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9 results on '"EU Marie-Curie IIF fellowship (PIIF-GA-2010-274574)"'

1. Dynamic Nuclear Polarization Enhanced Solid-State NMR Spectroscopy of Functionalized Metal-Organic Frameworks

Author

Werner Maas, Moreno Lelli, Lyndon Emsley, Alexandre Zagdoun, Aaron J. Rossini, Paul Tordo, Melanie Rosay, David Farrusseng, Christophe Copéret, Sonia Aguado, Anne Lesage, Olivier Ouari, Jérôme Canivet, ISA - Centre de RMN à très hauts champs, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC), Laboratoire Chimie Provence (LCP), Université de Provence - Aix-Marseille 1-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Bruker BioSpin Corporation, Laboratory for Inorganic Chemistry, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), EU Marie-Curie IIF Fellowship (PIIF-GA-2010-274574), ANR-EQUIPEX (ANR-10-EQPX-47-01), ETH Zurich, European Project, Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Deuterium NMR, Carbon-13 NMR satellite, Analytical chemistry, Fluorine-19 NMR, Nuclear magnetic resonance crystallography, 010402 general chemistry, 01 natural sciences, Catalysis, dynamic nuclear polarization, DESIGN, CHEMISTRY, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, TOPOLOGY, Transverse relaxation-optimized spectroscopy, metal-organic frameworks, solid-state NMR spectroscopy, POROUS COORDINATION POLYMERS, hyperpolarization, Chemistry, 010405 organic chemistry, RETICULAR SYNTHESIS, General Chemistry, Nuclear magnetic resonance spectroscopy, General Medicine, Carbon-13 NMR, MIL-68, 0104 chemical sciences, POSTSYNTHETIC MODIFICATION, Two-dimensional nuclear magnetic resonance spectroscopy, BUILDING-BLOCKS
Abstract

A matter of minutes: Dynamic nuclear polarization (DNP) is applied to enhance the signal of solid-state NMR spectra of metal-organic framework (MOF) materials. The signal enhancement enables the acquisition of high-quality 1D 13C solid-state NMR spectra, 2D 1H- 13C dipolar HETCOR and 1D 15N solid-state NMR spectra with natural isotopic abundance in experiment times on the order of minutes. MW=microwaves. © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.

Published
2011
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2. Non-aqueous solvents for DNP surface enhanced NMR spectroscopy

Author

Lyndon Emsley, David Gajan, Melanie Rosay, Aaron J. Rossini, Moreno Lelli, Olivier Ouari, Alexandre Zagdoun, Adrien Bourdolle, Christophe Copéret, Anne Lesage, Werner Maas, Paul Tordo, ISA - Centre de RMN à très hauts champs, Institut des Sciences Analytiques (ISA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratory for Inorganic, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université de Lyon-Université de Lyon-École Supérieure de Chimie Physique Électronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratoire Chimie Provence (LCP), Université de Provence - Aix-Marseille 1-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Bruker BioSpin Corporation, ANR EQUIPEX (ANR-10-EQPX-47-01), EU Marie-Curie IIF Fellowship (PIIF-GA-2010-274574), ETH Zurich, European Project, and Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Aqueous solution, 010405 organic chemistry, Chemistry, Metals and Alloys, General Chemistry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, Photochemistry, 01 natural sciences, Catalysis, Water based, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Yield (chemistry), Materials Chemistry, Ceramics and Composites, Organic chemistry, DYNAMIC NUCLEAR-POLARIZATION
Abstract

Cover article; International audience; A series of non-aqueous solvents combined with the exogenous biradical bTbK are developed for DNP NMR that yield enhancements comparable to the best available water based systems. 1,1,2,2-tetrachloroethane appears to be one of the most promising organic solvents for DNP solid-state NMR. Here this results in a reduction in experimental times by a factor of 1000. These new solvents are demonstrated with the first DNP surface enhanced NMR characterization of an organometallic complex supported on a hydrophobic surface.

