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1. Elaboration of microporous CeO2 thin layers having nanocrystallites network controlled by Pluronic P123: Impact of key experimental parameters

Author

Zijie Lu, Jérémy Causse, Xavier F. Le Goff, Diane Rébiscoul, Nicolas Mollard, Xavier Deschanels, Nanomatériaux pour l'Energie et le Recyclage (LNER), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Etude de la Matière en Mode Environnemental (L2ME), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Materials science, Nanoparticle, 02 engineering and technology, Thermal treatment, 010402 general chemistry, 01 natural sciences, law.invention, Biomaterials, law, Materials Chemistry, [CHIM]Chemical Sciences, Thin film, Crystallization, Porosity, Thin layers, General Chemistry, Microporous material, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Condensed Matter Physics, 0104 chemical sciences, Electronic, Optical and Magnetic Materials, Chemical engineering, Ceramics and Composites, Crystallite, 0210 nano-technology
Abstract

International audience; Microporous ceria thin films having nanocrystallites network were synthesized by evaporation-induced self-assemblyprocess, using P123 amphiphilic copolymer as structure-directing agent. The impact of key experimental parameters,i.e., the sol ageing, the relative humidity (RH), the thermal treatment, on the thin layer elaboration were investigated.The results show that the organization of the nanoparticles is possible for a sol ageing time lower than 16 days and thatthe size of the mesophase within the thin layer increases with the relative humidity fixed during the film deposition.Finally, an increase of the thermal treatment temperature from 300 to 1000 °C leads to the formation of fluorite-likedioxide material coupled with a loss of nanocrystallites organization and porosity due to the increase of the size of thecrystallites. This loss of nanocrystallites organization is more drastic in the direction perpendicular to the surface andless pronounced along the surface. Thus, a compromise between the crystallization and the preservation of the porosityneeds to be found.

Published
2019
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2. Deciphering the Crystal Structure of a Scarce 1D Polymeric Thorium Peroxo Sulfate

Author

Laura Bonato, Pierre Lecante, Sergey I. Nikitenko, Nicolas Dacheux, Thomas Dumas, Adel Mesbah, Philippe Moisy, Matthieu Virot, Damien Prieur, Xavier F. Le Goff, Christoph Hennig, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM), Département de recherche sur les procédés pour la mine et le recyclage du combustible (DMRC), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Interfaces de Matériaux en Evolution (LIME), Centre d'élaboration de matériaux et d'études structurales (CEMES), 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), Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Institut de Recherche pour le Développement (IRD)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), JRC Institute for Transuranium Elements [Karlsruhe] (ITU ), European Commission - Joint Research Centre [Karlsruhe] (JRC), Etude de la Matière en Mode Environnemental (L2ME), Institute of Resource Ecology [Dresden] (IRE), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Service de Chimie des Procédés de Séparation (SCPS), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), 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)-Centre National de la Recherche Scientifique (CNRS), European Synchrotron Radiation Facility (ESRF), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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 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)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)

Subjects
010405 organic chemistry, Ligand, Organic Chemistry, Thorium, chemistry.chemical_element, General Chemistry, Crystal structure, Structure type, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Peroxide, Catalysis, Synchrotron, 0104 chemical sciences, law.invention, chemistry.chemical_compound, Crystallography, chemistry, law, [CHIM.CRIS]Chemical Sciences/Cristallography, [CHIM]Chemical Sciences, Orthorhombic crystal system, Sulfate, [CHIM.RADIO]Chemical Sciences/Radiochemistry
Abstract

International audience; The preparation and structural characterization of an original Th peroxo sulfate dihydrate, crystallizing at room temperature in the form of stable 1D polymeric microfibres is described. A combination of laboratory and synchrotron techniques allowed solution of the structure of the Th(O2)(SO4)(H2O)2 compound, which crystallizes in a new structure type in the space group Pna21 of the orthorhombic crystal system. Particularly, the peroxide ligand coordinates to the Th cations in an unusual μ3‐η2:η2:η2 bridging mode, forming an infinite 1D chain decorated with sulfato ligands exhibiting simultaneously monodentate and bidentate coordination modes.

Published
2019
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3. Probing the Local Structure of Nanoscaled Actinide Oxides: A Comparison between PuO2 and ThO2 Nanoparticles Rules out PuO2+x Hypothesis

Author

Thierry Wiss, Laurent Venault, Philippe Moisy, Thomas Dumas, Adel Mesbah, Oliver Dieste Blanco, Matthieu Virot, Damien Prieur, Laura Bonato, Xavier F. Le Goff, Sergey I. Nikitenko, Elodie Dalodière, Michael Odorico, Nicolas Dacheux, André Rossberg, CEA, Contributeur MAP, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Northwestern University [Evanston], European Commission - Joint Research Centre [Karlsruhe] (JRC), Etude de la Matière en Mode Environnemental (L2ME), European Synchrotron Radiation Facility (ESRF), Département RadioChimie et Procédés (DRCP), CEA-Direction des Energies (ex-Direction de l'Energie Nucléaire) (CEA-DES (ex-DEN)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Interfaces de Matériaux en Evolution (LIME), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Institut des Sciences et technologies pour une Economie Circulaire des énergies bas carbone (ISEC)

Subjects
[CHIM.INOR] Chemical Sciences/Inorganic chemistry, Materials science, Oxide, Nanoparticle, Bioengineering, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Colloid, chemistry.chemical_compound, [CHIM.RADIO] Chemical Sciences/Radiochemistry, [CHIM.CRIS]Chemical Sciences/Cristallography, General Materials Science, Reactivity (chemistry), [CHIM.CRIS] Chemical Sciences/Cristallography, ComputingMilieux_MISCELLANEOUS, [CHIM.MATE] Chemical Sciences/Material chemistry, Extended X-ray absorption fine structure, General Engineering, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, Actinide, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, Characterization (materials science), Nanocrystal, chemistry, Chemical physics, 0210 nano-technology, [CHIM.RADIO]Chemical Sciences/Radiochemistry
Abstract

International audience; Actinide research at the nanoscale is gaining fundamental interest due to environmental and industrial issues. The knowledge of the local structure and speciation of actinide nanoparticles, which possibly exhibit specific physico-chemical properties in comparison to bulk materials, would help in a better and reliable description of their behaviour and reactivity. Herein, the synthesis and relevant characterization of PuO2 and ThO2 nanoparticles displayed as dispersed colloids, nanopowders or nanostructured oxide powders, allow to establish a clear relationship between the size of the nanocrystals composing these oxides and their corresponding An(IV) local structure investigated by EXAFS spectroscopy. Particularly, the probed An(IV) first oxygen shell evidences an analogous behaviour for both Pu and Th oxides. This observation suggests that the often observed and controversial splitting of the Pu-O shell on the Fourier transformed EXAFS signal of PuO2 samples is attributed to a local structural disorder driven by a nanoparticle surface effect rather than to the presence of PuO2+x species.

Published
2019
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4. Controlled 'golf ball shape' structuring of Mg surface under acoustic cavitation

Author

Xavier F. Le Goff, Ran Ji, Sergey I. Nikitenko, R. Pflieger, Renaud Podor, Matthieu Virot, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Etude de la Matière en Mode Environnemental (L2ME), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Acoustics and Ultrasonics, Sonication, Organic Chemistry, Nanotechnology, 02 engineering and technology, Surface finish, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, Microstructure, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Cavitation, Nano, Chemical Engineering (miscellaneous), Environmental Chemistry, Radiology, Nuclear Medicine and imaging, Ultrasonic sensor, Wetting, Composite material, 0210 nano-technology, Dissolution, ComputingMilieux_MISCELLANEOUS
Abstract

This manuscript describes the original structuring of Mg materials under ultrasound irradiation in mild conditions. Golf ball like extended structures can be prepared in dilute oxalic solutions at 20 °C under high frequency ultrasound (200 kHz). An original approach carried out through iterative 3D reconstruction of sonicated surfaces is used to describe surface evolutions and characterize the formed microstructures. A combination of SEM, ICP-AES, contact-angle measurements, and 3D image analyses allows to characterize the roughness and mass loss evolutions, and investigate the mechanism of formation for such architectures. A screening of the sonication experiments clearly points out an ultrasound frequency dependency for the effects generated at the surface. 200 kHz sonication in 0.01 M oxalic acid provides an unprecedented manufacturing of Mg samples which result from a controlled and localized dissolution of the material and characterized by a strong wetting surface with a roughness of 170 nm. The additional formation of newly formed secondary phases appearing with surface dissolution progress is also deciphered. More generally, the ultrasonic procedure used to prepare these engineered surfaces opens new alternatives for the nano- and micro-structuring of metallic materials which may exhibit advanced physical and chemical properties of potential interest for a large community.

