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1. Optimizing chemistry at the surface of prodrug-loaded cellulose nanofibrils with MAS-DNP

Author: Akshay Kumar, Bastien Watbled, Isabelle Baussanne, Sabine Hediger, Martine Demeunynck, and Gaël De Paëpe
Subjects: Chemistry, QD1-999
Abstract: Functionalized nanocellulose is a promising drug carrier, however, studying surface functionalization at the atomic scale remains challenging due to spectroscopic methodology limitations. Here, the authors use dynamic nuclear polarization enhanced 13C and 15N solid-state NMR to optimize the drug loading on nanocellulose using aqueous heterogeneous chemistry.
Published: 2023
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2. PyrroTriPol: a semi-rigid trityl-nitroxide for high field dynamic nuclear polarization

Author: Thomas Halbritter, Rania Harrabi, Subhradip Paul, Johan van Tol, Daniel Lee, Sabine Hediger, Snorri Th. Sigurdsson, Frédéric Mentink-Vigier, and Gaël De Paëpe
Subjects: General Chemistry
Abstract: Magic angle spinning (MAS) dynamic nuclear polarization (DNP) has significantly broadened the scope of solid-state NMR to study biomolecular systems and materials. In recent years, the advent of very high field DNP combined with fast MAS has brought new challenges in the design of polarizing agents (PA) used to enhance nuclear spin polarization. Here, we present a trityl-nitroxide PA family based on a piperazine linker, named PyrroTriPol, for both aqueous and organic solutions. These new radicals have similar properties to that of TEMTriPol-I and can be readily synthesized, and purified in large quantities thereby ensuring widespread application. The family relies on a rigid bridge connecting the trityl and the nitroxide offering a better control of the electron spin-spin interactions thus providing improved performance across a broad range of magnetic fields and MAS frequencies while requiring reduced microwave power compared to bis-nitroxides. We demonstrate the efficiency of the PyrroTriPol family under a magnetic field of 9.4, 14.1 and 18.8 T with respect to TEMTriPol-I. In particular, the superiority of PyrroTriPol was demonstrated on γ-Al2O3 nanoparticles which enabled the acquisition of a high signal-to-noise surface-selective 27Al multiple-quantum MAS experiment at 18.8 T and 40 kHz MAS frequency
Published: 2023
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3. Sonocrystallization of CMONS Needles and Nanocubes: Mechanistic Studies and Advanced Crystallinity Characterization by Combining X-ray and Electron Diffractions with DNP-Enhanced NMR

Author: Xavier Cattoën, Akshay Kumar, Fabien Dubois, Carole Vaillant, Mauricio Matta-Seclén, Olivier Leynaud, Stéphanie Kodjikian, Sabine Hediger, Gaël De Paëpe, Alain Ibanez, Optique et Matériaux (NEEL - OPTIMA), Institut Néel (NEEL), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA), Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), X'Press : diffraction et hautes pressions (NEEL - X'Press), Optique & Microscopies (NEEL - POM), ANR-16-CE11-0030,TransPepNMR,Etude par RMN du complexe L,D-transpeptidase/peptidoglycan et de son influence sur la maturation de la paroi des mycobactéries(2016), and ANR-17-EURE-0003,CBH-EUR-GS,CBH-EUR-GS(2017)
Subjects: Nanocrystallization, DNP-NMR, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Sonocrystallization, General Materials Science, [CHIM.MATE]Chemical Sciences/Material chemistry, General Chemistry, Condensed Matter Physics, Fluorescence, Organic Nanocrystals
Abstract: International audience; This study introduces a new nanocrystallization method assisted by ultrasounds that produces needles or nanocubes of CMONS, a stilbene dye, with an excellent control over the polymorphism, and with a narrow size distribution. Owing to the production of radicals from dissolved dioxygen by high-intensity ultrasounds, trans-to-cis isomerization was observed in the absence of nitrogen bubbling, with the formation of two distinct crystalline phases for the different diastereomers. The crystallinity of CMONS needles was probed by various techniques, including X-ray and electron diffractions, fluorescence spectroscopy, and dynamic nuclear polarization (DNP) enhanced solid-state nuclear magnetic resonance. The latter was used to hyperpolarize 1 H nuclei and to record 1 H-13 C and 1 H-15 N CPMAS NMR spectra at natural isotopic abundance with very high signal-to-noise ratio. With such sensitivity, one can easily discriminate between cis and trans-I forms of CMONS, detect the presence of multiple polymorphic phases (even with minor contributions) and check the absence of amorphous phase. Finally, the mechanism involved in the formation of CMONS needles was ascertained after stabilizing intermediate nanocubes against Ostwald ripening and ordered aggregation mechanisms using the CTAB surfactant.
Published: 2022
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4. Fast magic angle spinning for the characterization of milligram quantities of organic and biological solids at natural isotopic abundance by 13C–13C correlation DNP-enhanced NMR