Published
2012
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3. Unraveling the core-shell structure of ligand-capped Sn/SnOx nanoparticles by surface-enhanced nuclear magnetic resonance, Mössbauer, and X-ray absorption spectroscopies

Author

Maksym V. Kovalenko, Maxence Valla, Dominik Kriegner, Kostiantyn V. Kravchyk, Anne Lesage, Lyndon Emsley, Christophe Copéret, Bernard Malaman, Maarten Nachtegaal, Antoine de Kergommeaux, Peter Reiss, Julian Stangl, Marc Walter, Aaron J. Rossini, Loredana Protesescu, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Swiss Federal Laboratories for Materials Science and Technology [Dübendorf] (EMPA), Solid-State NMR Methods for Materials - Méthodes de RMN à l'état solide pour les matériaux, Institut des Sciences Analytiques (ISA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institute of Semiconductor and Solid State Physics, Johannes Kepler Universität Linz (JKU), Structures et propriétés d'architectures moléculaire (SPRAM - UMR 5819), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Paul Scherrer Institute (PSI), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), EQUIPEX contract ANR-10-EQPX-47-01, ERC Advanced Grant No. 320860, ERC Starting Grant No. 306733, EU Marie-Curie IIF fellowship (PIIF-GA-2010-274574), SNF fellowship (200021_143600), Austrian Academy of Sciences (DOC fellowship)., ANR-10-EQPX-0047,SENS,RMN de Surface Exalté par Polarisation Dynamique Nucléaire(2010), AII - Amsterdam institute for Infection and Immunity, APH - Amsterdam Public Health, Global Health, Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Institut Nanosciences et Cryogénie (INAC), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])

Subjects
Materials science, POLARIZATION, XAS, Analytical chemistry, General Physics and Astronomy, chemistry.chemical_element, Nanoparticle, Li-ion batteries, 02 engineering and technology, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, OXIDATION, 01 natural sciences, Nanomaterials, dynamic nuclear polarization, Nuclear magnetic resonance, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, General Materials Science, SEMICONDUCTOR NANOCRYSTALS, SNO2, X-ray absorption spectroscopy, HIGH-FREQUENCY, Extended X-ray absorption fine structure, colloidal, General Engineering, Nuclear magnetic resonance spectroscopy, 021001 nanoscience & nanotechnology, TRANSFORMATION, 0104 chemical sciences, EXAFS, Solid-state nuclear magnetic resonance, chemistry, TIN, NMR-SPECTROSCOPY, core/shell structure, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], solid-state NMR, MONODISPERSE, nanoparticles, Absorption (chemistry), 0210 nano-technology, Tin, Dynamic nuclear polarization, Solid-state NMR, Nanoparticles, Colloidal, Core/shell structure
Abstract

A particularly difficult challenge in the chemistry of nanomaterials is the detailed structural and chemical analysis of multicomponent nano-objects. This is especially true for the determination of spatially resolved information. In this study, we demonstrate that dynamic nuclear polarization surface-enhanced solid-state NMR spectroscopy (DNP-SENS), which provides selective and enhanced NMR signal collection from the (near) surface regions of a sample, can be used to resolve the core–shell structure of a nanoparticle. Li-ion anode materials, monodisperse 10–20 nm large tin nanoparticles covered with a ∼3 nm thick layer of native oxides, were used in this case study. DNP-SENS selectively enhanced the weak 119Sn NMR signal of the amorphous surface SnO2 layer. Mössbauer and X-ray absorption spectroscopies identified a subsurface SnO phase and quantified the atomic fractions of both oxides. Finally, temperature-dependent X-ray diffraction measurements were used to probe the metallic β-Sn core and indicated that even after 8 months of storage at 255 K there are no signs of conversion of the metallic β-Sn core into a brittle semiconducting α-phase, a phase transition which normally occurs in bulk tin at 286 K (13 °C). Taken together, these results indicate that Sn/SnOx nanoparticles have core/shell1/shell2 structure of Sn/SnO/SnO2 phases. The study suggests that DNP-SENS experiments can be carried on many types of uniform colloidal nanomaterials containing NMR-active nuclei, in the presence of either hydrophilic (ion-capped surfaces) or hydrophobic (capping ligands with long hydrocarbon chains) surface functionalities., ACS Nano, 8 (3), ISSN:1936-0851, ISSN:1936-086X

Published
2014
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4. WMe6 tamed by silica: ≡Si-O-WMe5 as an efficient, well-defined species for alkane metathesis, leading to the observation of a supported W-methyl/methylidyne species

Author

Emmanuel Callens, Raju Dey, Jean-Marie Basset, Cory M. Widdifield, Edy Abou-Hamad, Aaron J. Rossini, Manoja K. Samantaray, Lyndon Emsley, KAUST Catalysis Center (KCC), King Abdullah University of Sciences & Technologie, Solid-State NMR Methods for Materials - Méthodes de RMN à l'état solide pour les matériaux, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), EU Marie-Curie IIF fellowship (PIIF-GA-2010-274574), Natural Sciences and Engineering Council of Canada (NSERC), and King Abdullah University of Science and Technology

