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572 results on '"Chaudret, B."'

1. Iron wool as a heating agent for magnetic catalysis: Experiments and analysis of heating properties under a high-frequency magnetic field.

Author

Daccache, S., Ghosh, S., Marias, F., Chaudret, B., and Carrey, J.

Subjects
EDDY current losses, HETEROGENEOUS catalysis, MAGNETIC materials, HYSTERESIS loop, MAGNETIC fields, WOOL
Abstract

Magnetically induced heterogeneous catalysis has been attracting attention due to its high energy efficiency and flexibility for dynamic reactor control. Iron wool is a commercial, low-cost, and versatile heating agent, which has been used in several magnetic catalysis studies, but its heating properties have never been investigated. Here, the properties of three types of Fe wool were studied using optical and electronic microscopy, x-ray diffraction, and measurements of both heating power and high-frequency hysteresis loops. The effects of strand width, packing, and magnetic field amplitude and frequency were studied. A maximum specific absorption rate (SAR) around 700 W/g under a rms field of 47.4 mT at 93 kHz was measured for the larger width Fe wool. High-frequency hysteresis loops were used to quantify the contribution of hysteresis losses and eddy currents to total heating. Eddy currents contribute 65%–90% to the global heating depending on the strand width. Coating the wool with SiO2 and Ni has negative effects on the SAR but none on hysteresis losses. It is interpreted as originating from the cut-off of inter-wire eddy currents due to the insulating (SiO2, oxidized Ni) nature of the coating. Last, it was found that adding more Fe wool in a given volume mostly decreases the SAR. This effect could be not only due to the absorption and/or screening of the field by surface strands but also due to magnetic interactions. The results described in this work give insights into the magnetic heating of microscale magnetic materials and optimize their use for heterogeneous catalysis. [ABSTRACT FROM AUTHOR]

Published
2024
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2. Metal Nanoparticles for Hydrogen Isotope Exchange

Author

Palazzolo, A., Asensio, J. M., Bouzouita, D., Pieters, G., Tricard, S., Chaudret, B., van Leeuwen, Piet W. N. M., Series Editor, Claver, Carmen, Series Editor, Turner, Nicholas, Series Editor, and van Leeuwen, Piet W.N.M., editor

Published
2020
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3. Gases

Author

Yi, D., primary, Chaudret, B., additional, and Soulantica, K., additional

Published
2021
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4. Increase of magnetic hyperthermia efficiency due to dipolar interactions in low anisotropy magnetic nanoparticles : theoretical and experimental results

Author

Mehdaoui, B., Tan, R. P., Meffre, A., Carrey, J., Lachaize, S., Chaudret, B., and Respaud, M.

Subjects
Condensed Matter - Materials Science
Abstract

When magnetic nanoparticles (MNPs) are single-domain and magnetically independent, their magnetic properties and the conditions to optimize their efficiency in magnetic hyperthermia applications are now well-understood. However, the influence of magnetic interactions on magnetic hyperthermia properties is still unclear. Here, we report hyperthermia and high-frequency hysteresis loop measurements on a model system consisting of MNPs with the same size but a varying anisotropy, which is an interesting way to tune the relative strength of magnetic interactions. A clear correlation between the MNP anisotropy and the squareness of their hysteresis loop in colloidal solution is observed : the larger the anisotropy, the smaller the squareness. Since low anisotropy MNPs display a squareness higher than the one of magnetically independent nanoparticles, magnetic interactions enhance their heating power in this case. Hysteresis loop calculations of independent and coupled MNPs are compared to experimental results. It is shown that the observed features are a natural consequence of the formation of chains and columns of MNPs during hyperthermia experiments: in these structures, when the MNP magnetocristalline anisotropy is small enough to be dominated by magnetic interactions, the hysteresis loop shape tends to be rectangular, which enhance their efficiency. On the contrary, when MNPs do not form chains and columns, magnetic interactions reduces the hysteresis loop squareness and the efficiency of MNPs compared to independent ones. The present work should improve the understanding and interpretation of magnetic hyperthermia experiments., Comment: 21 pages, 9 figures

Published
2013
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5. Influence of a transverse static magnetic field on the magnetic hyperthermia properties and high-frequency hysteresis loops of ferromagnetic FeCo nanoparticles

Author

Mehdaoui, B., Carrey, J., Stadler, M., Cornejo, A., Nayral, C., Delpech, F., Chaudret, B., and Respaud, M.