Author: Adam N. Smith, Rania Harrabi, Thomas Halbritter, Daniel Lee, Fabien Aussenac, Patrick C.A. van der Wel, Sabine Hediger, Snorri Th. Sigurdsson, Gaël De Paëpe, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), University of Iceland [Reykjavik], Bruker, University of Groningen [Groningen], Institut de Chimie Moléculaire de Grenoble (ICMG), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), and Solid-state nuclear magnetic resonance
Subjects: Dynamic Nuclear Polarization, Nuclear and High Energy Physics, Radiation, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, Nuclear Magnetic Resonance, General Chemistry, MAS-DNP, Fast MAS, Pharmaceuticals, Instrumentation
Abstract: International audience; We show that multidimensional solid-state NMR 13C–13C correlation spectra of biomolecular assemblies and microcrystalline organic molecules can be acquired at natural isotopic abundance with only milligram quantities of sample. These experiments combine fast Magic Angle Spinning of the sample, low-power dipolar recoupling, and dynamic nuclear polarization performed with AsymPol biradicals, a recently introduced family of polarizing agents. Such experiments are essential for structural characterization as they provide short- and long-range distance information. This approach is demonstrated on diverse sample types, including polyglutamine fibrils implicated in Huntington's disease and microcrystalline ampicillin, a small antibiotic molecule.
Published: 2023
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5. Fast magic angle spinning for the characterization of milligram quantities of organic and biological solids at natural isotopic abundance by

Author: Adam N, Smith, Rania, Harrabi, Thomas, Halbritter, Daniel, Lee, Fabien, Aussenac, Patrick C A, van der Wel, Sabine, Hediger, Snorri Th, Sigurdsson, and Gaël, De Paëpe
Abstract: We show that multidimensional solid-state NMR
Published: 2022

6. Biomolecular and Biological Applications of Solid-State NMR with Dynamic Nuclear Polarization Enhancement

Author: Wing Ying Chow, Gaël De Paëpe, Sabine Hediger, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Groupe de RMN biomoléculaire (IBS-NMR), Institut de biologie structurale (IBS - UMR 5075), Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Centre National de la Recherche Scientifique (CNRS), and ANR-16-CE11-0030,TransPepNMR,Etude par RMN du complexe L,D-transpeptidase/peptidoglycan et de son influence sur la maturation de la paroi des mycobactéries(2016)
Subjects: [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Cell Nucleus, Magnetic Resonance Spectroscopy, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], General Chemistry, Magnetic Resonance Imaging, Nuclear Magnetic Resonance, Biomolecular
Abstract: International audience; Solid-state NMR spectroscopy (ssNMR) with magic-angle spinning (MAS) enables the investigation of biological systems within their native context, such as lipid membranes, viral capsid assemblies, and cells. However, such ambitious investigations often suffer from low sensitivity, due to the presence of significant amounts of other molecular species, which reduces the effective concentration of the biomolecule or interaction of interest. Certain investigations requiring the detection of very low concentration species remain unfeasible even with increasing experimental time for signal averaging. By applying dynamic nuclear polarization (DNP) to overcome the sensitivity challenge, the experimental time required can be reduced by orders of magnitude, broadening the feasible scope of applications for biological solid-state NMR. In this review, we outline strategies commonly adopted for biological applications of DNP, indicate ongoing 1 challenges, and present a comprehensive overview of biological investigations where MAS-DNP has led to unique insights.
Published: 2022
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7. Highly efficient polarizing agents for MAS‐DNP of proton‐dense molecular solids

