Author: "Anne, Lesage" / Topic: catalysis - Searchworks@Jio Institute Digital Library Search Results

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101 results on '"Anne, Lesage"'

1. Structure, Location, and Spatial Proximities of Hydroxyls on γ-Alumina Crystallites by High-Resolution Solid-State NMR and DFT Modeling: Why Edges Hold the Key

Author: Ana T. F. Batista, Thomas Pigeon, Jordan Meyet, Dorothea Wisser, Mickael Rivallan, David Gajan, Leonor Catita, Fabrice Diehl, Anne-Sophie Gay, Céline Chizallet, Anne Lesage, Pascal Raybaud, IFP Energies nouvelles (IFPEN), Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure de Lyon (ENS de Lyon)-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), ANR-16-IDEX-0005,IDEXLYON,IDEXLYON(2016), and ANR-10-EQPX-0047,SENS,RMN de Surface Exalté par Polarisation Dynamique Nucléaire(2010)
Subjects: Hydroxyl, Edge, Nuclear Magentic Resonnance, [CHIM]Chemical Sciences, [CHIM.CATA]Chemical Sciences/Catalysis, General Chemistry, Chlorine, γ-alumina, Density Functional Theory, Catalysis
Abstract: International audience; The atomic-scale characterization of surface active sites on γ-alumina still represents a great challenge for numerous catalytic applications. Here, we combine advanced density functional theory (DFT) calculations with one- and two-dimensional proton solid-state NMR experiments to identify the exact location and the spatial proximity of hydroxyl groups on γ-alumina crystallites. Our approach relies on revisited models for the (100), (111), basal (110)b, and lateral (110)l facets of γ-alumina, as well as for the edges at their intersections. Notably, we show that the ≃0 ppm AlTd-μ1-OH protons are predominantly located on edges, where these are free from the H-bond network. The proximities among the AlTd-μ1-OH as well as with μ2-OH groups are revealed by 1H–1H dipolar correlation experiments and analyzed in the light of the DFT calculations, which identify their location on the basal (110)b facet and on the (110)b/(100) and (110)b/(110)l edges. Using chlorine atoms to probe the presence of hydroxyls, we show that the chlorination occurs selectively by exchanging μ1-OH located on edges and on lateral (110)l facets. By contrast, the basal (110)b and lateral (111) facets are not probed by Cl. This exchange explains the disappearance of the ≃0 ppm peak and of the correlations involving AlTd-μ1-OH species. Moreover, after chlorination, a deshielding of the AlTd is observed on high-resolution 27Al NMR spectra. More subtle effects are visible on the proton correlation spectra, which are attributed to the disruption of the H-bond network in the course of chlorination.
Published: 2023
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2. Multiple Surface Site Three-Dimensional Structure Determination of a Supported Molecular Catalyst

Author: Ribal Jabbour, Marc Renom-Carrasco, Ka Wing Chan, Laura Völker, Pierrick Berruyer, Zhuoran Wang, Cory M. Widdifield, Moreno Lelli, David Gajan, Christophe Copéret, Chloé Thieuleux, Anne Lesage, Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure de Lyon (ENS de Lyon)-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), Catalyse, Polymérisation, Procédés et Matériaux (CP2M), Université Claude Bernard Lyon 1 (UCBL), 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), Department of Chemistry and Applied Biosciences [ETH Zürich] (D-CHAB), Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Ecole Polytechnique Fédérale de Lausanne (EPFL), University of Regina (UR), Magnetic Resonance Center (CERM), Università degli Studi di Firenze = University of Florence (UniFI), and ANR-17-CE29-0006,SEQUANS,Spectroscopie RMN Quadripolaire de Surface Exaltée par DNP(2017)
Subjects: Molecular Structure, spatial-distribution, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, General Chemistry, chemistry, Iridium, Ligands, Biochemistry, Catalysis, Colloid and Surface Chemistry, Heterocyclic Compounds, dynamic nuclear-polarization, metal-catalysts, screening model, Organometallic Compounds, solid-state nmr, dnp, solvation, organic functional-groups, approximation
Abstract: International audience; The structural characterization of supported molecular catalysts is challenging due to the low concentration of surface sites and the presence of several organic/organometallic surface groups resulting from the often complex surface chemistry associated with support functionalization. Here, we provide a complete atomic-scale description of all surface sites in a silica-supported iridium-N-heterocyclic carbene (Ir-NHC) catalytic material, at all stages of its synthesis. By combining a suitable isotope labelling strategy with the implementation of multi-nuclear dipolar recoupling DNP enhanced NMR experiments, the 3D structure of the Ir-NHC sites, as well as that of the synthesis intermediates were determined. As a significant fraction of parent surface fragments does not react during the multi-step synthesis, site-selective experiments were implemented to specifically probe proximities between the organometallic groups and the solid support. The NMR-derived structure of the iridium sites points to a well-defined conformation. By interpreting extended x-ray absorption fine structure (EXAFS) spectroscopy and chemical analysis data augmented by computational studies, the presence of two coordination geometries is demonstrated: Ir-NHC fragments coordinated by a 1,5-cyclooctadiene and one Cl ligand, as well as, more surprisingly, a fragment coordinated by two NHC and two Cl ligands. This study demonstrates a unique methodology to disclose individual surface structures in complex, multi-site environments, a long-standing challenge in the field of heterogeneous/supported catalysts, while revealing new, unexpected structural features of metallo-NHC supported substrates. It also highlights the potentially large diversity of surface sites present in functional materials prepared by surface chemistry, an essential knowledge to design materials with improved performances.
Published: 2022
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3. The Structure of Molecular and Surface Platinum Sites Determined by DNP-SENS and Fast MAS 195Pt Solid-State NMR Spectroscopy

Author: Ribal Jabbour, Amrit Venkatesh, Pierrick Berruyer, Christophe Copéret, Anne Lesage, David Gajan, Aaron J. Rossini, Christopher P. Gordon, Georges Menzildjian, Jasmine Viger-Gravel, Lukas Rochlitz, and Alicia Lund
Subjects: Analytical chemistry, chemistry.chemical_element, General Chemistry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, NMR spectra database, chemistry.chemical_compound, Colloid and Surface Chemistry, chemistry, Solid-state nuclear magnetic resonance, ddc:540, Magic angle spinning, Platinum, Spectroscopy, Organometallic chemistry
Abstract: The molecular level characterization of heterogeneous catalysts is challenging due to the low concentration of surface sites and the lack of techniques that can selectively probe the surface of a heterogeneous material. Here, we report the joint application of room temperature proton-detected NMR spectroscopy under fast magic angle spinning (MAS) and dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP-SENS), to obtain the 195Pt solid-state NMR spectra of a prototypical example of highly dispersed Pt sites (single site or single atom), here prepared via surface organometallic chemistry, by grafting [(COD)Pt(OSi(OtBu)3)2] (1, COD = 1,5-cyclooctadiene) on partially dehydroxylated silica (1@SiO2). Compound 1@SiO2 has a Pt loading of 3.7 wt %, a surface area of 200 m2/g, and a surface Pt density of around 0.6 Pt site/nm2. Fast MAS 1H{195Pt} dipolar-HMQC and S-REDOR experiments were implemented on both the molecular precursor 1 and on the surface complex 1@SiO2, providing access to 195Pt isotropic shifts and Pt–H distances, respectively. For 1@SiO2, the measured isotropic shift and width of the shift distribution constrain fits of the static wide-line DNP-enhanced 195Pt spectrum, allowing the 195Pt chemical shift tensor parameters to be determined. Overall the NMR data provide evidence for a well-defined, single-site structure of the isolated Pt sites.
Published: 2020
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4. Silica‐Grafted Tris(neopentyl)aluminum: A Monomeric Aluminum Solid Co‐catalyst for Efficient Nickel‐Catalyzed Ethene Dimerization

Author: Christopher P. Gordon, Jasmine Viger-Gravel, Pierre Florian, Ilia B. Moroz, Christophe Copéret, and Anne Lesage
Subjects: Tris, 010405 organic chemistry, Cationic polymerization, chemistry.chemical_element, General Chemistry, Nuclear magnetic resonance spectroscopy, General Medicine, 010402 general chemistry, 01 natural sciences, Chloride, Catalysis, 0104 chemical sciences, chemistry.chemical_compound, Nickel, Monomer, chemistry, Polymer chemistry, medicine, Organometallic chemistry, medicine.drug
Abstract: A silica-supported monomeric alkylaluminum co-catalyst was prepared via surface organometallic chemistry by contacting tris(neopentyl)aluminum and partially dehydroxylated silica. This system, fully characterized by solid-state 27 Al NMR spectroscopy augmented by computational studies, efficiently activates (n Bu3 P)2 NiCl2 towards dimerization of ethene, demonstrating comparable activity to previously reported dimeric diethylaluminum chloride supported on silica. Three types of aluminum surface species have been identified: monografted tetracoordinated Al species as well as two types of bisgrafted Al species-tetra- and pentacoordinated. Of them, only the monografted Al species is proposed to be able to activate the (n Bu3 P)2 NiCl2 complex and generate the active cationic species.
Published: 2020
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5. Structural Characterization of Phosphate Species Adsorbed on γ-Alumina by Combining DNP Surface Enhanced NMR Spectroscopy and DFT Calculations

Author: Anne Lesage, Pascal Raybaud, Leonor Catita, Dorothea Wisser, Manuel Corral Valero, Adrian Hühn, Carine Michel, Mickael Rivallan, Teddy Roy, Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure - Lyon (ENS Lyon)-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), IFP Energies nouvelles (IFPEN), ANR-16-IDEX-0005,IDEXLYON,IDEXLYON(2016), and École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: Materials science, 02 engineering and technology, 010402 general chemistry, chemical shift, 01 natural sciences, Catalysis, chemistry.chemical_compound, Adsorption, density functional theory, phosphate, nuclear magnetic resonance spectroscopy, polyphosphate, General Chemistry, Nuclear magnetic resonance spectroscopy, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, Phosphate, γ-alumina, DNP SENS, 0104 chemical sciences, γ alumina, Characterization (materials science), [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, chemistry, Physical chemistry, 0210 nano-technology
Abstract: International audience; Obtaining an atomic-scale description of the chemical interactions of phosphates with an oxide support, such as γ-Al2O3, is essential to get a rational understanding of the role of phosphate additives for a great number of heterogeneous catalysts, as well as to improve the use of this element. Combining cutting-edge Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) techniques with Density Functional Theory (DFT) calculations, we provide an accurate molecular description of phosphate speciation on γ-Al2O3 surfaces for various P surface coverages after drying at 120 °C. Thanks to 31P double- and triple-quantum filtered NMR experiments as well as to 27Al–31P dipolar- and scalar-based correlation spectra, we demonstrate the presence of polyphosphates and of Al–O–P connectivities at the exposed facets of γ-Al2O3. DFT-based thermodynamics shows that phosphates (mono- or di-) are preferentially covalently bonded on the (1 1 0) γ-Al2O3 facet with high-dentation modes. These high-dentation modes are favored by entropy gain due to water desorption. We used the gauge-including projector-augmented wave (GIPAW) DFT method for 31P NMR chemical shifts calculations and propose a systematic identification of the various types of phosphates covalently or noncovalently bonded to the alumina surface. The calculations confirm the existence of polyphosphates as observed experimentally. Since the surface condensation into polyphosphates is endergonic, the presence of polyphosphates on the surface is likely to result from their direct adsorption in impregnation solution. The observed increasing concentration of polyphosphates with the coverage could be related to a less likely hydrolysis due to the reduced availability of sites to stabilize the fragmented oligomers. This understanding opens the way to a better control over the speciation of phosphate species that are known to be key in the preparation of supported catalysts over alumina.
Published: 2021
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6. Metal–Metal Synergy in Well-Defined Surface Tantalum–Iridium Heterobimetallic Catalysts for H/D Exchange Reactions

Author: Sébastien Lassalle, Laurent Veyre, Anne Lesage, Tanya K. Todorova, Chloé Thieuleux, Ribal Jabbour, Clément Camp, David Gajan, Pauline Schiltz, Pierrick Berruyer, Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université Claude Bernard Lyon 1 (UCBL), 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), Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure - Lyon (ENS Lyon)-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), Laboratoire de Chimie des Processus Biologiques (LCPB), Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Sorbonne Université (SU)-Centre National de la Recherche Scientifique (CNRS), 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), and École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: H/D exchange, Alkane, chemistry.chemical_classification, tantalum, Chemistry, Surface organometallic chemistry, Tantalum, hydrides, chemistry.chemical_element, General Chemistry, iridium, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, Colloid and Surface Chemistry, Polymer chemistry, early/late heterobimetallics, [CHIM]Chemical Sciences, Metal metal, Iridium, Well-defined
Abstract: International audience; A novel heterobimetallic tantalum/iridium hydrido complex, [{Ta(CH2 t Bu)3}{IrH2(Cp*)}] 1, featuring a very short metal-metal bond, has been isolated through an original alkane elimination route from Ta(CH t Bu)(CH2 t Bu)3 and Cp*IrH4. This molecular precursor has been used to synthesize well-defined silica-supported low-coordinate heterobime-tallic hydrido species [≡SiOTa(CH2 t Bu)2{IrH2(Cp*)}] 5 and [≡SiOTa(CH2 t Bu)H{IrH2(Cp*)}] 6 using a surface organometallic chemistry approach (SOMC). The SOMC methodology prevents undesired dimerization as encountered in solution and leading to a tetranuclear species [{Ta(CH2 t Bu)2}(Cp*IrH)]2, 4. This approach therefore allows access to unique low-coordinate species not attainable in solution. These original supported Ta/Ir species exhibit drastically enhanced catalytic performances in H/D exchange reactions with respect to (i) monometallic analogues as well as (ii) homogeneous systems. In particular, material 6 promotes the H/D exchange between fluorobenzene and C6D6 or D2 as deuterium sources with excellent productivity (TON up to 1422; TOF up to 23.3 h-1) under mild conditions (25°C, subatmospheric D2 pressure) without any additives.
Published: 2019
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7. Specific Localization of Aluminum Sites Favors Ethene-to-Propene Conversion on (Al)MCM-41-Supported Ni(II) Single Sites