Published
2018
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5. Polyoxometalate/Polyethylene Glycol Interactions in Water: From Nanoassemblies in Water to Crystal Formation by Electrostatic Screening

Author

Pierre Bauduin, Arno Pfitzner, Bappaditya Naskar, Olivier Diat, Thomas Buchecker, Xavier F. Le Goff, Universität Regensburg (UR), Ions aux Interfaces Actives (L2IA), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Etude de la Matière en Mode Environnemental (L2ME), and University of Calcutta

Subjects
Ethylene oxide, 010405 organic chemistry, ddc:540, Organic Chemistry, General Chemistry, Polyethylene glycol, [CHIM.MATE]Chemical Sciences/Material chemistry, POLY(ETHYLENE GLYCOL), POLYETHYLENE-GLYCOL, OXIDATION REACTIONS, HYBRID, NANOPARTICLES, COMPOSITES, CONVERSION, HYDROGELS, SURFACES, SYSTEMS, (poly-)ethylene glycol, adsorption, composite materials, polyoxometalates, soft matter, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, law.invention, chemistry.chemical_compound, chemistry, Chemical engineering, law, Covalent bond, 540 Chemie, Polyoxometalate, Organic chemistry, Solvent effects, Crystallization, Selectivity, Hybrid material
Abstract

International audience; In the last decade organic–inorganic hybrid materials have become essential in materials science as they combine properties of both building blocks. Nowadays the main routes for their synthesis involve electrostatic coupling, covalent grafting, and/or solvent effects. In this field, polyoxometalates (POMs) have emerged as interesting inorganic functional building blocks due to their outstanding properties. In the present work the well‐known α‐Keggin polyoxometalate, α‐PW12O403− (PW), is shown to form hybrid crystalline materials with industrial (neutral) polyethylene glycol oligomers (PEG) under mild conditions, that is, in aqueous medium and at room temperature. The formation of these materials originates from the spontaneous self‐assembly of PW with EOx, (EO=ethylene oxide) with at least four EO units (x>4). The PW–PEG nanoassemblies, made of a POM surrounded by about two PEG oligomers, are stabilized by electrostatic repulsions between the negatively charged PW anions. Addition of NaCl, aimed at screening the inter‐nanoassembly repulsions, induces aggregation and formation of hybrid crystalline materials. Single‐crystal analysis showed a high selectivity of PW towards EO5–EO6 oligomers from PEG200, which is made of a mixture of EO3–8. Therefore, a general “soft” route to produce POM–organic composites is proposed here through the control of electrostatic repulsions between spontaneously formed nanoassemblies in water. However, this rational design of new POM hybrid (crystalline) materials with hydrophilic blocks, using such a simple mixing procedure of the components, requires a deep understanding of the molecular interactions.

Published
2017
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6. Micellization in vegetable oils: A structural characterisation

Author

Anne Rossignol-Castera, Ophélie Fadel, Olivier Diat, Pierre Bauduin, Annabelle L'hermitte, Luc Girard, Xavier F. Le Goff, Donatien Gomes Rodrigues, Ions aux Interfaces Actives (L2IA), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Etude de la Matière en Mode Environnemental (L2ME), and OLEOS

Subjects
Glycerol, Iridoid Glucosides, Supramolecular chemistry, Cosmetics, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Antioxidants, Colloid and Surface Chemistry, Glucosides, Humans, Plant Oils, Organic chemistry, Iridoids, Benzhydryl Compounds, Physical and Theoretical Chemistry, Micelles, ComputingMilieux_MISCELLANEOUS, Polyphenol antioxidant, Chemistry, Small-angle X-ray scattering, Reverse micelle, Surfaces and Interfaces, General Medicine, SAXS, [CHIM.MATE]Chemical Sciences/Material chemistry, Phenylethyl Alcohol, Flavones, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Vegetable oil, Solubility, Polyphenol, Emulsifying Agents, Waxes, Yield (chemistry), 0210 nano-technology, Stearic Acids, Biotechnology
Abstract

The solubilisation of polar and polyphenol antioxidant in vegetable oils was studied. It was shown that the use of a polyglyceryl-3-diisostearate (PG3DS), a bio-sourced emulsifier well known in cosmetics, increases the yield of solubilisation thanks to some aggregation properties analysed using x-ray scattering technique. We show indeed that PG3DS forms reverse aggregates with a critical concentration that depends on the oil polarity. PG3DS reverse aggregates are elongated with a polar core and cannot be really swollen by addition of water. This supramolecular organisation allows however an efficient solubilisation of polar antioxidants in vegetable oils.

Published
2017
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7. Insights into the structure and thermal stability of uranyl aluminate nanoparticles

Author

Sergey I. Nikitenko, Andreas C. Scheinost, Xavier F. Le Goff, Tony Chave, Sonochimie dans les Fluides Complexes (LSFC), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Etude de la Matière en Mode Environnemental (L2ME), Helmholtz-Zentrum Dresden-Rossendorf (HZDR), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
010405 organic chemistry, Precipitation (chemistry), Aluminate, Inorganic chemistry, chemistry.chemical_element, General Chemistry, Thermal treatment, [CHIM.MATE]Chemical Sciences/Material chemistry, Uranium, 010402 general chemistry, Uranyl, 01 natural sciences, Catalysis, 0104 chemical sciences, law.invention, X-ray absorption fine structure, chemistry.chemical_compound, chemistry, law, Materials Chemistry, Calcination, Mesoporous material
Abstract

International audience; Ultrasonically assisted hydrolytic precipitation of U(VI) in the presence of mesoporous alumina followed by thermal treatment of a solid precursor enabled the formation of crystallized uranyl aluminate (URAL) nanoparticles (NPs) dispersed in the alumina matrix. The effect of U(VI) concentration and calcination temperature on the yield of URAL NPs was studied using XRD, XAFS and HRTEM techniques. At 800 °C, URAL NPs (d ≈ 5 nm) are formed only for a low uranium loading of about 5 wt% whereas for a higher content of uranium, larger U3O8 NPs (d ≈ 20 nm) were identified as the principal uranium species. At 500 °C, URAL NPs are formed even for 25 wt% of uranium. The U LIII edge EXAFS spectra pointed out that uranyl cations in URAL are coordinated by bidentate aluminate groups. Presumably URAL is formed during the heating of the 2UO3·NH3·2H2O/AlO(OH) precursor. However, high temperature and higher content of uranium promote transformation of URAL to more thermodynamically stable U3O8. This process is accompanied by the growth of uranium NPs via the Ostwald ripening mechanism.

Published
2017
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8. Synthesis and Characterization of 1,1′-Diphosphaplumbocenes: Oxidative Ligand Transfer Reactions with Divalent Thulium Complexes

Author

Aurélien Momin, Louis Ricard, Agathe Martinez, Grégory Nocton, Dominique Harakat, Xavier F. Le Goff, Florian Jaroschik, Institut de Chimie Moléculaire de Reims - UMR 7312 (ICMR), SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-SFR CAP Santé (Champagne-Ardenne Picardie Santé), Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie moléculaire (LCM), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Lanthanide, chemistry.chemical_classification, 010405 organic chemistry, Chemistry, Ligand, Stereochemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Organic Chemistry, chemistry.chemical_element, Nuclear magnetic resonance spectroscopy, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Divalent, Inorganic Chemistry, NMR spectra database, Crystallography, Thulium, Cyclopentadienyl complex, Proton NMR, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry
Abstract

International audience; The new 1,1′-diphosphaplumbocenes Pb(Dtp)2(Dtp = 2,5-di-tert-butyl-3,4-dimethylphospholyl) and Pb(Dsp)2(Dsp = 2,5-ditrimethylsilyl-3,4-dimethylphospholyl) have beensynthesized and characterized by multinuclear NMR spectroscopy.207Pb NMR spectra of both complexes, as well as for theknown complex Pb(Htp)2 (Htp = 2,5-di-tert-butylphospholyl),show that the phospholyl ligands lead to an important downfieldshift compared with that of cyclopentadienyl based plumbocenes.X-ray diffraction studies of the Pb(Dtp)2 complex revealed astructure with two slightly bent η5-bound ligands. This complexwas employed in the oxidative ligand transfer reaction with bulkydivalent thulium complexes. In the case of Tm(Dtp)2, the firstexample of a monomeric trivalent tris(phospholyl)lanthanidecomplex Tm(Dtp)3 was obtained. X-ray diffraction studies andlow-temperature 1H NMR studies show the η1 coordination mode of the third Dtp ligand. In contrast, oxidation of Tm(Cpttt)2(Cpttt is for tris-tert-butylcyclopentadienyl) led presumably to the formation of the ion pair complex [Tm(Cpttt)2][Dtp], in whichno interaction between the free Dtp ligand and Tm was observed, as shown by variable temperature 1H and 31P NMR studies.The new trivalent complexes could be reduced back to the original divalent complexes with potassium graphite.