Subjects
METAL-HYDRIDES, Hexamethyltungsten, CATALYSTS, 010402 general chemistry, Photochemistry, HEXAMETHYLTUNGSTEN, 01 natural sciences, Biochemistry, Catalysis, chemistry.chemical_compound, Colloid and Surface Chemistry, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Propane, Polymer chemistry, Salt metathesis reaction, Homoleptic, Inert gas, ALKYLIDENE, SPECTROSCOPY, TUNGSTEN, OLEFIN-METATHESIS, 010405 organic chemistry, Alkane metathesis, General Chemistry, ORDER REGULAR APPROXIMATION, SOLID-STATE NMR, 3. Good health, 0104 chemical sciences, chemistry, Solid-state nuclear magnetic resonance, COMPLEXES
Abstract

International audience; The synthesis and full characterization of a well-defined silica-supported ≡Si-O-W(Me)5 species is reported. Under an inert atmosphere, it is a stable material at moderate temperature, whereas the homoleptic parent complex decomposes above -20 °C, demonstrating the stabilizing effect of immobilization of the molecular complex. Above 70 °C the grafted complex converts into the two methylidyne surface complexes [(≡SiO-)W(≡CH)Me2] and [(≡SiO-)2W(≡CH)Me]. All of these silica-supported complexes are active precursors for propane metathesis reactions.

Published
2013
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5. Large molecular weight nitroxide biradicals providing efficient dynamic nuclear polarization at temperatures up to 200 K

Author

Gilles Casano, Alexandre Zagdoun, Lyndon Emsley, Fabien Aussenac, Martin Schwarzwälder, Olivier Ouari, Gunnar Jeschke, Paul Tordo, Christophe Copéret, Maxim Yulikov, Anne Lesage, Aaron J. Rossini, ISA - Centre de RMN à très hauts champs, Institut des Sciences Analytiques (ISA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Laboratory of Inorganic Chemistry, Bruker BioSpin SA, EU Marie-Curie IIF Fellowship (PIIF-GA-2010-274574), SNF for financial support (200021_134775/1), EQUIPEX contract ANR-10-EQPX-47-01, ERC Advanced grant no. 320860, ETH Zurich., European Project, Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)

Subjects
Nitroxide mediated radical polymerization, Magnetic Resonance Spectroscopy, Free Radicals, Proton, PROTEINS, IMPACT, C-13, Analytical chemistry, 010402 general chemistry, 7. Clean energy, 01 natural sciences, Biochemistry, Catalysis, Colloid and Surface Chemistry, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Phase (matter), Magic angle spinning, Spectroscopy, Polarization (electrochemistry), SURFACE INTERACTIONS, SPECTROSCOPY, Molecular Structure, 010405 organic chemistry, Chemistry, Relaxation (NMR), ELECTRON-SPIN RELAXATION, Temperature, General Chemistry, 0104 chemical sciences, SOLID-STATE NMR, Molecular Weight, Solid-state nuclear magnetic resonance, Nitrogen Oxides, MEMBRANE, GLASSY SOLVENTS
Abstract

A series of seven functionalized nitroxide biradicals (the bTbK biradical and six derivatives) are investigated as exogenous polarization sources for dynamic nuclear polarization (DNP) solid-state NMR at 9.4 T and with ca. 100 K sample temperatures. The impact of electron relaxation times on the DNP enhancement (ε) is examined, and we observe that longer inversion recovery and phase memory relaxation times provide larger ε. All radicals are tested in both bulk 1,1,2,2-tetrachloroethane solutions and in mesoporous materials, and the difference in ε between the two cases is discussed. The impact of the sample temperature and magic angle spinning frequency on ε is investigated for several radicals each characterized by a range of electron relaxation times. In particular, TEKPol, a bulky derivative of bTbK with a molecular weight of 905 g·mol–1, is presented. Its high-saturation factor makes it a very efficient polarizing agent for DNP, yielding unprecedented proton enhancements of over 200 in both bulk and materials samples at 9.4 T and 100 K. TEKPol also yields encouraging enhancements of 33 at 180 K and 12 at 200 K, suggesting that with the continued improvement of radicals large ε may be obtained at higher temperatures., Journal of the American Chemical Society, 135 (34), ISSN:0002-7863, ISSN:1520-5126

Published
2013
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6. Molecular-level characterization of the structure and the surface chemistry of periodic mesoporous organosilicates using DNP-surface enhanced NMR spectroscopy