Author: Rania Harrabi, Thomas Halbritter, Fabien Aussenac, Ons Dakhlaoui, Johan van Tol, Krishna K. Damodaran, Daniel Lee, Subhradip Paul, Sabine Hediger, Frederic Mentink‐Vigier, Snorri Th. Sigurdsson, Gaël De Paëpe, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Université Grenoble Alpes (UGA), University of Iceland [Reykjavik], Bruker BioSpin, GmbH, Centre de Recherches sur les Macromolécules Végétales (CERMAV), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), National High Magnetic Field Laboratory (NHMFL), Florida State University [Tallahassee] (FSU), and ANR-16-CE11-0030,TransPepNMR,Etude par RMN du complexe L,D-transpeptidase/peptidoglycan et de son influence sur la maturation de la paroi des mycobactéries(2016)
Subjects: [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Magnetic Resonance Spectroscopy, Pharmaceutical Preparations, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Electron Spin Resonance Spectroscopy, General Chemistry, General Medicine, Protons, Catalysis, Article
Abstract: International audience; Efficiently hyperpolarizing proton-dense molecular solids through Dynamic Nuclear Polarization (DNP) solid-state NMR is still an unmet challenge. Polarizing agents (PAs) developed so far do not perform well on proton-rich systems, such as organic microcrystals and biomolecular assemblies. Herein we introduce a new PA, cAsymPol-POK, and report outstanding hyperpolarization efficiency on 12.76 kDa U-$^{13}$ C,$^{15}$ N-labeled LecA protein and pharmaceutical drugs at high magnetic fields (up to 18.8 T) and fast MAS frequencies (up to 40 kHz). The performance of cAsymPol-POK is rationalized by MAS-DNP simulations combined with Electron Paramagnetic Resonance (EPR), Density Functional Theory (DFT) and Molecular Dynamics (MD). This work shows that this new biradical is compatible with challenging biomolecular applications and unlocks the rapid acquisition of $^{13}$C-$^{13}$ C and $^{15}$N-$^{13}$C correlations of pharmaceutical drugs at natural isotopic abundance, which are key experiments for structure determination.
Published: 2022
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8. De novo prediction of cross-effect efficiency for magic angle spinning dynamic nuclear polarization

Author: Johan van Tol, Sabine Hediger, Anne-Laure Barra, Gaël De Paëpe, Daniel Lee, Frederic Mentink-Vigier, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), National High Magnetic Field Laboratory (NHMFL), Florida State University [Tallahassee] (FSU), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G ), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), FSU, Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), and Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: High-Field EPR, Materials science, Physics::Medical Physics, General Physics and Astronomy, 02 engineering and technology, Electron, 010402 general chemistry, DFT, 01 natural sciences, Molecular physics, Article, law.invention, Biradicals, depolarization, law, Magic angle spinning, Theory, Physical and Theoretical Chemistry, Electron paramagnetic resonance, Dynamic Nuclear Polarization, Cross effect, Nitroxides, [PHYS.PHYS.PHYS-ATM-PH]Physics [physics]/Physics [physics]/Atomic and Molecular Clusters [physics.atm-clus], MAS-DNP, 021001 nanoscience & nanotechnology, Polarization (waves), 0104 chemical sciences, Solid-state nuclear magnetic resonance, Microwave irradiation, solid-state NMR, 0210 nano-technology, Microwave
Abstract: International audience; Magic angle spinning dynamic nuclear polarization (MAS-DNP) has become a key approach to boost the intrinsic low sensitivity of NMR in solids. This method relies on the use of both stable radicals as polarizing agents (PAs) and suitable high frequency microwave irradiation to hyperpolarize nuclei of interest. Relating PA chemical structure to DNP efficiency has been, and is still, a long-standing problem. The complexity of the polarization transfer mechanism has so far limited the impact of analytical derivation. However, recent numerical approaches have profoundly improved the basic understanding of the phenomenon and have now evolved to a point where they can be used to help design new PAs. In this work, the potential of advanced MAS-DNP simulations combined with DFT calculations and high-field EPR to qualitatively and quantitatively predict hyperpolarization efficiency of particular PAs is analyzed. This approach is demonstrated on AMUPol and TEKPol, two widely-used bis-nitroxide PAs. The results notably highlight how the PA structure and EPR characteristics affect the detailed shape of the DNP field profile. We also show that refined simulations of this profile using the orientation dependency of the electron spin-lattice relaxation times can be used to estimate the microwave B 1 field experienced by the sample. Finally, we show how modelling the nuclear spin-lattice relaxation times of close and bulk nuclei while accounting for PA concentration allows for a prediction of DNP enhancement factors and hyperpolarization build-up times.
Published: 2019
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9. The surface chemistry of a nanocellulose drug carrier unravelled by MAS-DNP