Subjects
Condensed Matter - Materials Science
Abstract

The influence of a transverse static magnetic field on the magnetic hyperthermia properties is studied on a system of large-losses ferromagnetic FeCo nanoparticles. The simultaneous measurement of the high-frequency hysteresis loops and of the temperature rise provides an interesting insight into the losses and heating mechanisms. A static magnetic field of only 40 mT is enough to cancel the heating properties of the nanoparticles, a result reproduced using numerical simulations of hysteresis loops. These results cast doubt on the possibility to perform someday magnetic hyperthermia inside a magnetic resonance imaging setup., Comment: 6 pages, 3 figures

Published
2012
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6. Magnetic anisotropy determination and magnetic hyperthermia properties of small Fe nanoparticles in the superparamagnetic regime

Author

Mehdaoui, B., Meffre, A., Lacroix, L. -M., Carrey, J., Lachaize, S., Respaud, M., Gougeon, M., and Chaudret, B.

Subjects
Condensed Matter - Materials Science
Abstract

We report on the magnetic and hyperthermia properties of iron nanoparticles synthesized by organometallic chemistry. They are 5.5 nm in diameter and display a saturation magnetization close to the bulk one. Magnetic properties are dominated by the contribution of aggregates of nanoparticles with respect to individual isolated nanoparticles. Alternative susceptibility measurements are been performed on a low interacting system obtained after eliminating the aggregates by centrifugation. A quantitative analysis using the Gittleman s model allow a determination of the effective anisotropy Keff = 1.3 * 10^5 J.m^{-3}, more than two times the magnetocristalline value of bulk iron. Hyperthermia measurements are performed on agglomerates of nanoparticles at a magnetic field up to 66 mT and at frequencies in the range 5-300 kHz. Maximum measured SAR is 280 W/g at 300 kHz and 66 mT. Specific absorption rate (SAR) displays a square dependence with the magnetic field below 30 mT but deviates from this power law at higher value. SAR is linear with the applied frequency for mu_0H=19 mT. The deviations from the linear response theory are discussed. A refined estimation of the optimal size of iron nanoparticles for hyperthermia applications is provided using the determined effective anisotropy value.

Published
2009
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7. Large specific absorption rates in the magnetic hyperthermia properties of metallic iron nanocubes

Author

Mehdaoui, B., Meffre, A., Lacroix, L. -M., Carrey, J., Lachaize, S., Respaud, M., Gougeon, M., and Chaudret, B.

Subjects
Condensed Matter - Materials Science, Condensed Matter - Mesoscale and Nanoscale Physics, Physics - Medical Physics
Abstract

We report on the magnetic hyperthermia properties of chemically synthesized ferromagnetic 11 and 16 nm Fe(0) nanoparticles of cubic shape displaying the saturation magnetization of bulk iron. The specific absorption rate measured on 16 nm nanocubes is 1690+-160 W/g at 300 kHz and 66 mT. This corresponds to specific losses-per-cycle of 5.6 mJ/g, largely exceeding the ones reported in other systems. A way to quantify the degree of optimization of any system with respect to hyperthermia applications is proposed. Applied here, this method shows that our nanoparticles are not fully optimized, probably due to the strong influence of magnetic interactions on their magnetic response. Once protected from oxidation and further optimized, such nano-objects could constitute efficient magnetic cores for biomedical applications requiring very large heating power.

Published
2009
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8. Magnetic hyperthermia in single-domain monodisperse FeCo nanoparticles: Evidences for Stoner-Wohlfarth behaviour and large losses

Author

Lacroix, L. -M., Malaki, R. Bel, Carrey, J., Lachaize, S., Goya, G. F., Chaudret, B., and Respaud, M.

