the present high degree of consensus for these structures, it is of high interest to go back to previous suggestions concerning what happens in the S2–S3 transition. Analyses of extended X-ray adsorption fine structure (EXAFS) experiments have indicated relatively large structural changes in this transition, with changes of distances sometimes larger than 0.3 Å and a change of topology. In contrast, our previous density functional theory (DFT)(B3LYP) calculations on a cluster model showed very small changes, less than 0.1 Å. It is here found that the DFT structures are also consistent with the EXAFS spectra for the S2 and S3 states within normal errors of DFT. The analysis suggests that there are severe problems in interpreting EXAFS spectra for these complicated systems.

scholarly journals Understanding Two Different Structures in the Dark Stable State of the Oxygen-Evolving Complex of Photosystem II: Applicability of the Jahn-Teller Deformation Formula

ChemPhotoChem ◽  
2017 ◽  
Vol 2 (3) ◽  
pp. 257-270 ◽  
Author(s):  
Mitsuo Shoji ◽  
Hiroshi Isobe ◽  
Ayako Tanaka ◽  
Yoshimasa Fukushima ◽  
Keisuke Kawakami ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Stable State ◽  
Oxygen Evolving Complex ◽  
Jahn Teller ◽  
Oxygen Evolving

scholarly journals Recent pulsed EPR studies of the Photosystem II oxygen-evolving complex: implications as to water oxidation mechanisms

2004 ◽  
Vol 1655 ◽  
pp. 158-171 ◽  
Author(s):  
R.David Britt ◽  
Kristy A Campbell ◽  
Jeffrey M Peloquin ◽  
M.Lane Gilchrist ◽  
Constantino P Aznar ◽  
...  
Keyword(s):  
Photosystem Ii ◽  
Water Oxidation ◽  
Oxygen Evolving Complex ◽  
Pulsed Epr ◽  
Oxygen Evolving ◽  
Oxidation Mechanisms

55Mn ESE-ENDOR of a Mixed Valence Mn(III)Mn(IV) Complex: Comparison with the Mn Cluster of the Photosynthetic Oxygen-Evolving Complex

1995 ◽  
Vol 117 (47) ◽  
pp. 11780-11789 ◽  
Author(s):  
David W. Randall ◽  
Bradley E. Sturgeon ◽  
James A. Ball ◽  
Gary A. Lorigan ◽  
Michael K. Chan ◽  
...  
Keyword(s):  
Mixed Valence ◽  
Oxygen Evolving Complex ◽  
Photosynthetic Oxygen ◽  
Mn Cluster ◽  
Oxygen Evolving

Quantum mechanics/molecular mechanics structural models of the oxygen-evolving complex of photosystem II

2007 ◽  
Vol 17 (2) ◽  
pp. 173-180 ◽  
Author(s):  
Eduardo M Sproviero ◽  
José A Gascón ◽  
James P McEvoy ◽  
Gary W Brudvig ◽  
Victor S Batista
Keyword(s):  
Quantum Mechanics ◽  
Photosystem Ii ◽  
Molecular Mechanics ◽  
Structural Models ◽  
Oxygen Evolving Complex ◽  
Oxygen Evolving

scholarly journals Using small molecule complexes to elucidate features of photosynthetic water oxidation

2007 ◽  
Vol 363 (1494) ◽  
pp. 1271-1281 ◽  
Author(s):  
Kristof Meelich ◽  
Curtis M Zaleski ◽  
Vincent L Pecoraro
Keyword(s):  
Water Oxidation ◽  
Spectroscopic Characterization ◽  
Structural Features ◽  
Oxygen Evolving Complex ◽  
Model Complexes ◽  
Small Model ◽  
Oxygen Evolving ◽  
Photosynthetic Water Oxidation ◽  
Insight Into

The molecular oxygen produced in photosynthesis is generated via water oxidation at a manganese–calcium cluster called the oxygen-evolving complex (OEC). While studies in biophysics, biochemistry, and structural and molecular biology are well known to provide deeper insight into the structure and workings of this system, it is often less appreciated that biomimetic modelling provides the foundation for interpreting photosynthetic reactions. The synthesis and characterization of small model complexes, which either mimic structural features of the OEC or are capable of providing insight into the mechanism of O 2 evolution, have become a vital contributor to this scientific field. Our group has contributed to these findings in recent years through synthesis of model complexes, spectroscopic characterization of these systems and probing the reactivity in the context of water oxidation. In this article we describe how models have made significant contributions ranging from understanding the structure of the water-oxidation centre (e.g. contributions to defining a tetrameric Mn 3 Ca-cluster with a dangler Mn) to the ability to discriminate between different mechanistic proposals (e.g. showing that the Babcock scheme for water oxidation is unlikely).

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