Aqueous Chemistry of High-Valent Manganese. Structure, Magnetic, and Redox Properties of a New Type of Mn-Oxo Cluster, [Mn4IVO4(bpy)6]4+: Relevance to the Oxygen Evolving Center in Plants

1994 ◽  
Vol 116 (19) ◽  
pp. 8557-8565 ◽  
Author(s):  
Christian Philouze ◽  
Genevieve Blondin ◽  
Jean-Jacques Girerd ◽  
Jean Guilhem ◽  
Claudine Pascard ◽  
...  
Keyword(s):  
Redox Properties ◽  
Aqueous Chemistry ◽  
New Type ◽  
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

A new type of composite MOFs based on high-valent Sb(v)-based units and cuprous-halide clusters

2019 ◽  
Vol 55 (100) ◽  
pp. 15113-15116 ◽  
Author(s):  
Li-Dan Lin ◽  
Zhong Li ◽  
Jin-Hua Liu ◽  
Yan-Qiong Sun ◽  
Xin-Xiong Li ◽  
...  
Keyword(s):  
New Class ◽  
New Type ◽  
High Valent ◽  
First Time

In this work, an unusual high-valent Sb(v)-based [SbL2]− unit was developed for the first time to combine with various cuprous-halide clusters for the construction of a brand-new class of heterometallic MOFs.

scholarly journals In situ characterization of cofacial Co(IV) centers in Co4O4 cubane: Modeling the high-valent active site in oxygen-evolving catalysts

2017 ◽  
Vol 114 (15) ◽  
pp. 3855-3860 ◽  
Author(s):  
Casey N. Brodsky ◽  
Ryan G. Hadt ◽  
Dugan Hayes ◽  
Benjamin J. Reinhart ◽  
Nancy Li ◽  
...  
Keyword(s):  
Electronic Structure ◽  
Active Site ◽  
Resting State ◽  
Structural Model ◽  
Reorganization Energy ◽  
Electrochemical Kinetics ◽  
Absorption Data ◽  
High Valent ◽  
Oxygen Evolving

The Co4O4 cubane is a representative structural model of oxidic cobalt oxygen-evolving catalysts (Co-OECs). The Co-OECs are active when residing at two oxidation levels above an all-Co(III) resting state. This doubly oxidized Co(IV)2 state may be captured in a Co(III)2(IV)2 cubane. We demonstrate that the Co(III)2(IV)2 cubane may be electrochemically generated and the electronic properties of this unique high-valent state may be probed by in situ spectroscopy. Intervalence charge-transfer (IVCT) bands in the near-IR are observed for the Co(III)2(IV)2 cubane, and spectroscopic analysis together with electrochemical kinetics measurements reveal a larger reorganization energy and a smaller electron transfer rate constant for the doubly versus singly oxidized cubane. Spectroelectrochemical X-ray absorption data further reveal systematic spectral changes with successive oxidations from the cubane resting state. Electronic structure calculations correlated to experimental data suggest that this state is best represented as a localized, antiferromagnetically coupled Co(IV)2 dimer. The exchange coupling in the cofacial Co(IV)2 site allows for parallels to be drawn between the electronic structure of the Co4O4 cubane model system and the high-valent active site of the Co-OEC, with specific emphasis on the manifestation of a doubly oxidized Co(IV)2 center on O–O bond formation.

A new type of Mn-O cluster with a Mn4 chain unit. Relevance to the photosynthetic oxygen evolving center

1993 ◽  
Vol 51 (1-2) ◽  
pp. 282
Author(s):  
C. Philouze ◽  
G. Blondin ◽  
J.-J. Girerd ◽  
J. Guilhem ◽  
C. Pascard ◽  
...  
Keyword(s):  
Chain Unit ◽  
New Type ◽  
Photosynthetic Oxygen ◽  
Oxygen Evolving

Synthesis and non-linear optical and redox properties of 6-nitro-6′-piperidyl-2,2′-bisbenzothiazole: a new type of push–pull molecules