Author

Lyndon Emsley, Christophe Copéret, Anne Lesage, Aaron J. Rossini, Wolfram R. Grüning, Alexandre Zagdoun, David Gajan, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), ISA - Centre de RMN à très hauts champs, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratory of Inorganic Chemistry, EU Marie-Curie IIF Fellowship (PIIF-GA-2010-274574), ETH Zurich, EQUIPEX, European Project, Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Magnetic Resonance Spectroscopy, Surface Properties, Analytical chemistry, General Physics and Astronomy, Natural abundance, 010402 general chemistry, 01 natural sciences, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Organosilicon Compounds, Physical and Theoretical Chemistry, Particle Size, Polarization (electrochemistry), Molecular Structure, 010405 organic chemistry, Chemistry, Nuclear magnetic resonance spectroscopy, Carbon-13 NMR, FRAMEWORKS, ORGANIC GROUPS, 0104 chemical sciences, 3. Good health, Characterization (materials science), SOLID-STATE NMR, NMR spectra database, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Solid-state nuclear magnetic resonance, WALLS, Physical chemistry, DYNAMIC NUCLEAR-POLARIZATION, Mesoporous material, Porosity
Abstract

International audience; We present the molecular level characterization of a phenylpyridine-based periodicmesoporous organosilicate and its post-functionalized organometallic derivatives through the fast acquisition of high quality natural isotopic abundance 1D C-13, N-15, and Si-29 and 2D 1H-C-13 and 1H-Si-29 solid-state NMR spectra enhanced with dynamic nuclear polarization.

Published
2013
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7. One hundred fold overall sensitivity enhancements for Silicon-29 NMR spectroscopy of surfaces by dynamic nuclear polarization with CPMG acquisition

Author

Melanie Rosay, Moreno Lelli, Fernando Rascón, David Gajan, Alexandre Zagdoun, Lyndon Emsley, Aaron J. Rossini, Werner E. Maas, Christophe Copéret, Anne Lesage, ISA - Centre de RMN à très hauts champs, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Laboratory for Inorganic Chemistry, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Bruker BioSpin Corporation, EU Marie-Curie IIF Fellowship (PIIF-GA-2010-274574), ANR EQUIPEX (ANR-10-EQPX-47-01), ETH Zurich, European Project, Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
AMPLITUDE CROSS-POLARIZATION, Silicon, Analytical chemistry, chemistry.chemical_element, RELAXATION, Chemistry, SOLID-STATE NMR, MAGIC ANGLE-SPINNING NMR, DNP, 010402 general chemistry, 01 natural sciences, Paramagnetism, Nuclear magnetic resonance, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Sample preparation, Aqueous solution, INTEGER QUADRUPOLAR NUCLEI, 010405 organic chemistry, PULSE SEQUENCE, H-1, Pulse sequence, General Chemistry, Nuclear magnetic resonance spectroscopy, 0104 chemical sciences, NMR spectra database, ANGLE-SPINNING NMR, Solid-state nuclear magnetic resonance, RESOLUTION, MAS NMR, COMPLEXES
Abstract

International audience; Dynamic nuclear polarization (DNP) (29)Si solid-state NMR spectra of a hybrid mesoporous silica material impregnated with aqueous biradical solutions have been acquired with cross-polarization (CP) and cross-polarization Carr-Purcell Meiboom-Gill (CP/CPMG) pulse sequences. The integrated intensities (II) and signal to noise ratios (S/N) of the (29)Si solid-state NMR spectra are monitored in order to measure the DNP enhancement factors (epsilon(Si) (CP)) as well as the overall sensitivity enhancement (Sigma(Si) (CP)) available from the combination of DNP and CPMG acquisition. Here, Sigma(Si) (CP) (epsilon(Si) (CP)) ((sic)(Si)) root kappa, where theta(Si) is a factor which quantifies reduction of the NMR signal by paramagnetic effects (quenching) and kappa is the square root of the ratio of nuclear longitudinal relaxation times of the dry material and material impregnated with radical solution. It is found that Sigma(Si) (CP) is always substantially lower than the measured value of epsilon(Si) CP due to paramagnetic effects which reduce the II of the (29)Si CP solid-state NMR spectra at high biradical concentrations. In this system, it is observed that the sample preparation which provides optimal DNP signal enhancement does not provide optimal overall signal enhancement. Notably, optimal signal enhancements are obtained for CPMG acquisition of the (29)Si solid-state NMR spectra when lower radical concentrations are employed due to slower transverse relaxation rates. To the best of our knowledge this is the first study which seeks to quantify the overall sensitivity enhancements available from DNP solid-state NMR experiments.

