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1. Determining Local Magnetic Susceptibility Tensors in Paramagnetic Lanthanide Crystalline Powders from Solid-State NMR Chemical Shift Anisotropies

Author: Ridvan Ince, Abdelatif Doudouh, Nicolas Claiser, Éric Furet, Thierry Guizouarn, Laurent Le Pollès, Gwendal Kervern, Cristallographie, Résonance Magnétique et Modélisations (CRM2), Université de Lorraine (UL)-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), and Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)
Subjects: [CHIM]Chemical Sciences, Physical and Theoretical Chemistry
Abstract: International audience; Exploring magnetic properties at the molecular level is a challenge that have been met by developing many experimental and theoretical solutions such as polarized neutron diffraction (PND), muon-spin rotation (µ-SR), electron paramagnetic resonance (EPR), SQUID-based magnetometry measurements and advanced modelling on openshell systems and relativistic calculations. These methods are powerful tools that shed light on the local magnetic response in specifically designed magnetic materials such as contrast agents, for MRI, molecular magnets, magnetic tags for biological NMR etc.All of these methods have their advantages and disadvantages. In order to complement the possibilities offered by these methods, we propose a new tool that implements a new approach combining simulation and fitting for high-resolution solid-state NMR spectra of lanthanide-based paramagnetic species.This method relies on a rigorous acquisition thanks to Short Highpower Adiabatic Pulses (SHAP) of high-resolution solid-state NMR isotropic and anisotropic data on a powdered magnetic material. It is also based on an efficient modelling of this data thanks to a semi-empirical model based on a parametrization of the local magnetism and the crystal structure provided by diffraction methods. The efficiency of the calculation relies on a thorough simplification of the electron-nucleus interactions (point-dipole interaction, no Fermi-contact) which is validated by experimental analysis. By taking advantage of the efficient calculation possibilities offered by our method, we can compare a great number of simulated spectra to experimental data and find the best-matching local magnetic susceptibility tensor. This method was applied to a series of isostructural lanthanide oxalates which are used as a benchmark system for many analytical methods. We present the results of thorough solid-state NMR and extensive modelling of the hyperfine interaction (including up to 400 paramagnetic centers) that yields local magnetic susceptibility tensors measurements that are self-consistent aswell as consistent with bulk susceptibility measurements.
Published: 2023
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2. Investigation of Intermetallic Energy Transfers in Lanthanide Coordination Polymers Molecular Alloys: Case Study of Trimesate-Based Compounds

Author: Chloé Blais, Carole Daiguebonne, Yan Suffren, Kevin Bernot, Guillaume Calvez, Laurent Le Pollès, Claire Roiland, Stéphane Freslon, Olivier Guillou, Institut des Sciences Chimiques de Rennes (ISCR), 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: Inorganic Chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry
Abstract: International audience; Reactions in water at ambient temperature and pressure between a lanthanide ion and benzene-1,3,5-tricarboxylate (or trimesate) lead to two series of iso-structural coordination polymers. Their general chemical formula is [Ln(tma)(H(2)O)(6)](∞) for the lightest lanthanide ions (Ln = La-Dy except Pm), while it is [Ln(tma)(H(2)O)(5)·3.5H(2)O](∞) for the heaviest ones (Ho-Lu plus Y). For the heaviest lanthanide ions, reactions at 50 °C lead to a third structural family with the general chemical formula [Ln(tma)(H(2)O)(3)·1.5H(2)O](∞) with Ln = Ho-Lu plus Y. Homo-lanthanide coordination polymers that belong to the latter two families do not exhibit luminescence in the visible region. Therefore, we used a phase induction strategy to obtain molecular alloys that belong to these structural families and show sizeable emission. The random distribution of the lanthanide ions over the metallic sites has been investigated using (89)Y and (139)La solid-state NMR spectroscopy experiments. Luminescent properties of homo- and hetero-nuclear coordination polymers based on Eu(3+) and Tb(3+) have been studied in detail and compared. As a result, this study strongly suggests that exchange-based intermetallic energy transfer mechanisms play an important role in these systems. It also suggests the presence of an intermetallic exchange pathway through π-stacking interactions.
Published: 2022
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3. Multi-Emissive Lanthanide-Based Coordination Polymers for Potential Application as Luminescent Bar-Codes

Author: Guillaume Calvez, Stéphane Freslon, Yan Suffren, Kevin Bernot, Laurent Le Pollès, Claire Roiland, Carole Daiguebonne, Jinzeng Wang, Olivier Guillou, 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), Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES), The China Scholarship Council Ph.D. Program and the cooperation program with the French UT & INSA are acknowledged for financial support., 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), and Institut National des Sciences Appliquées (INSA)
Subjects: Lanthanide, chemistry.chemical_classification, 010405 organic chemistry, Chemistry, Intermetallic, Polymer, 010402 general chemistry, 01 natural sciences, Chemical formula, 0104 chemical sciences, Ion, Inorganic Chemistry, Physical chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Emission spectrum, Physical and Theoretical Chemistry, Isostructural, Luminescence, ComputingMilieux_MISCELLANEOUS
Abstract: Isostructural lanthanide-based coordination polymers that are obtained by reactions in water of a lanthanide chloride and the sodium salt of 5-methoxyisophthalate (mip2-) have the general chemical formula [Ln2(mip)3(H2O)8·4H2O]∞ with Ln = Nd-Er except Pm plus Y (symbolized by [Ln2(mip)3]∞). Some of these homo-lanthanide compounds present very high luminescence brightness. The weak intermetallic energy transfer between lanthanide ions observed in these compounds allows the design of hetero-lanthanide coordination polymers with tunable luminescence properties. A molecular alloy that involved six different lanthanide ions (Nd3+, Sm3+, Eu3+, Gd3+, Tb3+, Dy3+) has been prepared and its luminescent properties have been studied. This compound, under a unique irradiation wavelength (λexc = 325 nm), exhibits almost 20 emission peaks in both the visible and the NIR regions at room temperature. This unprecedented richness of the emission spectrum could be of great interest as far as luminescent bar-codes are targeted.
Published: 2019
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4. Synthesis and characterization of composite Hg-polyaniline powder material

Author: Sofiane, Bouazza, Didier, Hauchard, and Laurent, Le Pollès
Published: 2006
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5. Rationalization of solid-state NMR multi-pulse decoupling strategies: Coupling of spin I = ½ and half-integer quadrupolar nuclei

Author: Laurent Delevoye, Laurent Le Pollès, Nasima Kanwal, Eric Le Fur, Julien Trébosc, Sharon E. Ashbrook, Cassandre Kouvatas, Claire Roiland, Laboratoire catalyse et spectrochimie (LCS), Université de Caen Normandie (UNICAEN), Normandie Université (NU)-Normandie Université (NU)-École Nationale Supérieure d'Ingénieurs de Caen (ENSICAEN), Normandie Université (NU)-Centre National de la Recherche Scientifique (CNRS), Unité de Catalyse et de Chimie du Solide - UMR 8181 (UCCS), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Ecole Centrale de Lille-Université d'Artois (UA), Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-Ecole Nationale Supérieure de Chimie de Rennes-Centre National de la Recherche Scientifique (CNRS), School of Chemistry, University of St Andrews, University of St Andrews [Scotland], 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 Lille, Sciences et Technologies, Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), 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, School of Chemistry [University of St Andrews], ANR MOSAIC 13-BS08-0018-01, Agence Nationale de la RechercheAgence Nationale de la Recherche, ANR-13-BS08-0018,MOSAIC,Caractérisation structurale multiéchelle, Operando de Catalyseurs industriels de type phosphate de vanadium(2013), 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 d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), University of St Andrews. School of Chemistry, and University of St Andrews. EaSTCHEM
Subjects: Simulations, heteronuclear scalar interaction, Nuclear and High Energy Physics, Multi-phase decoupling, Scalar (mathematics), NDAS, Biophysics, Resolution improvement, characterization of inorganic materials, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, J-coupling, 01 natural sciences, Biochemistry, Spectral line, Half integer quadrupolar nucleus, 030218 nuclear medicine & medical imaging, Heteronuclear scalar interactions, resolution improvement, 03 medical and health sciences, 0302 clinical medicine, Characterization of inorganic materials, [CHIM.CRIS]Chemical Sciences/Cristallography, [CHIM]Chemical Sciences, QD, ComputingMilieux_MISCELLANEOUS, Solid state NMR, Physics, [CHIM.CATA]Chemical Sciences/Catalysis, [CHIM.MATE]Chemical Sciences/Material chemistry, Decoupling (cosmology), QD Chemistry, Condensed Matter Physics, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Dipole, Solid-state nuclear magnetic resonance, Heteronuclear molecule, Multi-Pulse decoupling, half integer quadrupolar nucleus, Half-integer, simulations, Atomic physics
Abstract: This work benefited from a grant from Agence Nationale de la Recherche (ANR MOSAIC 13-BS08-0018-01). In this paper we undertake a study of the decoupling efficiency of the Multiple-Pulse (MP) scheme, and a rationalization of its parameterization and of the choice of instrumental set up. This decoupling scheme is known to remove the broadening of spin-1/2 spectra I, produced by the heteronuclear scalar interaction with a half-integer quadrupolar nucleus S, without reintroducing heteronuclear dipolar interaction. The resulting resolution enhancement depends on the set-up of the length of the series of pulses and delays of the MP, and some intrinsic material and instrumental parameters. Firstly through a numerical approach, this study investigates the influence of the main intrinsic material parameters (heteronuclear dipolar and J coupling, quadrupolar interaction, spin nature) and instrumental parameters (spinning rate, pulse field strength) on efficiency and resolution enhancement of the scalar decoupling scheme. A guideline is then proposed to obtain quickly and easily the best resolution enhancement via the rationalization of the instrumental and parameter set up. It is then illustrated and tested through experimental data, probing the efficiency of MP-decoupling set up using this guideline. Various spin systems were tested (31P-51V in VOPO4, 31P-93Nb in NbOPO4, 119Sn-17O in Y2Sn2O7), combined with simulations results. Postprint Postprint
Published: 2019
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6. Anomalous Dynamics of a Nanoconfined Gas in a Soft Metal-Organics Framework

