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Influence of Organic Ligands on the Surface Oxidation State and Magnetic Properties of Iron Oxide Particles. Z PHYS CHEM 2018. [DOI: 10.1515/zpch-2017-1084] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.8] [Reference Citation Analysis] [Abstract] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/15/2022]
Abstract
Abstract
For the application of iron oxide nanoparticles from thermal decomposition approaches as contrast agents in magnetic resonance imaging (MRI), their initial hydrophobic ligands have to be replaced by hydrophilic ones. This exchange can influence the surface oxidation state and the magnetic properties of the particles. Here, the effect of the anchor group of three organic ligands, citric acid and two catechols, dihydrocaffeic acid and its nitrated derivative nitro dihydrocaffeic acid on iron oxide nanoparticles is evaluated. The oleate ligands of Fe3O4/γ-Fe2O3 nanoparticles prepared by the thermal decomposition of iron oleate were exchanged against the hydrophilic ligands. X-ray absorption spectroscopy, especially X-ray magnetic circular dichroism (XMCD) measurements in the total electron yield (TEY) mode was used to investigate local magnetic and electronic properties of the particles’ surface region before and after the ligand exchange. XMCD was combined with charge transfer multiplet calculations which provide information on the contributions of Fe2+ and Fe3+ at different lattice sites, i.e. either in tetrahedral or octahedral environment. The obtained data demonstrate that nitro hydrocaffeic acid leads to least reduction of the magnetizability of the surface region of the iron oxide nanoparticles compared to the two other ligands. For all hydrophilic samples, the proportion of Fe3+ ions in octahedral sites increases at the expense of the Fe2+ in octahedral sites whereas the percentage of Fe3+ in tetrahedral sites hardly changes. These observations suggest that an oxidation process took place, but a selective decrease of the Fe2+ ions in octahedral sites ions due to surface dissolution processes is unlikely. The citrate ligand has the least oxidative effect, whereas the degree of oxidation was similar for both catechol ligands regardless of the nitro group. Twenty-four hours of incubation in isotonic saline has nearly no influences on the magnetic properties of the nanoparticles, the least on those with the nitrated hydrocaffeic acid ligand.
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Kowalska JK, Nayyar B, Rees JA, Schiewer CE, Lee SC, Kovacs JA, Meyer F, Weyhermüller T, Otero E, DeBeer S. Iron L 2,3-Edge X-ray Absorption and X-ray Magnetic Circular Dichroism Studies of Molecular Iron Complexes with Relevance to the FeMoco and FeVco Active Sites of Nitrogenase. Inorg Chem 2017; 56:8147-8158. [PMID: 28653855 PMCID: PMC5516708 DOI: 10.1021/acs.inorgchem.7b00852] [Citation(s) in RCA: 32] [Impact Index Per Article: 4.6] [Reference Citation Analysis] [Abstract] [Track Full Text] [Download PDF] [Figures] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 01/29/2023]
Abstract
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Herein, a systematic study of a series
of molecular iron model complexes has been carried out using Fe L2,3-edge X-ray absorption (XAS) and X-ray magnetic circular
dichroism (XMCD) spectroscopies. This series spans iron complexes
of increasing complexity, starting from ferric and ferrous tetrachlorides
([FeCl4]−/2–), to ferric and ferrous
tetrathiolates ([Fe(SR)4]−/2–),
to diferric and mixed-valent iron–sulfur complexes [Fe2S2R4]2–/3–.
This test set of compounds is used to evaluate the sensitivity of
both Fe L2,3-edge XAS and XMCD spectroscopy to oxidation
state and ligation changes. It is demonstrated that the energy shift
and intensity of the L2,3-edge XAS spectra depends on both
the oxidation state and covalency of the system; however, the quantitative
information that can be extracted from these data is limited. On the
other hand, analysis of the Fe XMCD shows distinct changes in the
intensity at both L3 and L2 edges, depending
on the oxidation state of the system. It is also demonstrated that
the XMCD intensity is modulated by the covalency of the system. For
mononuclear systems, the experimental data are correlated with atomic
multiplet calculations in order to provide insights into the experimental
observations. Finally, XMCD is applied to the tetranuclear heterometal–iron–sulfur
clusters [MFe3S4]3+/2+ (M = Mo, V),
which serve as structural analogues of the FeMoco and FeVco active
sites of nitrogenase. It is demonstrated that the XMCD data can be
utilized to obtain information on the oxidation state distribution
in complex clusters that is not readily accessible for the Fe L2,3-edge XAS data alone. The advantages of XMCD relative to
standard K-edge and L2,3-edge XAS are highlighted. This
study provides an important foundation for future XMCD studies on
complex (bio)inorganic systems. A systematic Fe L2,3-edge X-ray absorption (XAS) and X-ray magnetic circular dichroism
(XMCD) study of iron tetrachlorides ([FeCl4]−/2−), iron tetrathiolates ([Fe(SR)4]−/2−), diferric and mixed-valent iron−sulfur dimers [Fe2S2R4]2−/3− and heterometal−iron−sulfur
tetramers [MFe3S4]3+/2+ (M = Mo,
V) is reported. The changes in XAS and XMCD energies and intensities
across this set of complexes are presented together with atomic multiplet
calculations. The advantages of XMCD as an electronic structure probe
of complex clusters are highlighted.