Tetrahedron ◽  
2004 ◽  
Vol 60 (2) ◽  
pp. 285-289 ◽  
Author(s):  
Francisco López-Calahorra ◽  
Mariano Martı́nez-Rubio ◽  
Dolores Velasco ◽  
Enric Brillas ◽  
Lluı́s Julià
Keyword(s):  
Redox Properties ◽  
Non Linear ◽  
New Type ◽  
Linear Optical

Thermodynamic characterization of the redox centres in a representative domain of a novel c-type multihaem cytochrome

2009 ◽  
Vol 420 (3) ◽  
pp. 485-492 ◽  
Author(s):  
Leonor Morgado ◽  
Ana P. Fernandes ◽  
Yuri Y. Londer ◽  
P. Raj Pokkuluri ◽  
Marianne Schiffer ◽  
...  
Keyword(s):  
Dominant Role ◽  
Redox Properties ◽  
Geobacter Sulfurreducens ◽  
Thermodynamic Characterization ◽  
Reduction Potentials ◽  
New Type ◽  
Uv Visible ◽  
Cytochrome C7 ◽  
The Individual

Multihaem cytochromes that could form protein “nanowires” were identified in the Geobacter sulfurreducens genome, and represent a new type of multihaem cytochrome. The sequences of these proteins, two with 12 haems (GSU1996, GSU0592) and one with 27 haems (GSU2210), suggest that they are formed with domains homologous to the trihaem cytochrome c7. Although all three haems have bis-His co-ordination in cytochromes c7, in each domain of the above polymers, the haem equivalent to haem IV has His-Met co-ordination. We previously determined the structure and measured the macroscopic redox potential of one representative domain (domain C) of a dodecahaem cytochrome (GSU1996). In the present study, the microscopic redox properties of the individual haem groups of domain C were determined using NMR and UV–visible spectroscopies. The reduction potentials of the haems for the fully reduced and protonated protein are different from each other (haem I, −106 mV; haem III, −136 mV; and haem IV, −125 mV) and are strongly modulated by redox interactions. This result is rather surprising since the His-Met co-ordinated haem IV does not have the highest potential as was expected. The polypeptide environment of each haem group and the strong haem pairwise redox interactions must play a dominant role in controlling the individual haem potentials. The strong redox interactions between the haems extend the range of their operating potentials at physiological pH (haem I, −71 mV, haem III, −146 mV and haem IV, −110 mV). Such a modulation in haem potentials is likely to have a functional significance in the metabolism of G. sulfurreducens.

scholarly journals Modeling Magnetic Interactions in High-Valent Trinuclear [Mn(IV)3O4]^4+ Complexes Through Highly Compressed Multi-Configurational Wave Functions

2021 ◽  
Author(s):  
Giovanni Li Manni
Keyword(s):  
Excited States ◽  
Electronic Structures ◽  
Body Wave ◽  
Wave Functions ◽  
Magnetic Interactions ◽  
Hamiltonian Matrix ◽  
Many Body ◽  
Unitary Transformations ◽  
High Valent ◽  
Oxygen Evolving

<p>In this work we apply a quantum chemical framework, recently designed in our laboratories, to rationalize the low-energy electronic spectrum and the magnetic properties of an homo-valent trinuclear [Mn<sup>(IV)</sup><sub>3</sub> O<sub>4</sub>]<sup>4+</sup> model of the oxygen-evolving center in photosystem II. The method is based on chemically motivated molecular orbital unitary transformations, and the optimization of spin-adapted many-body wave functions, both for ground- and excited-states, in the transformed MO basis. In this basis, the configuration interaction Hamiltonian matrix of exchange-coupled multi-center clusters is extremely sparse and characterized by a unique block diagonal structure. This property leads to highly compressed wave functions (oligo- or single-reference) and crucially enables state-specific optimizations. The reduced multi-reference character of the wave function greatly simplifies the interpretation of the ground- and excited-state electronic structures, and provides a route for the direct rationalization of magnetic interactions in these compounds, often considered a challenge in polynuclear transition-metal chemistry.</p>

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