Subjects
Condensed Matter - Materials Science
Abstract

We report on hyperthermia measurements on a colloidal solution of 15 nm monodisperse FeCo nanoparticles (NPs). Losses as a function of the magnetic field display a sharp increase followed by a plateau, which is what is expected for losses of ferromagnetic single-domain NPs. The frequency dependence of the coercive field is deduced from hyperthermia measurement and is in quantitative agreement with a simple model of non-interacting NPs. The measured losses (1.5 mJ/g) compare to the highest of the literature, though the saturation magnetization of the NPs is well below the bulk one., Comment: 14 pages, 3 figures

Published
2008
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9. Magnetoresistance and collective Coulomb blockade in super-lattices of ferromagnetic CoFe nanoparticles

Author

Tan, R. P., Carrey, J., Desvaux, C., Lacroix, L. -M., Renaud, P., Chaudret, B., and Respaud, M.

Subjects
Condensed Matter - Materials Science
Abstract

We report on transport properties of millimetric super-lattices of CoFe nanoparticles surrounded by organic ligands. R(T)s follow R(T) = R_0.exp(T/T_0)^0.5 with T_0 ranging from 13 to 256 K. At low temperature I(V)s follow I=K[(V-V_T)/V_T]^ksi with ksi ranging 3.5 to 5.2. I(V) superpose on a universal curve when shifted by a voltage proportional to the temperature. Between 1.8 and 10 K a high-field magnetoresistance with large amplitude and a strong voltage-dependence is observed. Its amplitude only depends on the magnetic field/temperature ratio. Its origin is attributed to the presence of paramagnetic states present at the surface or between the nanoparticles. Below 1.8 K, this high-field magnetoresistance abruptly disappears and inverse tunnelling magnetoresistance is observed, the amplitude of which does not exceed 1%. At this low temperature, some samples display in their I(V) characteristics abrupt and hysteretic transitions between the Coulomb blockade regime and the conductive regime. The increase of the current during these transitions can be as high as a factor 30. The electrical noise increases when the sample is near the transition. The application of a magnetic field decreases the voltage at which these transitions occur so magnetic-field induced transitions are also observed. Depending on the applied voltage, the temperature and the amplitude of the magnetic field, the magnetic-field induced transitions are either reversible or irreversible. These abrupt and hysteretic transitions are also observed in resistance-temperature measurements. They could be the soliton avalanches predicted by Sverdlov et al. [Phys. Rev. B 64, 041302 (R), 2001] or could also be interpreted as a true phase transition between a Coulomb glass phase to a liquid phase of electrons.

Published
2008
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12. Bringing Selectivity in H/D Exchange Reactions Catalyzed by Metal Nanoparticles through Modulation of the Metal and the Ligand Shell

Author

Universitat Rovira i Virgili, Martinez-Espinar, F; Salom-Català, A; Bresó-Femenia, E; Claver, C; Baletto, F; Ricart, JM; Chaudret, B; Carbó, JJ; Godard, C; Castillon, S, Universitat Rovira i Virgili, and Martinez-Espinar, F; Salom-Català, A; Bresó-Femenia, E; Claver, C; Baletto, F; Ricart, JM; Chaudret, B; Carbó, JJ; Godard, C; Castillon, S

Abstract

Ru and Rh nanoparticles catalyze the selective H/D exchange in phosphines using D2 as the deuterium source. The position of the deuterium incorporation is determined by the structure of the P-based substrates, while activity depends on the nature of the metal, the properties of the stabilizing agents, and the type of the substituent on phosphorus. The appropriate catalyst can thus be selected either for the exclusive H/D exchange in aromatic rings or also for alkyl substituents. The selectivity observed in each case provides relevant information on the coordination mode of the ligand. Density functional theory calculations provide insights into the H/D exchange mechanism and reveal a strong influence of the phosphine structure on the selectivity. The isotope exchange proceeds via C-H bond activation at nanoparticle edges. Phosphines with strong coordination through the phosphorus atom such as PPh3 or PPh2Me show preferred deuteration at ortho positions of aromatic rings and at the methyl substituents. This selectivity is observed because the corresponding C-H moieties can interact with the nanoparticle surface while the phosphine is P-coordinated, and the C-H activation results in stable metallacyclic intermediates. For weakly coordinating phosphines such as P(o-tolyl)3, the interaction with the nanoparticle can occur directly through phosphine substituents, and then, other deuteration patterns are observed.