Published
2012
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8. Dynamic nuclear polarization of quadrupolar nuclei using cross polarization from protons: surface-enhanced aluminium-27 NMR

Author

Christophe Copéret, Anne Lesage, David Gajan, Moreno Lelli, Alexandre Zagdoun, Aaron J. Rossini, Lyndon Emsley, Veronika Vitzthum, Geoffrey Bodenhausen, Pascal Miéville, Marc A. Caporini, Diego Carnevale, Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory for Inorganic Chemistry, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), ISA - Centre de RMN à très hauts champs, Institut des Sciences Analytiques (ISA), Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Université Pierre et Marie Curie - Paris 6 (UPMC), Institut des sciences et d'ingénierie chimiques (ISIC), Swiss National Science Foundation, Ecole Polytechnique Federale de Lausanne (EPFL), ETH Zurich, Swiss Commission for Technology and Innovation (CTI), French CNRS, EU Marie-Curie IIF Fellowship (PIIF-GA-2010-274574)., European Project, Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)

Subjects
Deuterium NMR, Carbon-13 NMR satellite, Analytical chemistry, Fluorine-19 NMR, 010402 general chemistry, 01 natural sciences, Molecular physics, Catalysis, OLEFIN METATHESIS, OXIDE CATALYSTS, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Materials Chemistry, Magic angle spinning, GAMMA-ALUMINA, QUANTUM MAS NMR, HETEROGENEOUS CATALYSTS, 010405 organic chemistry, Chemistry, Metals and Alloys, HYDROXYL-GROUPS, General Chemistry, Nuclear magnetic resonance spectroscopy, EXCHANGE-REACTION, Carbon-13 NMR, Polarization (waves), 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, MULTIPLE-QUANTUM, ANGLE-SPINNING NMR, Solid-state nuclear magnetic resonance, SILICA-ALUMINA, Ceramics and Composites
Abstract

International audience; The surface of gamma-alumina nanoparticles can be characterized by dynamic nuclear polarization (DNP) surface-enhanced NMR of Al-27. DNP is combined with cross-polarization and MQ-MAS to determine local symmetries of Al-27 sites at the surface.

Published
2012
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9. Methane Reacts with Heteropolyacids Chemisorbed on Silica to Produce Acetic Acid under Soft Conditions

Author

Jean-Marie Basset, Valérie Caps, Jérémie D. A. Pelletier, Edy Abou-Hamad, Miao Sun, Zhu Haibo, Jizhe Zhang, Anne Lesage, Lyndon Emsley, Aaron J. Rossini, KAUST Catalysis Center (KCC), King Abdullah University of Sciences & Technologie, Div Chem & Life Sci & Engn, King Abdullah Univ Sci & Technol, ISA - Centre de RMN à très hauts champs, Institut des Sciences Analytiques (ISA), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), EU Marie-Curie IIF fellowship (PIIF-GA-2010-274574, King Abdullah University of Science and Technology, SABIC (Saudi Basic Industries Corporation), and European Project

Subjects
LOW-TEMPERATURE OXIDATION, C-H ACTIVATION, Inorganic chemistry, Infrared spectroscopy, CATALYSTS, Silicotungstic acid, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, Methane, SILICOTUNGSTIC ACID, Acetic acid, chemistry.chemical_compound, Colloid and Surface Chemistry, X-ray photoelectron spectroscopy, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, 010405 organic chemistry, SUPER ACIDS, General Chemistry, Nuclear magnetic resonance spectroscopy, SELECTIVE OXIDATION, SOLID-STATE NMR, 0104 chemical sciences, chemistry, X-RAY, SINGLE-CRYSTALS, Cyclic voltammetry, HYDROGEN EXCHANGE
Abstract

International audience; Selective functionalization of methane at moderate temperature is of crucial economic, environmental, and scientific importance. Here, we report that methane reacts with heteropolyacids (HPAs) chemisorbed on silica to produce acetic acid under soft conditions. Specially, when chemisorbed on silica, H4SiW12O40, H3PW12O40, H4SiMo12O40, and H3PMo12O40 activate the primary C-H bond of methane at room temperature and atmospheric pressure. With these systems, acetic acid is produced directly from methane, in a single step, in the absence of Pd and without adding CO. Extensive surface characterization by solid-state NMR spectroscopy, IR spectroscopy, cyclic voltammetry, and X-ray photoelectron spectroscopy suggests that C-H activation of methane is triggered by the protons in the HPA-silica interface with concerted reduction of the Keggin cage, leading to water formation and hydration of the interface. This is the simplest and mildest way reported to date to functionalize methane.

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