Published
2016
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9. First experimental determination of the solubility constant of coffinite

Author

H.P. Brau, Xavier F. Le Goff, Adel Mesbah, Stéphanie Szenknect, Nicolas Dacheux, Nicolas Clavier, Rodney C. Ewing, T. Cordara, Christophe Poinssot, Interfaces de Matériaux en Evolution (LIME), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Etude de la Matière en Mode Environnemental (L2ME), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Department of Geological Sciences [Stanford] (GS), Stanford EARTH, Stanford University-Stanford University, and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Supersaturation, Aqueous solution, Chemistry, Analytical chemistry, Mineralogy, Solubility equilibrium, [CHIM.MATE]Chemical Sciences/Material chemistry, 010501 environmental sciences, solubility constant, 010502 geochemistry & geophysics, uranium silicate, 01 natural sciences, uraninite, coffinitization, Gibbs free energy, symbols.namesake, Uraninite, coffinite, Geochemistry and Petrology, silica, symbols, Coffinite, Quartz, Dissolution, 0105 earth and related environmental sciences
Abstract

Dissolution experiments have been performed in order to determine the solubility constant of coffinite, USiO4. Several assemblages of phases were used in under-saturated experiments performed in 0.1 mol L−1 HCl under Ar atmosphere, as well as in air. These samples were fully-characterized and were composed of either USiO4, solely, or USiO4 and additional oxide byproducts that resulted from the synthesis procedure. The solubility constant of coffinite was determined at 25 °C and 1 bar (log *KS°(USiO4, cr) = −5.25 ± 0.05), as well as the standard free energy of formation of coffinite (ΔfG°(298 K) = −1867.6 ± 3.2 kJ mol−1), which enables one to infer the relative stability of coffinite and uraninite as a function of groundwater composition. Geochemical simulations using PHREEQC 2 software and the Thermochimie data base indicate that coffinite precipitates at 25 °C under reducing conditions, at pH = 6, for H4SiO4(aq) concentration of 7 × 10−5 mol L−1 and U(OH)4(aq) concentration of 10−11 mol L−1. The ΔfG° value determined was used to calculate the standard free energy associated with the formation of coffinite from a mixture of uraninite and quartz. The value obtained (Δr,oxG° = 20.6 ± 5.2 kJ mol−1) indicates unambiguously that coffinite is less stable than the quartz + uraninite mixture at 25 °C. Geochemical simulations using PHREEQC 2 software indicate that coffinite precipitates in solutions supersaturated with respect to UO2(cr), but undersaturated with respect to UO2(am) in aqueous solutions with silica concentrations typical of groundwater. These favorable conditions during the formation of sedimentary uranium ore deposits, as well as slow dissolution kinetics, explain the common occurrence of coffinite.

Published
2016
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10. Influence of the solvent, structure and substituents of ruthenium(II) polypyridyl complexes on their electrochemical and photo-physical properties

Author

Jérôme Maynadié, Matthieu Autillo, Daniel Meyer, Xavier F. Le Goff, Kévin Ruffray, Systèmes HYbrides pour la Séparation (LHyS), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Etude de la Matière en Mode Environnemental (L2ME), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010405 organic chemistry, Ligand, Chemistry, chemistry.chemical_element, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, Electrochemistry, Photochemistry, 01 natural sciences, 0104 chemical sciences, Ruthenium, Inorganic Chemistry, Solvent, Electron transfer, Materials Chemistry, Molecule, Photosensitizer, Physical and Theoretical Chemistry, Solvent effects, ComputingMilieux_MISCELLANEOUS
Abstract

This work highlights the relative importance between structural issues, longer range interactions and solvent effects for a series of ruthenium compounds on their electrochemical and photochemical properties. To study these effects, eight complexes of general formula [Ru(bpy)2(L)]2+ have been synthesized and characterized, where L represents substituted phenyl-imidazophenanthrolines (pip), dipyridophenazines (dppz) and pyrazinophenanthrolines (pzp). This experimental work supported by an important theoretical investigation has pointed out that the electrochemical and the photo-physical behavior of these types of molecular systems depends mainly of the close environment around the photosensitizer. A relation between the ditopic ligand structure (aromatic central part and/or the distal substituents) and the absorption properties have been observed, along with the lower reduction potential of dipyridophenazine and pyrazinophenanthroline moieties. This study points out the influence of the nature of the distal substituents, as well as the significant impact of the solvent nature and the interaction with water molecules, on the photo-physical properties of these ruthenium compounds.

Published
2016
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11. Synthesis, electrochemical and spectroscopic properties of ruthenium( ii ) complexes containing 2,6-di(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)aryl ligands

Author

Violaine Goudy, Marc Fontecave, Daniel Meyer, Jérôme Maynadié, Xavier F. Le Goff, Systèmes HYbrides pour la Séparation (LHyS), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Etude de la Matière en Mode Environnemental (L2ME), Collège de France - Chaire Chimie des processus biologiques, Laboratoire de Chimie des Processus Biologiques (LCPB), Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Chaire Chimie des processus biologiques

Subjects
Absorption spectroscopy, 010405 organic chemistry, Stereochemistry, Aryl, chemistry.chemical_element, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, Redox, Catalysis, 0104 chemical sciences, Ruthenium, chemistry.chemical_compound, chemistry, Pyridine, Materials Chemistry, Moiety, Molecule, Bimetallic strip, ComputingMilieux_MISCELLANEOUS
Abstract

A series of dinuclear [(bpy)2Ru(L)Ru(bpy)2]4+ and mononuclear ruthenium(II) complexes [(bpy)2Ru(L)]2+ where bpy is 2,2′-bipyridine and L represents 2,6-di(1H-imidazo[4,5-f][1,10]phenanthrolin-2-yl)aryl ligands (DIP) were synthetized and characterized. An original pathway is proposed to obtain mono and hetero bi- and polymetallic Ru complexes and the relation between the molecular structure, the photophysical and electrochemical properties of the single Ru complexes is analysed. The investigated aryl cores are benzene, pyridine and 4-tert-butyl phenol. This work is focused on the effect of the aromatic moiety on the photoinduced charge transfer in the bimetallic compounds and the results are compared with the monometallic analogues. The absence of effect on the UV-visible absorption spectra and on the redox behavior upon varying the nature of the aryl moiety show that the two metallic centres in [(bpy)2Ru(L)Ru(bpy)2]4+ complexes are independent. However, luminescence measurements coupled with DFT calculations highlight a different photophysical behaviour between mono and dinuclear compounds incorporating the benzene core. Theoretical DFT and TD-DFT modelling was used to support the studied physico-chemical properties of these molecular systems.

Published
2016
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12. Divalent Tetra- and Penta-phenylcyclopentadienyl Europium and Samarium Sandwich and Half-Sandwich Complexes: Synthesis, Characterization, and Remarkable Luminescence Properties

Author

Daniel Werner, Xavier F. Le Goff, Jun Wang, Daisy Daniels, Toby D. M. Bell, Florian Jaroschik, Agathe Martinez, Glen B. Deacon, Gilles Lemercier, Rosalind P. Cox, Peter C. Junk, Rory Kelly, Monash University [Clayton], Institut de Chimie Moléculaire de Reims - UMR 7312 (ICMR), SFR Condorcet, Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Centre National de la Recherche Scientifique (CNRS)-SFR CAP Santé (Champagne-Ardenne Picardie Santé), Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), James Cook University (JCU), Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institute of Inorganic Chemistry, Karlsruhe Institute of Technology (KIT), School of Chemistry, École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie - UMR5182 (LC), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Université de Picardie Jules Verne (UPJV)-Université de Reims Champagne-Ardenne (URCA)-Centre National de la Recherche Scientifique (CNRS), Unité de Mécanique (UME), and École Nationale Supérieure de Techniques Avancées (ENSTA Paris)

Subjects
Lanthanide, chemistry.chemical_classification, 010405 organic chemistry, Ligand, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Organic Chemistry, Inorganic chemistry, chemistry.chemical_element, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Divalent, Inorganic Chemistry, Samarium, NMR spectra database, Crystallography, chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry, Luminescence, Europium, Two-dimensional nuclear magnetic resonance spectroscopy, ComputingMilieux_MISCELLANEOUS
Abstract