Author: Claire Roiland, Thierry Bataille, Laurent Le Pollès, Roald Boulé, Aziz Ghoufi, Nathalie Audebrand, 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 de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), ANR-17-CE29-0003, Agence Nationale de la Recherche, ANR-17-CE29-0003,MeaCoPA,Contrôle mécanique de la porosité pour une modulation à souhait des propriétés de captage et de séparation moléculaire(2017), 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 Rennes 1 (UR1), and Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)
Subjects: [PHYS]Physics [physics], Materials science, Nanoporous, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Molecular dynamics, Adsorption, Zigzag, Chemical physics, Molecule, [CHIM]Chemical Sciences, General Materials Science, Dynamical heterogeneity, Physical and Theoretical Chemistry, Diffusion (business), 0210 nano-technology, Porous medium
Abstract: International audience; Dynamics of confined molecules within porous materials is equally important as local structural order, and it is necessary to quantify it and to reveal the microscopic mechanisms ruling it for better control of adsorption applications. In this study, molecular dynamics simulations were carried out to investigate the translational and the rotational dynamics of methanol trapped into the flexible NH-MIL-53(Al) metal-organics framework (MOF). Indeed, atomistic simulation is nowadays a relevant tool to explore matter at the nanoscale. Very recently it has been shown that the NH-MIL-53(Al) MOF material was capable to undergo a reversible structural transition (breathing phenomenon) by combining adsorption and thermal stimuli. This flexibility can drastically affect the dynamics of confined molecules and therefore the successful conduct of adsorption applications such as gas storage and separation. Rotational and translational dynamics of confined methanol through nanoporous flexible NH-MIL-53(Al) MOF were then deeply investigated by exploring a broad range of dynamical properties to extract the molecular mechanisms ruling them. This study allowed us to shed light on the interplay of dynamics of confined fluids and flexibility of porous material and to highlight the physical insights in diffusion mechanisms of confined molecules. Anomalous translational diffusion was evidenced due to a dynamical heterogeneity caused by a combination of a localized dynamics at the subnanometric scale and translational jumps between nanodomains in a zigzag scheme between the hydroxide group of the NH-MIL-53(Al). Actually, the non-Fickian dynamics of methanol is the result of the specific host-guest interactions and the MOF flexibility involving the pore opening. Eventually, decoupling between both rotational and translational dynamics related to breaking in the Stokes-Einstein relation was highlighted.
Published: 2019
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7. Multinuclear NMR as a tool for studying local order and dynamics in CH3NH3PbX3(X = Cl, Br, I) hybrid perovskites

Author: Thierry Bataille, Claudine Katan, Jean-Claude Ameline, Laurent Le Pollès, Emmanuelle Deleporte, Bruno Alonso, Khaoula Jemli, Régis Gautier, Claire Roiland, Gaëlle Trippé-Allard, Jacky Even, Institut des Sciences Chimiques de Rennes (ISCR), 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 Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Rennes-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES), Laboratoire Aimé Cotton (LAC), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Photophysique et Photochimie Supramoléculaires et Macromoléculaires (PPSM), École normale supérieure - Cachan (ENS Cachan)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS), Institut de Physique de Rennes (IPR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Fonctions Optiques pour les Technologies de l'informatiON (FOTON), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université européenne de Bretagne - European University of Brittany (UEB)-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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-Télécom Bretagne, Cellule Energie du CNRS (SOLHYBTRANS Project)University of Rennes 1 (Action Incitative, D ́efis Scientifiques Emergents 2015). Banque Populaire de l’Ouest for its financial support (Grant PEROPHOT 2015). Rennes Métropole and Région Betagne (FEDER), European Project: 687008,H2020,H2020-FETOPEN-2014-2015-RIA,GOTSolar(2016), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École normale supérieure - Cachan (ENS Cachan), École normale supérieure - Cachan (ENS Cachan)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS), 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 Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), 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), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UR)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), and Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS)
Subjects: Deuterium NMR, Phase transition, Carbon-13 NMR satellite, Chemistry, Analytical chemistry, General Physics and Astronomy, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, Fluorine-19 NMR, Nuclear magnetic resonance spectroscopy, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, Carbon-13 NMR, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Transverse relaxation-optimized spectroscopy, Physical and Theoretical Chemistry, 0210 nano-technology, Perovskite (structure)
Abstract: We report on 207Pb, 79Br, 14N, 1H, 13C and 2H NMR experiments for studying the local order and dynamics in hybrid perovskite lattices. 207Pb NMR experiments conducted at room temperature on a series of MAPbX3 compounds (MA = CH3NH3+; X = Cl, Br and I) showed that the isotropic 207Pb NMR shift is strongly dependent on the nature of the halogen ions. Therefore 207Pb NMR appears to be a very promising tool for the characterisation of local order in mixed halogen hybrid perovskites. 207Pb NMR on MAPbBr2I served as a proof of concept. Proton, 13C and 14N NMR experiments confirmed the results previously reported in the literature. Low temperature deuterium NMR measurements, down to 25 K, were carried out to investigate the structural phase transitions of MAPbBr3. Spectral lineshapes allow following the successive phase transitions of MAPbBr3. Finally, quadrupolar NMR lineshapes recorded in the orthorhombic phase were compared with simulated spectra, using DFT calculated electric field gradients (EFG). Computed data do not take into account any temperature effect. Thus, the discrepancy between the calculated and experimental EFG evidences the fact that MA cations are still subject to significant dynamics, even at 25 K.
Published: 2016
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8. Experimental and Theoretical Insights into the Structure of Tellurium Chloride Glasses

Author: A. Lecomte, David Le Coq, Laurent Le Pollès, Shinji Kohara, Lila Bouëssel du Bourg, Eugene Bychkov, Chris J. Benmore, Eric Furet, 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), Argonne National Laboratory [Lemont] (ANL), Laboratoire de Physico-Chimie de l'Atmosphère (LPCA), Université du Littoral Côte d'Opale (ULCO)-Centre National de la Recherche Scientifique (CNRS), DE-AC02-06CH1135, DOE, U.S. Department of Energy, JAERI, Japan Atomic Energy Research Institute, 2011B1565, BES, Basic Energy Sciences, ANL, Argonne National Laboratory, 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: Bridging (networking), Chemistry, Ionic bonding, Binary number, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Inorganic Chemistry, Chalcogen, Molecular dynamics, Covalent bond, Chemical physics, 0103 physical sciences, Neutron, Physical and Theoretical Chemistry, 010306 general physics, Reciprocal
Abstract: International audience; The structure of the binary chalcohalide glasses TeCl (0.35 ≤ x ≤ 0.65) is considered by combining experimental and theoretical results. The structural network properties are influenced by a competition between ionic and covalent bonding in such glasses. At first, a focus is placed on the detailed information available by using the complementary high-energy X-ray and the neutron diffractions in both the reciprocal and real spaces. The main characteristic suggested by the structure factors S( Q) concerns the presence of three length scales in the intermediate range order. The total correlation function T( r) lets us also suppose that the structure of these glasses is more complicated than Te-chain fragments with terminal Cl as demonstrated in crystalline TeCl. Molecular dynamics simulations were subsequently performed on TeCl and TeCl, and coupled with the experimental data, a highly reticulated network of chalcogen atoms, with a fair amount of chlorine atoms bonded in a bridging mode, is proposed. The simulations clearly lead to a glass description that differs markedly from the simple structural model based on only Te atom chains and terminal Cl atoms. Solid-state NMR experiments and NMR parameters calculations allowed validation of the presence of Te highly coordinated with chlorine in these glasses.
Published: 2018
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9. Impact of Te on the structure and77Se NMR spectra of Se-rich Ge–Te–Se glasses: a combined experimental and computational investigation

Author: Michaël Deschamps, Bruno Bureau, Chris J. Pickard, Catherine Boussard-Plédel, Laurent Le Pollès, Lila Bouëssel du Bourg, Eric Furet, and Claire Roiland
Subjects: NMR spectra database, Molecular dynamics, Molecular model, Chemistry, Spin echo, Analytical chemistry, General Physics and Astronomy, chemistry.chemical_element, Physical and Theoretical Chemistry, Tellurium, Spinning
Abstract: Selenium-rich Ge–Te–Se glasses have been synthesized along the GeSe4–GeTe4 pseudo-composition line and acquired by 77Se Hahn echo magic-angle spinning NMR. The comparison with the GeSe4 spectrum shows a drastic modification of the typical double-resonance lineshape even at low Te concentrations (
Published: 2015
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10. Extended Investigations on Luminescent Cs2[Mo6Br14]@SiO2 Nanoparticles: Physico-Structural Characterizations and Toxicity Studies

Author: Francisco Cabello-Hurtado, Pascal Pellen, Claire Roiland, Hajime Haneda, Sylvie Jeanne, Tangi Aubert, Koji Kimoto, Fabien Grasset, Stéphane Cordier, Laurent Le Pollès, Chrystelle Neaime, Dominique Lebret-Chauvel, Noriko Saito, Marie-Andrée Esnault, Naoki Ohashi, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ecosystèmes, biodiversité, évolution [Rennes] (ECOBIO), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), National Institute for Materials Science (NIMS), Région Bretagne, College Doctoral Franco-Japonais, ANR-11-BS08-0013,CLUSTOP,Nanoparticules de silice multifonctionnelles à architectures complexes à base de clusters de métaux de transitions pour des applications en biotechnologies(2011), 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 de Rennes (UR)-Institut Ecologie et Environnement (INEE), Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), and Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Materials science, Photoluminescence, Nanoparticle, Nanotechnology, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Risk evaluation, Silica nanoparticles, General Energy, Silica matrix, Sio2 nanoparticles, Microemulsion, Physical and Theoretical Chemistry, 0210 nano-technology, Luminescence
Abstract: International audience; Functional silica nanoparticles and in particular luminescent silica nanoparticles constitute very promising candidates for many applications in the field of biotechnology, theranostics, and photonics. However, optimizing the design of such materials requires a deep understanding of their physicochemical properties. In this article are reported extended investigations on luminescent Cs2[Mo6Br14]@SiO2 nanoparticles prepared by a water-in-oil microemulsion technique. We bring here new insights into the structure of such nanoparticles and its interplay with their optical properties. The structural interactions between the cluster units and the silica matrix were investigated and are discussed in details on the basis of FE-SEM, HAADF-STEM, ICP-OES, BET, 29Si MAS NMR, and photoluminescence studies. As part of the risk evaluation before potential applications, the toxicity of the nanoparticles both on plants and on human cells was evaluated.
Published: 2013
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11. Multinuclear NMR as a tool for studying local order and dynamics in CH