Author: Isabelle Baussanne, Daniel Lee, Sabine Hediger, Sébastien Fort, Cyril Balsollier, Akshay Kumar, Bastien Watbled, Julien Bras, Cécile Sillard, Naceur Belgacem, Gaël De Paëpe, Hippolyte Durand, Martine Demeunynck, Elisa Zeno, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA)-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes (UGA), Laboratoire Génie des procédés papetiers (LGP2), Centre National de la Recherche Scientifique (CNRS)-Institut polytechnique de Grenoble - Grenoble Institute of Technology (Grenoble INP ), Université Grenoble Alpes (UGA)-Université Grenoble Alpes (UGA), Centre Technique du Papier (CTP), Centre de Recherches sur les Macromolécules Végétales (CERMAV), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes (UGA), Département de pharmacochimie moléculaire (DPM), Centre National de la Recherche Scientifique (CNRS), and ANR-17-EURE-0003,CBH-EUR-GS,CBH-EUR-GS(2017)
Subjects: Conductometry, Chemistry(all), Nanotechnology, 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, 3. Good health, Nanocellulose, chemistry.chemical_compound, Chemistry, Adsorption, chemistry, Covalent bond, Drug delivery, Surface modification, [CHIM]Chemical Sciences, Cellulose, 0210 nano-technology, Drug carrier
Abstract: Cellulose nanofibrils (CNF) are renewable bio-based materials with high specific area, which makes them ideal candidates for multiple emerging applications including for instance on-demand drug release. However, in-depth chemical and structural characterization of the CNF surface chemistry is still an open challenge, especially for low weight percentage of functionalization. This currently prevents the development of efficient, cost-effective and reproducible green synthetic routes and thus the widespread development of targeted and responsive drug-delivery CNF carriers. We show in this work how we use dynamic nuclear polarization (DNP) to overcome the sensitivity limitation of conventional solid-state NMR and gain insight into the surface chemistry of drug-functionalized TEMPO-oxidized cellulose nanofibrils. The DNP enhanced-NMR data can report unambiguously on the presence of trace amounts of TEMPO moieties and depolymerized cellulosic units in the starting material, as well as coupling agents on the CNFs surface (used in the heterogeneous reaction). This enables a precise estimation of the drug loading while differentiating adsorption from covalent bonding (∼1 wt% in our case) as opposed to other analytical techniques such as elemental analysis and conductometric titration that can neither detect the presence of coupling agents, nor differentiate unambiguously between adsorption and grafting. The approach, which does not rely on the use of 13C/15N enriched compounds, will be key to further develop efficient surface chemistry routes and has direct implication for the development of drug delivery applications both in terms of safety and dosage., DNP-enhanced solid-state NMR unravels the surface chemistry of functionalized nanocellulose.
Published: 2021
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10. Structural Fingerprinting of Protein Aggregates by Dynamic Nuclear Polarization-Enhanced Solid-State NMR at Natural Isotopic Abundance

Author: Ravindra Kodali, Patrick C.A. van der Wel, Jennifer C. Boatz, Irina Matlahov, Talia Piretra, Gaël De Paëpe, Adam N. Smith, Sabine Hediger, Katharina Märker, Magnetic Resonance [?-2019] (RM [?-2019]), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Magnetic Resonance (RM ), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), University of Pittsburgh School of Medicine, Pennsylvania Commonwealth System of Higher Education (PCSHE), and Duquesne University [Pittsburgh]
Subjects: 0301 basic medicine, Huntingtin, Protein Conformation, Mutant, Natural abundance, Protein aggregation, Fibril, Biochemistry, Catalysis, Isotopic labeling, Protein Aggregates, 03 medical and health sciences, Colloid and Surface Chemistry, Humans, [CHIM]Chemical Sciences, Particle Size, Polarization (electrochemistry), Nuclear Magnetic Resonance, Biomolecular, Carbon Isotopes, Huntingtin Protein, Nitrogen Isotopes, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], Chemistry, Communication, General Chemistry, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biomolecules [q-bio.BM], 030104 developmental biology, Solid-state nuclear magnetic resonance, Biophysics
Abstract: International audience; A pathological hallmark of Huntington's disease (HD) is the formation of neuronal protein deposits containing mutant huntingtin fragments with expanded polyglutamine (polyQ) domains. Prior studies have shown the strengths of solid-state NMR (ssNMR) to probe the atomic structure of such aggregates, but have required in vitro isotopic labeling. Herein, we present an approach for the structural fingerprinting of fibrils through ssNMR at natural isotopic abundance (NA). These methods will enable the spectroscopic fingerprinting of unlabeled (e.g., ex vivo) protein aggregates and the extraction of valuable new long-range 13 C− 13 C distance constraints
Published: 2018
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11. Correction: De novo prediction of cross-effect efficiency for magic angle spinning dynamic nuclear polarization