Author: Christophe Copéret, Anne Lesage, Alexey Fedorov, Alicia Lund, David Gajan, Ilia B. Moroz, Monu Kaushik, and Laurent Sévery
Subjects: 010405 organic chemistry, chemistry.chemical_element, General Chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Propene, chemistry.chemical_compound, MCM-41, chemistry, Aluminium, Polymer chemistry, Pyridine, Organometallic chemistry
Abstract: Single-site Ni(II) catalytic centers supported on MCM-41-type materials were prepared via surface organometallic chemistry using tailored thermolytic molecular precursors. These materials catalytic...
Published: 2019
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8. Preferential Siting of Aluminum Heteroatoms in the Zeolite Catalyst Al‐SSZ‐70

Author: Anne Lesage, Zachariah J. Berkson, Stacey I. Zones, Ming-Feng Hsieh, Bradley F. Chmelka, Lynne B. McCusker, David Gajan, Alicia Lund, Stef Smeets, Dan Xie, and Christian Baerlocher
Subjects: Materials science, 010405 organic chemistry, Heteroatom, General Chemistry, 010402 general chemistry, Fluid catalytic cracking, 01 natural sciences, Catalysis, 0104 chemical sciences, Adsorption, Aluminosilicate, Physical chemistry, Partial oxidation, Zeolite, Powder diffraction
Abstract: The adsorption and reaction properties of heterogeneous zeolite catalysts (e.g. for catalytic cracking of petroleum, partial oxidation of natural gas) depend strongly on the types and distributions of Al heteroatoms in the aluminosilicate frameworks. The origins of these properties have been challenging to discern, owing in part to the structural complexity of aluminosilicate zeolites. Herein, combined solid-state NMR and synchrotron X-ray powder diffraction analyses show the Al atoms locate preferentially in certain framework sites in the zeolite catalyst Al-SSZ-70. Through-covalent-bond 2D 27 Al{29 Si} J-correlation NMR spectra allow distinct framework Al sites to be identified and their relative occupancies quantified. The analyses show that 94 % of the Al atoms are located at the surfaces of the large-pore interlayer channels of Al-SSZ-70, while only 6 % are in the sub-nm intralayer channels. The selective siting of Al atoms accounts for the reaction properties of catalysts derived from SSZ-70.
Published: 2019
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9. Spectroscopic Signature and Structure of the Active Sites in Ziegler–Natta Polymerization Catalysts Revealed by Electron Paramagnetic Resonance

Author: Vincent Monteil, Anton Ashuiev, Gunnar Jeschke, David Gajan, Matthieu Humbert, Anne Lesage, Jan Blahut, Christophe Copéret, Daniel Klose, Jean Raynaud, Keith Searles, Sébastien Norsic, G. Pintacuda, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Catalyse, Polymérisation, Procédés et Matériaux (CP2M), Université Claude Bernard Lyon 1 (UCBL), 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), Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure - Lyon (ENS Lyon)-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 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), and École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: inorganic chemicals, Ethylene, Natta, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, law.invention, chemistry.chemical_compound, Colloid and Surface Chemistry, law, Electron paramagnetic resonance, Bimetallic strip, biology, BCL3, General Chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, biology.organism_classification, 0104 chemical sciences, 3. Good health, Crystallography, [CHIM.POLY]Chemical Sciences/Polymers, chemistry, Polymerization, Density functional theory
Abstract: International audience; Despite decades of extensive studies, the atomic-scale structure of the active sites in heterogeneous Ziegler–Natta (ZN) catalysts, one of the most important processes of the chemical industry, remains elusive and a matter of debate. In the present work, the structure of active sites of ZN catalysts in the absence of ethylene, referred to as dormant active sites, is elucidated from magnetic resonance experiments carried out on samples reacted with increasing amounts of BCl3 so as to enhance the concentration of active sites and observe clear spectroscopic signatures. Using electron paramagnetic resonance (EPR) and NMR spectroscopies, in particular 2D HYSCORE experiments complemented by density functional theory (DFT) calculations, we show that the activated ZN catalysts contain bimetallic alkyl-Ti(III),Al species whose amount is directly linked to the polymerization activity of MgCl2-supported Ziegler–Natta catalysts. This connects those spectroscopic signatures to the active species formed in the presence of ethylene and enables us to propose an ethylene polymerization mechanism on the observed bimetallic alkyl-Ti(III),Al species based on DFT computations.
Published: 2021
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10. Stepwise Construction of Silica-supported Tantalum/Iridium Heteropolymetallic Catalysts Using Surface Organometallic Chemistry

Author: Laurent Veyre, Laurent Maron, Sébastien Lassalle, Iker del Rosal, Ribal Jabbour, Clément Camp, Anne Lesage, Chloé Thieuleux, Emiliano Fonda, David Gajan, Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université Claude Bernard Lyon 1 (UCBL), 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), Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure - Lyon (ENS Lyon)-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 National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA), Synchrotron SOLEIL (SSOLEIL), Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC), 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), École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)
Subjects: Surface (mathematics), Molecular model, tantalum, Tantalum, chemistry.chemical_element, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, chemistry.chemical_compound, Surface OrganoMetallic Chemistry (SOMC), [CHIM]Chemical Sciences, hydrogen isotope exchange (HIE), [CHIM.COOR]Chemical Sciences/Coordination chemistry, Iridium, Physical and Theoretical Chemistry, Organometallic chemistry, X-ray absorption spectroscopy, alkane metathesis, 010405 organic chemistry, early/late heterobimetallic species, Alkane metathesis, hydrides, [CHIM.CATA]Chemical Sciences/Catalysis, iridium, 0104 chemical sciences, Crystallography, chemistry, supported Dual-Atom Catalysts (DACs)
Abstract: International audience; A stepwise surface organometallic chemistry (SOMC) methodology consisting in using a silica-supported tantalum species, [(≡SiO)Ta(CH t Bu)(CH2 t Bu)2], as a reactive center to coordinate an iridium site, was developed to construct tantalum/iridium heterobimetallic edifices. The resulting material, MAT-2, exhibits enhanced catalytic performances-both in H/D isotopic exchange and alkane metathesis reactions-in comparison to MAT-1, which was prepared from the direct grafting on silica of a well-defined heterobimetallic Ta/Ir complex. We projected that the difference in catalytic activity was due to the presence of distinct active sites and we used a combination of advanced spectroscopic methods (IR, solid-state NMR and XAS spectroscopies) as well as modeling (computational studies and molecular models) to identify the structure of these surface species. These investigations point towards the presence of three types of active sites at the surface of MAT-2: the heterobimetallic surface species, [≡SiOTa(CH2 t Bu)2{IrH2(Cp*)}] 2-s, which is also found in MAT-1, as well as an unanticipated heterotrimetallic species, [≡SiOTa(CH2 t Bu)2{IrH2(Cp*)}], 3-s along with some unreacted monometallic Ta sites [(≡SiO)Ta(CH t Bu)(CH2 t Bu)2], 1-s. The well-defined trimetallic surface species 3-s was independently prepared and characterized to support this hypothesis. This study highlights the importance of the synthetic methodology used for the preparation of heterobimetallic species through SOMC, and the difficulty to obtain true single-sites surface species.
Published: 2020
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11. Structural Analysis of an Antigen Chemically Coupled on Virus-Like Particles in Vaccine Formulation

Author: Kaspars Tars, Olivier Ouari, Anna Kirsteina, Guido Pintacuda, Gilles Casano, Andris Kazaks, Kristaps Jaudzems, Anne Lesage, Janis Bogans, and Tobias Schubeis
Subjects: Bioconjugation, biology, 010405 organic chemistry, Chemistry, Manufacturing process, Hemagglutinin (influenza), General Chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, Virus, 0104 chemical sciences, Solid-state nuclear magnetic resonance, Virus-like particle, Antigen, biology.protein, Biophysics, Vaccines, Virus-Like Particle, Antigens, Viral, Nuclear Magnetic Resonance, Biomolecular, Alpha helix
Abstract: Structure determination of adjuvant-coupled antigens is essential for rational vaccine development but has so far been hampered by the relatively low antigen content in vaccine formulations and by their heterogeneous composition. Here we show that magic-angle spinning (MAS) solid-state NMR can be used to assess the structure of the influenza virus hemagglutinin stalk long alpha helix antigen, both in its free, unformulated form and once chemically coupled to the surface of large virus-like particles (VLPs). The sensitivity boost provided by high-field dynamic nuclear polarization (DNP) and proton detection at fast MAS rates allows to overcome the penalty associated with the antigen dilution. Comparison of the MAS NMR fingerprints between the free and VLP-coupled forms of the antigen provides structural evidence of the conservation of its native fold upon bioconjugation. This work demonstrates that high-sensitivity MAS NMR is ripe to play a major role in vaccine design, formulation studies, and manufacturing process development.
Published: 2020

12. Spectroscopic Signature and Structure of Active Centers in Ziegler-Natta Polymerization Catalysts revealed by Electron Paramagnetic Resonance

Author: Jan Blahut, Gunnar Jeschke, Anton Ashuiev, Vincent Monteil, Guido Pintacuda, Sébastien Norsic, Christophe Copéret, Jean Raynaud, Matthieu Humbert, Keith Searles, Anne Lesage, Daniel Klose, David Gajan, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon, Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure - Lyon (ENS Lyon)-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), and École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: inorganic chemicals, Ethylene, Keith, 020209 energy, Anton, 02 engineering and technology, Natta, sebastien, 010402 general chemistry, Photochemistry, 01 natural sciences, Catalysis, law.invention, chemistry.chemical_compound, gajan, law, david, et al. (2020): Spectroscopic Signature and Structure of Active Centers in Ziegler-Natta Polymerization Catalysts revealed by Electron Paramagnetic Resonance. ChemRxiv. Preprint, 0202 electrical engineering, electronic engineering, information engineering, [CHIM]Chemical Sciences, mathieu, Ziegler–Natta catalyst, Electron paramagnetic resonance, Bimetallic strip, biology, blahut, humber, Polyethylene, biology.organism_classification, 3. Good health, 0104 chemical sciences, jean, Searles, chemistry, Polymerization, CC BY-NC-ND 4.0 Citation information: Ashuiev, norsic
Abstract: Despite decades of extensive studies, the atomic-scale structure of the active sites in heterogeneous Ziegler-Natta (ZN) catalysts, one of the most important processes of the chemical industry, remains elusive and a matter of debate. In the present work, the structure of “active sites” of ZN catalysts in the absence of ethylene, referred to as “dormant active sites”, is elucidated from magnetic resonance experiments, carried out on samples reacted with increasing amounts of BCl3 so as to enhance the concentration of active sites and observe clear spectroscopic signatures. Using EPR and NMR spectroscopies, in particular 2D HYSCORE experiments complemented by DFT calculations, we show that the activated ZN catalysts contain bimetallic alkyl-Ti(III),Al species whose amount is directly linked to the polymerization activity of MgCl2-supported Ziegler-Natta catalysts. This connects those spectroscopic signatures to the active species formed in the presence of ethylene, and enables us propose an ethylene polymerization mechanism on the observed bimetallic alkyl-Ti(III),Al species based on DFT computations
Published: 2020
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13. Open and Closed Radicals: Local Geometry around Unpaired Electrons Governs Magic-Angle Spinning Dynamic Nuclear Polarization Performance

Author: Laura Esteban Hofer, Georges Menzildjian, Maxim Yulikov, Yu Rao, Lyndon Emsley, Olivier Ouari, Gilles Casano, Dominik J. Kubicki, Gabriele Stevanato, Moreno Lelli, Hakim Karoui, Manuel Cordova, Anne Lesage, Didier Siri, and Gunnar Jeschke
Subjects: Chemistry, Dynamic nuclear polarisation, Geometry, General Chemistry, Electron, 010402 general chemistry, Polarization (waves), 01 natural sciences, Biochemistry, Catalysis, 3. Good health, 0104 chemical sciences, law.invention, Colloid and Surface Chemistry, Unpaired electron, law, Magic angle spinning, Dynamic Nuclear Polarisation, NMR, radical, EPR, Electron paramagnetic resonance, Conformational isomerism, Order of magnitude
Abstract: The development of magic-angle spinning dynamic nuclear polarization (MAS DNP) has allowed atomic-level characterization of materials for which conventional solid-state NMR is impractical due to the lack of sensitivity. The rapid progress of MAS DNP has been largely enabled through the understanding of rational design concepts for more efficient polarizing agents (PAs). Here, we identify a new design principle which has so far been overlooked. We find that the local geometry around the unpaired electron can change the DNP enhancement by an order of magnitude for two otherwise identical conformers. We present a set of 13 new stable mono- and dinitroxide PAs for MAS DNP NMR where this principle is demonstrated. The radicals are divided into two groups of isomers, named open (O-) and closed (C-), based on the ring conformations in the vicinity of the N-O bond. In all cases, the open conformers exhibit dramatically improved DNP performance as compared to the closed counterparts. In particular, a new urea-based biradical named HydrOPol and a mononitroxide O-MbPyTol yield enhancements of 330 ± 60 and 119 ± 25, respectively, at 9.4 T and 100 K, which are the highest enhancements reported so far in the aqueous solvents used here. We find that while the conformational changes do not significantly affect electron spin-spin distances, they do affect the distribution of the exchange couplings in these biradicals. Electron spin echo envelope modulation (ESEEM) experiments suggest that the improved performance of the open conformers is correlated with higher solvent accessibility.
Published: 2020