International audience; The synthesis of the bulky divalent(polyphenylcyclopentadienyl)lanthanoid sandwich complexes[Ln(C5Ph5)2] (Ln = Sm, Eu) and [Ln(C5Ph4H)2(solv)] (Ln =Sm, solv = thf; Ln = Eu, solv = dme)], from redoxtransmetalation/protolysis (RTP) reactions, has beenachieved. An analogous reaction with Yb afforded thesolvent-separated ion pair [Yb(dme)4][C5Ph4H]2. In addition,rare divalent samarium halide complexes [Sm(C5Ph5)(μ-Br)(thf)2]2 and [Sm(C5Ph4H)I(thf)3], were also prepared,either by RTP or ligand rearrangement. X-ray studies showedthat the [Ln(C5Ph5)2] complexes adopt highly symmetrical sandwich structures, whereas the [Ln(C5Ph4H)2(solv)] complexeshave open sandwich structures. The unexpected, but limited, solubility of the [Ln(C5Ph5)2] complexes allowed for variabletemperatureNMR spectra of [Sm(C5Ph5)2] to be obtained. Detailed 1D and 2D NMR studies were conducted on[Sm(C5Ph4H)2(thf)] to ascertain its structure in donor and nondonor solvents. During the course of these studies, the mixedtetraarylcyclopentadienyl sandwich complex [Sm{C5(2,5-Ph)2(3,4-p-tol2)H}2(thf)] was also prepared in order to fully assign thespectrum of [Sm(C5Ph4H)2(thf)]. The europium sandwich complexes [Eu(C5Ph5)2] and [Eu(C5Ph4H)2(dme)] exhibitremarkable luminescence properties with high quantum yields (45% and 41%, respectively) coupled with long emission lifetimes(approximately 800 and 1300 ns, respectively) in toluene.

Published
2015
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13. Micro-distribution of uranium in bone after contamination: new insight into its mechanism of accumulation into bone tissue

Author

Georges Boivin, Claude Vidaud, Brigitte Burt-Pichat, Damien Bourgeois, Xavier F. Le Goff, Luc Van Hoorebeke, Laszlo Vincze, Gerald Falkenberg, Jan Garrevoet, Daniel Meyer, Melissa A. Denecke, Pieter Tack, Systèmes HYbrides pour la Séparation (LHyS), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Ostéoporose et Qualité osseuse (Site Laennec), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-IFR62-Institut National de la Santé et de la Recherche Médicale (INSERM), Etude de la Matière en Mode Environnemental (L2ME), Universiteit Gent = Ghent University [Belgium] (UGENT), Department of Analytical Chemistry, Institut für Nukleare Entsorgung (INE), Karlsruher Institut für Technologie (KIT), Service de Biochimie et Toxicologie Nucléaire (SBTN), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Ostéoporose et Qualité Osseuse, Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), and Universiteit Gent = Ghent University (UGENT)

Subjects
Male, inorganic chemicals, chemistry.chemical_element, In Vitro Techniques, Bone tissue, complex mixtures, Biochemistry, Apatite, Analytical Chemistry, Rats, Sprague-Dawley, chemistry.chemical_compound, Bone cell, medicine, Animals, Tissue Distribution, Femur, ComputingMilieux_MISCELLANEOUS, Cartilage, Radiochemistry, technology, industry, and agriculture, Absorption, Radiation, Spectrometry, X-Ray Emission, [CHIM.MATE]Chemical Sciences/Material chemistry, Radiation Exposure, Uranium, Uranyl, Skeleton (computer programming), Rats, medicine.anatomical_structure, chemistry, visual_art, Biophysics, Bone Trabeculae, visual_art.visual_art_medium
Abstract

After internal contamination, uranium rapidly distributes in the body; up to 20 % of the initial dose is retained in the skeleton, where it remains for years. Several studies suggest that uranium has a deleterious effect on the bone cell system, but little is known regarding the mechanisms leading to accumulation of uranium in bone tissue. We have performed synchrotron radiation-based micro-X-ray fluorescence (SR μ-XRF) studies to assess the initial distribution of uranium within cortical and trabecular bones in contaminated rats' femurs at the micrometer scale. This sensitive technique with high spatial resolution is the only method available that can be successfully applied, given the small amount of uranium in bone tissue. Uranium was found preferentially located in calcifying zones in exposed rats and rapidly accumulates in the endosteal and periosteal area of femoral metaphyses, in calcifying cartilage and in recently formed bone tissue along trabecular bone. Furthermore, specific localized areas with high accumulation of uranium were observed in regions identified as micro-vessels and on bone trabeculae. These observations are of high importance in the study of the accumulation of uranium in bone tissue, as the generally proposed passive chemical sorption on the surface of the inorganic part (apatite) of bone tissue cannot account for these results. Our study opens original perspectives in the field of exogenous metal bio-mineralization.

Published
2015
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14. Organosilica-metallic sandwich materials as precursors for palladium and platinum nanoparticle synthesis

Author

Xavier F. Le Goff, Julien Cambedouzou, Romain Besnard, Stéphane Pellet-Rostaing, Guilhem Arrachart, Tri ionique par les Systèmes Moléculaires auto-assemblés (LTSM), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Etude de la Matière en Mode Environnemental (L2ME), and Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)

Subjects
Thermogravimetric analysis, Materials science, General Chemical Engineering, Inorganic chemistry, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, Platinum nanoparticles, 01 natural sciences, Catalysis, Metal, symbols.namesake, ComputingMilieux_MISCELLANEOUS, Substrate (chemistry), General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Template, chemistry, visual_art, visual_art.visual_art_medium, symbols, 0210 nano-technology, Raman spectroscopy, Palladium
Abstract

A promising strategy to design highly active catalysts is to use multicomponent catalysts including active metals (such as platinoids) and organosilica as a substrate. In this article, we develop stable OrganoSilica Sandwiches (OSS) consisting of sandwiched metallic layers between organosilica layers. The formation of such a sandwich-like organosilica@platinoid@organosilica material was obtained from bis-silica-alkylammonium carbamate dimers, acting as a template for the immobilization of platinoid salt complexes or metallic nanoparticles in the interlayer space after a reduction treatment. The layered templates and the sandwich structures were investigated by small angle X-ray scattering, coupled thermogravimetric analysis and mass spectrometry, and Raman spectroscopy. It was demonstrated that the meso-structure of the initial template material is not affected by the chemical steps involved in the synthesis of the material and does not depend on the incorporated metal.

Published
2015
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15. Geometry Flexibility of Copper Iodide Clusters: Variability in Luminescence Thermochromism

Author

Aurélie Berhault, Alain Garcia, Charlotte Martineau, Alexandre Fargues, Julien Trébosc, Sandrine Perruchas, Xavier F. Le Goff, Quentin Benito, Grégory Nocton, Samia Kahlal, Jean-Pierre Boilot, Thierry Gacoin, Jean-Yves Saillard, Laboratoire de physique de la matière condensée (LPMC), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de chimie moléculaire (LCM), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université européenne de Bretagne - European University of Brittany (UEB), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Lille, Sciences et Technologies, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), The authors thank the CNRS and the Ecole Polytechnique for funding. J.Y.S. thanks the IUF for its support. Financial support from the TGIR-RMN-THC Fr3050 CNRS for conducting the research is gratefully acknowledged. C.M. is grateful for financial support from Contract No. ANR-12-JS08-0008., Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), and Centrale Lille Institut (CLIL)-Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille

Subjects
Models, Molecular, Luminescence, Magnetic Resonance Spectroscopy, Phosphines, Iodide, Geometry, Crystallography, X-Ray, Ligands, Inorganic Chemistry, chemistry.chemical_compound, Cluster (physics), Organometallic Compounds, Molecule, [CHIM]Chemical Sciences, Molecular orbital, Physical and Theoretical Chemistry, chemistry.chemical_classification, Thermochromism, Molecular Structure, Temperature, [CHIM.MATE]Chemical Sciences/Material chemistry, Iodides, chemistry, Cubane, Quantum Theory, Thermodynamics, Density functional theory, Copper
Abstract

International audience; An original copper(I) iodide cluster of novel geometry obtained by using a diphosphine ligand is reported and is formulated [Cu6I6(PPh2(CH2)3PPh2)3] (1). Interestingly, this sort of “eared cubane” cluster based on the [Cu6I6] inorganic core can be viewed as a combination of the two known [Cu4I4] units, namely, the cubane and the open-chair isomeric geometries. The synthesis, structural and photophysical characterisations, as well as theoretical study of this copper iodide along with the derived cubane (3) and open-chair (2) [Cu4I4(PPh3)4] forms, were investigated. A new polymorph of the cubane [Cu4I4(PPh3)4] cluster is indeed presented (3). The structural differences of the clusters were analyzed by solid-state nuclear magnetic resonance spectroscopy. Luminescence properties of the three clusters were studied in detail as a function of the temperature showing reversible luminescence thermochromism for 1 with an intense orange emission at room temperature. This behavior presents different feature compared to the cubane cluster and completely contrasts with the open isomer, which is almost nonemissive at room temperature. Indeed, the thermochromism of 1 differs by a concomitant increase of the two emission bands by lowering the temperature, in contrast to an equilibrium phenomenon for 3. The luminescence properties of 2 are very different by exhibiting only one single band when cooled. To rationalize the different optical properties observed, density functional theory calculations were performed for the three clusters giving straightforward explanation for the different luminescence thermochromism observed, which is attributed to different contributions of the ligands to the molecular orbitals. Comparison of 3 with its [Cu4I4(PPh3)4] cubane polymorphs highlights the sensibility of the emission properties to the cuprophilic interactions.