Author: Frédéric Mentink-Vigier, Anne-Laure Barra, Johan van Tol, Sabine Hediger, Daniel Lee, and Gaël De Paëpe
Subjects: General Physics and Astronomy, Physical and Theoretical Chemistry
Abstract: Correction for ‘De novo prediction of cross-effect efficiency for magic angle spinning dynamic nuclear polarization’ by Frédéric Mentink-Vigier et al., Phys. Chem. Chem. Phys., 2019, 21, 2166–2176, DOI: 10.1039/C8CP06819D.
Published: 2021
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12. Natural Isotopic Abundance 13C and 15N Multidimensional Solid-State NMR Enabled by Dynamic Nuclear Polarization

Author: Gaël De Paëpe, Katharina Märker, Sabine Hediger, Adam N. Smith, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), University of Cambridge [UK] (CAM), ANR-11-LABX-0003,ARCANE,Grenoble, une chimie bio-motivée(2011), ANR-15-IDEX-0002,UGA,IDEX UGA(2015), and ANR-16-CE11-0030,TransPepNMR,Etude par RMN du complexe L,D-transpeptidase/peptidoglycan et de son influence sur la maturation de la paroi des mycobactéries(2016)
Subjects: Dynamic Nuclear Polarization, dipolar recoupling, Distance constraints, Materials science, 010405 organic chemistry, Natural abundance, sensitivity enhancement, 010402 general chemistry, Polarization (waves), dipolar truncation, 01 natural sciences, 0104 chemical sciences, Magic angle spinning, correlation experiment, Solid-state nuclear magnetic resonance, Chemical physics, [CHIM]Chemical Sciences, General Materials Science, Physical and Theoretical Chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: International audience; Dynamic nuclear polarization (DNP) has made feasible solid-state NMR experiments that were previously thought impractical due to sensitivity limitations. One such class of experiments is the structural characterization of organic and biological samples at natural isotopic abundance (NA). Herein, we describe the many advantages of DNP-enabled ssNMR at NA, including the extraction of long-range distance constraints using dipolar recoupling pulse sequences without the deleterious effects of dipolar truncation. In addition to the theoretical underpinnings in the analysis of these types of experiments, numerous applications of DNPenabled ssNMR at NA are discussed.
Published: 2019
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13. Natural Isotopic Abundance

Author: Adam N, Smith, Katharina, Märker, Sabine, Hediger, and Gaël, De Paëpe
Abstract: Dynamic nuclear polarization (DNP) has made feasible solid-state NMR experiments that were previously thought impractical due to sensitivity limitations. One such class of experiments is the structural characterization of organic and biological samples at natural isotopic abundance (NA). Herein, we describe the many advantages of DNP-enabled ssNMR at NA, including the extraction of long-range distance constraints using dipolar recoupling pulse sequences without the deleterious effects of dipolar truncation. In addition to the theoretical underpinnings in the analysis of these types of experiments, numerous applications of DNP-enabled ssNMR at NA are discussed.
Published: 2019

14. Ultra-low temperature MAS-DNP

Author: Eric Bouleau, Gaël De Paëpe, Daniel Lee, Pierre Saint-Bonnet, Sabine Hediger, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Calculs et Conception Cryogénique (L3C ), Service des Basses Températures (SBT ), Laboratoire de Cryogénie pour la Fusion (LCF ), ANR-11-LABX-0003,ARCANE,Grenoble, une chimie bio-motivée(2011), ANR-08-CEXC-0003,DNP4NanoCarac,Polarisation Dynamique Nucléaire : amélioration de la sensibilité en RMN solide haute résolution pour l'étude structurale 3D de nanotubes fonctionnalisés et autres nano-objets(2008), ANR-12-BS08-0016,CryoMAS4DNP,Polarisation dynamique nucléaire en rotation à l'angle magique à très basse température et à haut champ magnétique(2012), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Cryostat, Nuclear and High Energy Physics, Magic angle, Enhanced NMR, Biophysics, Analytical chemistry, 010402 general chemistry, Solid-state NMR, 01 natural sciences, Biochemistry, Dynamic nuclear polarization, Magic angle spinning, Helium sample spinning, C-13 NMR, Spectroscopy, Spinning, [PHYS]Physics [physics], Physics, Spins, 010405 organic chemistry, business.industry, Atmospheric temperature range, Condensed Matter Physics, 0104 chemical sciences, Cryogenic helium, Solid-state nuclear magnetic resonance, C-13-C-13 correlation spectroscopy, Optoelectronics, business
Abstract: International audience; Since the infancy of NMR spectroscopy, sensitivity and resolution have been the limiting factors of the technique. Regular essential developments on this front have led to the widely applicable, versatile, and powerful spectroscopy that we know today. However, the Holy Grail of ultimate sensitivity and resolution is not yet reached, and technical improvements are still ongoing. Hence, high-field dynamic nuclear polarization (DNP) making use of high-frequency, high-power microwave irradiation of electron spins has become very promising in combination with magic angle sample spinning (MAS) solid-state NMR experiments. This is because it leads to a transfer of the much larger polarization of these electron spins under suitable irradiation to surrounding nuclei, greatly increasing NMR sensitivity. Currently, this boom in MAS-DNP is mainly performed at minimum sample temperatures of about 100 K, using cold nitrogen gas to pneumatically spin and cool the sample. This Perspective deals with the desire to improve further the sensitivity and resolution by providing "ultra"-low temperatures for MAS-DNP, using cryogenic helium gas. Different designs on how this technological challenge has been overcome are described. It is shown that stable and fast spinning can be attained for sample temperatures down to 30 K using a large cryostat developed in our laboratory. Using this cryostat to cool a closed-loop of helium gas brings the additional advantage of sample spinning frequencies that can greatly surpass those achievable with nitrogen gas, due to the differing fluidic properties of these two gases. It is shown that using ultra-low temperatures for MAS-DNP results in substantial experimental sensitivity enhancements and according time-savings. Access to this temperature range is demonstrated to be both viable and highly pertinent. (C) 2015 Elsevier Inc. All rights reserved.
Published: 2016
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15. High-Field Solid-State NMR with Dynamic Nuclear Polarization