Published
2023

15. Unraveling the role of zinc complexes on indium phosphide nanocrystal chemistry.

Author

McVey, B. F. P., Swain, R. A., Lagarde, D., Tison, Y., Martinez, H., Chaudret, B., Nayral, C., and Delpech, F.

Subjects
INDIUM phosphide, ZINC, SURFACE passivation, CHEMISTRY, OPTICAL properties
Abstract

The addition of zinc complexes to the syntheses of indium phosphide nanocrystals (InP NCs) has become commonplace, due to their ability to alter and significantly improve observed optical properties. In this paper, the role of zinc complexes on the synthesis and observed properties of InP is carefully examined. Produced InP and InP:Zn2+ NCs are thoroughly characterized from both structural (core and surface) and optical perspectives over a wide range of Zn2+ compositions (0%–43% atomic content). We find no differences in the physical (NC size and polydispersity) and structural properties (crystallographic phase) of InP and InP:Zn2+ NCs. Optically, significant changes are observed when zinc is added to InP syntheses, including blueshifted absorption edges and maxima, increased quantum yields, and the near elimination of surface state emission. These improved optical properties result from surface passivation by zinc carboxylate moieties. Changes to the optical properties begin at zinc concentrations as low as 5%, demonstrating the high sensitivity of InP optical properties to exogenous species. [ABSTRACT FROM AUTHOR]

Published
2019
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21. CHAPTER 5. Gases

Author

Yi, D., Chaudret, B., Soulantika, Aikaterini, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Fédération de recherche « Matière et interactions » (FeRMI), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), 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 National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)

Subjects
[CHIM.MATE]Chemical Sciences/Material chemistry, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2021
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25. X-Ray magnetic circular dichroism studies of FeRh nanoparticles

Author

Smekhova, A., Ciuculescu, D., Lecante, P., Wilhelm, F., Amiens, C., Rogalev, A., and Chaudret, B.

Subjects
Magnetic moment -- Analysis, Nanoparticles -- Analysis, Business, Electronics, Electronics and electrical industries
Abstract

[Fe.sub.x][Rh.sub.100-x] (x = 50, 80) nanoparticles (NPs) with an average diameter of ~2 nm were prepared by simultaneous decomposition of stoichiometric quantities of Fe[[N[(Si[([CH.sub.3]).sub.3]).sub.2])].sub.2] and Rh[([C.sub.3][H.sub.5]).sub.3] using two different routes: 1) a standard hydrogenation procedure and 2) a new one based on use of amino-borane as a reducing agent. All samples were found to be superparamagnetic with a blocking temperature below 10 K. Results of X-Ray magnetic circular dichroism (XMCD) experiments at the Fe K-edge and the Rh [L.sub.2,3] edges have shown that not only iron but also rhodium atoms are magnetic as a result of hybridization of Fe 3d states with 4d states of Rh. The total induced magnetic moment of Rh atoms as well as its spin and orbital contributions are shown to depend on chemical composition of [NP.sub.S] and the preparation method. Index Terms--Induced magnetic moment, magnetic nanoparticles, X-ray magnetic circular dichroism.