14. Atomic-Scale Description of Interfaces between Antigen and Aluminum-Based Adjuvants Used in Vaccines by Dynamic Nuclear Polarization (DNP) Enhanced NMR Spectroscopy

Author: Pierre Florian, David Gajan, Anne Lesage, Corinne Cazaux, Jasmine Viger-Gravel, Amandine Leleu, Frédéric Ronzon, Ribal Jabbour, Federico M. Paruzzo, and Françoise Canini
Subjects: Magnetic Resonance Spectroscopy, medicine.medical_treatment, Drug Compounding, 010402 general chemistry, 01 natural sciences, Catalysis, Adsorption, Antigen, Adjuvants, Immunologic, Magic angle spinning, medicine, Non-covalent interactions, Antigens, Polarization (electrochemistry), chemistry.chemical_classification, Vaccines, 010405 organic chemistry, Chemistry, Organic Chemistry, General Chemistry, Nuclear magnetic resonance spectroscopy, 0104 chemical sciences, Covalent bond, Chemical physics, Adjuvant, Aluminum
Abstract: The addition of aluminum-based adjuvants in vaccines enhances the immune response to antigens. The strength of antigen adsorption on adjuvant gels is known to modulate vaccine efficacy. However, a detailed understanding of the mechanisms of interaction between aluminum gels and antigens is still missing. Herein, a new analytical approach based on dynamic nuclear polarization (DNP) enhanced NMR spectroscopy under magic angle spinning (MAS) is implemented to provide a molecular description of the antigen-adjuvant interface. This approach is demonstrated on hepatitis B surface antigen particles in combination with three aluminum gels obtained from different suppliers. Both noncovalent and covalent interactions between the phospholipids of the antigen particles and the surface of the aluminum gels are identified by using MAS DNP NMR 27 Al and 31 P correlation experiments. Although covalent interactions were detected for only one of the formulations, dipolar recoupling rotational echo adiabatic passage double resonance (REAPDOR) experiments reveal significant differences in the strength of weak interactions.
Published: 2020

15. Beyond y-Al2O3crystallite surfaces: The hidden features of edgesrevealed by solid-state1H NMR and DFT calculations

Author: Anne Lesage, Ana Teresa Fialho Batista, Céline Chizallet, Thomas Pigeon, Pascal Raybaud, Mickael Rivallan, Leonor Catita, Dorothea Wisser, David Gajan, Fabrice Diehl, IFP Energies nouvelles (IFPEN), Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure - Lyon (ENS Lyon)-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), ANR-16-IDEX-0005,IDEXLYON,IDEXLYON(2016), and École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: Surface (mathematics), Work (thermodynamics), 010405 organic chemistry, Hydrogen bond, Chemistry, edge, [CHIM.CATA]Chemical Sciences/Catalysis, Edge (geometry), 010402 general chemistry, 01 natural sciences, alumina, Catalysis, 0104 chemical sciences, Crystallography, NMR spectroscopy, hydroxyls, Proton NMR, [CHIM]Chemical Sciences, Density functional theory, Crystallite, Physical and Theoretical Chemistry, density functional theory
Abstract: International audience; Elucidating the nature of high surface area gamma alumina sites is of great interest for numerous catalytic applications. In this work, the structural and spectroscopic features of edge sites are unravelled thanks to density functional theory (DFT) calculations combined with high field 1H MAS NMR of two high surface area alumina samples exhibiting distinct morphologies. DFT chemical shift calculations were carried out for relevant surface models with different hydration degrees. However, the best assignment is achieved by considering the first DFT model representing the hydroxylated edges located at the intersection of (1 1 0) and (1 0 0) alumina facets. The sharp 1H NMR peak at 0 ppm corresponds to µ1-OH groups which are located on this edge and are free from hydrogen bonding. Moreover, we show that these edge sites are the most reactive with respect to chlorine exchange.
Published: 2019
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16. Supported Ru olefin metathesis catalysts via a thiolate tether

Author: Giovanni Occhipinti, David Gajan, Marc Renom-Carrasco, Vidar R. Jensen, Laurent Veyre, Anne Lesage, Philipp Mania, Chloé Thieuleux, R. Sayah, Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Centre National de la Recherche Scientifique (CNRS), 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), University of Bergen (UiB), Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure - Lyon (ENS Lyon)-Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon
Subjects: Olefin metathesis, 010405 organic chemistry, chemistry.chemical_element, [CHIM.MATE]Chemical Sciences/Material chemistry, [CHIM.CATA]Chemical Sciences/Catalysis, 010402 general chemistry, 01 natural sciences, Combinatorial chemistry, 0104 chemical sciences, Ruthenium, Catalysis, Inorganic Chemistry, chemistry, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; Thiolate-coordinated ruthenium alkylidene complexes can give high Z-selectivity and stereoretentivity in olefin metathesis. To investigate their applicability as heterogeneous catalysts, we have successfully developed a methodology to easily immobilize prototype ruthenium alkylidenes onto hybrid mesostructured silica via a thiolate tether. In contrast, the preparation of the corresponding molecular complexes appeared very challenging in solution. These prototype supported complexes contain small thiolates but still, they are slightly more Z-selective than their molecular analogues. These results open the door to more active and selective heterogeneous catalysts by supporting more advanced thiolate Ru-complexes.
Published: 2019
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17. The Nature of Secondary Interactions at Electrophilic Metal Sites of Molecular and Silica-Supported Organolutetium Complexes from Solid-State NMR Spectroscopy

Author: Richard A. Andersen, Laurent Maron, Christophe Copéret, Anne Lesage, Wayne W. Lukens, Kevin J. Sanders, David Gajan, Iker del Rosal, Matthew P. Conley, Giuseppe Lapadula, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Biological Solid-State NMR Methods - Méthodes de RMN à l'état solide en biologie, 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), Solid-State NMR Methods for Materials - Méthodes de RMN à l'état solide pour les matériaux, Laboratoire de physique et chimie des nano-objets (LPCNO), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Institut de Chimie de Toulouse (ICT-FR 2599), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Department of Chemistry [Berkeley], University of California [Berkeley], University of California-University of California, C.C. thanks the Miller Institute for a Visiting Professor position at UC Berkeley, during which this manuscript was finalized. Portions of this work were performed at Lawrence Berkeley National Laboratory under contract no. DE-AC02-05CH11231 and at the Stanford Synchrotron Radiation Lightsource (SSRL). Use of the Stanford Synchrotron Radiation Lightsource, SLAC National Accelerator Laboratory, is supported by the U.S. Department of Energy, Office of Science, Office of Basic Energy Sciences under contract no. DE-AC02-76SF00515. Portions of this work were supported by the U.S. Department of Energy, Office of Science, Basic Energy Sciences, Chemical Sciences, Biosciences, and Geosciences Division (CSGB), Heavy Element Chemistry Program and were performed at Lawrence Berkeley National Laboratory under contract no. DE-AC02-05CH11231. We also thank the HPCs CALcul en Midi-Pyrennes (CALIMP-EOS, grant P0833) for the generous allocation of computer time. Financial support from the TGIR-RMN-THC Fr3050 CNRS for conducting the research is gratefully acknowledged., 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 National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut de Chimie de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche sur les Systèmes Atomiques et Moléculaires Complexes (IRSAMC), Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Centre National de la Recherche Scientifique (CNRS), University of California [Berkeley] (UC Berkeley), and University of California (UC)-University of California (UC)
Subjects: 010405 organic chemistry, Chemistry, Resonance, Nanotechnology, General Chemistry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, Spectral line, 0104 chemical sciences, Crystallography, Colloid and Surface Chemistry, Solid-state nuclear magnetic resonance, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Chemical Sciences, Electrophile, Proton NMR, [CHIM]Chemical Sciences, Spectroscopy, Natural bond orbital
Abstract: International audience; Lu[CH(SiMe3)2]3 reacts with [SiO2-700] to give [(≡SiO)Lu[CH(SiMe3)2]2] and CH2(SiMe3)2. [(≡SiO)Lu[CH(SiMe3)2]2] is characterized by solid-state NMR and EXAFS spectroscopy, which show that secondary Lu···C and Lu···O interactions, involving a γ-CH3 and a siloxane bridge, are present. From X-ray crystallographic analysis, the molecular analogues Lu[CH(SiMe3)2]3-x[O-2,6-tBu-C6H3]x (x = 0-2) also have secondary Lu···C interactions. The (1)H NMR spectrum of Lu[CH(SiMe3)2]3 shows that the -SiMe3 groups are equivalent to -125 °C and inequivalent below that temperature, ΔG(⧧)(Tc = 148 K) = 7.1 kcal mol(-1). Both -SiMe3 groups in Lu[CH(SiMe3)2]3 have (1)JCH = 117 ± 1 Hz at -140 °C. The solid-state (13)C CPMAS NMR spectrum at 20 °C shows three chemically inequivalent resonances in the area ratio of 4:1:1 (12:3:3); the J-resolved spectra for each resonance give (1)JCH = 117 ± 2 Hz. The (29)Si CPMAS NMR spectrum shows two chemically inequivalent resonances with different values of chemical shift anisotropy. Similar observations are obtained for Lu[CH(SiMe3)2]3-x[O-2,6-tBu-C6H3]x (x = 1 and 2). The spectroscopic data point to short Lu···Cγ contacts corresponding to 3c-2e Lu···Cγ-Siβ interactions, which are supported by DFT calculations. Calculated natural bond orbital (NBO) charges show that Cγ carries a negative charge, while Lu, Hγ, and Siβ carry positive charges; as the number of O-based ligands increases so does the positive charge at Lu, which in turns shortens the Lu···Cγ distance. The change in NBO charges and the resulting changes in the spectroscopic and crystallographic properties show how ligands and surface-support sites rearrange to accommodate these changes, consistent with Pauling's electroneutrality concept.
Published: 2016
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18. F-19 Magic Angle Spinning Dynamic Nuclear Polarization Enhanced NMR Spectroscopy

Author: Lyndon Emsley, David Gajan, Olivier Ouari, Dominik J. Kubicki, Jasmine Viger-Gravel, Moreno Lelli, Claudia E. Avalos, Anne Lesage, Ecole Polytechnique Fédérale de Lausanne (EPFL), Centre de RMN à très hauts champs de Lyon (CRMN), École normale supérieure de Lyon (ENS de Lyon)-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), Ctr Magnet Resonance, Università degli Studi di Firenze = University of Florence (UniFI), Department of Chemistry 'Ugo Schiff', Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), École normale supérieure - Lyon (ENS Lyon)-Université Claude Bernard Lyon 1 (UCBL), and Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI)
Subjects: active pharmaceutical ingredients, polarizing agent, Materials science, h-1, Analytical chemistry, 010402 general chemistry, 01 natural sciences, Catalysis, efficient, dynamic nuclear polarization, nmr spectroscopy, magic angle spinning, Magic angle spinning, solid-state nmr, [CHIM]Chemical Sciences, Hyperpolarization (physics), hyperpolarization, Incipient wetness impregnation, 010405 organic chemistry, overhauser-dnp, magnetic-resonance, General Medicine, General Chemistry, Nuclear magnetic resonance spectroscopy, 0104 chemical sciences, Microcrystalline, Solid-state nuclear magnetic resonance, Hybrid material, Microwave
Abstract: WOS:000474803100008; The introduction of high-frequency, high-power microwave sources, tailored biradicals, and low-temperature magic angle spinning (MAS) probes has led to a rapid development of hyperpolarization strategies for solids and frozen solutions, leading to large gains in NMR sensitivity. Here, we introduce a protocol for efficient hyperpolarization of F-19 nuclei in MAS DNP enhanced NMR spectroscopy. We identified trifluoroethanol-d(3) as a versatile glassy matrix and show that 12mm AMUPol (with microcrystalline KBr) provides direct F-19 DNP enhancements of over 100 at 9.4T. We applied this protocol to obtain DNP-enhanced F-19 and F-19-C-13 cross-polarization (CP) spectra for an active pharmaceutical ingredient and a fluorinated mesostructured hybrid material, using incipient wetness impregnation, with enhancements of approximately 25 and 10 in the bulk solid, respectively. This strategy is a general and straightforward method for obtaining enhanced F-19 MAS spectra from fluorinated materials.
Published: 2019
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19. Dynamic Nuclear Polarization-Enhanced Biomolecular NMR Spectroscopy at High Magnetic Field with Fast Magic-Angle Spinning