Author: Sabine Hediger, Gaël De Paëpe, Daniel Lee, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Materials science, Carbon-13 NMR satellite, 010405 organic chemistry, Nuclear magnetic resonance spectroscopy, Fluorine-19 NMR, Nuclear magnetic resonance crystallography, 010402 general chemistry, 01 natural sciences, 0104 chemical sciences, Solid-state nuclear magnetic resonance, Chemical physics, [CHIM]Chemical Sciences, Hyperpolarization (physics), Insensitive nuclei enhanced by polarization transfer, ComputingMilieux_MISCELLANEOUS, Earth's field NMR
Abstract: International audience
Published: 2018
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16. Welcoming natural isotopic abundance in solid-state NMR: probing π-stacking and supramolecular structure of organic nanoassemblies using DNP

Author: Daniel Lee, Katharina Märker, Subhradip Paul, Gaël De Paëpe, Sabine Hediger, Carlos Fernández‐de‐Alba, Jean-Marie Mouesca, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Magnetic Resonance (RM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), and Centre National de la Recherche Scientifique (CNRS)
Subjects: 010405 organic chemistry, Stereochemistry, [CHIM.ORGA]Chemical Sciences/Organic chemistry, Intermolecular force, Supramolecular chemistry, Stacking, Molecular electronics, General Chemistry, Crystal structure, Nuclear magnetic resonance crystallography, 010402 general chemistry, 01 natural sciences, 3. Good health, 0104 chemical sciences, Chemistry, chemistry.chemical_compound, Solid-state nuclear magnetic resonance, chemistry, Chemical physics, [CHIM]Chemical Sciences, Diphenylalanine, ComputingMilieux_MISCELLANEOUS
Abstract: The low natural abundance of 13C combined with MAS-DNP enables 13C–13C polarization transfer up to ∼7 Å and observation of π-stacking., The self-assembly of small organic molecules is an intriguing phenomenon, which provides nanoscale structures for applications in numerous fields from medicine to molecular electronics. Detailed knowledge of their structure, in particular on the supramolecular level, is a prerequisite for the rational design of improved self-assembled systems. In this work, we prove the feasibility of a novel concept of NMR-based 3D structure determination of such assemblies in the solid state. The key point of this concept is the deliberate use of samples that contain 13C at its natural isotopic abundance (NA, 1.1%), while exploiting magic-angle spinning dynamic nuclear polarization (MAS-DNP) to compensate for the reduced sensitivity. Since dipolar truncation effects are suppressed to a large extent in NA samples, unique and highly informative spectra can be recorded which are impossible to obtain on an isotopically labeled system. On the self-assembled cyclic diphenylalanine peptide, we demonstrate the detection of long-range internuclear distances up to ∼7 Å, allowing us to observe π-stacking through 13C–13C correlation spectra, providing a powerful tool for the analysis of one of the most important non-covalent interactions. Furthermore, experimental polarization transfer curves are in remarkable agreement with numerical simulations based on the crystallographic structure, and can be fully rationalized as the superposition of intra- and intermolecular contributions. This new approach to NMR crystallography provides access to rich and precise structural information, opening up a new avenue to de novo crystal structure determination by NMR.
Published: 2017
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17. Efficient 2D double-quantum solid-state NMR spectroscopy with large spectral widths