Published
2015
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16. Observing and predicting the preferential functionalization of metallic or semiconducting single-walled carbon nanotubes

Author

Julien Cambedouzou, Jimmy Nicolle, Xavier F. Le Goff, Agnès Grandjean, Nanomatériaux pour l'Energie et le Recyclage (LNER), Institut de Chimie Séparative de Marcoule (ICSM - UMR 5257), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Etude de la Matière en Mode Environnemental (L2ME), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Selective chemistry of single-walled nanotubes, General Physics and Astronomy, chemistry.chemical_element, Nanotechnology, 02 engineering and technology, Electronic structure, Carbon nanotube, 010402 general chemistry, 01 natural sciences, law.invention, Condensed Matter::Materials Science, symbols.namesake, law, Molecule, [CHIM]Chemical Sciences, Physics::Chemical Physics, ComputingMilieux_MISCELLANEOUS, Condensed Matter::Mesoscopic Systems and Quantum Hall Effect, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Optical properties of carbon nanotubes, chemistry, Chemical engineering, symbols, Surface modification, 0210 nano-technology, Raman spectroscopy, Carbon
Abstract

The functionalization of single-walled carbon nanotubes was performed with four organic molecules. A careful study involving thermo-gravimetric analysis and Raman spectroscopy allowed us to quantify the grafting rate of each molecule, and to evidence a preferential grafting of metallic or semiconducting tube depending on the molecule under consideration. In order to understand the origin of this selectivity, we performed DFT calculations of the electronic structure of the molecules, and compared it to the electron density of states of carbon nanotubes. This approach allowed us to propose a paradigm for explaining the grafting affinity of organic molecules towards metallic or semiconducting nanotubes, and for estimating the grafting efficiency. It could further be used in order to predict the selectivity of any molecule containing a double or triple carbon bond towards metallic or semiconducting carbon nanotubes.

Published
2014
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17. Polymorphic copper iodide clusters: insights into the mechanochromic luminescence properties

Author

Xavier F. Le Goff, Sandrine Perruchas, Charlotte Martineau, Jean-Pierre Boilot, Samia Kahlal, Quentin Benito, Francis Taulelle, Thierry Gacoin, Sébastien Maron, Alain Garcia, Alexandre Fargues, Laboratoire de physique de la matière condensée (LPMC), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Institut Lavoisier de Versailles (ILV), Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Chimiques de Rennes (ISCR), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Mechanochromic luminescence, Thermochromism, Chemistry, Intermolecular force, chemistry.chemical_element, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, Photochemistry, Biochemistry, Copper, Catalysis, Crystal, Colloid and Surface Chemistry, Polymorphism (materials science), Cluster (physics), Luminescence
Abstract

International audience; An in-depth study of mechanochromic and thermochromic luminescent copper iodide clusters exhibiting structural polymorphism is reported and gives new insights into the origin of the mechanochromic luminescence properties. The two different crystalline polymorphs exhibit distinct luminescence properties with one being green emissive and the other one being yellow emissive. Upon mechanical grinding, only one of the polymorphs exhibits great modification of its emission from green to yellow. Interestingly, the photophysical properties of the resulting partially amorphous crushed compound are closed to those of the other yellow polymorph. Comparative structural and optical analyses of the different phases including a solution of clusters permit us to establish a correlation between the Cu-Cu bond distances and the luminescence properties. In addition, the local structure of the [Cu4I4P4] cluster cores has been probed by (31)P and (65)Cu solid-state NMR analysis, which readily indicates that the grinding process modifies the phosphorus and copper atoms environments. The mechanochromic phenomenon is thus explained by the disruption of the crystal packing within intermolecular interactions inducing shortening of the Cu-Cu bond distances in the [Cu4I4] cluster core and eventually modification of the emissive state. These results definitely establish the role of cuprophilic interactions in the mechanochromism of copper iodide clusters. More generally, this study constitutes a step further into the understanding of the mechanism involved in the mechanochromic luminescent properties of metal-based compounds.

Published
2014
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18. Magnetic properties of structurally characterized binuclear lanthanide complexes bridged by 2,2′-bipyrimidine

Author

Gaël Zucchi, Xavier F. Le Goff, Laboratoire de physique des interfaces et des couches minces [Palaiseau] (LPICM), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Lanthanide, 010405 organic chemistry, Chemistry, Magnetism, Structure, 010402 general chemistry, Photochemistry, 01 natural sciences, Antiferromagnetic coupling, 0104 chemical sciences, Ion, Inorganic Chemistry, Metal, Crystallography, Ferromagnetism, visual_art, 2'-Bipyrimidine, Materials Chemistry, visual_art.visual_art_medium, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry
Abstract

International audience; A family of five homobimetallic complexes with magnetically-active trivalent lanthanides of the second half of the series with general formula [{Ln(tta)3}2(μ-bpm)] (Ln = Gd, Tb, Dy, Ho, Er, tta = 2-thenoyltrifluoroacetonato, bpm = 2,2′-bipyrimidine) has been structurally characterized by X-ray diffraction and the magnetic properties of these complexes are reported. The two lanthanide ions are coordinated to the bridging bpm ligand which connects the two metallic centers. The magnetic behavior of these complexes has been investigated. It revealed that a weak antiferromagnetic coupling is observed with the TbIII, DyIII, HoIII, and ErIII ions while a very weak ferromagnetic exchange between the two GdIII ions was observed.

Published
2012
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19. Transmetalation of a nucleophilic carbene fragment: from early to late transition metals

Author

Xavier F. Le Goff, Hadrien Heuclin, Marie Fustier-Boutignon, Nicolas Mézailles, Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
010405 organic chemistry, Chemistry, Transition metal carbene complex, Metals and Alloys, General Chemistry, 010402 general chemistry, Photochemistry, 01 natural sciences, Medicinal chemistry, Catalysis, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, Transmetalation, Nucleophile, Transition metal, Materials Chemistry, Ceramics and Composites, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Carbene
Abstract

International audience; Early transition metal nucleophilic carbene complexes have been used as stoichiometric carbene transfer agents in a transmetalation process.

Published
2012
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20. Yttrium phosphasalen initiators for rac-lactide polymerization: Excellent rates and high iso-selectivities

Author

Xavier F. Le Goff, Clare Bakewell, Audrey Auffrant, Thi-Phuong-Anh Cao, Nicholas J. Long, Charlotte K. Williams, Department of Chemistry [Imperial College London], Imperial College London, Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Models, Molecular, métal, Iminophosphorane, Polyesters, complexes organométalliques, chemistry.chemical_element, 010402 general chemistry, Ligands, ligand, 01 natural sciences, Biochemistry, Catalysis, catalyse, Polymerization, Metal, Dioxanes, chemistry.chemical_compound, Colloid and Surface Chemistry, Polymer chemistry, Yttrium, [CHIM.COOR]Chemical Sciences/Coordination chemistry, High rate, Lactide, 010405 organic chemistry, Ligand, Stereoisomerism, General Chemistry, Ethylenediamines, 0104 chemical sciences, chemistry, visual_art, chimie de coordination, visual_art.visual_art_medium, Derivative (chemistry)
Abstract

International audience; Highly active yttrium phosphasalen initiators for the stereocontrolled ring-opening polymerization of rac-lactide are reported. The initiators are coordinated by a new class of ancillary ligand: an iminophosphorane derivative of the popular "salen" ligand, termed "phosphasalen". Changing the phosphasalen structure enables access to high iso-selectivities (Pi = 0.84) or hetero-selectivities (Ps = 0.87). The initiators also show very high rates, excellent polymerization control, and tolerance to low loadings; furthermore, no chiral auxiliaries/ligands are needed for the stereocontrol. The combination of such high rates with high iso-selectivities is very unusual.