Author: Claire, Roiland, Gaelle, Trippé-Allard, Khaoula, Jemli, Bruno, Alonso, Jean-Claude, Ameline, Régis, Gautier, Thierry, Bataille, Laurent, Le Pollès, Emmanuelle, Deleporte, Jacky, Even, and Claudine, Katan
Abstract: We report on
Published: 2016

12. Magic Angle Spinning 207 Pb and low temperature deuterium NMR as a tool for studying local order and dynamics in CH 3 NH 3 PbX 3 (X=Cl, Br, I) hybrid perovskites

Author: Claire Roiland, Gaëlle Trippé-Allard, Jemli, K., Alonso, C., Jean-Claude Ameline, Regis Gautier, Laurent Le Pollès, Emmanuelle Deleporte, Jacky Even, Claudine Katan, 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), Laboratoire Aimé Cotton (LAC), École normale supérieure - Cachan (ENS Cachan)-Université Paris-Sud - Paris 11 (UP11)-Centre National de la Recherche Scientifique (CNRS), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM), 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 de Physique de Rennes (IPR), Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS), Fonctions Optiques pour les Technologies de l'informatiON (FOTON), Université de Rennes (UR)-Université européenne de Bretagne - European University of Brittany (UEB)-Institut National des Sciences Appliquées - Rennes (INSA Rennes), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Télécom Bretagne-Centre National de la Recherche Scientifique (CNRS), European Project: 687008,H2020,H2020-FETOPEN-2014-2015-RIA,GOTSolar(2016), 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), Centre National de la Recherche Scientifique (CNRS)-Université Paris-Sud - Paris 11 (UP11)-École normale supérieure - Cachan (ENS Cachan), Institut Charles Gerhardt Montpellier - Institut de Chimie Moléculaire et des Matériaux de Montpellier (ICGM ICMMM), Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Centre National de la Recherche Scientifique (CNRS)-Université de Montpellier (UM)-Université Montpellier 1 (UM1)-Université Montpellier 2 - Sciences et Techniques (UM2)-Institut de Chimie du CNRS (INC), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université européenne de Bretagne - European University of Brittany (UEB)-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)-École Nationale Supérieure des Sciences Appliquées et de Technologie (ENSSAT)-Centre National de la Recherche Scientifique (CNRS)-Télécom Bretagne
Subjects: [CHIM.MATE]Chemical Sciences/Material chemistry, [PHYS.COND]Physics [physics]/Condensed Matter [cond-mat], ComputingMilieux_MISCELLANEOUS
Abstract: National audience
Published: 2016

13. Synthesis, Crystal and Electronic Structures, and Magnetic Properties of LiLn9Mo16O35 (Ln=La, Ce, Pr, and Nd) Compounds Containing the Original Cluster Mo16O36

Author: Jérôme Cuny, Patrick Gougeon, Laurent Delevoye, Régis Gautier, Philippe Gall, Julien Trébosc, Laurent Le Pollès, 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), Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), 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, Région Bretagne, 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), and Université d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS)
Subjects: Inorganic chemistry, chemistry.chemical_element, Electronic structure, Crystal structure, 010402 general chemistry, 01 natural sciences, Catalysis, Crystal, molybdenum, NMR spectroscopy, Lanthanum, 010405 organic chemistry, Chemistry, Organic Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, electronic structure, Magnetic susceptibility, 0104 chemical sciences, Crystallography, Octahedron, 13. Climate action, density functional calculations, cluster compounds, Lithium, Single crystal
Abstract: International audience; The new compounds LiLn(9)Mo(16)O(35) (Ln=La, Ce, Pr, and Nd) were synthesized from stoichiometric mixtures of Li(2)MoO(4), Ln(2)O(3), Pr(6)O(11) or CeO(2), MoO(3), and Mo heated at 1600 °C for 48 h in a molybdenum crucible sealed under a low argon pressure. The crystal structure, determined from a single crystal of the Nd member, showed that the main building block is the Mo(16)O(36) unit, the Mo(16) core of which is totally new and results from the fusion of two bioctahedral Mo(10) clusters. It can also be viewed as a fragment of an infinite twin chain of edge-sharing Mo(6) octahedra. The Mo(16)O(36) cluster units share some oxygen atoms to form infinite chains running parallel to the b axis, which are separated by the rare-earth and lithium cations. (7)Li-NMR experiments, carried out at high field on the nonmagnetic LiLa(9)Mo(16)O(35), provided insights into the local environment of the lithium ions. Magnetic susceptibility measurements confirmed the trivalent oxidation state of the magnetic rare-earth cations and indicated the absence of localized moments on the Mo(16) clusters. The electronic structure of the LiLn(9)Mo(16)O(35) compounds was analyzed using molecular and periodic quantum calculations. The study of the molecular orbital diagrams of isolated Mo(16)O(36) models allowed the understanding of this unique metallic architecture. Periodic density functional theory calculations demonstrated that few interactions occur between the Mo(16) clusters, and predicted semiconducting properties for LiLn(9)Mo(16)O(35) as a band gap of 0.57 eV was computed for the lanthanum phase.
Published: 2011
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14. Etude in situ par DRX sur poudre et RMN du solide de catalyseurs industriels vanadophosphates : focus sur la phase ω-VOPO4

Author: Kouvatas, C., Thierry Bataille, Laurent Le Pollès, Carmelo Prestipino, Claire Roiland, Laurent Delevoye, Ian Farnan, Erik Elkaim, Gaëtan Louarn, Eric Le Fur, 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), 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), Department of Earth Sciences [Cambridge, UK], University of Cambridge [UK] (CAM), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), 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: [CHIM.CRIS]Chemical Sciences/Cristallography, [CHIM]Chemical Sciences, [CHIM.MATE]Chemical Sciences/Material chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2016

15. Combining in situ XRPD and solid state NMR to study ω-VOPO4 among industrial vanadium phosphate catalysts

Author: Kouvatas, C., Thierry Bataille, Laurent Le Pollès, Carmelo Prestipino, Claire Roiland, Laurent Delevoye, Erik Elkaïm, Eric Le Fur, 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), 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), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), 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: [CHIM.CRIS]Chemical Sciences/Cristallography, [CHIM]Chemical Sciences, [CHIM.MATE]Chemical Sciences/Material chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2016

16. Structure and Stability of VO2+ in Aqueous Solution: A Car−Parrinello and Static ab Initio Study

Author: Aymeric Sadoc, Laurent Le Pollès, Eric Furet, Sabri Messaoudi, Jean-Yves Pivan, Eric Le Fur, Régis Gautier, 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 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: Aqueous solution, 010405 organic chemistry, Chemistry, Coordination number, Nucleation, Ab initio, Thermodynamics, General Medicine, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Stability (probability), 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Inorganic Chemistry, Computational chemistry, Density functional theory, Physical and Theoretical Chemistry, 0210 nano-technology, Hydration energy, Conformational isomerism
Abstract: International audience; Quantum chemical calculations have been carried out to get some insight concerning the effects of temperature and solvent acidity on the structure and stability of solvated VO2+ as the elementary chemical unit involved in the nucleation of vanadophosphates. First, because some recent theoretical studies have suggested a tendency of density functional theory (DFT) to favor lower coordination numbers for such systems, static calculations have been performed on [VO2(H2O)(4-n)]+*nH2O (n = 0−2) conformers at the MP2 and DFT level of theory, using two different combinations of basis sets. The results of two pure-GGA (BP86 and PBEPBE), two hybrid-GGA (PBE1PBE and mPWPW91), and two hybrid-meta-GGA (mPW1B95 and B1B95) functionals were analyzed on these systems. The comparison of the results indicates that the stability differences between the two methodologies are resolved when hydration energy is taken into account, provided that some amount of HF exchange is introduced in the DFT calculations. In a second step, Car−Parrinello simulations have been carried out starting from VO2(H2O)4+ surrounded by water molecules. The calculations at 300 K show the natural tendency of VO2(H2O)4+ to decompose to VO2(OH)2- and the requirements to work with an already acidified medium to be able to investigate the coordination sphere of VO2+ for an extended period of time. Under such conditions, we have obtained a clear preference for a five-coordinated vanadium. The molecular dynamics simulations performed at 500 K starting from hydrated VO2+ in a protonated medium found VO(OH)3 to be the most stable structure, whereas this ideal candidate for oxolation reactions is expected to be a very minor species at room temperature.
Published: 2007
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17. Impact of ⁷⁷Te on the structure and Se NMR spectra of Se-rich Ge-Te-Se glasses: a combined experimental and computational investigation

Author: Lila, Bouëssel du Bourg, Claire, Roiland, Laurent, le Pollès, Michaël, Deschamps, Catherine, Boussard-Plédel, Bruno, Bureau, Chris J, Pickard, and Eric, Furet
Abstract: Selenium-rich Ge-Te-Se glasses have been synthesized along the GeSe4-GeTe4 pseudo-composition line and acquired by (77)Se Hahn echo magic-angle spinning NMR. The comparison with the GeSe4 spectrum shows a drastic modification of the typical double-resonance lineshape even at low Te concentrations (10%). In order to rationalize this feature and to understand the effect of Te on the structure of our glasses, first-principles molecular dynamics simulations and gauge including projector augmented wave NMR parameter calculations have been performed. The distribution of the tellurium atoms in the selenium phase was shown to be mainly responsible for the (77)Se lineshape changes. Another possible factor related to the perturbation of the δiso value due to Te proximity appears to be much more limited in the bulk, while the results obtained using molecular models suggest shifts of several hundreds of ppm.
Published: 2015

