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25 results on '"Barra , A.L"'

2. Electron paramagnetic resonance spectroscopy of iron(III)-doped MFI zeolite 1 multifrequency CW-EPR

Author

Ferretti, A.M., Barra, A.L., Forni, L., Oliva, C., and Schweiger, A.; Ponti, A.

Subjects
Electron paramagnetic resonance -- Research, Silicates -- Research, Silicates -- Chemical properties, Iron compounds -- Research, Iron compounds -- Chemical properties, Iron compounds -- Atomic properties, Chemicals, plastics and rubber industries
Abstract

The inhomogeneity of the zero field splitting (ZFS) interaction is reported. Details of the multifrequency continuous wave electron paramagnetic resonance (CW-EPR) study of Fe(III)-doped MFI zeolite is provided to establish the inhomogeneity of ZFS interaction.

Published
2004

3. Single-molecule magnet behavior of a tetranuclear iron(III) complex: the origin of slow magnetic relaxation in iron(III) clusters

Author

Barra, A.L., Caneschi, A., Cornia, A., Biani, F. Fabrizi de, Gatteschi, D., Sangregorio, C., Sessoli, R., and Sorace, L.

Subjects
Coordination compounds -- Research, Metal ions -- Research, Iron compounds -- Research, Magnetic materials -- Research, Anisotropy -- Research, Chemistry
Abstract

A study on the molecular clusters of magnetic transition metal ions presents the synthesis, structure and magnetic characterization of a tetranuclear iron (III) cluster of Fe4-(OCH3)6(dpm)6 where Hdpm = dipivaloylmethane. This cluster has a ground state of S = 5 and exhibits superparamagnetic-like behavior. It is suggested that this compound as a case history can elucidate the origin of magnetic anisotropy of iron(III) clusters and more generally show which criteria must be satisfied to achieve single-molecule magnets.

Published
1999

5. Layered magnetic structure of a metal cluster ion

Author

Gatteschi, D., Pardi, L., Barra, A.L., Muller, A., and Doring, J.

Subjects
Vanadium -- Research, Molecular electronics -- Research, Ions -- Composition, Environmental issues, Science and technology, Zoology and wildlife conservation
Published
1991

6. Zero-Field Splitting in {MnIII3(mu3-O)} Core Single-Molecule Magnets Investigated by Inelastic Neutron Scattering and High-Field EPR Spectroscopy

Author

Sigrist, M., Tregenna-Piggott, P.L.W., Pedersen, K.S., Sørensen, M.A., Barra, A.L, Hauser, J., Decurtins, S., Mutka, H., Bendix, Jesper, Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Universität Bern [Bern], Institut Laue-Langevin (ILL), ILL, Department of Chemistry [Copenhagen], Faculty of Science [Copenhagen], University of Copenhagen = Københavns Universitet (KU)-University of Copenhagen = Københavns Universitet (KU), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), and Universität Bern [Bern] (UNIBE)

Subjects
[PHYS.PHYS.PHYS-ATM-PH]Physics [physics]/Physics [physics]/Atomic and Molecular Clusters [physics.atm-clus], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2015

7. Redox Non-Innocence of the Bridge in Copper(II) Salophen and bis-Oxamato Complexes

Author

De Bellefeuille , D., Orio , M., Barra , A.L, Aukauloo , A., JOURNAUX , Yves, Philouze , C., Ottenwaelder , X., Thomas , F., Department of Chemistry and Biochemistry, Concordia University [Montreal, Canada], Laboratoire national des champs magnétiques intenses - Grenoble ( LNCMI ), Centre National de la Recherche Scientifique ( CNRS ), Service de Bioénergétique, Biologie Stucturale, et Mécanismes ( SB2SM ), Centre National de la Recherche Scientifique ( CNRS ) -Institut de Biologie Intégrative de la Cellule ( I2BC ), Université Paris-Sud - Paris 11 ( UP11 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ) -Université Paris-Sud - Paris 11 ( UP11 ) -Commissariat à l'énergie atomique et aux énergies alternatives ( CEA ) -Université Paris-Saclay-Centre National de la Recherche Scientifique ( CNRS ), Institut de Chimie Moléculaire et des Matériaux d'Orsay ( ICMMO ), Université Paris-Sud - Paris 11 ( UP11 ) -Centre National de la Recherche Scientifique ( CNRS ), Institut Parisien de Chimie Moléculaire ( IPCM ), Université Pierre et Marie Curie - Paris 6 ( UPMC ) -Centre National de la Recherche Scientifique ( CNRS ), Département de Chimie Moléculaire - Chimie Inorganique Redox Biomimétique ( DCM - CIRE ), Centre National de la Recherche Scientifique ( CNRS ) -Université Joseph Fourier - Grenoble 1 ( UJF ) -Institut de Chimie Moléculaire de Grenoble (ICMG), Concordia University [Montreal], Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Joseph Fourier - Grenoble 1 (UJF)-Université Grenoble Alpes (UGA), Service de Bioénergétique, Biologie Stucturale, et Mécanismes (SB2SM), Centre National de la Recherche Scientifique (CNRS)-Institut de Biologie Intégrative de la Cellule (I2BC), Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Paris-Saclay-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Moléculaire et des Matériaux d'Orsay (ICMMO), Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut Parisien de Chimie Moléculaire (IPCM), Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC), Département de Chimie Moléculaire - Chimie Inorganique Redox Biomimétique (DCM - CIRE), and Université Joseph Fourier - Grenoble 1 (UJF)-Institut de Chimie Moléculaire de Grenoble (ICMG)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)