Published
2012
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21. Mixed (P=S/P=O)-Stabilized Geminal Dianion: Facile Diastereoselective Intramolecular C-H Activations by a Related Ruthenium-Carbene Complex

Author

Xavier F. Le Goff, Nicolas Mézailles, Hadrien Heuclin, Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Phosphine oxide, Geminal, 010405 organic chemistry, Organic Chemistry, chemistry.chemical_element, General Chemistry, 010402 general chemistry, Photochemistry, 01 natural sciences, Medicinal chemistry, Catalysis, 0104 chemical sciences, Ruthenium, chemistry.chemical_compound, chemistry, Intramolecular force, Moiety, Phenyl group, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Carbene, Phosphine
Abstract

International audience; A new unsymmetrical geminal dianion that contained both a phosphine oxide moiety and a phosphine sulfide moiety has been synthesized. Its reactivity towards Ru(II) was explored, which led to the formation of a highly reactive carbene complex that evolved at room temperature to yield a kinetic orthometalated Ru(II) complex through C-H activation of the phenyl group of the phosphine oxide moiety. This insertion was found to be thermally reversible and a second C-H insertion occurred at a phenyl group of the phosphine sulfide moiety to form the thermodynamic orthometalated Ru(II) complex in a diastereospecific manner. DFT calculations fully rationalized the experimental findings in terms of the relative energies of the kinetic and thermodynamic products and allowed the mechanism of this process to be fully understood.

Published
2012
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22. Phosphasalen Yttrium Complexes: Highly Active and Stereoselective Initiators for Lactide Polymerization

Author

Antoine Buchard, Audrey Auffrant, Thi-Phuong-Anh Cao, Xavier F. Le Goff, Charlotte K. Williams, Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Imperial College London

Subjects
Lactide, 010405 organic chemistry, Chemistry, Ligand, Imine, chemistry.chemical_element, Nuclear magnetic resonance spectroscopy, Yttrium, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Catalysis, Inorganic Chemistry, chemistry.chemical_compound, Polymerization, Alkoxide, Polymer chemistry, Organic chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry
Abstract

International audience; Preparation and characterization of three yttrium alkoxide complexes with new phosphasalen ligands are reported. The phosphasalens are analogues of the well-known salen ligands but with iminophosphorane donors replacing the imine function- ality. The three yttrium alkoxide complexes show mono- and dinuclear structures in the solid state, depending on the substituents on the ligand. The new ligands and complexes are characterized using multinuclear NMR spectr oscopy, mass spectrometry, elemental analysis, and single-crystal X-ray diffraction experiments. The complexes are all rapid initiators for lactide polymerization; they show excellent polymerization control on addition of exogeneous alcohol. The mononuclear complex shows extremely rapid rates and a high degree of stereocontrol in rac-lactide polymerization, yielding heterotactic PLA (Psof 0.9). The phosphasalens are, therefore, excellent ligands for lactide ring-opening polymerization catalysis showing superior rates and stereocontrol versus salen ligands, which may be related to their excellent donating ability and the high degrees of steric protection they can confer.

Published
2012
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23. Siloxanol-functionalized copper iodide cluster as a thermochromic luminescent building block

Author

Sandrine Perruchas, Xavier F. Le Goff, Alexandre Fargues, Alain Garcia, Thierry Gacoin, Sébastien Maron, Jean-Pierre Boilot, Nicolas Desboeufs, Laboratoire de physique de la matière condensée (LPMC), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB)

Subjects
chemistry.chemical_classification, Thermochromism, Iodide, Luminescence, 010405 organic chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, Optically active, 010402 general chemistry, Photochemistry, Block (periodic table), 01 natural sciences, Thermochromic materials, Silanol groups, 0104 chemical sciences, Inorganic Chemistry, Silanol, chemistry.chemical_compound, chemistry, Cluster (physics), Physical and Theoretical Chemistry, Copper iodide
Abstract

International audience; A copper iodide cluster bearing reactive silanol groups exhibits thermochromic luminescence properties sensitive to its chemical environment and is thus a suitable building block for the synthesis of optically active materials.

Published
2012
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24. Magneto-structural and photophysical investigations on a dinuclear Sm(III) complex featuring 2,2'-bipyrimidine

Author

Gaël Zucchi, Xavier F. Le Goff, Laboratoire de physique des interfaces et des couches minces [Palaiseau] (LPICM), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Lanthanide, Diffraction, Luminescence, Magnetism, chemistry.chemical_element, 02 engineering and technology, Crystal structure, 010402 general chemistry, Photochemistry, 01 natural sciences, Inorganic Chemistry, Metal, Materials Chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry, Samarium, Chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Crystallography, visual_art, visual_art.visual_art_medium, 0210 nano-technology, Excitation
Abstract

International audience; A homobimetallic complex, [{Sm(tta)3(MeOH)}2(μ-bpm)]*1 bpm (tta = 2-thenoyltrifluoroacetonato, bpm = 2,2′-bipyrimidine) has been synthesized and structurally characterized by single-crystal X-ray diffraction. Magnetic measurements (between 5 and 295 K) show that the two metal centers bridged by the bpm connector are magnetically almost isolated. The SmIII emission is observed upon excitation in a wide range of wavelengths going from the UV to the visible (250-500 nm).

Published
2012
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25. Thermochromic luminescence of copper iodide clusters: the case of phosphine ligands

Author

Thierry Gacoin, Xavier F. Le Goff, Sandrine Perruchas, Cédric Tard, Jean-Yves Saillard, Jean-Pierre Boilot, Samia Kahlal, Alain Garcia, Alexandre Fargues, Laboratoire de physique de la matière condensée (LPMC), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Université de Bordeaux (UB)-Institut Polytechnique de Bordeaux-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes (UR)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université européenne de Bretagne - European University of Brittany (UEB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, Thermochromism, Iodide, Photoluminescence, 010405 organic chemistry, Thermochromic luminescence, [CHIM.MATE]Chemical Sciences/Material chemistry, 010402 general chemistry, Photochemistry, Ligands, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Crystallography, chemistry.chemical_compound, chemistry, Excited state, Cluster (physics), Physical and Theoretical Chemistry, Luminescence, Phosphine, Copper, Monoclinic crystal system
Abstract

International audience; Three copper(I) iodide clusters coordinated by different phosphine ligands formulated [Cu(4)I(4)(PPh(3))(4)] (1), [Cu(4)I(4)(Pcpent(3))(4)] (2), and [Cu(4)I(4)(PPh(2)Pr)(4)] (3) (PPh(3) = triphenylphosphine, Pcpent(3) = tricyclopentylphosphine, and PPh(2)Pr = diphenylpropylphosphine) have been synthesized and characterized by (1)H and (31)P NMR, elemental analysis and single crystal X-ray diffraction analysis. They crystallize in different space groups, namely, monoclinic P21/c, cubic Pa3̅, and tetragonal I4̅2m for 1, 2, and 3, respectively. The photoluminescence properties of clusters 1 and 3 show reversible luminescence thermochromism with two highly intense emission bands whose intensities are temperature dependent. In accordance to Density Functional Theory (DFT) calculations, these two emission bands have been attributed to two different transitions, a cluster centered (CC) one and a mixed XMCT/XLCT one. Cluster 2 does not exhibit luminescence variation in temperature because of the lack of the latter transition. The absorption spectra of the three clusters have been also rationalized by time dependent DFT (TDDFT) calculations. A simplified model is suggested to represent the luminescence thermochromism attributed to the two different excited states in thermal equilibrium. In contrast with the pyridine derivatives, similar excitation profiles and low activation energy for these phosphine-based clusters reflect high coupling of the two emissive states. The effect of the Cu-Cu interactions on the emission properties of these clusters is also discussed. Especially, cluster 3 with long Cu-Cu contacts exhibits a controlled thermochromic luminescence which is to our knowledge, unknown for this family of copper iodide clusters. These phosphine-based clusters appear particularly interesting for the synthesis of original emissive materials.