18. Evaluation of 95Mo Nuclear Shielding and Chemical Shift of [Mo6X14]2- Clusters in the Liquid Phase

Author: Chris J. Pickard, Thi Hoai Thuong Nguyen, Stéphane Cordier, Yann Molard, Julie Jung, Julien Trébosc, Xavier Trivelli, Régis Gautier, Laurent Le Pollès, Jérôme Cuny, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-Ecole Nationale Supérieure de Chimie de Rennes-Centre National de la Recherche Scientifique (CNRS), Unité de Glycobiologie Structurale et Fonctionnelle - UMR 8576 (UGSF), Université de Lille-Centre National de la Recherche Scientifique (CNRS)-Institut National de la Recherche Agronomique (INRA), Université de Lille, Sciences et Technologies, Unité de Catalyse et de Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Ecole Centrale de Lille-Ecole Nationale Supérieure de Chimie de Lille (ENSCL)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Modélisation, Agrégats, Dynamique (LCPQ) (MAD), Laboratoire de Chimie et Physique Quantiques (LCPQ), Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS), ANR-09-JCJC-0088-01, Agence Nationale de la Recherche, TGIR-RMN-THC Fr3050, Centre National de la Recherche Scientifique, 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), Unité de Glycobiologie Structurale et Fonctionnelle UMR 8576 (UGSF), Université de Lille-Centre National de la Recherche Scientifique (CNRS), Unité de Catalyse et Chimie du Solide - UMR 8181 (UCCS), Université d'Artois (UA)-Centrale Lille-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université de Lille, Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-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 du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), ANR-09-JCJC-0088,NMRTHEO(2009), 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 d'Artois (UA)-Centrale Lille-Institut de Chimie du CNRS (INC)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Institut National de la Recherche Agronomique (INRA)-Université de Lille-Centre National de la Recherche Scientifique (CNRS), 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: Magnetic Resonance Spectroscopy, Complex system, Molecular Conformation, 02 engineering and technology, Molecular Dynamics Simulation, 010402 general chemistry, 01 natural sciences, Molecular physics, Inorganic Chemistry, Molecular dynamics, Isotopes, Computational chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, Basis set, Molybdenum, Aqueous solution, Chemistry, Nuclear magnetic resonance spectroscopy, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Electromagnetic shielding, Solvents, Quantum Theory, Density functional theory, Solvent effects, 0210 nano-technology
Abstract: International audience; [Mo6X14](2-) octahedral molybdenum clusters are the main building blocks of a large range of materials. Although (95)Mo nuclear magnetic resonance was proposed to be a powerful tool to characterize their structural and dynamical properties in solution, these measurements have never been complemented by theoretical studies which can limit their interpretation for complex systems. In this Article, we use quantum chemical calculations to evaluate the (95)Mo chemical shift of three clusters: [Mo6Cl14](2-), [Mo6Br14](2-), and [Mo6I14](2-). In particular, we test various computational parameters influencing the quality of the results: size of the basis set, treatment of relativistic and solvent effects. Furthermore, to provide quantum chemical calculations that are directly comparable with experimental data, we evaluate for the first time the (95)Mo nuclear magnetic shielding of the experimental reference, namely, MoO4(2-) in aqueous solution. This is achieved by combining ab initio molecular dynamics simulations with a periodic approach to evaluate the (95)Mo nuclear shieldings. The results demonstrate that, despite the difficulty to obtain accurate (95)Mo chemical shifts, relative values for a cluster series can be fairly well-reproduced by DFT calculations. We also show that performing an explicit solvent treatment for the reference compound improves by ∼50 ppm the agreement between theory and experiment. Finally, the standard deviation of ∼70 ppm that we calculate for the (95)Mo nuclear shielding of the reference provides an estimation of the accuracy we can achieve for the calculation of the (95)Mo chemical shifts using a static approach. These results demonstrate the growing ability of quantum chemical calculations to complement and interpret complex experimental measurements.
Published: 2015
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19. Chemical Characterization and Botanical Origin of French Ambers

Author: Youssef Nohra, Dany Azar, Vincent Perrichot, Laurent Le Pollès, Laurent Jeanneau, Géosciences Rennes (GR), Centre National de la Recherche Scientifique (CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES), 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), Lebanese University [Beirut] (LU), Université Libanaise, Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Observatoire des Sciences de l'Univers de Rennes (OSUR), Université de Rennes (UR)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-Institut national des sciences de l'Univers (INSU - CNRS)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-Institut National de Recherche pour l’Agriculture, l’Alimentation et l’Environnement (INRAE)-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: 010506 paleontology, Molecular composition, Cupressaceae, Spectrophotometry, Infrared, Tetrahydronaphthalenes, Plant composition, Pharmaceutical Science, Araucariaceae, [SDU.STU]Sciences of the Universe [physics]/Earth Sciences, 010502 geochemistry & geophysics, 01 natural sciences, GEOF, Gas Chromatography-Mass Spectrometry, Analytical Chemistry, Paleontology, Drug Discovery, Botany, Dicarboxylic Acids, 0105 earth and related environmental sciences, Pharmacology, biology, Molecular Structure, Terpenes, Organic Chemistry, Fabaceae, Plants, biology.organism_classification, Cretaceous, Amber, Cheirolepidiaceae, Tracheophyta, Complementary and alternative medicine, Molecular Medicine, France, Cenomanian, Diterpenes, Geology
Abstract: International audience; The molecular composition of 10 Cretaceous andone Eocene ambers from France was analyzed by infraredspectroscopy, solid-state 13C nuclear magnetic resonance spectroscopy,and thermochemolysis gas chromatography−massspectrometry. The terpenoids identified in the samples wereused as biomarkers for the botanical origin of the resins. TheCretaceous samples, comprising the so-called Alpine, Anjou,Charentese, Provence, Pyrenean, and Vendean ambers, rangedfrom the Albian−Cenomanian transition to the early Santonian(100 to 85 Ma) and correspond to class Ib resins typical ofconifers. The extinct conifer family Cheirolepidiaceae wasproposed as the plant source of Pyrenean and brown Charenteseambers. Araucariaceae or Cheirolepidiaceae were the plant sourcesof the Cenomanian Alpine, Anjou, and yellow Charentese ambers.The Santonian ambers of Provence and Vendée were found to derive from the Cupressaceae. The Eocene Oise amber (ca. 53Ma) is a class Ic resin typical of angiosperms and was produced by a Fabaceae. The evolution of resin sources from the earlyCretaceous to the Eocene periods is discussed. Finally, a possible fingerprint hitherto unveiled is proposed for cheirolepidiaceousresins, defined by the simultaneous presence of phenolic diterpenoids, labdanoic acids, callitrisate structures, and their respectivederivatives.
Published: 2015
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20. A family of lanthanide-based coordination polymers with boronic Acid as ligand

Author: Stéphane Freslon, Xiaohui Yi, Olivier Guillou, Carole Daiguebonne, Laurent Le Pollès, Xiao Fan, Kevin Bernot, Gang Huang, Guillaume Calvez, 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), Software Engineering Institute [Peking], Peking University [Beijing], China Scholarship Council, 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), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: chemistry.chemical_classification, Lanthanide, 010405 organic chemistry, Ligand, Nuclear magnetic resonance spectroscopy, Polymer, 010402 general chemistry, Photochemistry, 01 natural sciences, Chemical formula, 0104 chemical sciences, Inorganic Chemistry, Crystallography, chemistry.chemical_compound, chemistry, [CHIM]Chemical Sciences, Physical and Theoretical Chemistry, Phosphorescence, Luminescence, Boronic acid
Abstract: International audience; Reactions in water between the sodium salt of 4-carboxyphenylboronic acid (Hcpb) and lanthanide ions (Pr-Nd, Sm-Lu, and Y) led to a family of lanthanide-based coordination polymers with general chemical formula \[Ln(cpbOH)(H2O)2](cpb)\∞. Structural characterizations were ensured by single-crystal X-ray diffraction and solid-state NMR spectroscopy ((11)B, (13)C, and (89)Y). This family of compounds constitutes the first example of lanthanide-based coordination polymers involving 4-carboxyphenylboronic acid as ligand. To evaluate their potential usefulness, luminescent and magnetic properties of some of the compounds that constitute this family were explored. From a magnetic point of view, the Yb(III) compound is the more promising. On the other hand, upon UV irradiation (λexc = 303 nm) ligand phosphorescence is quite intense and offers a sizable blue component to emission spectra. This is quite unusual and can constitute an asset as far as white emission is targeted. Moreover, luminescence properties of these compounds are highly temperature-dependent, and some of them seem promising as molecular thermometers.[on SciFinder (R)]
Published: 2015
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21. Disorder and Dynamics in Pollucite from 133Cs and 27Al NMR

Author: Ian Farnan, Sharon E. Ashbrook, Karl R. Whittle, and Laurent Le Pollès
Subjects: Ion exchange, Chemistry, Analytical chemistry, engineering.material, Thermal diffusivity, Nmr data, Tetragonal crystal system, Pollucite, visual_art, Materials Chemistry, Ceramics and Composites, engineering, visual_art.visual_art_medium, Ceramic, Leucite, Nuclear chemistry
Abstract: Pollucite, CsAlSi2O6, a Cs polymorph of leucite (KAlSi2O6), has been proposed for ceramic immobilization of 135Cs and 137Cs fission products. 133Cs NMR of both low- (tetragonal) and high-temperature (cubic) forms of pollucite exhibit a considerable distribution of local Cs environments. 29Si and 27Al NMR data from directly prepared pollucite show greater Al/Si disorder than either leucite, or pollucite produced by ion exchange. Little evidence for Cs motion is observed in tetragonal or cubic pollucite, and only at high temperatures (∼850°C) is any substantial dynamic behavior detected. Dynamic NMR lineshape calculations allow a determination of the frequency of Cs motion and diffusivity.
Published: 2005
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22. Crystal structures, physical properties and NMR experiments on the ternary rare-earth metal silicide boride compounds RE5Si2B8 (RE=Y, Sm, Gd, Tb, Dy, Ho)

Author: Roland Guérin, Volodymyr Babizhetskyy, Jérome Roger, Kurt Hiebl, Sharon Elisabeth Ashbrook, Laurent Le Pollès, Josef Bauer, Jean-François Halet, and Stéphane Cordier
Subjects: Materials science, chemistry.chemical_element, Crystal structure, Nuclear magnetic resonance spectroscopy, Condensed Matter Physics, Electronic, Optical and Magnetic Materials, Inorganic Chemistry, Crystallography, chemistry.chemical_compound, Paramagnetism, Tetragonal crystal system, chemistry, Boride, Materials Chemistry, Ceramics and Composites, Dysprosium, Antiferromagnetism, Physical and Theoretical Chemistry, Néel temperature
Abstract: The ternary rare-earth metal silicide borides RE5Si2B8 (RE=Y, Sm, Gd, Tb, Dy Ho) were prepared by arc melting the elemental components and subsequent annealing up to T = 1850 K . The crystal structure was determined for each term of the series from single-crystal X-ray data: tetragonal symmetry, space group P4/mbm, Z = 2 ; unit cell parameters a = 7.2616 ( 3 ) , c = 8.2260 ( 3 ) A and a = 7.1830 ( 2 ) , c = 7.9900 ( 3 ) A for Sm5Si2B8 and Ho5Si2B8, respectively. The structure is a new type and can be structurally described as an intergrowth of ThB4-like and U3Si2-like slabs of composition REB4 and RE3Si2, respectively, alternating along the c direction. The boron and silicon substructures are wholly independent and well ordered. The magnetic properties are as follows: Y5Si2B8 is a Pauli-type paramagnet above 1.8 K, Gd5Si2B8 undergoes a weak (canted) ferromagnetic-like order at 70 K followed by a colinear antiferromagnetic spin alignment at 44 K. Tb5Si2B8 and Dy5Si2B8 order antiferromagnetically at a Neel temperature of T N = 45 and 28 K, respectively. In the paramagnetic regime, the effective moments are in good accord with the theoretical RE3+ free ion moments. The temperature dependence of the electrical resistivities for the Y, Gd, Tb, and Dy containing samples corroborates with the metallic state of the nonmagnetic (Y) and the magnetically ordered compounds. 11B, 29Si and 89Y nuclear magnetic resonance (NMR) spectroscopy on nonmagnetic Y5Si2B8 shows different signals, which correspond to the expected number of distinct crystallographic sites in the structure. 11B NMR on Y5Si2B8 indicates that the local magnetic susceptibilities are substantially different from the ones observed in the related compound YB4.
Published: 2005
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23. A combined ⁷⁷Se NMR and molecular dynamics contribution to the structural understanding of the chalcogenide glasses