Author: Olivier Ouari, Diane Cala de Paepe, Inara Akopjana, Svetlana Kotelovica, G. Pintacuda, Anne Lesage, Andrea Pica, Andrew J. Pell, Kristaps Jaudzems, Andrea Bertarello, Sachin Rama Chaudhari, Emeline Barbet-Massin, Kaspars Tars, David Gajan, Biological Solid-State NMR Methods - Méthodes de RMN à l'état solide en biologie, 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), Solid-State NMR Methods for Materials - Méthodes de RMN à l'état solide pour les matériaux, Dipartimento di Scienze Chimiche, Università degli studi di Napoli Federico II, Department of Materials and Environmental Chemistry - Arrhenius Laboratory, Biomed Res & Study Ctr, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), We acknowledge financial support from the CNRS, the EQUIPEX (contract ANR-10-EQPX-47-01), the Agence Nationale de la Recherche (contract ANR15-CE29-002202), and the People Programme of the European Union's FP7 (FP7- PEOPLE-2012-ITN no. 317127 'pNMR'). K.J. is supported by a MC incoming fellowship (REA grant agreement no. 661175 'virus-DNP-NMR'). A.P. is supported by Fondazione con il Sud (grant 2011-PDR-19)., ANR-10-EQPX-0047,SENS,RMN de Surface Exalté par Polarisation Dynamique Nucléaire(2010), European Project: 317127,EC:FP7:PEOPLE,FP7-PEOPLE-2012-ITN,PNMR(2013), 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), and University of Naples Federico II = Università degli studi di Napoli Federico II
Subjects: Materials science, magic-angle spinning, 010405 organic chemistry, General Medicine, General Chemistry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, Polarization (waves), 01 natural sciences, Molecular physics, Catalysis, Spectral line, 0104 chemical sciences, NMR spectra database, dynamic nuclear polarization, Paramagnetism, Magic angle spinning, [CHIM]Chemical Sciences, biomolecular NMR, solid-state NMR spectroscopy, High magnetic field, Coherence (physics)
Abstract: International audience; Dynamic nuclear polarization (DNP) is a powerful way to overcome the sensitivity limitation of magic-angle-spinning (MAS) NMR experiments. However, the resolution of the DNPNMR spectra of proteins is compromised by severe line broadening associated with the necessity to perform experiments at cryogenic temperatures and in the presence of paramagnetic radicals. High-quality DNP-enhanced NMR spectra of the Acinetobacter phage 205 (AP205) nucleocapsid can be obtained by combining high magnetic field (800MHz) and fast MAS (40kHz). These conditions yield enhanced resolution and long coherence lifetimes allowing the acquisition of resolved 2D correlation spectra and of previously unfeasible scalar-based experiments. This enables the assignment of aromatic resonances of the AP205 coat protein and its packaged RNA, as well as the detection of long-range contacts, which are not observed at room temperature, opening new possibilities for structure determination.
Published: 2018
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20. Superstructure of a Substituted Zeolitic Imidazolate Metal-Organic Framework Determined by Combining Proton Solid-State NMR Spectroscopy and DFT Calculations

Author: Lyndon Emsley, Sonia Aguado, David Farrusseng, Nathalie Audebrand, Virginie Moizan-Basle, Jérôme Canivet, Anne Lesage, Maria Baias, 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), IRCELYON-Ingéniérie, du matériau au réacteur (ING), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), 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 Chimie du CNRS (INC), IFP Energies nouvelles (IFPEN), 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: 02 engineering and technology, Nuclear magnetic resonance crystallography, 010402 general chemistry, 01 natural sciences, Catalysis, Condensed Matter::Materials Science, chemistry.chemical_compound, metal–organic frameworks, Computational chemistry, Imidazolate, [CHIM]Chemical Sciences, Spectroscopy, metal-organic frameworks, solid-state NMR spectroscopy, Chemistry, General Chemistry, General Medicine, 021001 nanoscience & nanotechnology, [SDE.ES]Environmental Sciences/Environmental and Society, 0104 chemical sciences, X-ray diffraction, Density functional calculations, Solid-state nuclear magnetic resonance, X-ray crystallography, Physical chemistry, Metal-organic framework, Density functional theory, 0210 nano-technology, Superstructure (condensed matter), porous materials
Abstract: SSCI-VIDE+CARE:CDFA+MBE:PVE; International audience; We report the supercell crystal structure of a ZIF-8 analog substituted imidazolate metal–organic framework (SIM-1) obtained by combining solid-state nuclear magnetic resonance and powder X-ray diffraction experiments with density functional theory calculations
Published: 2015
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21. Hammett Parameter in Microporous Solids as Macroligands for Heterogenized Photocatalysts

Author: Anne Lesage, Luis Cardenas, Elsje Alessandra Quadrelli, Florian M. Wisser, Pierrick Berruyer, David Farrusseng, Jérôme Canivet, Yorck Mohr, IRCELYON-Ingéniérie, du matériau au réacteur (ING), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), 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 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), IRCELYON-Etudes & analyse de surfaces, XPS, LEIS (XPS), Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), 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), The authors are very grateful to N. Cristin and P. Mascunan for ICP-OES analysis, to L. Burel for electron microscopy, to Prof. Dr. G. Kickelbick (Saarland University) for providing access to CHN-analysis and to Dr. O. Ouari and Prof. Dr. P. Tordo (both from Aix -Marseille University) for providing polarizing agent TEKPOL. F.M.W. gratefully acknowledges financial support from the Deutsche Forschungsgemeinschaft (DFG, Postdoctoral Research Fellowship, grant number WI 4721/1-1). The authors acknowledge financial support from ERC Advanced Grant No. 320860., European Project: 320860,EC:FP7:ERC,ERC-2012-ADG_20120216,HI-SENS(2013), and 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)
Subjects: conjugated microporous polymers, 02 engineering and technology, 010402 general chemistry, Heterogeneous catalysis, 01 natural sciences, Catalysis, Conjugated microporous polymer, Electronic effect, Electrochemical reduction of carbon dioxide, chemistry.chemical_classification, carbon dioxide reduction, microporous materials, General Chemistry, Polymer, Microporous material, [CHIM.CATA]Chemical Sciences/Catalysis, 021001 nanoscience & nanotechnology, Hammett constant, 0104 chemical sciences, chemistry, Chemical engineering, Photocatalysis, 0210 nano-technology, photocatalysis, rhodium complex
Abstract: XPS+ING+FWI:LCS:YMO:DFA:JEC; International audience; Here we present a series of heterogeneous catalysts based on metal–organic frameworks and microporous polymers used as macroligands for heterogenized organometallic complexes. We show that both homogeneous and heterogenized catalysts follow the same linear correlation between the electronic effect of the ligand, described by the Hammett parameter, and the catalytic activity. This correlation highlights the crucial impact of the local electronic environment surrounding the active catalytic center over the long-range framework structure of the porous support. The rational design of heterogenized catalysts can thus be guided by molecular chemistry rules. The conception of highly efficient heterogeneous catalyst based on porous polymer support and driven by the Hammett parameter of bipyridine-chelating macroligand is demonstrated here for the Rh-catalyzed photoreduction of carbon dioxide with turnover frequencies up to 28 h–1, among the highest reported for heterogeneous photocatalytic formate production.
Published: 2018
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22. Frozen Acrylamide Gels as Dynamic Nuclear Polarization Matrices

Author: David Gajan, Lyndon Emsley, Jean-Marie Basset, Jasmine Viger-Gravel, Pierrick Berruyer, Anne Lesage, Olivier Ouari, Paul Tordo, Institut des sciences et ingénierie chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 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), KAUST Catalysis Center (KCC), King Abdullah University of Sciences & Technologie, Institut de Chimie Radicalaire (ICR), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), This work was supported by ERC Advanced Grant No. 320860., European Project: 320860,EC:FP7:ERC,ERC-2012-ADG_20120216,HI-SENS(2013), Aix Marseille Université (AMU)-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)-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: Analytical chemistry, Nanoparticle, quantum dots, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Catalysis, Spectral line, dynamic nuclear polarization, chemistry.chemical_compound, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, [CHIM]Chemical Sciences, Polarization (electrochemistry), Aqueous solution, 010405 organic chemistry, Chemistry, technology, industry, and agriculture, polyacrylamide gel, General Medicine, General Chemistry, Nuclear magnetic resonance spectroscopy, 021001 nanoscience & nanotechnology, 0104 chemical sciences, NMR spectra database, acrylamide gels, Quantum dot, Acrylamide, nanoparticles, 0210 nano-technology
Abstract: We thank Dr. B.J. Walder for help in processing the PASS data, Dr. C. Chamignon for assistance with quantitative liquid-state NMR, and Dr. D. Cala for her insight and advice in gel synthesis.; International audience; Aqueous acrylamide gels can be used to provide dynamic nuclear polarization (DNP) NMR signal enhancements of around 200 at 9.4 T and 100 K. The enhancements are shown to increase with crosslinker concentration and low concentrations of the AMUPol biradical. This DNP matrix can be used in situations where conventional incipient wetness methods fail, such as to obtain DNP surface enhanced NMR spectra from inorganic nanoparticles. In particular, we obtain Cd-113 spectra from CdTe-COOH NPs in minutes. The spectra clearly indicate a highly disordered cadmium-rich surface.
Published: 2017
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23. Dynamic Nuclear Polarization Efficiency Increased by Very Fast Magic Angle Spinning

Author: Lyndon Emsley, Pierrick Berruyer, Sachin Rama Chaudhari, Arthur C. Pinon, David Gajan, Olivier Ouari, Paul Tordo, Moreno Lelli, Christophe Copéret, Anne Lesage, Frank Engelke, Dorothea Wisser, Christian Reiter, 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), Institut des sciences et ingénierie chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Bruker BioSpin GmbH, affiliation inconnue, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Center for Magnetic Resonance, Università degli Studi di Firenze = University of Florence [Firenze] (UNIFI), ANR-10-EQPX-0047,SENS,RMN de Surface Exalté par Polarisation Dynamique Nucléaire(2010), ANR-15-CE29-0022,VHF-DNP-NMR,PDN/RMN du solide à trés haut champ(2015), European Project: 320860,NHMRC::Programs(2005), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU), Institut des Sciences Analytiques ( ISA ), École normale supérieure - Lyon ( ENS Lyon ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ) -École normale supérieure - Lyon ( ENS Lyon ) -Université Claude Bernard Lyon 1 ( UCBL ), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique ( CNRS ), Institut des sciences et ingénierie chimiques ( ISIC ), Ecole Polytechnique Fédérale de Lausanne ( EPFL ), Institut de Chimie Radicalaire ( ICR ), Aix Marseille Université ( AMU ) -Centre National de la Recherche Scientifique ( CNRS ), ETH - Dept Chem & Appl Biosci, Swiss Federal Institute of Technology in Zürich ( ETH Zürich ), University of Florence, ANR-10-EQPX-47-01,SENS,RMN de Surface Exalté par Polarisation Dynamique Nucléaire, ANR-15-CE29-0022-02,VHF-DNP-NMR,PDN/RMN du solide à trés haut champ, European Project : 320860,NHMRC::Programs ( 2005 ), 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), and Università degli Studi di Firenze = University of Florence (UniFI)
Subjects: 010405 organic chemistry, Chemistry, Communication, Analytical chemistry, General Chemistry, Nuclear Overhauser effect, 010402 general chemistry, Polarization (waves), 01 natural sciences, Biochemistry, Molecular physics, Catalysis, Spectral line, 0104 chemical sciences, Magnetic field, Colloid and Surface Chemistry, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Magic angle spinning, [ CHIM.ANAL ] Chemical Sciences/Analytical chemistry, Mesoporous material
Abstract: International audience; Dynamic Nuclear Polarization has recently emerged as a tool to enhance the sensitivity of solid-state NMR experiments. However, so far high enhancements (>100) are limited to relatively low magnetic fields, and DNP at fields higher than 9.4 T significantly drops in efficiency. Here we report solid-state Overhauser effect DNP enhancements of over 100 at 18.8 T. This is achieved through the unexpected discovery that enhancements increase rapidly with increasing magic angle spinning rates. The measurements are made using 1,3-bisdiphenylene-2-phenylallyl (BDPA) dissolved in ortho-terphenyl (OTP) at 40 kHz MAS. We introduce a source-sink diffusion model for polarization transfer which is capable of explaining the experimental observations. The advantage of this approach is demonstrated on mesoporous alumina with the acquisition of well-resolved DNP surface enhanced 27Al CP spectra.
Published: 2017
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24. Local Structures and Heterogeneity of Silica-Supported M(III) Sites Evidenced by EPR, IR, NMR, and Luminescence Spectroscopies

Author: Christophe Copéret, Anne Lesage, Aaron J. Rossini, Dirk Baabe, Gunnar Jeschke, Giuseppe Lapadula, Lyndon Emsley, Murielle F. Delley, Marc D. Walter, Olivier Maury, Francisco Núñez-Zarur, Vidmantas Kalendra, Aleix Comas-Vives, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), University Medellin, Vilnius University, Inst Anorgan & Analyt Chem, Braunschweig University of Technology, Institut des sciences et ingénierie chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), 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), Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), M.F.D. thanks ETH Zurich and the Scholarship Fund of the Swiss Chemical Industry for financial support. The Swiss National Foundation (SNF) (Ambizione project PZ00P2_148059 to A.C.-V.), the Holcim Stiftung Foundation (Fellowship to A.C.-V.), and the SCCER Heat and Energy Storage are acknowledged for financial support., 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), and École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL)
Subjects: X-ray absorption spectroscopy, 010405 organic chemistry, Analytical chemistry, Siloxide, General Chemistry, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, law.invention, Crystallography, chemistry.chemical_compound, Colloid and Surface Chemistry, chemistry, law, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Amide, Dehydrogenation, Reactivity (chemistry), Electron paramagnetic resonance, Spectroscopy, Luminescence
Abstract: The authors thank Dr. Olga V. Safonova (Paul Scherrer Institute, Switzerland) for assistance with X-ray absorption spectroscopy, Dr. Maxence Valla (ETH Zurich, Switzerland) for help with NMR measurements, Dr. Sebastien Norsic and Dr. Vincent Monteil (CPE Lyon, France) for HT-SEC and differential scanning calorimetry measurements, Dr. Yannick Guyot (ILM, Universite de Lyon, France) for NIR lifetime measurements, Prof. Dr. Martin Broring (TU Braunschweig, Germany) for access to the SQUID magnetometer, and Mr. D. Trummer for recording X-ray diffraction.; International audience; Grafting molecular precursors on partially dehydroxylated silica followed by a thermal treatment yields silica-supported M(III) sites for a broad range of metals. They display unique properties such as high activity in olefin polymerization and alkane dehydrogenation (M = Cr) or efficient luminescence properties (M = Yb and Eu) essential for bioimaging. Here, we interrogate the local structure of the M(III) surface sites obtained from two molecular precursors, amides M(N(SiMe3)(2))(3) vs siloxides (M(OSi((OBu)-Bu-t)(3))(3)center dot L with L = (THF)(2) or HOSi((OBu)-Bu-t)(3) for M = Cr, Yb, Eu, and Y, by a combination of advanced spectroscopic techniques (EPR, IR, XAS, UV-vis, NMR, luminescence spectroscopies). For paramagnetic Cr(III), EPR (HYSCORE) spectroscopy shows hyperfine coupling to nitrogen only when the amide precursor is used, consistent with the presence of nitrogen neighbors. This changes their specific reactivity compared to Cr(III) sites in oxygen environments obtained from siloxide precursors: no coordination of CO and oligomer formation during the polymerization of ethylene due to the presence of a N donor ligand. The presence of the N-ligand also affects the photophysical properties of Yb and Eu by decreasing their lifetime, probably due to nonradiative deactivation of excited states by N-H bonds. Both types of precursors lead to a distribution of surface sites according to reactivity for Cr, luminescence spectroscopy for Yb and Eu, and dynamic nuclear polarization surface enhanced Y-89 NMR spectroscopy (DNP SENS). In particular, DNP SENS provides molecular-level information about the structure of surface sites by evidencing the presence of tri-, tetra-, and pentacoordinated Y-surface sites. This study provides unprecedented evidence and tools to assess the local structure of metal surface sites in relation to their chemical and physical properties.
Published: 2017
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25. Amplifying Dynamic Nuclear Polarization of Frozen Solutions by Incorporating Dielectric Particles