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Affiliation(s)
- Joanna K Kowalska
- Max Planck Institute for Chemical Energy Conversion , Stiftstraβe 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Brahamjot Nayyar
- Department of Chemistry, University of Waterloo , Waterloo, Ontario, Canada N2L 3G1
| | - Julian A Rees
- Max Planck Institute for Chemical Energy Conversion , Stiftstraβe 34-36, D-45470 Mülheim an der Ruhr, Germany.,Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States
| | - Christine E Schiewer
- University of Göttingen, Institute of Inorganic Chemistry , Tammannstraβe 4, D-37007 Göttingen, Germany
| | - Sonny C Lee
- Department of Chemistry, University of Waterloo , Waterloo, Ontario, Canada N2L 3G1
| | - Julie A Kovacs
- Department of Chemistry, University of Washington , Box 351700, Seattle, Washington 98195-1700, United States
| | - Franc Meyer
- University of Göttingen, Institute of Inorganic Chemistry , Tammannstraβe 4, D-37007 Göttingen, Germany
| | - Thomas Weyhermüller
- Max Planck Institute for Chemical Energy Conversion , Stiftstraβe 34-36, D-45470 Mülheim an der Ruhr, Germany
| | - Edwige Otero
- SOLEIL, L'Orme des Merisiers , 91190 Saint-Aubin, France
| | - Serena DeBeer
- Max Planck Institute for Chemical Energy Conversion , Stiftstraβe 34-36, D-45470 Mülheim an der Ruhr, Germany
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Joly L, Muller B, Sternitzky E, Faullumel JG, Boulard A, Otero E, Choueikani F, Kappler JP, Studniarek M, Bowen M, Ohresser P. Versatile variable temperature insert at the DEIMOS beamline for in situ electrical transport measurements. JOURNAL OF SYNCHROTRON RADIATION 2016; 23:652-657. [PMID: 27140143 DOI: 10.1107/s1600577516002551] [Citation(s) in RCA: 0] [Impact Index Per Article: 0] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/04/2015] [Accepted: 02/11/2016] [Indexed: 06/05/2023]
Abstract
The design and the first experiments are described of a versatile cryogenic insert used for its electrical transport capabilities. The insert is designed for the cryomagnet installed on the DEIMOS beamline at the SOLEIL synchrotron dedicated to magnetic characterizations through X-ray absorption spectroscopy (XAS) measurements. This development was spurred by the multifunctional properties of novel materials such as multiferroics, in which, for example, the magnetic and electrical orders are intertwined and may be probed using XAS. The insert thus enables XAS to in situ probe this interplay. The implementation of redundant wiring and careful shielding also enables studies on operating electronic devices. Measurements on magnetic tunnel junctions illustrate the potential of the equipment toward XAS studies of in operando electronic devices.