Author: Kateryna, Sykina, Bruno, Bureau, Laurent, Le Pollès, Claire, Roiland, Michaël, Deschamps, Chris J, Pickard, and Eric, Furet
Abstract: Solid-state (77)Se NMR measurements, first-principles molecular dynamics and DFT calculations of NMR parameters were performed to gain insight into the structure of selenium-rich GexSe(1-x) glasses. We recorded the fully-relaxed NMR spectra on natural abundance and 100% isotopically enriched GeSe4 samples, which led us to reconsider the level of structural heterogeneity in this material. In this paper, we propose an alternative procedure to initialise molecular dynamics runs for the chalcogenide glasses. The (77)Se NMR spectra calculated on the basis of the structural models deduced from these simulations are consistent with the experimental spectrum.
Published: 2014

24. Heteronuclear lanthanide-based coordination polymers exhibiting tunable multiple emission spectra

Author: Laurent Le Pollès, Stéphane Freslon, Xiao Fan, Kevin Bernot, Guillaume Calvez, Olivier Guillou, Carole Daiguebonne, 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 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: Lanthanide, Materials science, Intermetallic, Analytical chemistry, 02 engineering and technology, General Chemistry, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 7. Clean energy, 0104 chemical sciences, Electron transfer, Solid-state nuclear magnetic resonance, Heteronuclear molecule, Materials Chemistry, Physical chemistry, Emission spectrum, 0210 nano-technology, Luminescence, Spectroscopy
Abstract: International audience; Reactions in water at room temperature between lanthanide ions and 5-hydroxy-1,3-benzene-dicarboxylic acid hereafter referred to as H2(hip) lead to a new family of lanthanide-based hetero-nuclear compounds with the general chemical formula [Ln2 2xLn2x 0(hip)2(H2O)10,(hip),4H2O]N where Ln and Ln0 ¼ Pr-Lu or Y and where 0 # x # 1. The physico-chemical properties of this family have been characterized by PXRD, TDXD, TG/TD, EDS, SEM, 89Y solid state NMR spectroscopy and optical spectroscopy. The luminescent properties of these compounds are studied in detail. This study reveals that the competition between intermetallic energy transfer and photo-induced electron transfer gives rise to complex multiple emission spectra. It is therefore possible, for some Ln/Ln0 compositions, to obtain green, yellow or red emission by tuning the excitation wavelength over a 50 nm range. From a global point of view, this study shows that this series of compounds could be of great interest as far as luminescent coordination polymers usable as taggants for the fight against counterfeiting are aimed.
Published: 2014
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25. A combined 77Se NMR and molecular dynamics contribution to the structural understanding of the chalcogenide glasses

Author: Bruno Bureau, Michaël Deschamps, Chris J. Pickard, Kateryna Sykina, Claire Roiland, Laurent Le Pollès, Eric Furet, Institut des Sciences Chimiques de Rennes ( ISCR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Ecole Nationale Supérieure de Chimie de Rennes-Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), Conditions Extrêmes et Matériaux : Haute Température et Irradiation ( CEMHTI ), Université d'Orléans ( UO ) -Centre National de la Recherche Scientifique ( CNRS ), Fédération RMN du Solide à Hauts Champs ( FRMN-SHC ), Réseau sur le stockage électrochimique de l'énergie ( RS2E ), Centre National de la Recherche Scientifique ( CNRS ), Department of Physics and Astronomy [UCL London], University College of London [London] ( UCL ), 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), Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Université d'Orléans (UO)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Fédération RMN du Solide à Hauts Champs (FRMN-SHC), Réseau sur le stockage électrochimique de l'énergie (RS2E), Université de Nantes (UN)-Aix Marseille Université (AMU)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Université de Picardie Jules Verne (UPJV)-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Pau et des Pays de l'Adour (UPPA)-Institut de Chimie du CNRS (INC)-Université de Montpellier (UM)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), University College of London [London] (UCL), 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 Picardie Jules Verne (UPJV)-Institut de Chimie du CNRS (INC)-Aix Marseille Université (AMU)-Université de Pau et des Pays de l'Adour (UPPA)-Université de Nantes (UN)-Université de Montpellier (UM)-Centre National de la Recherche Scientifique (CNRS)-Sorbonne Université (SU)-Ecole Nationale Supérieure de Chimie de Paris - Chimie ParisTech-PSL (ENSCP), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Université de Haute-Alsace (UHA) Mulhouse - Colmar (Université de Haute-Alsace (UHA))-Collège de France (CdF (institution))-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA)-Institut National Polytechnique (Toulouse) (Toulouse INP), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Ecole Nationale Supérieure de Chimie de Montpellier (ENSCM)
Subjects: Chemistry, Chalcogenide, Relaxation (NMR), General Physics and Astronomy, 02 engineering and technology, Nuclear magnetic resonance crystallography, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, NMR spectra database, Molecular dynamics, chemistry.chemical_compound, Solid-state nuclear magnetic resonance, [ CHIM.MATE ] Chemical Sciences/Material chemistry, 0103 physical sciences, Physical chemistry, Transverse relaxation-optimized spectroscopy, Physical and Theoretical Chemistry, 010306 general physics, 0210 nano-technology, Spectroscopy
Abstract: International audience; Solid-state 77Se NMR measurements, first-principles mol. dynamics and DFT calcns. of NMR parameters were performed to gain insight into the structure of selenium-rich GexSe(1-x) glasses. We recorded the fully-relaxed NMR spectra on natural abundance and 100% isotopically enriched GeSe4 samples, which led us to reconsider the level of structural heterogeneity in this material. In this paper, we propose an alternative procedure to initialize mol. dynamics runs for the chalcogenide glasses. The 77Se NMR spectra calcd. on the basis of the structural models deduced from these simulations are consistent with the exptl. spectrum.
Published: 2014
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26. Coordination polymers based on heterohexanuclear rare earth complexes: toward independent luminescence brightness and color tuning

Author: Laurent Le Pollès, Guillaume Calvez, James Ledoux, Kevin Bernot, François Le Natur, Olivier Guillou, Carole Daiguebonne, Claire Roiland, 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 de Recherche Mathématique de Rennes (IRMAR), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-École normale supérieure - Rennes (ENS Rennes)-Université de Rennes 2 (UR2)-Centre National de la Recherche Scientifique (CNRS)-INSTITUT AGRO Agrocampus Ouest, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), AGROCAMPUS OUEST, Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Institut national d'enseignement supérieur pour l'agriculture, l'alimentation et l'environnement (Institut Agro)-Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Université de Rennes 2 (UR2), Université de Rennes (UNIV-RENNES)-École normale supérieure - Rennes (ENS Rennes)-Centre National de la Recherche Scientifique (CNRS)-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)
Subjects: Lanthanide, Models, Molecular, Luminescence, Luminescent Measurements, Coordination polymer, Polymers, Inorganic chemistry, Color, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, Crystallography, X-Ray, 01 natural sciences, Lanthanoid Series Elements, Inorganic Chemistry, Metal, chemistry.chemical_compound, Organometallic Compounds, Physical and Theoretical Chemistry, Terephthalic acid, 010405 organic chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, Chemical formula, 0104 chemical sciences, Crystallography, Solid-state nuclear magnetic resonance, chemistry, visual_art, visual_art.visual_art_medium
Abstract: International audience; Reactions in solvothermal conditions between hexanuclear rare earth complexes and H2bdc, where H2bdc symbolizes terephthalic acid, lead to a family of monodimensional coordination polymers in which hexanuclear complexes act as metallic nodes. The hexanuclear cores can be either homometallic with general chemical formula [Ln6O(OH)8(NO3)6](2+) (Ln = Pr-Lu plus Y) or heterometallic with general chemical formula [Ln6xLn'6-6xO(OH)8(NO3)6](2+) (Ln and Ln' = Pr-Lu plus Y). Whatever the hexanuclear entity is, the resulting coordination polymer is iso-structural to [Y6O(OH)8(NO3)2(bdc)(Hbdc)2.2NO3.H2bdc]infinity, a coordination polymer that we have previously reported. The random distribution of the lanthanide ions over the six metallic sites of the hexanuclear entities is demonstrated by (89)Y solid state NMR, X-ray diffraction (XRD), and luminescent measurements. The luminescent and colorimetric properties of selected compounds that belong to this family have been studied. These studies demonstrate that some of these compounds exhibit very promising optical properties and that there are two ways of modulating the luminescent properties: (i) playing with the composition of the heterohexanuclear entities or (ii) playing with the relative ratio between two different hexanuclear entities. This enables the independent tuning of luminescence intensity and color.
Published: 2013
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27. DFT-assisted structure determination of α1- and α2-VOPO4: new insights into the understanding of the catalytic performances of vanadium phosphates