Subjects
[ PHYS.PHYS.PHYS-CHEM-PH ] Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], [PHYS.PHYS.PHYS-ATM-PH]Physics [physics]/Physics [physics]/Atomic and Molecular Clusters [physics.atm-clus], [PHYS.PHYS.PHYS-CHEM-PH]Physics [physics]/Physics [physics]/Chemical Physics [physics.chem-ph], [ PHYS.PHYS.PHYS-ATM-PH ] Physics [physics]/Physics [physics]/Atomic and Molecular Clusters [physics.atm-clus], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2015

8. Synthesis, Structures and Single Molecule-Magnet Behaviour of High Nuclearity Ni(II) Dicubane-type Complexes with Pyridyl-Alcohol Ligands

Author

Hameury, S., Kayser, L., Pattacini, R., Rosa, P., Barra, A.L, Braunstein, Pierre, Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G), Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de Strasbourg, and Université de Strasbourg (UNISTRA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
[PHYS.PHYS.PHYS-ATM-PH]Physics [physics]/Physics [physics]/Atomic and Molecular Clusters [physics.atm-clus], ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2015

9. Electron paramagnetic resonance spectroscopy of iron (III)-doped MF1 zeolite. 1. Multifrequency CW-EPR

Author

Ferretti A.M., Barra A.L., Forni L., Oliva C., Schweiger A., and Ponti A.

Abstract

Iron-containing zeolites with MFI structure are effective catalysts for several important reactions, among which the one-step hydroxylation of benzene to phenol by N2O stands out. We report on a multifrequency (9-475 GHz) continuous-wave electron paramagnetic resonance (CW-EPR) study of an Fe(III)-doped MFI zeolite catalyst either as synthesized and after detemplation, steaming, and treatment by aqueous dithionite. The presence of substantial inhomogeneity of the zero-field splitting (ZFS) interaction has been recognized and a novel computational strategy has been implemented to fit the spectroscopic results. This procedure enabled us to obtain quantitative measures of the ZFS distribution features and to draw structural conclusions regarding the nature and environment of Fe(III) ions in the as-synthesized catalyst and after each treatment.

Published
2004
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10. Epr of Mn2+ Impurities in Calcite: A Detailed Study Pertinent to Marble Provenance Determination

Author

Weihe, H., Piligkos, S., Barra, A.L., Laursen, I., Johnsen, O., Weihe, H., Piligkos, S., Barra, A.L., Laursen, I., and Johnsen, O.

Abstract

Udgivelsesdato: 2009, We demonstrate that the electron paramagnetic resonance spectrum of Mn2+ impurities in calcite, and therefore also in marble, may be accurately reproduced by a traditional spin Hamiltonian formalism. The success of such a treatment, however, very much depends on the spin Hamiltonian parameters having the correct signs as well as magnitudes. We present data that determine the sign of the axial anisotropy parameter and thereby facilitate future quantum mechanical characterizations of marble electron paramagnetic resonance spectra that supplement provenance determination

Published
2009

11. Characterization of a new tyrosyl free radical in Salmonella typhimurium ribonucleotide reductase with EPR at 9.45 and 245 GHz

Author

Allard, P., Barra, A.L., Andersson, K.K., Schmidt, P.P., Atta, M., and Graslund, A.

Subjects
Free radicals (Chemistry) -- Analysis, Salmonella typhimurium -- Research, Electron paramagnetic resonance spectroscopy -- Research, Chemistry
Abstract

The EPR spectra of a new type of tyrosyl free radical in ribonucleotide reductase (RNR) from Salmonella typhimurium have been obtained at 9.45 and 245 GHz. The results showed the similarity of the X-band EPR spectrum to that of the photosystem II tyrosyl radicals. The g-anisotropy has been found to be similar to that of the Escherichia coli RNR radical.

Published
1996

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