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Affiliation(s)
- L Joly
- Institut de Physique et de Chimie des Materiaux de Strasbourg, Université de Strasbourg, UMR 7504, 23 Rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
| | - B Muller
- Institut de Physique et de Chimie des Materiaux de Strasbourg, Université de Strasbourg, UMR 7504, 23 Rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
| | - E Sternitzky
- Institut de Physique et de Chimie des Materiaux de Strasbourg, Université de Strasbourg, UMR 7504, 23 Rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
| | - J G Faullumel
- Institut de Physique et de Chimie des Materiaux de Strasbourg, Université de Strasbourg, UMR 7504, 23 Rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
| | - A Boulard
- Institut de Physique et de Chimie des Materiaux de Strasbourg, Université de Strasbourg, UMR 7504, 23 Rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
| | - E Otero
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - F Choueikani
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - J P Kappler
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - M Studniarek
- Institut de Physique et de Chimie des Materiaux de Strasbourg, Université de Strasbourg, UMR 7504, 23 Rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
| | - M Bowen
- Institut de Physique et de Chimie des Materiaux de Strasbourg, Université de Strasbourg, UMR 7504, 23 Rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
| | - P Ohresser
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
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Joly L, Otero E, Choueikani F, Marteau F, Chapuis L, Ohresser P. Fast continuous energy scan with dynamic coupling of the monochromator and undulator at the DEIMOS beamline. JOURNAL OF SYNCHROTRON RADIATION 2014; 21:502-506. [PMID: 24763639 DOI: 10.1107/s1600577514003671] [Citation(s) in RCA: 5] [Impact Index Per Article: 0.5] [Reference Citation Analysis] [Abstract] [Key Words] [Track Full Text] [Subscribe] [Scholar Register] [Received: 12/11/2013] [Accepted: 02/18/2014] [Indexed: 06/03/2023]
Abstract
In order to improve the efficiency of X-ray absorption data recording, a fast scan method, the Turboscan, has been developed on the DEIMOS beamline at Synchrotron SOLEIL, consisting of a software-synchronized continuous motion of the monochromator and undulator motors. This process suppresses the time loss when waiting for the motors to reach their target positions, as well as software dead-time, while preserving excellent beam characteristics.
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Affiliation(s)
- L Joly
- Institut de Physique et de Chimie des Materiaux de Strasbourg, Université de Strasbourg, UMR 7504, 23 Rue du Loess, BP 43, 67034 Strasbourg Cedex 2, France
| | - E Otero
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - F Choueikani
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - F Marteau
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - L Chapuis
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
| | - P Ohresser
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin, BP 48, 91192 Gif-sur-Yvette, France
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Ohresser P, Otero E, Choueikani F, Chen K, Stanescu S, Deschamps F, Moreno T, Polack F, Lagarde B, Daguerre JP, Marteau F, Scheurer F, Joly L, Kappler JP, Muller B, Bunau O, Sainctavit P. DEIMOS: a beamline dedicated to dichroism measurements in the 350-2500 eV energy range. THE REVIEW OF SCIENTIFIC INSTRUMENTS 2014; 85:013106. [PMID: 24517744 DOI: 10.1063/1.4861191] [Citation(s) in RCA: 22] [Impact Index Per Article: 2.2] [Reference Citation Analysis] [Abstract] [Track Full Text] [Subscribe] [Scholar Register] [Indexed: 06/03/2023]
Abstract
The DEIMOS (Dichroism Experimental Installation for Magneto-Optical Spectroscopy) beamline was part of the second phase of the beamline development at French Synchrotron SOLEIL (Source Optimisée de Lumière à Energie Intermédiaire du LURE) and opened to users in March 2011. It delivers polarized soft x-rays to perform x-ray absorption spectroscopy, x-ray magnetic circular dichroism, and x-ray linear dichroism in the energy range 350-2500 eV. The beamline has been optimized for stability and reproducibility in terms of photon flux and photon energy. The main end-station consists in a cryo-magnet with 2 split coils providing a 7 T magnetic field along the beam or 2 T perpendicular to the beam with a controllable temperature on the sample from 370 K down to 1.5 K.
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Affiliation(s)
- P Ohresser
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - E Otero
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - F Choueikani
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - K Chen
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - S Stanescu
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - F Deschamps
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - T Moreno
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - F Polack
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - B Lagarde
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - J-P Daguerre
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - F Marteau
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - F Scheurer
- Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 UdS-CNRS, 67034 Strasbourg Cedex 2, France
| | - L Joly
- Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 UdS-CNRS, 67034 Strasbourg Cedex 2, France
| | - J-P Kappler
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - B Muller
- Institut de Physique et Chimie des Matériaux de Strasbourg, UMR 7504 UdS-CNRS, 67034 Strasbourg Cedex 2, France
| | - O Bunau
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
| | - Ph Sainctavit
- Synchrotron SOLEIL, L'Orme des Merisiers, Saint-Aubin - BP 48, 91192 Gif-sur-Yvette, France
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Davesne V, Gruber M, Miyamachi T, Da Costa V, Boukari S, Scheurer F, Joly L, Ohresser P, Otero E, Choueikani F, Gaspar AB, Real JA, Wulfhekel W, Bowen M, Beaurepaire E. First glimpse of the soft x-ray induced excited spin-state trapping effect dynamics on spin cross-over molecules. J Chem Phys 2013; 139:074708. [DOI: 10.1063/1.4818603] [Citation(s) in RCA: 29] [Impact Index Per Article: 2.6] [Reference Citation Analysis] [Track Full Text] [Journal Information] [Subscribe] [Scholar Register] [Indexed: 11/14/2022] Open
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