Published
2008

26. Spin crossover in Fe(triazole)-Pt nanoparticle self-assembly structured at the sub-5 nm scale

Author

Usmani S., Mikolasek M., Gillet A., Sanchez Costa J., Rigoulet M., Chaudret B., Bousseksou A., Lassalle-Kaiser B., Demont P., Molnár G., Salmon L., Carrey J., Tricard S. and We thank Marc Respaud and Sébastien Pinaud for their significant help in magnetic measurements. We also thank Sébastien Cher for experimental support, Thomas Blon for gold evaporation on substrates and Gautier Félix for insightful discussions. We acknowledge SOLEIL for provision of synchrotron radiation facilities on the LUCIA beamline. Financial support from Agence Nationale de la Recherche (PhoCatSA grant ANR-10-LABX-0037-NEXT, MOSC grant ANR-18-CE09-0007 and Nanohybrid grant ANR-13-BS07-0020-01), from the Marie-Curie research program (NanoSCOpe 328078) and from the Indo-French Centre for the Promotion of Advanced Research – CEFIPRA is acknowledged. This study has been partially supported through the EUR grant NanoX n° ANR-17-EURE-0009 in the framework of the Programme des Investissements d’Avenir. JSC is grateful to the Spanish MINECO through National Research Project (CTQ2016-80635-P) and the Ramon y Cajal Research program (RYC-2014-16866).

Published
2020

28. Spin crossover in Fe(triazole)-Pt nanoparticle self-assembly structured at the sub-5 nm scale

Author

Usmani S., Mikolasek M., Gillet A., Sánchez Costa, Jose, Rigoulet M., Chaudret B., Bousseksou A., Lassalle-Kaiser B., Demont P., Molnár G., Salmon L., Carrey J., Tricard S., Usmani S., Mikolasek M., Gillet A., Sánchez Costa, Jose, Rigoulet M., Chaudret B., Bousseksou A., Lassalle-Kaiser B., Demont P., Molnár G., Salmon L., Carrey J., and Tricard S.

Published
2020

30. Chemisorption on nickel nanoparticles of various shapes: lnfluence on magnetism

Author

Cordente, N., Amiens, C., Chaudret, B., Respaud, M., Senocq, F., and Casanove, M.-J.

Subjects
Ligands -- Magnetic properties, Organometallic chemistry -- Research, Nickel -- Magnetic properties, Physics
Abstract

Nanoparticles of nickel have been obtained in solution through reaction of an organometallic precursor, Ni(COD)(sub 2) (COD=cycloocta-1, 5-diene), with dihydrogen, in the presence of various stabilizing agents. This stabilizing agent was selected for the production of nickel anorods, and the influence of ligands on the effective anisotropy is discussed.

Published
2003

31. Synthesis and magnetism of CoxRh(sub 1-x) and CoxRu(sub 1-x) nanoparticles

Author

Zitoun, D., Amiens, C., Chaudret, B., Fromen, M.-C., Lecante, P., Casanove, M.-J., and Respaud, M.

Subjects
Ruthenium -- Research, Ruthenium -- Magnetic properties, Chemistry, Physical and theoretical -- Research, Chemicals, plastics and rubber industries
Abstract

The synthesis of CoxRh(sub 1-x) and CoxRu(sub 1-x) alloys of nanometric size dispersed in a polymer matrix through the simultaneous decomposition of the organometallic precursors in solution in mild conditions is described. These structural studies enable to find some analogies between three CoM systems (M= Ru, Rh, Pt).

Published
2003

34. Nanoscale bimetallic CoxPt1-x particles dispersed in poly(vinylpyrrolidone): synthesis from organometallic precursors and characterization

Author

Ely, T. Ould, Pan, Cheng, Amiens, C., Chaudret, B., Dassenoy, F., Lecante, P., Casanove, M.-J., Mosset, A., Broto, J.-M., and Respaud, M.

Subjects
Laminated metals -- Research, Organometallic chemistry -- Research, Chemicals, plastics and rubber industries
Abstract

It has been possible to demonstrate the synthesis of CoxPt1-x particles of nanometric size dispersed in an inert organic matrix through the simultaneous decomposition of the organometallic precursors Co(eta3-C8H13)(eta4-C8H12) and Pt2(dba)3 in solution in mild conditions.