Author: Lyndon Emsley, Olivier Ouari, Paul Tordo, Anne Lesage, Frank Engelke, Aaron J. Rossini, Alexandre Zagdoun, Dominik J. Kubicki, Armin Purea, 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), Bruker BioSpin GmbH, D-76287 Rheinstetten, Germany, affiliation inconnue, Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL), This work was supported by ERC Advanced Grant No. 320860., 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: Diffraction, C-13, Analytical chemistry, EFFICIENT, Nanoparticle, Dielectric, 010402 general chemistry, 01 natural sciences, Biochemistry, Molecular physics, Article, Catalysis, Colloid and Surface Chemistry, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, TEMPERATURES, NANOPARTICLES, Spectroscopy, SPECTROSCOPY, 010405 organic chemistry, Chemistry, Scattering, General Chemistry, Polarization (waves), SOLID-STATE NMR, 0104 chemical sciences, SIGNAL ENHANCEMENT, Dielectric loss, POLYMERS, Microwave
Abstract: We thank Claire Sauvee and Dr. Gilles Casano (Universite Aix-Marseille) for synthesizing the biradicals used here. We thank Bruker France and Drs. Alain Belguise and Fabien Aussenac for providing initial access to the DNP spectrometer.; International audience; There is currently great interest in understanding the limits on NMR signal enhancements provided by dynamic nuclear polarization (DNP), and in particular if the theoretical maximum enhancements can be achieved. We show that over a 2-fold improvement in cross-effect DNP enhancements can be achieved in MAS experiments on frozen solutions by simply incorporating solid particles into the sample. At 9.4 T and similar to 105 K, enhancements up to epsilon(H) = 515 are obtained in this way, corresponding to 78% of the theoretical maximum. We also underline that degassing of the sample is important to achieve highest enhancements. We link the amplification effect to the dielectric properties of the solid material, which probably gives rise to scattering, diffraction, and amplification of the microwave field in the sample. This is substantiated by simulations of microwave propagation. A reduction in sample heating at a given microwave power also likely occurs due to reduced dielectric loss. Simulations indicate that the microwave field (and thus the DNP enhancement) is inhomogeneous in the sample, and we deduce that in these experiments between 5 and 10% of the solution actually yields the theoretical maximum signal enhancement of 658. The effect is demonstrated for a variety of particles added to both aqueous and organic biradical solutions.
Published: 2014
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26. Inside Back Cover: Preferential Siting of Aluminum Heteroatoms in the Zeolite Catalyst Al‐SSZ‐70 (Angew. Chem. Int. Ed. 19/2019)

Author: Stacey I. Zones, Lynne B. McCusker, Ming-Feng Hsieh, Anne Lesage, Christian Baerlocher, Zachariah J. Berkson, Alicia Lund, Stef Smeets, David Gajan, Dan Xie, and Bradley F. Chmelka
Subjects: Materials science, chemistry, Chemical engineering, Aluminium, INT, Heteroatom, chemistry.chemical_element, Cover (algebra), General Chemistry, Nuclear magnetic resonance spectroscopy, Zeolite, Catalysis
Published: 2019
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27. Innenrücktitelbild: Preferential Siting of Aluminum Heteroatoms in the Zeolite Catalyst Al‐SSZ‐70 (Angew. Chem. 19/2019)

Author: Alicia Lund, Anne Lesage, Stef Smeets, Lynne B. McCusker, David Gajan, Zachariah J. Berkson, Bradley F. Chmelka, Dan Xie, Stacey I. Zones, Ming-Feng Hsieh, and Christian Baerlocher
Subjects: Materials science, chemistry, Chemical engineering, Aluminium, Heteroatom, chemistry.chemical_element, General Medicine, Zeolite, Catalysis
Published: 2019
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28. Hydrophobic radicals embedded in neutral surfactants for dynamic nuclear polarization of aqueous environments at 9.4 Tesla

Author: Lyndon Emsley, Anne Lesage, Aaron J. Rossini, Paul Tordo, Moreno Lelli, Olivier Ouari, Gilles Casano, 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), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ERC Advanced Grant No. 320860., 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: Aqueous solution, Radical, Metals and Alloys, Analytical chemistry, General Chemistry, Photochemistry, Polyvinyl alcohol, Micelle, Catalysis, 3. Good health, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, chemistry.chemical_compound, chemistry, Pulmonary surfactant, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Amphiphile, Materials Chemistry, Ceramics and Composites, Polarization (electrochemistry)
Abstract: We thank Brad Chmelka for discussions and suggestions.; International audience; We show how large DNP enhancements of NMR signals can be obtained from several hydrophobic radicals that are solubilised in aqueous environments by a variety of biologically compatible neutral amphiphiles. In particular we show that the bi-radical TEKPOL can be incorporated into micelles formed by the surfactant polysorbate 80 (Tween-80), where we obtain large DNP enhancements (similar to 60) at 9.4 T and similar to 100 K.
Published: 2014
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29. Silica-surface reorganization during organotin grafting evidenced by Sn-119 DNP SENS: a tandem reaction of gem-silanols and strained siloxane bridges

Author: Christophe Copéret, Anne Lesage, Maxence Valla, Gilles Casano, Paul Tordo, Matthew P. Conley, Lyndon Emsley, Aaron J. Rossini, Olivier Ouari, Aleix Comas-Vives, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), 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), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ERC Advanced Grant No. 320860, 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: General Physics and Astronomy, 010402 general chemistry, 01 natural sciences, Catalysis, chemistry.chemical_compound, DOUBLE-RESONANCE NMR, Cascade reaction, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Polymer chemistry, Organic chemistry, ROTATIONAL-ECHO, Reactivity (chemistry), Physical and Theoretical Chemistry, ENHANCED NMR-SPECTROSCOPY, Geminal, 010405 organic chemistry, CATALYSIS, DEHYDROXYLATED SILICA, Nuclear magnetic resonance spectroscopy, Grafting, 0104 chemical sciences, SOLID-STATE NMR, ORGANOMETALLIC CHEMISTRY, chemistry, TIN, Siloxane, COMPLEXES, DYNAMIC NUCLEAR-POLARIZATION, Vicinal
Abstract: Dr Fabien Aussenac (Bruker France) for assistance with the DNP NMR experiments the Swiss National Science Foundation (Ambizione project PZ00P2_148059) for support.; International audience; Grafting reactive molecular complexes on dehydroxylated amorphous silica is a strategy to develop "single-site" heterogeneous catalysts. In general, only the reactivity of isolated silanols is invoked for silica dehydroxylated at 700 degrees C ([SiO2-700]), though ca. 10% of the surface silanols are in fact geminal Q(2)-silanols. Here we report the reaction of allyltributylstannane with (SiO2-700] and find that the geminal Q(2)-silanols react to form products that would formally arise from vicinal Q(3)-silanols that are not present on (SiO2-700], indicating that a surface rearrangement occurs. The reorganization of the silica surface is unique to silica dehydroxylated at 700 degrees C or above. The findings were identified using Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) combined with DFT calculations.
Published: 2014
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30. Dendritic polarizing agents for DNP SENS

Author: Christophe Copéret, David Gajan, Anne Lesage, Wei-Chih Liao, Roman Schowner, Margherita Pucino, Florian Bernada, Olivier Ouari, Gunnar Jeschke, Ta-Chung Ong, Lyndon Emsley, Martin Schwarzwälder, Claire Sauvée, Michael R. Buchmeiser, Paul Tordo, Maxim Yulikov, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), 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), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Inst Polymerchem, University of Stuttgart, Ecole Polytechnique Fédérale de Lausanne (EPFL), We acknowledge financial support from the SNF for the 600 MHz DNP spectrometer (206021_150710) and for WCL (200020_149704), and ERC Advanced Grant No. 320860, the University of Aix-Marseille and the CNRS. MRB acknowledges financial support by the Deutsche Forschungsgemeinschaft (DFG, BU 2174/19-1). The EU COST action TD1103 Eurohyperpol is gratefully acknowledged for stimulating interactions and travel funds., European Project: 320860,EC:FP7:ERC,ERC-2012-ADG_20120216,HI-SENS(2013), 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), and Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Aix Marseille Université (AMU)
Subjects: Chemical substance, 010405 organic chemistry, Chemistry, Nanotechnology, General Chemistry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, Photochemistry, Metathesis, 01 natural sciences, 0104 chemical sciences, Catalysis, Unpaired electron, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Dendrimer, Polarization (electrochemistry), Science, technology and society
Abstract: Dynamic Nuclear Polarization Surface Enhanced NMR Spectroscopy (DNP SENS) is an effective method to significantly improve solid-state NMR investigation of solid surfaces. The presence of unpaired electrons (polarizing agents) is crucial for DNP, but it has drawbacks such as leading to faster nuclear spin relaxation, or even reaction with the substrate under investigation. The latter can be a particular problem for heterogeneous catalysts. Here, we present a series of carbosilane-based dendritic polarizing agents, in which the bulky dendrimer can reduce the interaction between the solid surface and the free radical. We thereby preserve long nuclear T′2 of the surface species, and even successfully enhance a reactive heterogeneous metathesis catalyst., Chemical Science, 8 (1), ISSN:2041-6520, ISSN:2041-6539
Published: 2017
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31. Phenylazide Hybrid-Silica – Polarization Platform for Dynamic Nuclear Polarization at Cryogenic Temperatures

Author: Aurélien Bornet, Laurent Veyre, David Baudouin, David Gajan, Sami Jannin, Jonas Milani, Wolfram R. Grüning, Geoffrey Bodenhausen, Harald Bieringer, Chloé Thieuleux, Christophe Copéret, Anne Lesage, Martin Schwarzwälder, Basile Vuichoud, Laboratory of Inorganic Chemistry, 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 des sciences et d'ingénierie chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), ISA - Hyperpolarized Magnetic Resonance, Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université Claude Bernard Lyon 1 (UCBL), 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), Institut des Sciences et Ingénierie Chimiques, and Ecole Polytechnique Fédérale de Lausanne (EPFL)-Batochime
Subjects: Sol-Gel, Analytical chemistry, 02 engineering and technology, 010402 general chemistry, Photochemistry, 01 natural sciences, Biochemistry, Catalysis, Spectral line, Inorganic Chemistry, chemistry.chemical_compound, Phenyl azide, Drug Discovery, Magic angle spinning, [CHIM]Chemical Sciences, Hyperpolarization (physics), Physical and Theoretical Chemistry, Dissolution, Sol-gel, Dynamic Nuclear Polarization, Chemistry, Organic Chemistry, 021001 nanoscience & nanotechnology, Polarization (waves), Hybrid Materials, 0104 chemical sciences, Hyperpolarization, 0210 nano-technology, Hybrid material
Abstract: Hyperpolarization of NMR-active nuclei is key to gather high quality spectra of rare species and insensitive isotopes. We have recently established that silica-based materials containing regularly distributed nitroxyl radicals connected to the silica matrix by flexible linkers can serve as promising polarization matrices for dynamic nuclear polarization (DNP). Here we investigate the influence of the linker on the efficiency of the polarization. The materials were fully characterized and exhibit high surface areas and narrow pore size distributions with a tunable amount of phenyl azide groups over a broad range of concentrations. The phenyl azide groups can be easily functionalized via a two-step procedure with 4-carboxy-2,2,6,6-tetramethyl-1-oxylpiperidine (TEMPO) to give polarizing matrices with controllable radical content. The DNP efficiency was found to be similar as in materials with flexible linkers, both for magic angle spinning at 105 K and dissolution DNP at 4 K.
Published: 2017
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32. Molecular Level Characterization of the Structure and Interactions in Peptide-Functionalized Metal-Organic Frameworks

