Bruijnincx Pieter C. A; Buurmans, ILC.; Huang, Y.; Juhász, G.; Viciano-Chumillas, M.; Quesada Vilar, M.; Reedijk, J.... (2011). Mono- and dinuclear iron complexes of bis(1-methylimidazol-2-yl)ketone (bik): structure, magnetic properties, and catalytic oxidation studies. Inorganic Chemistry. 9243-9255. https://doi.org/10.1021/ic200332y
Por favor, use este identificador para citar o enlazar este ítem: http://hdl.handle.net/10251/28137
Título:
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Mono- and dinuclear iron complexes of bis(1-methylimidazol-2-yl)ketone (bik): structure, magnetic properties, and catalytic oxidation studies
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Autor:
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Bruijnincx Pieter C. A
Buurmans, Inge L. C
Huang, Yuxing
Juhász, Gergely
Viciano-Chumillas, Marta
Quesada Vilar, Manuel
Reedijk, Jan
Lutz, Martin
Spek, Anthony L.
Munck, Eckard
Bominaar, Emile L.
Klein Gebbink, Robertus J. M.
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Entidad UPV:
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Universitat Politècnica de València. Instituto Universitario Mixto de Tecnología Química - Institut Universitari Mixt de Tecnologia Química
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Fecha difusión:
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Resumen:
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[EN] The newly synthesized dinuclear complex [Fe-2(III)(mu-OH)(2)(bik)(4)](NO3)(4) (1) (bik, bis(1-methylimidazol-2-yl)ketone) shows rather short Fe center dot center dot center dot Fe (3.0723(6) angstrom) and Fe-O distances ...[+]
[EN] The newly synthesized dinuclear complex [Fe-2(III)(mu-OH)(2)(bik)(4)](NO3)(4) (1) (bik, bis(1-methylimidazol-2-yl)ketone) shows rather short Fe center dot center dot center dot Fe (3.0723(6) angstrom) and Fe-O distances (1.941(2)/1.949(2) angstrom) compared to other unsupported Fe-2(III)(mu-OH)(2) complexes. The bridging hydroxide groups of 1 are strongly hydrogen-bonded to a nitrate anion. The Fe-57 isomer shift (delta = 0.45 mm s(-1)) and quadrupole splitting (Delta E-Q = 0.26 mm s(-1)) obtained from Mossbauer spectroscopy are consistent with the presence of two identical high-spin iron(III) sites. Variable-temperature magnetic susceptibility studies revealed antiferromagnetic exchange (J = 35.9 cm(-1) and H = JS(1).S-2) of the metal ions. The optimized DFT geometry of the cation of 1 in the gas phase agrees well with the crystal structure, but both the Fe center dot center dot center dot Fe and Fe-OH distances are overestimated (3.281 and 2.034 angstrom, respectively). The agreement in these parameters improves dramatically (3.074 and 1.966 angstrom) when the hydrogen-bonded nitrate groups are included, reducing the value calculated for J. by 35%. Spontaneous reduction of 1 was observed in methanol, yielding a blue [Fe-II(bik)(3)](2+) species. Variable-temperature magnetic susceptibility measurements of [Fe-II(bik)(3)](OTf)(2) (2) revealed spin-crossover behavior. Thermal hysteresis was observed with 2, due to a loss of cocrystallized solvent molecules, as monitored by thermogravimetric analysis. The hysteresis disappears once the solvent is fully depleted by thermal cycling. [Fe-II(bik)(3)](OTf)(2) (2) catalyzes the oxidation of alkanes with t-BuOOH. High selectivity for tertiary C-H bond oxidation was observed with adamantane (3 degrees/2 degrees value of 29.6); low alcohol/ketone ratios in cyclohexane and ethylbenzene oxidation, a strong dependence of total turnover number on the presence of O-2, and a low retention of configuration in cis-1,2-dimethylcyclohexane oxidation were observed. Stereoselective oxidation of olefins with dihydrogen peroxide yielding epoxides was observed under both limiting oxidant and substrate conditions.
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Palabras clave:
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2-HIS-1-carboxylate facial
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Bridged diiron(III) complexes
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Alkane oxidation
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Biomimetic nonheme iron
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Crystal-structures
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Ribonucleotide reductase
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Derechos de uso:
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Reserva de todos los derechos
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Fuente:
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Inorganic Chemistry. (issn:
0020-1669
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DOI:
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10.1021/ic200332y
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Editorial:
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American Chemical Society
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Versión del editor:
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http://doi.org/10.1021/ic200332y
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Código del Proyecto:
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info:eu-repo/grantAgreement/EC/FP6/515767/EU/Molecular approach to nanomagnets and multifunctional materials/MAGMANET/
info:eu-repo/grantAgreement/EC/FP6/504880/EU/Quantum Effects in Molecular Nanomagnets/QUEMOLNA/
info:eu-repo/grantAgreement/NIH//001475/
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Agradecimientos:
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This work was financially supported by the National Research School Combination-Catalysis (P.C.A.B.), the Council for Chemical Sciences of The Netherlands Organization for Scientific Research (CW-NWO) (M.L. and A.L.S.), ...[+]
This work was financially supported by the National Research School Combination-Catalysis (P.C.A.B.), the Council for Chemical Sciences of The Netherlands Organization for Scientific Research (CW-NWO) (M.L. and A.L.S.), and the National Institutes of Health Grant EB-001475 (E.M.). Dr. Stefania Tanase-Grecea is kindly acknowledged for her help with the collection of the magnetic measurements. Part of the work was financially supported the EC-RTN "QuEMolNa" (No. MRTN-CT-2003-504880) and the EC Network of Excellence "MAG-MANet" (No. 515767-2).
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Tipo:
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Artículo
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