Published
2000

35. Zwitterionic amidinates as effective ligands for platinum nanoparticle hydrogenation catalysts† †Electronic supplementary information (ESI) available. See DOI: 10.1039/c6sc05551f Click here for additional data file

Author

Martínez-Prieto, L. M., Cano, I., Márquez, A., Baquero, E. A., Tricard, S., Cusinato, L., del Rosal, I., Poteau, R., Coppel, Y., Philippot, K., Chaudret, B., Cámpora, J., and van Leeuwen, P. W. N. M.

Subjects
Chemistry
Abstract

Pt NPs covered with zwitterionic amidinates as ligands exhibit an exciting ligand effect in the hydrogenation of carbonyl groups when electron donor/acceptor groups are introduced in the N-substituents., Ligand control of metal nanoparticles (MNPs) is rapidly gaining importance as ligands can stabilize the MNPs and regulate their catalytic properties. Herein we report the first example of Pt NPs ligated by imidazolium-amidinate ligands that bind strongly through the amidinate anion to the platinum surface atoms. The binding was established by 15N NMR spectroscopy, a precedent for nitrogen ligands on MNPs, and XPS. Both monodentate and bidentate coordination modes were found. DFT showed a high bonding energy of up to –48 kcal mol–1 for bidentate bonding to two adjacent metal atoms, which decreased to –28 ± 4 kcal mol–1 for monodentate bonding in the absence of impediments by other ligands. While the surface is densely covered with ligands, both IR and 13C MAS NMR spectra proved the adsorption of CO on the surface and thus the availability of sites for catalysis. A particle size dependent Knight shift was observed in the 13C MAS NMR spectra for the atoms that coordinate to the surface, but for small particles, ∼1.2 nm, it almost vanished, as theory for MNPs predicts; this had not been experimentally verified before. The Pt NPs were found to be catalysts for the hydrogenation of ketones and a notable ligand effect was observed in the hydrogenation of electron-poor carbonyl groups. The catalytic activity is influenced by remote electron donor/acceptor groups introduced in the aryl-N-substituents of the amidinates; p-anisyl groups on the ligand gave catalysts several times faster the ligand containing p-chlorophenyl groups.

Published
2017

42. Uniform Ru nanoparticles on N-doped graphene for selective hydrogenation of fatty acids to alcohols

Author

Universitat Politècnica de València. Instituto Universitario Mixto de Tecnología Química - Institut Universitari Mixt de Tecnologia Química, Universitat Politècnica de València. Departamento de Química - Departament de Química, Universitat Politècnica de València, Ministerio de Economía y Competitividad, Martínez-Prieto, Luis Miguel, Puche Panadero, Marta, Cerezo-Navarrete, Christian, CHAUDRET, B., Universitat Politècnica de València. Instituto Universitario Mixto de Tecnología Química - Institut Universitari Mixt de Tecnologia Química, Universitat Politècnica de València. Departamento de Química - Departament de Química, Universitat Politècnica de València, Ministerio de Economía y Competitividad, Martínez-Prieto, Luis Miguel, Puche Panadero, Marta, Cerezo-Navarrete, Christian, and CHAUDRET, B.

Abstract

[EN] Ruthenium nanoparticles (Ru NPs) supported on reduced-graphene oxide doped with N (NH2-rGO) was synthesized and used for the selective hydrogenation of fatty acids to alcohols, being the hydrogenation of palmitic acid selected as model. Ru was stabilized forming uniform nanometer size particles on N-doped graphene (Ru/NH2-rGO). The resultant catalyst was very selective for the carbonyl reduction giving 93% of the aliphatic alcohol at 99% conversion. The Ru/NH2-rGO catalysts was more active and selective than the corresponding Ru on non-doped graphene (Ru/rGO) or Ru on carbon (Ru/C). Mechanistic studies points to a dual mechanism for H-2 dissociation, i.e. homolytic and heterolytic cleavage exists on the Ru/NH2-rGO, while only the homolytic H-2 dissociation occurs on Ru/rGO. This heterolytic splitting, which activates the carbonyl groups and facilitates the hydrogenation of aliphatic acids, is due to the presence of basic centres next to the Ru atoms. The presence of N atoms also increases the stability of the catalyst, allowing a reuse up to four times. (C) 2019 Elsevier Inc. All rights reserved.

