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Electron paramagnetic resonance study of the S=1/2 ground state of a radiolysis-generated manganese(III)-trimanganese(IV) form of [Mn-IV;O-4(6)(bipy)(6)](4+) (bipy=2,2'-bipyridine). Comparison with the photosynthetic Oxygen Evolving Complex

Blondin, Geneviève; Davydov, Roman; Philouze, Christian; Charlot, Marie-France; Styring, Stenbjörn LU ; Åkermark, Björn; Girerd, Jean-Jacques and Boussac, Alain (1997) In Dalton Transactions 1997(21). p.4069-4074
Abstract
gamma-Ray irradiation at liquid nitrogen temperature of a dimethylformamide solution of the tetranuclear complex [(Mn4O6)-O-IV(bipy)(6)](4+) (bipy = 2,2'-bipyridine) allowed the generation of the first mixed-valence tetranuclear system containing Mn-III and Mn-IV ions and exhibiting a S = 1/2 ground state. The X-band EPR spectrum of this tetranuclear system has been obtained. Simulations have been undertaken and the Mn hyperfine coupling tensors determined clearly show a (MnMn3IV)-Mn-III, composition for the EPR active species. A general approach for the analysis of the isotropic components of the Mn hyperfine tensors is presented in detail. This allowed the determination of the spin projection value for each Mn site. A three J coupling... (More)
gamma-Ray irradiation at liquid nitrogen temperature of a dimethylformamide solution of the tetranuclear complex [(Mn4O6)-O-IV(bipy)(6)](4+) (bipy = 2,2'-bipyridine) allowed the generation of the first mixed-valence tetranuclear system containing Mn-III and Mn-IV ions and exhibiting a S = 1/2 ground state. The X-band EPR spectrum of this tetranuclear system has been obtained. Simulations have been undertaken and the Mn hyperfine coupling tensors determined clearly show a (MnMn3IV)-Mn-III, composition for the EPR active species. A general approach for the analysis of the isotropic components of the Mn hyperfine tensors is presented in detail. This allowed the determination of the spin projection value for each Mn site. A three J coupling scheme assuming that the linear topology of the starting compound remains is able to reproduce these spin projection values if and only if the Mn-III ion is located at a terminal position in a N4O2 environment. The EPR signal of this [Mn4O6(bipy)(6)](3+) species is compared with the multiline signal observed in the S-2 state of the photosynthetic Oxygen Evolving Complex. (Less)
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author
organization
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type
Contribution to journal
publication status
published
subject
keywords
PLANTS, WATER, S2 STATE, SIMULATION, REDOX PROPERTIES, MANGANESE CLUSTER, MULTILINE EPR SIGNALS, MN-OXO CLUSTER, PHOTOSYSTEM-II, OXIDATION
in
Dalton Transactions
volume
1997
issue
21
pages
4069 - 4074
publisher
Royal Society of Chemistry
ISSN
1477-9234
DOI
10.1039/a703381h
language
English
LU publication?
yes
id
944e436a-1bb4-4e16-8126-e3e0f0c4f2d4 (old id 126137)
date added to LUP
2007-07-04 14:02:05
date last changed
2016-04-15 19:55:14
@article{944e436a-1bb4-4e16-8126-e3e0f0c4f2d4,
  abstract     = {gamma-Ray irradiation at liquid nitrogen temperature of a dimethylformamide solution of the tetranuclear complex [(Mn4O6)-O-IV(bipy)(6)](4+) (bipy = 2,2'-bipyridine) allowed the generation of the first mixed-valence tetranuclear system containing Mn-III and Mn-IV ions and exhibiting a S = 1/2 ground state. The X-band EPR spectrum of this tetranuclear system has been obtained. Simulations have been undertaken and the Mn hyperfine coupling tensors determined clearly show a (MnMn3IV)-Mn-III, composition for the EPR active species. A general approach for the analysis of the isotropic components of the Mn hyperfine tensors is presented in detail. This allowed the determination of the spin projection value for each Mn site. A three J coupling scheme assuming that the linear topology of the starting compound remains is able to reproduce these spin projection values if and only if the Mn-III ion is located at a terminal position in a N4O2 environment. The EPR signal of this [Mn4O6(bipy)(6)](3+) species is compared with the multiline signal observed in the S-2 state of the photosynthetic Oxygen Evolving Complex.},
  author       = {Blondin, Geneviève and Davydov, Roman and Philouze, Christian and Charlot, Marie-France and Styring, Stenbjörn and Åkermark, Björn and Girerd, Jean-Jacques and Boussac, Alain},
  issn         = {1477-9234},
  keyword      = {PLANTS,WATER,S2 STATE,SIMULATION,REDOX PROPERTIES,MANGANESE CLUSTER,MULTILINE EPR SIGNALS,MN-OXO CLUSTER,PHOTOSYSTEM-II,OXIDATION},
  language     = {eng},
  number       = {21},
  pages        = {4069--4074},
  publisher    = {Royal Society of Chemistry},
  series       = {Dalton Transactions},
  title        = {Electron paramagnetic resonance study of the S=1/2 ground state of a radiolysis-generated manganese(III)-trimanganese(IV) form of [Mn-IV;O-4(6)(bipy)(6)](4+) (bipy=2,2'-bipyridine). Comparison with the photosynthetic Oxygen Evolving Complex},
  url          = {http://dx.doi.org/10.1039/a703381h},
  volume       = {1997},
  year         = {1997},
}