Author: Alexandre Legrand, Lyndon Emsley, David Farrusseng, Pierrick Berruyer, Jérôme Canivet, Caroline Mellot-Draznieks, Xavier Rozanska, Tanya K. Todorova, Linh Ngoc Ho, Christel Gervais, Anne Lesage, Laboratoire de Chimie des Processus Biologiques (LCPB), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), SARL Mat Design, Spectroscopie, Modélisation, Interfaces pour L'Environnement et la Santé (SMiLES), Laboratoire de Chimie de la Matière Condensée de Paris (LCMCP), Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), IRCELYON-Ingéniérie, du matériau au réacteur (ING), Institut de recherches sur la catalyse et l'environnement de Lyon (IRCELYON), 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), Solid-State NMR Methods for Materials - Méthodes de RMN à l'état solide pour les matériaux, Institut des Sciences Analytiques (ISA), Institut des sciences et ingénierie chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), We acknowledge financial support from the French National Research Agency (ANR project: HOPFAME ANR-13-BS07-0002-01), the Fondation de l'Orangerie and the ERC Advanced Grant No. 320860. The calculations were performed by using the HPC resources from GENCI (CINES/TGCC/IDRIS) through Grants 2016-097343 and -097535., ANR-13-BS07-0002,HOPFAME,Matériaux poreux hybrides comme métalloenzymes artificielles(2013), European Project: 320860,EC:FP7:ERC,ERC-2012-ADG_20120216,HI-SENS(2013), Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC)-Université Pierre et Marie Curie - Paris 6 (UPMC)-Centre National de la Recherche Scientifique (CNRS)-Collège de France (CdF (institution))-Institut de Chimie du CNRS (INC), 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)-Institut de Chimie du CNRS (INC)
Subjects: Magnetic Resonance Spectroscopy, Proline, Glycine, Molecular Conformation, Peptide, 02 engineering and technology, Molecular Dynamics Simulation, 010402 general chemistry, 01 natural sciences, Catalysis, Molecular dynamics, NMR spectroscopy, Computational chemistry, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, [CHIM]Chemical Sciences, metal-organic frameworks, chemistry.chemical_classification, Hydrogen bond, Chemical shift, Organic Chemistry, fungi, Hydrogen Bonding, General Chemistry, Nuclear magnetic resonance spectroscopy, Dipeptides, 021001 nanoscience & nanotechnology, molecular dynamics, 0104 chemical sciences, Characterization (materials science), chemistry, density functional calculations, peptides, Metal-organic framework, Density functional theory, 0210 nano-technology
Abstract: We thank Prof. Paul Tordo and Dr. Olivier Ouari for providing TEKPoL2.; International audience; We use density functional theory, newly parameterized molecular dynamics simulations, and last generation (15) N dynamic nuclear polarization surface enhanced solid-state NMR spectroscopy (DNP SENS) to understand graft-host interactions and effects imposed by the metal-organic framework (MOF) host on peptide conformations in a peptide-functionalized MOF. Focusing on two grafts typified by MIL-68-proline (-Pro) and MIL-68-glycine-proline (-Gly-Pro), we identified the most likely peptide conformations adopted in the functionalized hybrid frameworks. We found that hydrogen bond interactions between the graft and the surface hydroxyl groups of the MOF are essential in determining the peptides conformation(s). DNP SENS methodology shows unprecedented signal enhancements when applied to these peptide-functionalized MOFs. The calculated chemical shifts of selected MIL-68-NH-Pro and MIL-68-NH-Gly-Pro conformations are in a good agreement with the experimentally obtained (15) N NMR signals. The study shows that the conformations of peptides when grafted in a MOF host are unlikely to be freely distributed, and conformational selection is directed by strong host-guest interactions.
Published: 2016
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33. Structural Characterization of the EtOH-TiCl 4 -MgCl 2 Ziegler-Natta Precatalyst

Author: Sébastien Norsic, Christophe Copéret, Andrew J. Pell, Guido Pintacuda, Vincent Monteil, Anne Lesage, Philippe Sautet, David Gajan, Kevin J. Sanders, V. d'Anna, Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC), 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), Biological Solid-State NMR Methods - Méthodes de RMN à l'état solide en biologie, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), V.D. acknowledges the Swiss National Science Foundation (Early Post-Doc mobility, no. P2GEP2_155679)., École normale supérieure de Lyon (ENS de Lyon)-Université Claude Bernard Lyon 1 (UCBL), and 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)
Subjects: biology, 010405 organic chemistry, Chemistry, Nuclear magnetic resonance spectroscopy, [CHIM.MATE]Chemical Sciences/Material chemistry, Natta, Polyethylene, 010402 general chemistry, biology.organism_classification, 01 natural sciences, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Catalysis, Characterization (materials science), NMR spectra database, chemistry.chemical_compound, General Energy, Polymerization, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Polymer chemistry, Organic chemistry, Lewis acids and bases, Physical and Theoretical Chemistry
Abstract: The authors thank the PSMN, CINES, and IDRIS for the computational resources.; International audience; The Ziegler-Natta polymerization is one major example of application of catalysis in industry. Since the first discovery of Ziegler and Natta, several modifications of the catalyst have been developed, in order to improve its performance. Nowadays, a typical Ziegler-Natta catalyst for polyethylene synthesis consists of a precatalyst, composed of TiCl4 supported on MgCl2 in the presence of a Lewis base, activated by organoaluminum. The atomic-scale characterization of the Ziegler-Natta catalyst is crucial for further improvement of the catalyst. Here, the precatalyst TiCl4-MgCl2 with EtOH as internal. Lewis base is characterized combining solid-state NMR spectroscopy and periodic density functional theory calculations. From total energy and NMR spectra, eight surface species were proposed showing EtO- ligands on the Ti and EtOH/EtO- on the surface Mg species, These species lead to a complete interpretation of the NMR two-dimensional spectra. Hence a detailed molecular scale description of the precatalyst was obtained.
Published: 2016
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34. Correlating synthetic methods, morphology, atomic-level structure, and catalytic activity of Sn-beta catalysts

Author: Ive Hermans, Christophe Copéret, Anne Lesage, Maxence Valla, Lyndon Emsley, Connor Firth, Francisco Núñez-Zarur, Patrick Wolf, Aleix Comas-Vives, Aaron J. Rossini, Hana Kallas, Dept Biol & Chem, University of Wisconsin-Madison, Dept Chem, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Instituto de Quimica, Universidad de Antioquia, Ecole Polytechnique Fédérale de Lausanne (EPFL), Dept Chem, Ames, Iowa State University (ISU), 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), SNF Grants No. 200021_143600 and 200021_146661, Ambizione project PZ00P2_148059, EQUIPEX contract ANR-10-EQPX-47-01, and ERC Advanced Grant No. 320860, ANR-10-EQPX-0047,SENS,RMN de Surface Exalté par Polarisation Dynamique Nucléaire(2010), and European Project
Subjects: BAEYER-VILLIGER OXIDATIONS, 010402 general chemistry, 01 natural sciences, Catalysis, EFFECTIVE CORE POTENTIALS, Sn-beta zeolites, DENSITY-FUNCTIONAL THEORY, Hydrolysis, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Sn-119 solid-state NMR, Organic chemistry, Zeolite, LEWIS-ACID SITES, ENHANCED NMR-SPECTROSCOPY, Ion exchange, 010405 organic chemistry, Chemistry, ab initio calculations, stannosilicates, Aqueous two-phase system, General Chemistry, Nuclear magnetic resonance spectroscopy, [CHIM.CATA]Chemical Sciences/Catalysis, GLUCOSE ISOMERIZATION, DNP SENS, ORDER REGULAR APPROXIMATION, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Crystallography, MEERWEIN-PONNDORF-VERLEY, ANGLE-SPINNING NMR, Density functional theory, DYNAMIC NUCLEAR-POLARIZATION, Isomerization
Abstract: Dr. Frank Krumeich is gratefully thanked for the SEM-EDX measurements. We also thank Dr. Ta-Chung Ong and Wei-Chih Liao for their help with some of the DNP-NMR experiments.; International audience; Sn-beta zeolites prepared using different recipes feature very different catalytic activities for aqueous phase glucose isomerization, suggesting the presence of different active sites. A systematic study of the morphology and atomic-level structure of the materials using DNP NMR spectroscopy in combination with first-principles calculations allows for the discrimination between potential sites and leads to a proposal of specific structural features that are important for high activity. The results indicate that the materials showing the highest activity possess a highly hydrophobic, defect-free zeolite framework. Those materials show so-called closed and associated partially hydrolyzed Sn(IV) sites in the T6 and T5/T7 lattice positions. On the other hand, postsynthetically synthesized Sn-beta samples prepared in two steps via dealumination and subsequent solid-state ion exchange from Al-beta show significantly lower activity, which is associated with a hydrophilic framework and/or a lower accessibility and different lattice position of the Sn sites in the zeolite crystal. Further, we provide a method to distinguish between different Sn sites on the basis of NMR cartography using chemical shift and chemical shift anisotropy as readily measurable parameters. This cartography allows identifying not only the nature of the active sites (closed, defect-open, and hydrolyzed-open) but also their position within the BEA framework.
Published: 2016
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35. Weak and transient protein interactions determined by solid-state NMR

Author: Stefan Jehle, Lyndon Emsley, Michele Felletti, Yao Wang, Hugh R. W. Dannatt, Nicholas E. Dixon, Anne Lesage, Guido Pintacuda, Biological Solid-State NMR Methods - Méthodes de RMN à l'état solide en biologie, 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), Ctr Med & Mol Biosci, University of Wollongong [Australia], Ecole Polytechnique Fédérale de Lausanne (EPFL), Solid-State NMR Methods for Materials - Méthodes de RMN à l'état solide pour les matériaux, We acknowledge support from the Agence Nationale de la Recherche (ANR10-BLAN-713-01), the Joint Research Activity within Research Infrastructures in the 7th Framework program of the EC (BioNMR, contract n. 261863), the IR-RMN-THC FR3050 CNRS, and the Australian Research Council (DP0984797)., 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: DYNAMICS, protein-protein interactions, Nuclear magnetic resonance spectroscopy of nucleic acids, Nuclear magnetic resonance crystallography, PROTON-DETECTED NMR, DNA replication, 010402 general chemistry, 01 natural sciences, Catalysis, Protein structure, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, magic angle spinning, Magic angle spinning, Transverse relaxation-optimized spectroscopy, protein structure, C-TERMINAL DOMAIN, SPECTROSCOPY, 010405 organic chemistry, Chemistry, Relaxation (NMR), General Chemistry, Nuclear magnetic resonance spectroscopy, 0104 chemical sciences, Crystallography, BINDING-PROTEIN, ESCHERICHIA-COLI SSB, Solid-state nuclear magnetic resonance, RESOLUTION, SINGLE-STRANDED-DNA, MAS NMR, solid-state NMR, BACKBONE ASSIGNMENT
Abstract: We are grateful to Gottfried Otting for his helpful comments.; International audience; Despite their roles in controlling many cellular processes, weak and transient interactions between large structured macromolecules and disordered protein segments cannot currently be characterized at atomic resolution by Xray crystallography or solution NMR. Solid-state NMR does not suffer from the molecular size limitations affecting solution NMR, and it can be applied to molecules in different aggregation states, including non-crystalline precipitates and sediments. A solid-state NMR approach based on high magnetic fields, fast magic-angle sample spinning, and deuteration provides chemical-shift and relaxation mapping that enabled the characterization of the structure and dynamics of the transient association between two regions in an 80 kDa protein assembly. This led to direct verification of a mechanism of regulation of E. coli DNA metabolism.
Published: 2016
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36. Atomistic Description of Reaction Intermediates for Supported Metathesis Catalysts Enabled by DNP SENS

Author: Ta-Chung Ong, Lyndon Emsley, Christophe Copéret, Anne Lesage, Wei-Chih Liao, Victor Mougel, David Gajan, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), 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), Institut des sciences et ingénierie chimiques (ISIC), and Ecole Polytechnique Fédérale de Lausanne (EPFL)
Subjects: DFT calculation, surface chemistry, Reaction intermediate, 010402 general chemistry, Heterogeneous catalysis, Metathesis, 01 natural sciences, Catalysis, Isotopic labeling, dynamic nuclear polarization, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Organic chemistry, [CHIM]Chemical Sciences, chemistry.chemical_classification, 010405 organic chemistry, Chemistry, Alkene, General Medicine, General Chemistry, Combinatorial chemistry, Cycloaddition, 0104 chemical sciences, 3. Good health, Catalytic cycle, solid-state NMR, metathesis
Abstract: International audience; Obtaining detailed structural information of reaction intermediates remains a key challenge in heterogeneous catalysis because of the amorphous nature of the support and/or the support interface that prohibits the use of diffraction-based techniques. Combining isotopic labeling and dynamic nuclear polarization (DNP) increases the sensitivity of surface enhanced solid-state NMR spectroscopy (SENS) towards surface species in heterogeneous alkene metathesis catalysts; this in turn allows direct determination of the bond connectivity and measurement of the carbon-carbon bond distance in metallacycles, which are the cycloaddition intermediates in the alkene metathesis catalytic cycle. Furthermore, this approach makes possible the understanding of the slow initiation and deactivation steps in these heterogeneous metathesis catalysts.
Published: 2016
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37. Backbone Assignment of Fully Protonated Solid Proteins by1H Detection and Ultrafast Magic-Angle-Spinning NMR Spectroscopy

Author: Alessandro Marchetti, Lyndon Emsley, Stefan Jehle, Michele Felletti, Gottfried Otting, Anne Lesage, Guido Pintacuda, Michael J. Knight, Ah Young Park, Zhi-Qiang Xu, Nicholas E. Dixon, Yao Wang, 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), Scuola Normale Superiore di Pisa (SNS), School of Chemistry [Wollongong], University of Wollongong [Australia], Research School of Chemistry, Australian National University (ANU), Agence Nationale de la Recherche (ANR 08-BLAN-0035-01 and 10-BLAN-713-01), the Joint Research Activity within Research Infrastructures in the 7th Framework program of the EC (BioNMR, contract n. 261863), the Australian Research Council., and European Project
Subjects: STRUCTURAL BASIS, magic-angle spinning, TERMINAL DOMAIN, Protonation, DNA polymerase, 010402 general chemistry, 01 natural sciences, Catalysis, NMR spectroscopy, Protein structure, Magic angle spinning, Transverse relaxation-optimized spectroscopy, Spectroscopy, Nuclear Magnetic Resonance, Biomolecular, ComputingMilieux_MISCELLANEOUS, DNA Polymerase III, Carbon Isotopes, Nitrogen Isotopes, 010405 organic chemistry, Chemistry, scalar transfers, Proteins, PEPTIDES, General Medicine, General Chemistry, Nuclear magnetic resonance spectroscopy, Deuterium, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Crystallography, MAS, RESOLUTION, STATE NMR, protein structures, Proton NMR, Protons, Hydrogen
Abstract: Narrow 1H NMR linewidths can be obtained for fully protonated protein samples in the solid state by using ultrafast magic-angle spinning (60 kHz). Medium-size microcrystalline and noncrystalline proteins can be analyzed without any need for deuteration of the protein sample. This approach provides assignments of the backbone 1H, 15N, 13C α, and 13CO resonances and yields information about 1H-1H proximities. Copyright © 2012 WILEY-VCH Verlag GmbH & Co. KGaA, Weinheim.
Published: 2012
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38. 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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39. Well-Defined Silica-Supported Mo-Alkylidene Catalyst Precursors Containing One OR Substituent: Methods of Preparation and Structure-Reactivity Relationship in Alkene Metathesis