Published
2011
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26. Pd(II) and Ni(II) complexes featuring a 'phosphasalen' ligand: synthesis and DFT study

Author

Yves Jean, Audrey Auffrant, Pascal Le Floch, Stéphanie Labouille, Xavier F. Le Goff, Thi-Phuong-Anh Cao, Le Goff, Xavier, Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Stereochemistry, Imine, chemistry.chemical_element, Salt (chemistry), 010402 general chemistry, 01 natural sciences, Inorganic Chemistry, Metal, chemistry.chemical_compound, Metal salen complexes, [CHIM.COOR]Chemical Sciences/Coordination chemistry, ComputingMilieux_MISCELLANEOUS, chemistry.chemical_classification, Magnetic moment, 010405 organic chemistry, Ligand, [CHIM.COOR] Chemical Sciences/Coordination chemistry, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Crystallography, Nickel, [CHIM.THEO] Chemical Sciences/Theoretical and/or physical chemistry, chemistry, visual_art, visual_art.visual_art_medium, Cyclic voltammetry
Abstract

A phosphorus analog of salen ligands featuring iminophosphorane functionalities in place of the imine groups was synthesised in 2 steps from o-diphenylphosphinophenol via the preparation of the corresponding bis-aminophosphonium salt. This novel tetradentate ligand (1), which we named phosphasalen, was coordinated to Pd(II) and Ni(II) metal centres affording complexes 6 and 7 respectively, which were characterised by multinuclear NMR, elemental and X-ray diffraction analyses. Both neutral complexes adopt a nearly square-planar geometry around the metal with coordination of all iminophosphorane and phenolate moieties. The electronic properties of these new complexes were investigated by cyclic voltammetry and comparison with known salens was made when possible. Moreover, the particular behaviour of the phosphasalen nickel complex 7 was further investigated through magnetic moment measurements and a DFT study.

Published
2011

27. Magnetic Core−Shell Nanoparticles from Nanoscale-Induced Phase Segregation

Author

Xavier F. Le Goff, Sophie Carenco, Lucian Roiban, Clément Sanchez, Cédric Boissière, Nicolas Mézailles, Jing Shi, Ovidiu Ersen, Laboratoire de Chimie de la Matière Condensée de Paris (site Paris VI) (LCMCP (site Paris VI)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF)-Ecole Nationale Supérieure de Chimie de Paris- Chimie ParisTech-PSL (ENSCP)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, General Chemical Engineering, Shell (structure), Nanoparticle, chemistry.chemical_element, Nanotechnology, General Chemistry, Core shell nanoparticles, Nickel, Magnetic core, chemistry, Chemical physics, Phase (matter), Materials Chemistry, [CHIM]Chemical Sciences, Nanoscopic scale
Abstract

International audience; Nanoscaling of the nickel phosphides profoundly alters their domains of stability. An original mechanism of “nanoscale-induced phase segregation” was uncovered in the present study: the appearance of two crystallized phases inside each single nanoparticle (here, Ni2P and Ni fcc), where the single-phase product (Ni3P) would have been preferred at the bulk scale. This behavior was obtained by reacting at low temperature (

Published
2011
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28. Protonation of a Xantphos-Phosphole Ligand. Intramolecular Trapping of a P-HPhospholium Salt

Author

Xavier F. Le Goff, Aurélie Escalle, Pascal Le Floch, Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Cyclic compound, Denticity, Intramolecular reaction, 010405 organic chemistry, Xantphos, Ligand, Stereochemistry, Organic Chemistry, Phosphole, Protonation, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, chemistry.chemical_compound, chemistry, Intramolecular force, [CHIM.COOR]Chemical Sciences/Coordination chemistry, ComputingMilieux_MISCELLANEOUS
Abstract

Protonation of a bidentate xantphos-phosphole ligand by HBF(4) affords only one enantiomer of a cyclic phospholium dihydropholene structure. DFT calculations allowed us to establish that protonation initially takes place at the phosphorus atom of the phosphole moiety to afford a transient P-H phospholium salt, which in turn protonates the C=C double bond of the second phosphole unit.

Published
2009
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29. Cationic Dimetallic Gold Hydride Complex Stabilized by a Xantphos-Phosphole ligand: Synthesis, X-ray Crystal Structure, and Density Functional Theory Study

Author

Fabien Gagosz, Nicolas Mézailles, Aurélie Escalle, Pascal Le Floch, Guilhem Mora, Xavier F. Le Goff, Yves Jean, Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire de synthèse organique (DCSO)

Subjects
010405 organic chemistry, Hydride, Ligand, Xantphos, Phosphole, Crystal structure, 010402 general chemistry, Antibonding molecular orbital, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Bond length, chemistry.chemical_compound, Crystallography, chemistry, Density functional theory, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS
Abstract

The bis-2,5-diphenylphosphole xantphos ligand (XDPP) 1 reacts with the [AuCl(tht)] complex to afford the monocoordinated [Au(XDPP)Cl] 2 and the dicoordinated chelate species [Au(XDPP)Cl] 3. Addition of AgOTf on this mixture, at room temperature, affords the cationic [Au(XDPP)][OTf] complex 4 which was fully characterized. An X-ray crystal structure analysis confirms the bent structure of this 14 VE [ML(2)](+) complex. Reaction of 4 with HSiMe(2)Ph in tetrahydrofuran at -78 degrees C yields the dinuclear [(XDPP)Au-H-Au(XDPP)](+) cationic complex 5, in which the hydride bridges the two [Au(XDPP)](+) metal fragments. In 5, the Au-P bond lengths are different and the phosphorus atoms which are located nearly trans to the hydride ligand exhibit significantly shorter P-Au bond lengths. Reaction of 4 with DSiMe(2)Ph to form the [(XDPP)Au-D-Au(XDPP)](+) complex 6 allowed to unambiguously ascribe the chemical shift of the deuteride in (2)H NMR (delta = 7.0 ppm with a (2)J(DP) = 8.4 Hz. The electronic structure of the [(XDPP)Au-H-Au(XDPP)](+) complex was studied through density functional theory calculations. An orbital analysis is developed in which complex 5 is viewed as the combination of two 12 electrons fragments [Au(XDPP)](+) with H(-). This analysis reveals that the hydride interacts in a bonding way with the sigma MO between the two gold atoms and in an antibonding way with a combination of d orbitals at the metal centers. This simple description allows to rationalize the inequivalence of the two types of P-Au bonds in 5.

Published
2009
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30. The Effect of a Fourth Binding Site on the Stabilization of Cationic SPS Pincer Palladium Complexes : Experimental, DFT, and Mass Spectrometric Studies

Author

Nicolas Mezailles, Marjolaine Doux, Xavier F. Le Goff, Matthias Blug, Philippe Maître, Pascal Le Floch, François Ribot, Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Université Paris-Sud - Paris 11 (UP11), Laboratoire de Chimie de la Matière Condensée de Paris (site Paris VI) (LCMCP (site Paris VI)), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, Diphenylphosphine, Sulfide, 010405 organic chemistry, Stereochemistry, Ligand, Organic Chemistry, Cationic polymerization, chemistry.chemical_element, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Pincer movement, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Moiety, Picoline, Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS, Palladium
Abstract

A potentially tetradentate ligand was synthesized by the addition of α-Li-picoline to the 2,6-bis(diphenylphosphine sulfide)-3,5-diphenylphosphinine (SPS) ligand. The corresponding Pd complex (3) was obtained by the reaction with [(COD)PdCl2]. An air-stable cationic Pd(II) complex (4) was obtained after abstraction of Cl− with silver salt. The role of the additional binding site in the stabilization of the cationic complex was explored using NMR spectroscopic and tandem ESI-MS studies combined with DFT calculations. Additionally the picoline moiety was used to tune the electronic properties of the cationic complex 7 to modify the activity in the Lewis acid-catalyzed allylation of aldehydes.

Published
2009
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31. Gold(I) catalyzed cycloizomerisation of 1,7- and 1,8-enzymes: application to the synthesis of e new allocochicinoid

Author

Xavier F. Le Goff, François-Didier Boyer, Issam Hanna, Chimie Biologique (UCB), Institut National de la Recherche Agronomique (INRA)-AgroParisTech, Laboratoire Hétéroéléments et Coordination (DCPH), Centre National de la Recherche Scientifique (CNRS)-École polytechnique (X), Laboratoire de synthèse organique (DCSO), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Models, Molecular, Molecular Structure, 010405 organic chemistry, Stereochemistry, Organic Chemistry, Aromatization, 010402 general chemistry, Ring (chemistry), 01 natural sciences, Chemical synthesis, Catalysis, 0104 chemical sciences, Cyclopropane, chemistry.chemical_compound, Cycloisomerization, chemistry, Molecule, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Gold, Colchicine, Isomerization, ComputingMilieux_MISCELLANEOUS
Abstract

Gold(I)-catalyzed cycloisomerization of 1,7- and 1,8-enyne propargylic acetates afforded cyclopropyl derivatives containing seven- and eight-membered rings, respectively. This reaction was used for the synthesis of a new allocolchicinoid having a cyclopropane ring fused to the B seven-membered ring at the C6-C7 positions.