Author: Eric Furet, Olivier Hernandez, Claire Roiland, Régis Gautier, Nathalie Audebrand, Romain Gautier, Laurent Le Pollès, Eric Le Fur, Erik Elkaim, Thierry Bataille, 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), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), 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), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: Diffraction, Materials science, Vanadium, chemistry.chemical_element, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Synchrotron, 0104 chemical sciences, Catalysis, law.invention, Light hydrocarbons, Inorganic Chemistry, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Crystallography, chemistry, Catalytic oxidation, Chemical engineering, law, Lamellar structure, 0210 nano-technology, Powder diffraction
Abstract: International audience; Structural investigations on vanadium phosphates, which are extensively used as catalysts in industry, often resulted in important advances in the understanding of the mechanisms driving the catalytic oxidation of light hydrocarbons. Layer translations in the two lamellar vanadium phosphates α1- and α2-VOPO4 phases identified during the catalysis were investigated by the combination of first-principles calculations, synchrotron X-ray powder diffraction, single-crystal X-ray diffraction and solid-state NMR. This analysis reveals an important feature: the α1-form is the only polymorph of VOPO4 to exhibit layer translations that prevent the formation of infinite VO6 chains. A detailed investigation of this structural characteristic in vanadium phosphates reveals the correlation between the presence of infinite VO6 chains and the catalytic performances of related phases.
Published: 2013
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28. 95Mo solid-state nuclear magnetic resonance spectroscopy and quantum simulations : synergetic tools for the study of molybdenum cluster materials

Author: Christiane Perrin, Laurent Delevoye, Stéphane Cordier, Zhehong Gan, Chris J. Pickard, Julien Trébosc, Régis Gautier, Laurent Le Pollès, Jérôme Cuny, 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), 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), Laboratoire de cristallochimie et physicochimie du solide (LCPS), Université de Lille, Sciences et Technologies-Centre National de la Recherche Scientifique (CNRS), National High Magnetic Field Laboratory, Region Bretagne, TGE RMN THC Fr [3050], National Science Foundation, State of Florida [DMR-0084173], 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: HYDRODESULFURIZATION CATALYSTS, MO6S3I6 NANOWIRES, Analytical chemistry, chemistry.chemical_element, 02 engineering and technology, Crystal structure, TRANSITION-METAL CLUSTERS, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, NMR CHEMICAL-SHIFTS, Inorganic Chemistry, DENSITY-FUNCTIONAL THEORY, QUADRUPOLAR NUCLEI, MAS-NMR, CRYSTAL-STRUCTURES, Physical and Theoretical Chemistry, Spectroscopy, Pulse sequence, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Bond length, MO6S4.5I4.5 NANOWIRES, chemistry, Solid-state nuclear magnetic resonance, Molybdenum, Density functional theory, 0210 nano-technology, PROJECTOR-AUGMENTED-WAVE, Electric field gradient
Abstract: International audience; The ability of (95)Mo solid-state nuclear magnetic resonance (SSNMR) spectroscopy to probe the atomic and electronic structures of inorganic molybdenum cluster materials has been demonstrated for the first time. Six cluster compounds were studied: MoBr(2), Cs(2)Mo(6)Br(14), (Bu(4)N)(2)Mo(6)Br(14), each containing the octahedral Mo(6)Br(14)(2-) cluster unit, and MoS(2)Cl(3), Mo(3)S(7)Cl(4), and MoSCl that contain metallic dimers, trimers, and tetramers, respectively. To overcome inherent difficulties due to the low sensitivity of (95)Mo SSNMR, both high-magnetic-field spectrometers and the quadrupolar Carr-Purcell Meiboom-Gill sensitivity enhancement pulse sequence under magic-angle-spinning conditions, combined with a hyperbolic-secant pulse were used. Experimental measurements as well as characterization of the (95)Mo electric field gradient and chemical shift tensors have been performed with the help of quantum-chemical calculations under periodic boundary conditions using the projector augmented-wave and the gauge-including projector augmented-wave methods, respectively. A large (95)Mo chemical shift range is measured, ∼3150 ppm, and the isotropic chemical shift of the Mo atoms is clearly correlated to their formal oxidation degree in the various clusters. Furthermore, a direct relation is evidenced between the molybdenum quadrupolar coupling constant and the bond lengths with its surrounding ligands. Our results demonstrate the efficiency of the combined use of quantum-chemical calculations and (95)Mo SSNMR experiments to study inorganic molybdenum cluster compounds.
Published: 2013
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29. Color and Brightness Tuning in Heteronuclear Lanthanide Terephthalate Coordination Polymers

Author: Olivier Guillou, Guillaume Calvez, Martin R. Mitchell, Carole Daiguebonne, Victor Haquin, Mael Etienne, Jean-Claude G. Bünzli, Svetlana V. Eliseeva, Laurent Le Pollès, Sharon E. Ashbrook, Stéphane Freslon, Kevin Bernot, 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), Department of Chemistry 'Ugo Schiff', Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), Ecole Polytechnique Fédérale de Lausanne (EPFL), 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), and Università degli Studi di Firenze = University of Florence (UniFI)
Subjects: chemistry.chemical_classification, Lanthanide, Brightness, Luminescence, Chemistry, Structure elucidation, Inorganic chemistry, Intermetallic, 02 engineering and technology, Polymer, Nuclear magnetic resonance spectroscopy, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Chemical formula, 0104 chemical sciences, Inorganic Chemistry, Coordination polymers, Heteronuclear molecule, Lanthanides, Physical chemistry, 0210 nano-technology
Abstract: International audience; Heteronuclear lanthanide terephthalate coordination polymers with the general chemical formula [Ln2-2xLn′2x(bdc)3(H2O)4]∞, for which bdc2- symbolizes benzene-1,4-dicarboxylate (or terephthalate) and Ln and Ln′ represent trivalent rare earth ions, were synthesized and structurally characterized. Analysis of the Y/Lu compounds by 89Y and 13C solid-state NMR spectroscopy was carried out, and the results support the hypothesis of randomly distributed lanthanide ions. The spectroscopic and colorimetric properties of this family of compounds were investigated in detail. The resulting data demonstrate that this series of compounds presents highly tunable luminescence properties and clearly indicate that intermetallic deactivation processes play an important role in the emission mechanism. Playing with intermetallic distances allows one to tune the color and the brightness of the lanthanide emission in these coordination polymers.
Published: 2013
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30. ChemInform Abstract: Structural, Electronic and Magnetic Properties of Layered REB2C Compounds (RE: Dy, Tm, Lu)

Author: Constantin Hoch, Arndt Simon, Volodymyr Babizhetskyy, Kurt Hiebl, Régis Gautier, Laurent Le Pollès, and Jean-Francois Halet
Subjects: Lanthanide, Crystallography, Chemistry, Inorganic chemistry, General Medicine, Crystal structure, Single crystal
Abstract: The isotypic title compounds are prepared from the elements (1270 K, 1 month) and the crystal structure of LuB2C is determined by powder and single crystal XRD.
Published: 2012
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31. ChemInform Abstract: Synthesis, Crystal and Electronic Structures, and Magnetic Properties of LiLn9Mo16O35(Ln: La, Ce, Pr, and Nd) Compounds Containing the Original Cluster Mo16O36

Author: Laurent Delevoye, Patrick Gougeon, Laurent Le Pollès, Régis Gautier, Philippe Gall, Julien Trébosc, and Jérôme Cuny
Subjects: Lanthanide, Crystal, Crystallography, Chemistry, Cluster (physics), Crucible, General Medicine, Stoichiometry
Abstract: The new title compounds are prepared from stoichiometric mixtures of Li2MoO4, Ln2O3 (Ln: La, Nd) , Pr6O11, or CeO2, MoO3, and Mo (Mo crucible, Ar, 1600 °C, 48 h).
Published: 2012
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32. 95Mo nuclear magnetic resonance parameters of molybdenum hexacarbonyl from density functional theory: appraisal of computational and geometrical parameters

Author: Jérôme Cuny, Chris J. Pickard, Bruno Fontaine, Laurent Le Pollès, Kateryna Sykina, Régis Gautier, 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), Department of Physics and Astronomy [UCL London], University College of London [London] (UCL), Institut des Sciences Chimiques de Rennes ( ISCR ), Université de Rennes 1 ( UR1 ), Université de Rennes ( UNIV-RENNES ) -Université de Rennes ( UNIV-RENNES ) -Ecole Nationale Supérieure de Chimie de Rennes-Institut National des Sciences Appliquées ( INSA ) -Centre National de la Recherche Scientifique ( CNRS ), University College of London [London] ( UCL ), 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: 010304 chemical physics, Chemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, General Physics and Astronomy, Nuclear magnetic resonance spectroscopy, Nuclear magnetic resonance crystallography, 010402 general chemistry, 01 natural sciences, Molybdenum hexacarbonyl, 0104 chemical sciences, chemistry.chemical_compound, Nuclear magnetic resonance, Solid-state nuclear magnetic resonance, [ CHIM.ORGA ] Chemical Sciences/Organic chemistry, 0103 physical sciences, Transverse relaxation-optimized spectroscopy, Density functional theory, Physical and Theoretical Chemistry, Two-dimensional nuclear magnetic resonance spectroscopy, Basis set
Abstract: International audience; Solid-state (95)Mo nuclear magnetic resonance (NMR) properties of molybdenum hexacarbonyl have been computed using density functional theory (DFT) based methods. Both quadrupolar coupling and chemical shift parameters were evaluated and compared with parameters of high precision determined using single-crystal (95)Mo NMR experiments. Within a molecular approach, the effects of major computational parameters, i.e. basis set, exchange-correlation functional, treatment of relativity, have been evaluated. Except for the isotropic parameter of both chemical shift and chemical shielding, computed NMR parameters are more sensitive to geometrical variations than computational details. Relativistic effects do not play a crucial part in the calculations of such parameters for the 4d transition metal, in particular isotropic chemical shift. Periodic DFT calculations were tackled to measure the influence of neighbouring molecules on the crystal structure. These effects have to be taken into account to compute accurate solid-state (95)Mo NMR parameters even for such an inorganic molecular compound.
Published: 2011
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33. 77Se solid-state NMR investigations on As(x)Se(1-x) glasses using CPMG acquisition under MAS