Author: Rojendra Singh, Lyndon Emsley, Jean-Marie Basset, David Gajan, Smaranda C. Marinescu, Frédéric Blanc, Christophe Copéret, Nuria Rendón, Anne Lesage, Richard R. Schrock, Tarun K. Maishal, and Romain Berthoud
Subjects: chemistry.chemical_classification, Stereochemistry, Alkene, silica supports, Organic Chemistry, Substituent, chemistry.chemical_element, surface chemistry, General Chemistry, Nuclear magnetic resonance spectroscopy, Metathesis, Medicinal chemistry, Catalysis, Metal, chemistry.chemical_compound, molybdenum, chemistry, Molybdenum, visual_art, Alkoxy group, visual_art.visual_art_medium, metathesis, solid-state NMR spectroscopy
Abstract: The monosiloxy surface complexes [([triple bond]SiO)Mo([triple bond]NAr)(=CHCMe(2)R')(OR)] (R' = Me or Ph; OR = OtBu, OCMe(CF(3))(2) or OAr) are obtained by grafting onto SiO(2-(700)) either symmetric Mo-alkylidene derivatives [Mo([triple bond]NAr)(=CHCMe(2)R')(OR)(2)] or asymmetric derivatives, that is, with two different pendant ligands, one amido and one alkoxy/aryloxy, [Mo([triple bond]NAr)(=CHCMe(2)R')(OR)(NC(6)H(8))]. The formation of these complexes was confirmed by mass-balance analysis, and infrared (IR) and NMR spectroscopies. These systems are highly efficient catalyst precursors for the metathesis of acyclic alkenes; the best results were seen when OR=OCMe(CF(3))(2). Nevertheless, they display poor performances in ring-closing metathesis, possibly due to the rigidity of the metal center (as evidenced by NMR spectroscopy), which therefore slows the rate of the metathesis.
Published: 2009
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40. Atomic-level organization of vicinal acid?base pairs through the chemisorption of aniline and derivatives onto mesoporous SBA15

Author: Rachid Sougrat, Lyndon Emsley, Andrei Gurinov, Anissa Bendjeriou-Sedjerari, Edy Abou-Hamad, Jean-Marie Basset, Bilel Hamzaoui, Anne Lesage, Kuo-Wei Huang, David Gajan, Eva Pump, 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), Institut des sciences et ingénierie chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), and This work received support from the King Abdullah University of Science and Technology (KAUST) Office of Sponsored Research (OSR) under Award No. CRG_R2_13_BASS_KAUST_1.
Subjects: 010405 organic chemistry, General Chemistry, 010402 general chemistry, Photochemistry, Heterogeneous catalysis, 01 natural sciences, 0104 chemical sciences, Catalysis, chemistry.chemical_compound, Aniline, chemistry, Chemisorption, Covalent bond, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Polymer chemistry, [CHIM]Chemical Sciences, Knoevenagel condensation, Bifunctional, Vicinal
Abstract: We thank Dr Olivier Ouari and Paul Tordo for providing the TeKPol radical.; International audience; The design of novel heterogeneous catalysts with multiple adjacent functionalities is of high interest to heterogeneous catalysis. Herein, we report a method to obtain a majority of bifunctional acid-base pairs on SBA15. Aniline reacts with SBA15 by opening siloxane bridges leading to N-phenylsilanamine- silanol pairs. In contrast with ammonia treated surfaces, the material is stable under air/moisture. Advanced solid state MAS NMR (2D H-1-H-1 double-quantum, H-1-C-13 HETCOR) experiments and dynamic nuclear polarization enhanced Si-29 and N-15 spectra demonstrate both the close proximity between the two moieties and the formation of a covalent Si-N surface bond and confirm the design of vicinal acid-base pairs. This approach was successfully applied to the design of a series of aniline derivatives of bifunctional SBA15. A correlation between the substituent effects on the aromatic ring (Hammett parameters) with the kinetics of a model Knoevenagel reaction is observed.
Published: 2016
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41. Predictive morphology, stoichiometry and structure of surface species in supported Ru nanoparticles under H-2 and CO atmospheres from combined experimental and DFT studies

Author: Christophe Copéret, Karol Furman, Anne Lesage, David Gajan, Fabio H. Ribeiro, M. Cem Akatay, Aleix Comas-Vives, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), 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), Purdue University [West Lafayette], and We thank the Swiss National Foundation for founding (SNF project number 200021_134775/1 Controlled Surface Chemistry for Catalyst Design and Ambizione project PZ00P2_148059)
Subjects: Materials science, General Physics and Astronomy, Infrared spectroscopy, Nanoparticle, Nanotechnology, 02 engineering and technology, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, Catalysis, Adsorption, Chemical engineering, Ab initio quantum chemistry methods, Chemisorption, Methanation, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Physical and Theoretical Chemistry, 0210 nano-technology, Stoichiometry
Abstract: We are also grateful to Frank Krumeich and Emma Oakton for electron microscopy images, obtained on the ScopeM platform and to Maxence Valla for assistance with the NMR experiments. In addition, we are thankful to GLANTREO Ltd (Ireland) especially Dr John Hanrahan for providing SiO2-spheres support. We acknowledge the support from the Swiss National Supercomputing Center for computational resources.; International audience; Further understanding of the chemisorption properties towards CO and H-2 on silica-supported Ru nanoparticles is crucial in order to rationalize their high activity towards methanation, Fischer Tropsch and Water Gas Shift reactions. Ru nanoparticles having the same chemisorption properties towards CO and H-2 were synthesized on different silica-based supports in order to combine various analytical techniques and obtain complimentary detailed information on their structure; while silica spheres were used in order to obtain high-resolution TEM images of the Ru nanoparticles, high surface area silica-based material (SBA) allowed CO chemisorption to be monitored by C-13 NMR spectroscopy. In addition, a model of the hcp-based Ru nanoparticles observed by HR-TEM was used to predict by ab initio calculations the CO and H-2 coverages on the Ru nanoparticle under different conditions of interest in catalysis. For both adsorbates we show and quantify how the adsorption properties of the nanoparticle differ from the commonly used slab models. For the case of CO we show how the top, bridge and hollow sites can be present on the Ru nanoparticle, providing a description at atomistic level in good agreement with the IR spectroscopy measurements.
Published: 2016
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42. Iridium(I)/N-Heterocyclic Carbene Hybrid Materials: Surface Stabilization of Low-Valent Iridium Species for High Catalytic Hydrogenation Performance

Author: Delphine Crozet, Lénaic Leroux, Emmanuel Lacôte, Laurent Veyre, Lyndon Emsley, Iuliia Romanenko, Anne Lesage, Erwan Jeanneau, Christine Lucas, Chloé Thieuleux, David Gajan, R. Sayah, Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université Claude Bernard Lyon 1 (UCBL), 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), 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), Laboratoire des Multimatériaux et Interfaces (LMI), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL), We thank CNRS, CPE, Universite Claude Bernard Lyon 1, ANR (CFLOW-OM, NHCX), and Total (postdoctoral funding to D.C.) for financial support of this work. I.R. thanks CNRS/CPE for a doctoral stipend. TGIR RMN THC (FR 3050 CNRS) and ERC Advanced grant number 320860, are kindly acknowledged for the NMR characterizations. We thank the Centre Technologique des Microstructures (CT mu) for the TEM measurements., ANR-12-CDII-0002,CFLOW-OM,IMMOBILISATION DE CATALYSEURS DE METATHESE D'OLEFINES : APPLICATIONS EN PROCEDES BATCH & FLUX CONTINUS(2012), ANR-11-BS07-0008,NHCX,Chimie des complexes carbène-borane et carbène-silane(2011), European Project, 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), and 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)
Subjects: chemistry.chemical_element, Photochemistry, 7. Clean energy, Catalysis, chemistry.chemical_compound, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, ROUTE, Organic chemistry, Reactivity (chemistry), Iridium, supported catalysts, ENHANCED NMR-SPECTROSCOPY, ASYMMETRIC HYDROGENATION, Chemistry, Asymmetric hydrogenation, General Medicine, General Chemistry, Nuclear magnetic resonance spectroscopy, ENANTIOSELECTIVE HYDROGENATION, Mesoporous silica, iridium, ALKENE METATHESIS, REACTIVITY, carbenes, MESOPOROUS SILICA, solid-state structures, COMPLEXES, LIGANDS, hydrogenation, DYNAMIC NUCLEAR-POLARIZATION, Hybrid material, Carbene
Abstract: International audience; An Ir-I(NHC)-based hybrid material was prepared using a methodology which allowed the precise positioning and isolation of the Ir centers along the pore channels of a silica framework. The full characterization of the material by solid-state NMR spectroscopy showed that the supported Ir sites were stabilized by the silica surface, as low-coordinated single-site complexes. The material is extremely efficient for the hydrogenation of functional alkenes. The catalytic performance (TOF and TON) is one to two orders of magnitude higher than those of their molecular Ir analogues, and could be related to the prevention of the bimolecular deactivation of Ir complexes observed under homogeneous conditions.
Published: 2015
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43. Atomic Description of the Interface between Silica and Alumina in Aluminosilicates through Dynamic Nuclear Polarization Surface-Enhanced NMR Spectroscopy and First-Principles Calculations

Author: Céline Chizallet, Maxime Caillot, Aaron J. Rossini, Pascal Raybaud, Maxence Valla, Lyndon Emsley, Christophe Copéret, Jeroen A. van Bokhoven, Anne Lesage, Mathieu Digne, Alexandra Chaumonnot, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Ecole Polytechnique Fédérale de Lausanne (EPFL), IFP Energies nouvelles (IFPEN), 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), Paul Scherrer Institute (PSI), M.V. thanks the SNF foundation for financial support (Grant No. 200021_142600). This work was funded in part by the ERC Advanced Grant No. 320860 and SNF equipment grant (206021_150710)., and European Project
Subjects: AMORPHOUS SILICA, inorganic chemicals, Silicon, Industrial catalysts, chemistry.chemical_element, Biochemistry, complex mixtures, Catalysis, Article, BRONSTED ACID SITES, Colloid and Surface Chemistry, Aluminosilicate, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, MAGNETIC-RESONANCE, M-XYLENE ISOMERIZATION, GAMMA-ALUMINA, Organic chemistry, Polarization (electrochemistry), AL-27 NMR, SN-BETA ZEOLITE, INTEGER QUADRUPOLAR NUCLEI, technology, industry, and agriculture, General Chemistry, Nuclear magnetic resonance spectroscopy, equipment and supplies, Amorphous solid, SOLID-STATE NMR, RESOLUTION SI-29 NMR, Solid-state nuclear magnetic resonance, chemistry, Chemical engineering, Density functional theory
Abstract: Despite the widespread use of amorphous aluminosilicates (ASA) in various industrial catalysts, the nature of the interface between silica and alumina and the atomic structure of the catalytically active sites are still subject to debate. Here, by the use of dynamic nuclear polarization surface enhanced NMR spectroscopy (DNP SENS) and density functional theory (DFT) calculations, we show that on silica and alumina surfaces, molecular aluminum and silicon precursors are, respectively, preferentially grafted on sites that enable the formation of Al(IV) and Si(IV) interfacial sites. We also link the genesis of Brønsted acidity to the surface coverage of aluminum and silicon on silica and alumina, respectively., Journal of the American Chemical Society, 137 (33), ISSN:0002-7863, ISSN:1520-5126
Published: 2015
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44. Solid-State NMR of a Paramagnetic DIAD-FeII Catalyst: Sensitivity, Resolution Enhancement, and Structure-Based Assignments