Author: Katharina Märker, Sabine Hediger, Gaël De Paëpe, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Centre National de la Recherche Scientifique (CNRS), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Distance constraints, Mathematics::Functional Analysis, Chemistry, Metals and Alloys, Analytical chemistry, Phase (waves), 02 engineering and technology, General Chemistry, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, Molecular physics, Catalysis, Spectral line, 0104 chemical sciences, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Solid-state nuclear magnetic resonance, Materials Chemistry, Ceramics and Composites, Double quantum, 0210 nano-technology, Spectroscopy
Abstract: International audience; 2D double-quantum single-quantum correlation spectra with arbitrary spectral widths can be recorded with SR26 and related supercycled recoupling sequences when applying Supercycle-Timing-Compensation (STiC) phase shifts. This concept widely extends the applicability of supercycled sequences, most importantly for obtaining long-range distance constraints for structure determination with solid-state NMR.
Published: 2017
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18. Efficient cross-effect dynamic nuclear polarization without depolarization in high-resolution MAS NMR

Author: Anne-Laure Barra, Gaël De Paëpe, Guinevere Mathies, Frederic Mentink-Vigier, Sabine Hediger, Yangping Liu, Daniel Lee, Robert G. Griffin, Marc A. Caporini, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), MIT - Francis Bitter Magnet Lab, Massachusetts Institute of Technology (MIT), Tianjin University (TJU), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G ), Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Bruker BioSpin [Billerica, MA], Centre National de la Recherche Scientifique (CNRS), ANR-12-BS08-0016,CryoMAS4DNP,Polarisation dynamique nucléaire en rotation à l'angle magique à très basse température et à haut champ magnétique(2012), ANR-11-LABX-0003,ARCANE,Grenoble, une chimie bio-motivée(2011), ANR-10-EQPX-0047,SENS,RMN de Surface Exalté par Polarisation Dynamique Nucléaire(2010), European Project: 682895, Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Cross effect, 010405 organic chemistry, Chemistry, [PHYS.PHYS.PHYS-ATM-PH]Physics [physics]/Physics [physics]/Atomic and Molecular Clusters [physics.atm-clus], Analytical chemistry, High resolution, Natural abundance, Depolarization, General Chemistry, 010402 general chemistry, Polarization (waves), 01 natural sciences, 0104 chemical sciences, Magnetic field, Atomic resolution, Chemical physics, ddc:540, Spinning, ComputingMilieux_MISCELLANEOUS
Abstract: The mixed trityl-TEMPO biradical TEMTriPol-1 provides excellent MAS NMR sensitivity with DNP while avoiding nuclear depolarization., Dynamic nuclear polarization (DNP) has the potential to enhance the sensitivity of magic-angle spinning (MAS) NMR by many orders of magnitude and therefore to revolutionize atomic resolution structural analysis. Currently, the most widely used approach to DNP for studies of chemical, material, and biological systems involves the cross-effect (CE) mechanism, which relies on biradicals as polarizing agents. However, at high magnetic fields (≥5 T), the best biradicals used for CE MAS-DNP are still far from optimal, primarily because of the nuclear depolarization effects they induce. In the presence of bisnitroxide biradicals, magic-angle rotation results in a reverse CE that can deplete the initial proton Boltzmann polarization by more than a factor of 2. In this paper we show that these depolarization losses can be avoided by using a polarizing agent composed of a narrow-line trityl radical tethered to a broad-line TEMPO. Consequently, we show that a biocompatible trityl-nitroxide biradical, TEMTriPol-1, provides the highest MAS NMR sensitivity at ≥10 T, and its relative efficiency increases with the magnetic field strength. We use numerical simulations to explain the absence of depolarization for TEMTriPol-1 and its high efficiency, paving the way for the next generation of polarizing agents for DNP. We demonstrate the superior sensitivity enhancement using TEMTriPol-1 by recording the first solid-state 2D 13C–13C correlation spectrum at natural isotopic abundance at a magnetic field of 18.8 T.
Published: 2017
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19. Optimization of an absolute sensitivity in a glassy matrix during DNP-enhanced multidimensional solid-state NMR experiments