Published
2008
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32. Palladium-Catalyzed Deallylation of Allyl Ethers with a Xanthene Phosphole Ligand. Experimental and DFT Mechanistic Studies

Author

Olivier Piechaczyk, Xavier F. Le Goff, Pascal Le Floch, Guilhem Mora, Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Xanthene, inorganic chemicals, 010405 organic chemistry, Chemistry, Ligand, organic chemicals, Organic Chemistry, Phosphole, Cationic polymerization, chemistry.chemical_element, food and beverages, Ether, 010402 general chemistry, Cleavage (embryo), 01 natural sciences, Medicinal chemistry, 3. Good health, 0104 chemical sciences, Catalysis, Inorganic Chemistry, chemistry.chemical_compound, Organic chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry, Palladium
Abstract

International audience; A cationic xanthene phosphole palladium allyl complex efficiently catalyzes the deallylation of allyl ethers into alcohols and the concomitant formation of allyl amines. Parallel experiments and DFT calculations show that acidic catalysis plays a significant role in promoting the cleavage of the C−O bond in a 16 VE complex featuring an allyl ether as η2-ligand.

Published
2008
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33. Thermochromic luminescence of sol−fel films based on copper Iodide clusters

Author

Cédric Tard, Arnaud Etcheberry, Xavier F. Le Goff, Sandrine Perruchas, François Guillen, Thierry Gacoin, Jacky Vigneron, Sébastien Maron, Alain Garcia, Jean-Pierre Boilot, Laboratoire de physique de la matière condensée (LPMC), École polytechnique (X)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Hétéroéléments et Coordination (DCPH), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie de la Matière Condensée de Bordeaux (ICMCB), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut Polytechnique de Bordeaux-Université de Bordeaux (UB), Institut Lavoisier de Versailles (ILV), and Université de Versailles Saint-Quentin-en-Yvelines (UVSQ)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Materials science, Luminescence, General Chemical Engineering, Gel matrix, Inorganic compounds, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, chemistry.chemical_compound, X-ray photoelectron spectroscopy, Materials Chemistry, Sol-gel process, Sol-gel, Films, Thermochromism, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, chemistry, Light emission, 0210 nano-technology, Phosphine, Copper iodide
Abstract

International audience; The incorporation of copper iodide clusters in sol−gel silica has been investigated to prepare materials with original luminescent properties. The synthesis, structural characterizations, and optical properties of sol−gel films containing [Cu4I4L4] clusters, L = phosphine-based ligands, are reported. Clusters studied are [Cu4I4(PPh2(CH2)2Si(OCH2CH3)3)4] (C1), able to copolymerize with the silica matrix, and [Cu4I4(PPh2(CH2)2CH3)4] (C2) used as a reference for the characterizations. The luminescent films exhibit the optical properties of these clusters in accordance with XPS and NMR studies demonstrating their integrity in the gel matrix. The temperature dependence of light emission properties of clusters and films shows, for the first time for phosphine-based [Cu4X4L4] clusters, thermochromic luminescence with bright yellow luminescence at room temperature and purple emission at 77 K. As a result of weak Cu−Cu interactions, the two emissive states appear as highly coupled with a low energy barrier (2 kJ·mol−1), leading to a controlled thermochromism in a large temperature range.

Published
2008
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34. Synthesis, Structure, and Coordination Properties of 1,1'- bis(bis(trifluoromethyl)phosphino)ferrocene, dfmpf

Author

Louis Ricard, Euclides J. Velazco, Andrew J. M. Caffyn, Xavier F. Le Goff, Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Trifluoromethyl, 010405 organic chemistry, Stereochemistry, Organic Chemistry, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 3. Good health, 0104 chemical sciences, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Ferrocene, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS
Abstract

The new highly electron deficient ferrocenyldiphosphines [Fe{η5-C5H4P(CF3)2}2] (dfmpf) and [Fe{η5-C5H4P(C2F5)2}2] (dfepf) were synthesized by reaction of [Fe{η5-C5H4P(OPh)2}2] with CnF2n+1SiMe3/CsF...

Published
2008
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35. Ring-Closing Metathesis in the Synthesis of BC Ring-Systems of Taxol

Author

Cong Ma, Stéphanie Schiltz, Joëlle Prunet, Xavier F. Le Goff, Laboratoire de synthèse organique (DCSO), École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), and Laboratoire Hétéroéléments et Coordination (DCPH)

Subjects
Models, Molecular, Magnetic Resonance Spectroscopy, Paclitaxel, Stereochemistry, Taxol, chemistry.chemical_element, 010402 general chemistry, Metathesis, Ring (chemistry), 01 natural sciences, Catalysis, Mass Spectrometry, Ring-Closing Metathesis, Ring-closing metathesis, Salt metathesis reaction, Moiety, Protecting group, 010405 organic chemistry, Chemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Organic Chemistry, General Chemistry, Antineoplastic Agents, Phytogenic, 0104 chemical sciences, Ruthenium, Cyclization
Abstract

International audience; BC ring-systems of taxol with different or no protecting group for the C1,C2 diol moiety have been efficiently synthesized. The 8-membered B ring is formed by a ring-closing metathesis (RCM) between the C10 and C11 carbons. The influence of the 1,2-diol protecting group on the RCM reaction has been studied in details.

Published
2008
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36. Xanthene-phosphole ligands: Synthesis, coordination chemistry, and activity in the palladium-catalyzed amine allylation

Author

Pascal Le Floch, Xavier F. Le Goff, and Louis Ricard, Steven van Zutphen, Guilhem Mora, Bernard Deschamps, Laboratoire Hétéroéléments et Coordination (DCPH), and École polytechnique (X)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
chemistry.chemical_classification, Allyl chloride, Double bond, 010405 organic chemistry, Ligand, Stereochemistry, Organic Chemistry, Phosphole, chemistry.chemical_element, 010402 general chemistry, 01 natural sciences, Medicinal chemistry, 0104 chemical sciences, Coordination complex, Inorganic Chemistry, chemistry.chemical_compound, chemistry, Nucleophilic substitution, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry, Trifluoromethanesulfonate, Palladium
Abstract

International audience; Two new xanthene-phosphole derivatives, 3 and 4, were synthesized through the nucleophilic substitution of the cyano group in 1-P-cyano-2,5-diphenylphosphole (1) and 1-P-cyano- 3,4- dimethylphosphole (2) by the 4,5-dilithium salt of 9,9'-dimethylxanthene. For this, a new synthetic procedure was developed, allowing the synthesis of the required 1-P-cyano-2,5-diphenylphosphole from the 1,2,5-triphenylphosphole. Both ligands (DPP-Xantphos 3 for the diphenyl derivative and DMP-Xantphos 4 for the dimethyl derivative) react with [Pd(allyl)Cl](2) to afford the corresponding cationic complexes 5Cl and 6Cl. Using AgOTf, stable triflate complexes 5OTf and 6OTf could be isolated. The chloride complexes, on the other hand, exhibit a limited stability in solution. The DPP-Xantphos derivative 5Cl eliminates allyl chloride to yield the dimeric palladium(0) complex 7 of general formula [Pd(3)](2), in which each palladium is coordinated to the two phosphorus atoms of the same ligand and to one double bond of one phosphole unit of the second ligand. Decomposition of complex 6Cl furnished a mixture of compounds featuring a dimeric trinuclear species of general formula [Pd-3(4)(2)Cl-2]. This complex was also synthesized directly. Reaction of the DMP-Xantphos ligand 4 with 1 equiv of [Pd(COD)Cl-2] and 2 equiv of [Pd(dba)(2)] afforded dimer 8, which features one 18-VE Pd-0 center and two Pd-Cl fragments, which are coordinated to the dienic system of the two phosphole ligands and connected through a single Pd-Pd bond. The catalytic activity of the triflate complexes 5OTf and 6OTf was evaluated in the allylation of aniline. Whereas the DMP-Xantphos derivative 6OTf exhibited a poor catalytic activity, very good conversion yields were obtained with the DPP-Xantphos complex 5OTf. On the basis of X-ray structure data and DFT calculations, it was concluded that the high catalytic activity of the DPP-Xantphos derivative complex [Pd(allyl)(3)]-[OTf] (6OTf) results from the combination of two effects: a large P-Pd-P bite angle, which enhances the reactivity of the allyl ligand, and the strong pi-accepting capacity of the diphenylphosphole moiety, which allows the easy formation of a 14-VE complex.

Published
2007
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