Author: Charbel Roukoss, Christophe Copéret, Lyndon Emsley, Eberhardt Herdtweck, Eric Oldfield, Emile Kuntz, Gwendal Kervern, Jean Marie Basset, Yong Zhang, Guido Pintacuda, Anne Lesage, Sylvian Cadars, Laboratoire de Chimie - UMR5182 (LC), École normale supérieure de Lyon (ENS de Lyon)-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), Anorganisch-chemisches Institut, Technische Universität Munchen - Université Technique de Munich [Munich, Allemagne] (TUM), Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université Claude Bernard Lyon 1 (UCBL), 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), 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), Laboratory for Inorganic, Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC)
Subjects: Magnetic Resonance Spectroscopy, Magic angle, Cations, Divalent, Carbon-13 NMR satellite, Iron, Analytical chemistry, Fluorine-19 NMR, Crystallography, X-Ray, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, Magnetics, Colloid and Surface Chemistry, Organometallic Compounds, Magic angle spinning, [CHIM]Chemical Sciences, ComputingMilieux_MISCELLANEOUS, Earth's field NMR, Carbon Isotopes, 010405 organic chemistry, Chemistry, General Chemistry, Nuclear magnetic resonance spectroscopy, Carbon-13 NMR, Deuterium, Carbon, 0104 chemical sciences, Solid-state nuclear magnetic resonance, Anisotropy, Quantum Theory, Spin Labels, Condensed Matter::Strongly Correlated Electrons, Protons, Algorithms
Abstract: A general protocol for the structural characterization of paramagnetic molecular solids using solid-state NMR is provided and illustrated by the characterization of a high-spin Fe(II) catalyst precursor. We show how good NMR performance can be obtained on a molecular powder sample at natural abundance by using very fast (30 kHz) magic angle spinning (MAS), even though the individual NMR resonances have highly anisotropic shifts and very short relaxation times. The results include the optimization of broadband heteronuclear (proton-carbon) recoupling sequences for polarization transfer; the observation of single or multiple quantum correlation spectra between coupled spins as a tool for removing the inhomogeneous bulk magnetic susceptibility (BMS) broadening; and the combination of NMR experiments and density functional theory calculations, to yield assignments.
Published: 2006
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45. Surface versus Molecular Siloxy Ligands in Well-Defined Olefin Metathesis Catalysts: [{(RO)3SiO}Mo(NAr)(CHtBu)(CH2tBu)]

Author: Anne Lesage, Christophe Copéret, Frédéric Blanc, Richard R. Schrock, Jean Thivolle-Cazat, Lyndon Emsley, Amritanshu Sinha, and Jean-Marie Basset
Subjects: Olefin metathesis, Web of science, chemistry.chemical_element, General Chemistry, General Medicine, Metathesis, Heterogeneous catalysis, Catalysis, chemistry.chemical_compound, chemistry, Molybdenum, Organic chemistry, Well-defined, Carbene
Abstract: Keywords: carbene ligands ; heterogeneous catalysis ; metathesis ; molybdenum Reference EPFL-ARTICLE-204411doi:10.1002/anie.200503205View record in Web of Science Record created on 2015-01-08, modified on 2017-12-03
Published: 2006
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46. Detailed Structural Investigation of the Grafting of [Ta(CHtBu)(CH2tBu)3] and [Cp*TaMe4] on Silica Partially Dehydroxylated at 700 °C and the Activity of the Grafted Complexes toward Alkane Metathesis

Author: Jean Thivolle-Cazat, Jean-Marie Basset, Mathieu Chabanas, Lyndon Emsley, Glenn J. Sunley, E. Alessandra Quadrelli, Aimery De Mallmann, Christophe Coperet, Erwan Le Roux, Anne Lesage, Anne Baudouin, Wayne W. Lukens, University of Bergen (UiB), Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Université Claude Bernard Lyon 1 (UCBL), 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), Chemical Sciences Division [LBNL Berkeley] (CSD), Lawrence Berkeley National Laboratory [Berkeley] (LBNL), Laboratoire de Chimie - UMR5182 (LC), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC), Ecole Polytech Fed Lausanne, Inst Sci & Ingn Chim, BCH, CH-1015 Lausanne, Switzerland, 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), École normale supérieure de Lyon (ENS de Lyon)-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: Agostic interaction, Extended X-ray absorption fine structure, 010405 organic chemistry, Chemistry, Ligand, Stereochemistry, Carbon-13, Alkane metathesis, [CHIM.CATA]Chemical Sciences/Catalysis, General Chemistry, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, Metathesis, J-coupling, 01 natural sciences, Biochemistry, Catalysis, 3. Good health, 0104 chemical sciences, Crystallography, Colloid and Surface Chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: The reaction of [Ta({double_bond}CHtBu)(CH{sub 2}tBu){sub 3}] or [Cp*Ta(CH{sub 3}){sub 4}] with a silica partially dehydroxylated at 700 C gives the corresponding monosiloxy surface complexes [({triple_bond}SiO)Ta({double_bond}CHtBu)(CH{sub 2}tBu){sub 2}] and [({triple_bond}SiO)Ta(CH{sub 3}){sub 3}Cp*] by eliminating a {sigma}-bonded ligand as the corresponding alkane (H-CH{sub 2}tBu or H-CH{sub 3}). EXAFS data show that an adjacent siloxane bridge of the surface plays the role of an extra surface ligand, which most likely stabilizes these complexes as in [({triple_bond}SiO)Ta({double_bond}CHtBu)(CH{sub 2}tBu){sub 2}({triple_bond}SiOSi{triple_bond})] (1a') and [({triple_bond}SiO)Ta(CH{sub 3}){sub 3}Cp*({triple_bond}SiOSi{triple_bond})] (2a'). In the case of [({triple_bond}SiO)Ta({double_bond}CHtBu)(CH{sub 2}tBu){sub 2}({triple_bond}SiOSi{triple_bond})], the structure is further stabilized by an additional interaction: a C-H agostic bond as evidenced by the small J coupling constant for the carbenic C-H (H{sub C-H} = 80 Hz), which was measured by J-resolved 2D solid-state NMR spectroscopy. The product selectivity in propane metathesis in the presence of [({triple_bond}SiO)Ta({double_bond}CHtBu)-(CH{sub 2}tBu){sub 2}({triple_bond}SiOSi{triple_bond})] (1a') as a catalyst precursor and the inactivity of the surface complex [({triple_bond}SiO)Ta-(CH{sub 3}){sub 3}Cp*({triple_bond}SiOSi{triple_bond})] (2a') show that the active site is required to be highly electrophilic and probably involves a metallacyclobutane intermediate.
Published: 2004
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47. 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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48. Solid-State Dynamic Nuclear Polarization at 9.4 and 18.8 T from 100 K to Room Temperature

Author: David Gajan, Moreno Lelli, Aaron J. Rossini, Olivier Ouari, Gilles Casano, Anne Lesage, Lyndon Emsley, Paul Tordo, Sachin Rama Chaudhari, 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), Institut de Chimie Radicalaire (ICR), Aix Marseille Université (AMU)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), Ecole Polytechnique Fédérale de Lausanne (EPFL), Financial support is acknowledged from ERC Advanced Grant No. 320860 and EQUIPEX contract ANR-10-EQPX-47-01., ANR-10-EQPX-0047,SENS,RMN de Surface Exalté par Polarisation Dynamique Nucléaire(2010), European Project: 320860,EC:FP7:ERC,ERC-2012-ADG_20120216,HI-SENS(2013), 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: Catalysis, Chemistry, Surface Chemistry, ENHANCED NMR-SPECTROSCOPY, SPIN-LATTICE-RELAXATION, HIGH-FREQUENCY DNP POLARIZING AGENT, O-TERPHENYL, Cross effect, Communication, Spin–lattice relaxation, Solid-state, Analytical chemistry, General Chemistry, Polarization (waves), Biochemistry, 3. Good health, Solvent, Molecular dynamics, Colloid and Surface Chemistry, Nuclear magnetic resonance, [CHIM]Chemical Sciences, Glass transition
Abstract: We thank Lenaic Leroux for technical help.; International audience; Efficient dynamic nuclear polarization (DNP) in solids, which enables very high sensitivity NMR experiments, is currently limited to temperatures of around 100 K and below. Here we show how by choosing an adequate solvent, 1H cross effect DNP enhancements of over 80 can be obtained at 240 K. To achieve this we use the biradical TEKPol dissolved in a glassy phase of ortho-terphenyl (OTP). We study the solvent DNP enhancement of both TEKPol and BDPA in OTP in the range from 100 to 300 K at 9.4 and 18.8 T. Surprisingly, we find that the DNP enhancement decreases only relatively slowly for temperatures below the glass transition of OTP (Tg = 243 K), and 1H enhancements around 15–20 at ambient temperature can be observed. We use this to monitor molecular dynamic transitions in the pharmaceutically relevant solids Ambroxol and Ibuprofen.
Published: 2015
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49. Tailored Polarizing Hybrid Solids with Nitroxide Radicals Localized in Mesostructured Silica Walls

Author: Pierrick Berruyer, Ta-Chung Ong, Laurent Veyre, Geoffrey Bodenhausen, Henri A. van Kalkeren, Sami Jannin, Lyndon Emsley, Christophe Copéret, Maxim Yulikov, David Baudouin, Basile Vuichoud, Anne Lesage, Mathieu Baudin, Matthieu Cavaillès, Chloé Thieuleux, Daniel L. Silverio, David Gajan, Gunnar Jeschke, Aurélien Bornet, Sachin Rama Chaudhari, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Institut des Sciences et Ingénierie Chimiques (ISIC), Ecole Polytechnique Fédérale de Lausanne (EPFL), Laboratory of Inorganic Chemistry, Laboratoire de Chimie, Catalyse, Polymères et Procédés, R 5265 (C2P2), Centre National de la Recherche Scientifique (CNRS)-École supérieure de Chimie Physique Electronique de Lyon (CPE)-Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Institut de Chimie du CNRS (INC), 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), ISA - Centre de RMN à très hauts champs, Laboratoire de chimie de coordination (LCC), Institut National Polytechnique (Toulouse) (Toulouse INP), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie de Toulouse (ICT-FR 2599), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche pour le Développement (IRD)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS), ISA - Hyperpolarized Magnetic Resonance, Institut des sciences et d'ingénierie chimiques (ISIC), Institut des Sciences et Ingénierie Chimiques, Ecole Polytechnique Fédérale de Lausanne (EPFL)-Batochime, Ecole Polytech Fed Lausanne, Inst Sci & Ingn Chim, BCH, CH-1015 Lausanne, Switzerland, Université Claude Bernard Lyon 1 (UCBL), 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), 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), 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 de Toulouse (ICT), Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Université de Toulouse (UT)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Institut National Polytechnique (Toulouse) (Toulouse INP), Université de Toulouse (UT)-Institut de Recherche pour le Développement (IRD)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nitroxide mediated radical polymerization, Radical, Magic angle spinning dynamic nuclear polarization, Inorganic chemistry, Hybrid organic-inorganic materials, Chemical interaction, 010402 general chemistry, Photochemistry, 01 natural sciences, Biochemistry, Catalysis, Inorganic Chemistry, Paramagnetism, Molecular glasses, Drug Discovery, [CHIM]Chemical Sciences, Molecule, Physics::Chemical Physics, Physical and Theoretical Chemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, 010405 organic chemistry, Chemistry, Organic Chemistry, Dissolution dynamic nuclear polarization, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Microwave irradiation, Mesostructured silica
Abstract: International audience; Hyperpolarization by dynamic nuclear polarization relies on the microwave irradiation of paramagnetic radicals dispersed in molecular glasses to enhance the nuclear magnetic resonance (NMR) signals of target molecules. However, magnetic or chemical interactions between the radicals and the target molecules can lead to attenuation of the NMR signal through paramagnetic quenching and/or radical decomposition. Here we describe polarizing materials incorporating nitroxide radicals within the walls of the solids to minimize interactions between the radicals and the solute. These materials can hyperpolarize pure pyruvic acid, a particularly important substrate of clinical interest, while nitroxide radicals cannot be used, even when incorporated in the pores of silica, because of reactions between pyruvic acid and the radicals. The properties of these materials can be engineered by tuning the composition of the wall by introducing organic functionalities.
Published: 2017
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50. NMR signatures of the active sites in Sn-beta zeolite

Author: Francisco Núñez-Zarur, Lyndon Emsley, Bernard Malaman, Ive Hermans, Maxence Valla, Aleix Comas-Vives, Patrick Wolf, Christophe Copéret, Anne Lesage, Aaron J. Rossini, Department of Chemistry and Applied Biosciences [ETH Zürich], Eidgenössische Technische Hochschule - Swiss Federal Institute of Technology [Zürich] (ETH Zürich), Dept Chem, University of Wisconsin-Madison, Dept Biol & Chem, 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), Institut Jean Lamour (IJL), Institut de Chimie du CNRS (INC)-Université de Lorraine (UL)-Centre National de la Recherche Scientifique (CNRS), We acknowledge SNF Grants No. 200021_143600 and 200021_146661, Ambizione project PZ00P2_148059, EQUIPEX contract ANR-10-EQPX-47-01, and ERC Advanced Grant No. 320860 for funding., ANR-10-EQPX-0047,SENS,RMN de Surface Exalté par Polarisation Dynamique Nucléaire(2010), 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: Magic angle, BAEYER-VILLIGER OXIDATIONS, Inorganic chemistry, Mossbauer spectroscopy, AROMATIC-ALDEHYDES, chemistry.chemical_element, zeolites, [CHIM.INOR]Chemical Sciences/Inorganic chemistry, 010402 general chemistry, WATER-TOLERANT, 01 natural sciences, Catalysis, DENSITY-FUNCTIONAL THEORY, MAGIC-ANGLE, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, active sites, Mössbauer spectroscopy, LEWIS-ACID CATALYST, Zeolite, Polarization (electrochemistry), solid-state NMR spectroscopy, 010405 organic chemistry, General Chemistry, GLUCOSE ISOMERIZATION, DNP SENS, 0104 chemical sciences, Lewis acid catalysis, Crystallography, MEERWEIN-PONNDORF-VERLEY, chemistry, Octahedron, [PHYS.COND.CM-MS]Physics [physics]/Condensed Matter [cond-mat]/Materials Science [cond-mat.mtrl-sci], Density functional theory, DYNAMIC NUCLEAR-POLARIZATION, LACTIC-ACID: active sites, Tin
Abstract: International audience; Dynamic nuclear polarization surface enhanced NMR (DNP-SENS), Mossbauer spectroscopy, and computational chemistry were combined to obtain structural information on the active-site speciation in Sn-beta zeolite. This approach unambiguously shows the presence of framework Sn-IV-active sites in an octahedral environment, which probably correspond to so-called open and closed sites, respectively (namely, tin bound to three or four siloxy groups of the zeolite framework).
Published: 2014
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101 results on '"Anne, Lesage"'

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