Author: Guang Yang, Dominique Massiot, Michaël Deschamps, Claire Roiland, Laurent Le Pollès, Bruno Bureau, Conditions Extrêmes et Matériaux : Haute Température et Irradiation (CEMHTI), Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université d'Orléans (UO), 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), LAboratoire de Recherche en Mécanique Appliquée (LARMAUR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-Centre National de la Recherche Scientifique (CNRS), Université d'Orléans (UO)-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), 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), and Université de Rennes (UR)-Centre National de la Recherche Scientifique (CNRS)
Subjects: J-coupling, Nuclear and High Energy Physics, Analytical chemistry, 02 engineering and technology, 010402 general chemistry, Arsenide, 01 natural sciences, Spectral line, Magnetization, chemistry.chemical_compound, Selenium, Selenide, Magic angle spinning, Anisotropy, Instrumentation, CPMG, Radiation, General Chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, Solid-state nuclear magnetic resonance, chemistry, Glass, 0210 nano-technology
Abstract: International audience; (77)Se (I=1/2) solid-state NMR is a very sensitive probe of the local structure of selenide glasses, which themselves are promising for optical applications. In this work, we show that although (77)Se has a low natural abundance (7.58%) and a wide spectral range, the sensitivity can be dramatically increased using Carr-Purcell-Meiboom-Gill (CPMG) trains of rotor-synchronized π pulses during the detection of (77)Se magnetization but may be affected by chemical shift anisotropy when the Magic Angle Spinning rate is not fast enough and by offset effects. The indirect dimension of the T(2)(CPMG)-resolved spectrum shows a strong influence of the J-couplings between naturally occurring (77)Se pairs. The resulting spectra show that the structural model known as "chains crossing model" is not entirely suitable to describe the glassy network of the Se-rich compositions.
Published: 2011
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34. Improving sensitivity and resolution of MQMAS spectra: a 45Sc-NMR case study of scandium sulphate pentahydrate

Author: Jérôme Cuny, Chris J. Pickard, Thomas Bräuniger, C. Vinod Chandran, Laurent Le Pollès, Régis Gautier, 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), Deutsche Forschungsgemeinschaft (DFG), with Grants BR 3370/3-1 and BR 3370/4-1, 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), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: Nuclear and High Energy Physics, Magnetic Resonance Spectroscopy, Dephasing, Biophysics, Analytical chemistry, chemistry.chemical_element, Crystal structure, 010402 general chemistry, DFT calculations, 01 natural sciences, Biochemistry, Solid-state NMR, Spectral line, Scandium, Spectral resolution, MQMAS, Sulfates, 010405 organic chemistry, [CHIM.MATE]Chemical Sciences/Material chemistry, Condensed Matter Physics, 0104 chemical sciences, Heteronuclear molecule, chemistry, Solid-state nuclear magnetic resonance, Spin decoupling, Density functional theory, Algorithms, FAM pulse sequences
Abstract: International audience; To efficiently obtain multiple-quantum magic-angle spinning (MQMAS) spectra of the nuclide 45Sc (I=7/2), we have combined several previously suggested techniques to enhance the signal-to-noise ratio and to improve spectral resolution for the test sample, scandium sulphate pentahydrate (ScSPH). Whereas the 45Sc-3QMAS spectrum of ScSPH does not offer sufficient resolution to clearly distinguish between the 3 scandium sites present in the crystal structure, these sites are well-resolved in the 5QMAS spectrum. The loss of sensitivity incurred by using MQMAS with 5Q coherence order is partly compensated for by using fast-amplitude modulated (FAM) sequences to improve the efficiency of both 5Q coherence excitation and conversion. Also, heteronuclear decoupling is employed to minimise dephasing of the 45Sc signal during the 5Q evolution period due to dipolar couplings with the water protons in the ScSPH sample. Application of multi-pulse decoupling schemes such as TPPM and SPINAL results in improved sensitivity and resolution in the F(1) (isotropic) dimension of the 5QMAS spectrum, the best results being achieved with the recently suggested SW(f)-TPPM sequence. By numerical fitting of the 45Sc-NMR spectra of ScSPH from 3QMAS, 5QMAS and single-quantum MAS at magnetic fields B(0)=9.4 T and 17.6 T, the isotropic chemical shift delta(iso), the quadrupolar coupling constant chi, and the asymmetry parameter eta were obtained. Averaging over all experiments, the NMR parameters determined for the 3 scandium sites, designated (a), (b) and (c) are: delta(iso)(a)=-15.5+/-0.5 ppm, chi(a)=5.60+/-0.10 MHz, eta(a)=0.06+/-0.05; delta(iso)(b)=-12.9+/-0.5 ppm, chi(b)=4.50+/-0.10 MHz, eta(b)=1.00+/-0.00; and delta(iso)(c)=-4.7+/-0.2 ppm, chi(c)=4.55+/-0.05 MHz, eta(c)=0.50+/-0.02. The NMR scandium species were assigned to the independent crystallographic sites by evaluating their experimental response to proton decoupling, and by density functional theory (DFT) calculations using the PAW and GIPAW approaches, in the following way: Sc(1) to (c), Sc(2) to (a), and Sc(3) to (b). The need to compute NMR parameters using an energy-optimised crystal structure is once again demonstrated.
Published: 2010
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35. Density functional theory calculations of 95Mo NMR parameters in solid-state compounds

Author: Chris J. Pickard, Régis Gautier, Laurent Le Pollès, Jean-Baptiste d’Espinose de Lacaillerie, Eric Furet, Jérôme Cuny, 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), Laboratoire de Physico-Chimie des Polymères et des Milieux Dispersés (PPMD), Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)-Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), 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), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), and Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Magnetic Resonance Spectroscopy, Plane wave, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Molecular physics, transition metals, law.invention, molybdenum, NMR spectroscopy, Atomic orbital, law, Computational chemistry, Ab initio quantum chemistry methods, Tensor, Physical and Theoretical Chemistry, Chemistry, Nuclear magnetic resonance spectroscopy, 021001 nanoscience & nanotechnology, Atomic and Molecular Physics, and Optics, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Projector, density functional calculations, solid-state structures, Density functional theory, 0210 nano-technology, Algorithms, Electric field gradient
Abstract: International audience; The application of periodic density functional theory-based methods to the calculation of (95)Mo electric field gradient (EFG) and chemical shift (CS) tensors in solid-state molybdenum compounds is presented. Calculations of EFG tensors are performed using the projector augmented-wave (PAW) method. Comparison of the results with those obtained using the augmented plane wave + local orbitals (APW+lo) method and with available experimental values shows the reliability of the approach for (95)Mo EFG tensor calculation. CS tensors are calculated using the recently developed gauge-including projector augmented-wave (GIPAW) method. This work is the first application of the GIPAW method to a 4d transition-metal nucleus. The effects of ultra-soft pseudo-potential parameters, exchange-correlation functionals and structural parameters are precisely examined. Comparison with experimental results allows the validation of this computational formalism.
Published: 2009
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36. ChemInform Abstract: Synthesis, Electronic and Crystal Structures, and Physical Studies of the Superconductor Cs≈1Mo12S14, Final Step of the Condensation of the Mo6L8iL6aUnit

Author: Diala Salloum, Laurent Le Pollès, Régis Gautier, Jerme Cuny, Michel Potel, Marie Le Foch, and Patrick Gougeon
Subjects: Superconductivity, Chemistry, Condensation, Physical chemistry, Nanotechnology, General Medicine, Crystal structure, Unit (ring theory)
Published: 2009
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37. DFT calculations of quadrupolar solid-state NMR properties: Some examples in solid-state inorganic chemistry

Author: Chris J. Pickard, Jean-François Halet, Sabri Messaoudi, Jérôme Cuny, Veronique Alonzo, Eric Furet, Eric Le Fur, Laurent Le Pollès, Régis Gautier, Sharon E. Ashbrook, 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 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: solid state NMR, Chemical substance, Chemistry, Neutron diffraction, Inorganic chemistry, Ab initio, inorganic materials, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, DFT calculations, 01 natural sciences, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Computational Mathematics, electric field gradient, Solid-state nuclear magnetic resonance, Yield (chemistry), Density functional theory, Condensed Matter::Strongly Correlated Electrons, 0210 nano-technology, Spectroscopy, Electric field gradient, quadrupolar interaction
Abstract: International audience; This article presents results of first-principles calculations of quadrupolar parameters measured by solid-state nuclear magnetic measurement (NMR) spectroscopy. Different computational methods based on density functional theory were used to calculate the quadrupolar parameters. Through a series of illustrations from different areas of solid state inorganic chemistry, it is shown how quadrupolar solid-state NMR properties can be tackled by a theoretical approach and can yield structural information.
Published: 2008
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38. First-principles calculations of solid-state (17)O and (29)Si NMR spectra of Mg(2)SiO(4) polymorphs

Author: Laurent Le Pollès, Stephen Wimperis, Ian Farnan, Chris J. Pickard, Sharon E. Ashbrook, and Andrew J. Berry
Subjects: Chemistry, General Physics and Astronomy, Nuclear magnetic resonance spectroscopy, engineering.material, Wadsleyite, Molecular physics, Pseudopotential, NMR spectra database, Ringwoodite, Nuclear magnetic resonance, engineering, Density functional theory, Physical and Theoretical Chemistry, Basis set, Electric field gradient
Abstract: The nuclear magnetic resonance (NMR) shielding and electric field gradient (EFG) tensors of three polymorphs of Mg(2)SiO(4), forsterite (alpha-Mg(2)SiO(4)), wadsleyite (beta-Mg(2)SiO(4)) and ringwoodite (gamma-Mg(2)SiO(4)), have been calculated using a density functional theory (DFT) approach with a planewave basis set and pseudopotential approximation. These Mg(2)SiO(4) polymorphs are the principal components of the Earth down to depths of 660 km and have been proposed as the hosts of water in the Earth's upper mantle and transition zone. A comparison of our calculations with single-crystal spectroscopic data in the literature for the alpha-polymorph, forsterite, shows that both the magnitude and orientation of the shielding and EFG tensors for O and Si can be obtained with sufficient accuracy to distinguish subtle differences in atomic positions between published structures. We compare calculated (17)O MAS NMR quadrupolar powder lineshapes directly with experimental lineshapes and show that we are able to reproduce them within the precision with which the NMR parameters may be determined from multi-parameter fitting. The relatively small amounts of sample available for the beta- and gamma-polymorphs, arising from the high pressures required for synthesis, has hindered the extraction of NMR parameters in previous work. The application of DFT calculations to these high-pressure polymorphs confirms previous spectral assignments, and provides deeper insight into the empirical correlations and observations reported in the literature. These first-principles methods are highly promising for the determination of local bonding in more complex materials, such as the hydrated forms of Mg(2)SiO(4), by aiding analysis of their multinuclear NMR spectra.
Published: 2007

39. (23)Na multiple-quantum MAS NMR of the perovskites NaNbO(3) and NaTaO(3)