Published
2019

44. Reactivity and structural evolution of urchin-like Co nanostructures under controlled environments

Author

Soulantika, Aikaterini, Dembele, K., Moldovan, S., Hirlimann, Ch., Harmel, J., SOULANTICA, K., Serp, P., Chaudret, B., Gay, A.-S., Maury, S., Berliet, A., FECANT, A., Ersen, O., Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Centre National de la Recherche Scientifique (CNRS)-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 (UPS), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), Institut de Physique et Chimie des Matériaux de Strasbourg (IPCMS), Université de Strasbourg (UNISTRA)-Centre National de la Recherche Scientifique (CNRS)-Matériaux et nanosciences d'Alsace, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Institut National de la Santé et de la Recherche Médicale (INSERM)-Centre National de la Recherche Scientifique (CNRS)-Réseau nanophotonique et optique, Université de Strasbourg (UNISTRA)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Centre National de la Recherche Scientifique (CNRS)-Université de Strasbourg (UNISTRA), IPCMS, Université Strasbourg-CNRS, Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UPS), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Plasticité, Endommagement et Corrosion des Matériaux (PECM-ENSMSE), École des Mines de Saint-Étienne (Mines Saint-Étienne MSE), Institut Mines-Télécom [Paris] (IMT)-Institut Mines-Télécom [Paris] (IMT)-SMS-Centre National de la Recherche Scientifique (CNRS), IFP Energies nouvelles (IFPEN), and Université Louis Pasteur - Strasbourg I-Centre National de la Recherche Scientifique (CNRS)

Subjects
[CHIM.MATE]Chemical Sciences/Material chemistry, ComputingMilieux_MISCELLANEOUS
Abstract

International audience

Published
2018
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50. NHC-stabilised Rh nanoparticles: Surface study and application in the catalytic hydrogenation of aromatic substrates

Author

Blondeau, P., Martinez-Espinar, F., Nolis, P., Chaudret, B., Claver, C., Castillón, S., Godard, C., Departament de Quimica Fisica i Inorganica, Universitat Rovira i Virgili, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Departament de Quimica Analitica i Quimica Organica, Servei de Ressonància Magnètica Nuclear, Facultat de Ciències, Universitat Autònoma de Barcelona, Universitat Autònoma de Barcelona (UAB), Centre Tecnològic de Química, Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC), Síntesis Orgànica Estereoselectiva, Organometàl.lics i Catàlisi Homogènia, Grup de Quimiometria, Qualimetria i Nanosensors, Química Física i Inorgànica, and Química Analítica i Química Orgànica

Subjects
rhodium nanoparticles, Phenol, NHC, NHCs, Pyridine, Quinoline, Química, 0021-9517, Surface, Chemistry, Aromatic ketone, Rodi, Nanoparticles, Rhodium, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Hydrogenation, Hidrogenació
Abstract

International audience; New Rh-NPs stabilised by N-Heterocyclic Carbenes (NHC) were synthesized by decomposition of [Rh(η3-C3H5)3] under H2 atmosphere and fully characterized. Surface studies by FT-IR and NMR spectroscopy employing isotopically labelled ligands were also performed. The Rh0.2 NPs are active catalysts in the reduction of various aromatic substrates. In the reduction of phenol, high selectivities to cyclohexanone or cyclohexanol were obtained depending on the reaction conditions. However, this catalytic system exhibited much lower activity in the hydrogenation of substituted phenols. Pyridine was easily hydrogenated under mild conditions and interestingly, the hydrogenation of 4-methyl and 4-trifluoromethylpyridine resulted slower than that of 2-methylpyridine. The hydrogenation of 1-(pyridin-2-yl)propan-2-one provided the β-enaminone 13a in high yield as a consequence of the partial reduction of the pyridine ring followed by isomerization. Quinoline could be either partially hydrogenated to 1,2,3,4-tetrahydroquinoline or fully reduced to decahydroquinoline by adjusting the reaction conditions.

Published
2017
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