Author: Chris J. Pickard, Laurent Le Pollès, Régis Gautier, Richard I. Walton, Sharon E. Ashbrook, Department of Earth Sciences [Cambridge, UK], University of Cambridge [UK] (CAM), 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), Cavendish Laboratory, Department of Chemistry, The Open University [Milton Keynes] (OU), 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), and Institut National des Sciences Appliquées (INSA)-Université de Rennes (UNIV-RENNES)-Institut National des Sciences Appliquées (INSA)
Subjects: Models, Molecular, Magnetic Resonance Spectroscopy, Sodium, Niobium, Molecular Conformation, General Physics and Astronomy, chemistry.chemical_element, 02 engineering and technology, Tantalum, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Nuclear magnetic resonance, Hydrothermal synthesis, Computer Simulation, Physical and Theoretical Chemistry, Perovskite (structure), Titanium, Chemical shift, Oxides, Nuclear magnetic resonance spectroscopy, Calcium Compounds, 021001 nanoscience & nanotechnology, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, NMR spectra database, Crystallography, chemistry, Models, Chemical, X-ray crystallography, Quantum Theory, Density functional theory, Sodium Isotopes, 0210 nano-technology
Abstract: International audience; The distorted perovskites NaTaO(3) and NaNbO(3) have been studied using (23)Na multiple-quantum (MQ) MAS NMR. NaTaO(3) was prepared by high temperature solid state synthesis and the NMR spectra are consistent with the expected room temperature structure of the material (space group Pbnm), with a single crystallographic sodium site. Two samples of NaNbO(3) were studied. The first, a commercially available sample which was annealed at 900 degrees C, showed two crystallographic sodium sites, as expected for the room temperature structure of the material (space group Pbcm). The second sample, prepared by a low temperature hydrothermal method, showed the presence of four sodium sites, two of which match the expected room temperature structure and the second pair, another polymorph of the material (space group P21ma). This is consistent with powder X-ray diffraction data which showed weak extra peaks which can be accounted for by the presence of this second polymorph. Density functional theory (DFT) calculations support our conclusions, and aid assignment of the NMR spectra. Finally, we discuss the measured NMR parameters in relation to other studies of sodium in high coordination sites in the solid state.
Published: 2006
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40. 95Mo magic angle spinning NMR at high field: improved measurements and structural analysis of the quadrupole interaction in monomolybdates and isopolymolybdates

Author: Jean-Baptiste d'Espinose de Lacaillerie, Fabien Barberon, Zhehong Gan, Olga B. Lapina, Laurent Le Pollès, Régis Gautier, Konstantin Romanenko, Laboratoire de Physique Quantique (LPQ), Ecole Superieure de Physique et de Chimie Industrielles de la Ville de Paris (ESPCI Paris), Université Paris sciences et lettres (PSL)-Université Paris sciences et lettres (PSL), Boreskov Institute of Catalysis, Siberian Branch of the Russian Academy of Sciences (SB RAS), Laboratoire de Chimie du solide et inorganique moléculaire (LCSIM), 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 des Sciences Chimiques de Rennes (ISCR), 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), National High Magnetic Field Laboratory (NHMFL), and Florida State University [Tallahassee] (FSU)
Subjects: Magic angle, Field (physics), Chemistry, Analytical chemistry, Ab initio, Molecular physics, Surfaces, Coatings and Films, Solid-state nuclear magnetic resonance, Quadrupole, Materials Chemistry, Magic angle spinning, [CHIM]Chemical Sciences, Density functional theory, Physical and Theoretical Chemistry, Electric field gradient, MAS NMR SPECTROSCOPY
Abstract: In this study, 95Mo quadrupole couplings in various molydbates were measured easily and accurately with magic angle spinning (MAS) NMR under a directing field of 19.6 T. The resonance frequency of 54 MHz was sufficiently high to remove acoustic ringing artifacts, and the spectra could be analyzed in the usual terms of chemical shift and quadrupolar line shapes. For monomolybdates and molybdite, the quadrupole coupling dominated the NMR response, and the quadrupole parameters could be measured with better accuracy than in previous lower field studies. Moreover, despite the low symmetry of the molybdenum coordination, the usefulness of such measurements to probe molybdenum environments was established by ab initio density functional theory (DFT) calculations of the electric field gradient from known structures. The experimental NMR data correlated perfectly with the refined structures. In isopolymolybdates, the resonances were shapeless and DFT calculations were impossible because of the large and low symmetry unit cells. Nevertheless, empirical but clear NMR signatures were obtained from the spinning sidebands analysis or the MQMAS spectra. This was possible for the first time thanks to the improved baseline and sensitivity at high fields. With the generalization of NMR spectrometers operating above 17 T, it was predicted that 95Mo MAS NMR could evolve as a routine characterization tool for ill-defined structures such as supported molybdates in catalysis.
Published: 2006
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41. 77Se solid-state NMR of As2Se3, As4Se4 and As4Se3 crystals: a combined experimental and computational study

Author: Bruno Bureau, Chris J. Pickard, Kateryna Sykina, Eric Furet, Laurent Le Pollès, Guang Yang, Eric Le Fur, Claire Roiland, Institut des Sciences Chimiques de Rennes (ISCR), Université de Rennes 1 (UR1), Université de Rennes (UNIV-RENNES)-Université de Rennes (UNIV-RENNES)-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)-Ecole Nationale Supérieure de Chimie de Rennes (ENSCR)-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: 010302 applied physics, Chemistry, Chemical shift, Intermolecular force, General Physics and Astronomy, [CHIM.MATE]Chemical Sciences/Material chemistry, 02 engineering and technology, Crystal structure, Nuclear magnetic resonance crystallography, 021001 nanoscience & nanotechnology, 01 natural sciences, Spectral line, NMR spectra database, Crystallography, Solid-state nuclear magnetic resonance, Chemical physics, 0103 physical sciences, Molecule, Physical and Theoretical Chemistry, 0210 nano-technology
Abstract: International audience; (77)Se NMR parameters for three prototypical crystalline compounds (As2Se3, As4Se4 and As4Se3) have been determined from solid-state NMR spectra in the framework of an investigation concerning AsxSe(1-x) glass structure understanding. Density functional NMR calculations using the gauge including projector augmented wave methodology have been performed on X-ray and optimized crystal structures for a set of selenium-based crystals. These theoretical results have been combined with the experimental data in order to achieve a precise assignment of the spectral lines. This work and the high sensitivity of solid-state NMR to local order show that the structure of As4Se3 should be reinvestigated using state-of-the-art diffraction techniques. Calculations performed on several molecules derived from the crystal structures have demonstrated the limited effect of interlayer or intermolecular interactions on the isotropic chemical shifts. These interactions are therefore not responsible for the unexpected large chemical shift difference observed between these three systems that could mostly be attributed to the presence of short rings.
Published: 2013
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42. First-principles calculations of solid-state 17O and 29Si NMR spectra of Mg2SiO4 polymorphs.

Author: Sharon E. Ashbrook, Laurent Le Pollès, Chris J. Pickard, Andrew J. Berry, Stephen Wimperis, and Ian Farnan
Abstract: The nuclear magnetic resonance (NMR) shielding and electric field gradient (EFG) tensors of three polymorphs of Mg2SiO4, forsterite (α-Mg2SiO4), wadsleyite (β-Mg2SiO4) and ringwoodite (γ-Mg2SiO4), have been calculated using a density functional theory (DFT) approach with a planewave basis set and pseudopotential approximation. These Mg2SiO4 polymorphs are the principal components of the Earth down to depths of 660 km and have been proposed as the hosts of water in the Earth’s upper mantle and transition zone. A comparison of our calculations with single-crystal spectroscopic data in the literature for the α-polymorph, forsterite, shows that both the magnitude and orientation of the shielding and EFG tensors for O and Si can be obtained with sufficient accuracy to distinguish subtle differences in atomic positions between published structures. We compare calculated 17O MAS NMR quadrupolar powder lineshapes directly with experimental lineshapes and show that we are able to reproduce them within the precision with which the NMR parameters may be determined from multi-parameter fitting. The relatively small amounts of sample available for the β- and γ-polymorphs, arising from the high pressures required for synthesis, has hindered the extraction of NMR parameters in previous work. The application of DFT calculations to these high-pressure polymorphs confirms previous spectral assignments, and provides deeper insight into the empirical correlations and observations reported in the literature. These first-principles methods are highly promising for the determination of local bonding in more complex materials, such as the hydrated forms of Mg2SiO4, by aiding analysis of their multinuclear NMR spectra. [ABSTRACT FROM AUTHOR]
Published: 2007
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43. 23Na multiple-quantum MAS NMR of the perovskites NaNbO3 and NaTaO3.

Author: Sharon E. AshbrookPresent address: School of Chemistry and EaStCHEM, University of St Andrews, North Haugh, St Andrews, Fife, UK KY16 9ST., Laurent Le Pollès, Régis Gautier, Chris J. PickardPresent address: School of Physics and Astronomy, UK KY16 9SS., and Richard I. Walton
Published: 2006

44. Thermal and Guest-Assisted Structural Transition in the NH2-MIL-53(Al) Metal Organic Framework: A Molecular Dynamics Simulation Investigation

Author: Roald Boulé, Claire Roland, Laurent Le Pollés, Nathalie Audebrand, and Aziz Ghoufi
Subjects: NH2-MIL-53(Al), MOFs, molecular simulation, structural transition, Chemistry, QD1-999
Abstract: Reversible structural transition between the Large (LP) and Narrow Pore (NP) forms (breathing phenomena) of the MIL-53(X, X = Al, Cr, Fe, Ga) Metal Organic Framework (MOF) is probably one of the most amazing physical properties of this class of soft-porous materials. Whereas great attention has been paid to the elucidation of the physical mechanism ruling this reversible transition, the effect of the functionalization on the flexibility has been less explored. Among functionalized MIL-53(Al) materials, the case of NH2-MIL-53(Al) is undoubtedly a very intriguing structural transition rarely observed, and the steadier phase corresponds to the narrow pore form. In this work, the flexibility of the NH2-MIL-53(Al) metal organic framework was investigated by means of molecular dynamics simulations. Guest (methanol) and thermal breathing of the NH2-MIL-53(Al) was thus explored. We show that it is possible to trigger a reversible transition between NP and LP forms upon adsorption, and we highlight the existence of stable intermediate forms and a very large pore phase. Furthermore, the NP form is found thermodynamically stable from 240 to 400 K, which is the result of strong intramolecular hydrogen bonds.
Published: 2018
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