Author: Sabine Hediger, Anne-Laure Barra, Vincent Maurel, Hiroki Takahashi, Carlos Fernández‐de‐Alba, Serge Gambarelli, Gaël De Paëpe, Michel Bardet, Daniel Lee, Service de Chimie Inorganique et Biologique (SCIB - UMR E3), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), Centre National de la Recherche Scientifique (CNRS), Laboratoire national des champs magnétiques intenses - Grenoble (LNCMI-G), Centre National de la Recherche Scientifique (CNRS)-Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Institut National des Sciences Appliquées (INSA)-Université Toulouse III - Paul Sabatier (UT3), Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées, Université Joseph Fourier - Grenoble 1 (UJF)-Institut National des Sciences Appliquées - Toulouse (INSA Toulouse), Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Institut National des Sciences Appliquées (INSA)-Université de Toulouse (UT)-Université Toulouse III - Paul Sabatier (UT3), Université de Toulouse (UT)-Centre National de la Recherche Scientifique (CNRS), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS), and Université Fédérale Toulouse Midi-Pyrénées-Université Fédérale Toulouse Midi-Pyrénées-Centre National de la Recherche Scientifique (CNRS)
Subjects: Nuclear and High Energy Physics, 010405 organic chemistry, Chemistry, Physics::Medical Physics, Biophysics, Analytical chemistry, Electron, 010402 general chemistry, Condensed Matter Physics, Polarization (waves), 01 natural sciences, Biochemistry, Spectral line, 0104 chemical sciences, law.invention, Magnetization, Solid-state nuclear magnetic resonance, law, [CHIM]Chemical Sciences, Glass transition, Electron paramagnetic resonance, ComputingMilieux_MISCELLANEOUS, Microwave
Abstract: Thanks to instrumental and theoretical development, notably the access to high-power and high-frequency microwave sources, high-field dynamic nuclear polarization (DNP) on solid-state NMR currently appears as a promising solution to enhance nuclear magnetization in many different types of systems. In magic-angle-spinning DNP experiments, systems of interest are usually dissolved or suspended in glass-forming matrices doped with polarizing agents and measured at low temperature (down to ∼100K). In this work, we discuss the influence of sample conditions (radical concentration, sample temperature, etc.) on DNP enhancements and various nuclear relaxation times which affect the absolute sensitivity of DNP spectra, especially in multidimensional experiments. Furthermore, DNP-enhanced solid-state NMR experiments performed at 9.4 T are complemented by high-field CW EPR measurements performed at the same magnetic field. Microwave absorption by the DNP glassy matrix is observed even below the glass transition temperature caused by softening of the glass. Shortening of electron relaxation times due to glass softening and its impact in terms of DNP sensitivity is discussed.
Published: 2014
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20. Application of 7Li NMR to characterize the evolution of intercalated and non-intercalated lithium in LiFePO4-based materials for Li-ion batteries

Author: Sébastien Patoux, Guillaume Gerbaud, Sabine Hediger, Michel Bardet, Gaël De Paëpe, Carole Bourbon, and Anton Buzlukov
Subjects: Materials science, Lithium vanadium phosphate battery, Lithium iron phosphate, Inorganic chemistry, chemistry.chemical_element, Electrolyte, Condensed Matter Physics, Electrochemistry, Cathode, law.invention, chemistry.chemical_compound, Solid-state nuclear magnetic resonance, chemistry, law, General Materials Science, Lithium, Grain boundary, Electrical and Electronic Engineering
Abstract: Different synthesis batches of LiFePO4/C materials were prepared, and their electrochemical properties as positive cathodes for lithium-ion batteries were evaluated. Using standard solid-state NMR conditions, such as a 7-mm magic-angle-spinning probe performing at low spinning rates, information on both intercalated and non-intercalated (stored on the grain boundaries) lithium was obtained. A sharp signal assigned to non-intercalated lithium could be observed by diluting the active material in silica. Correlations could be, thus, obtained between the amount of each type of lithium and the electrochemical history and state of the material, revealing that the relative amount of surface lithium in a pristine LiFePO4/C material is rather constant and cannot be used as a criterion for its further specification. However, a drastic increase of this surface lithium was observed in the cathode materials of out-of-order batteries. As the cathode material recovered from the batteries after electrochemical testing was carefully washed before analysis, we can conclude that the non-intercalated lithium is strongly bound to the active material probably inside the so-called solid electrolyte interface layer at the surfaces of LiFePO4 particles. This work illustrates that solid-state lithium NMR can allow rapid characterization and testing of LiFePO4/C cathode materials.
Published: 2013
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21. Rapid Natural-Abundance 2D13C-13C Correlation Spectroscopy Using Dynamic Nuclear Polarization Enhanced Solid-State NMR and Matrix-Free Sample Preparation

Author: Lionel Dubois, Daniel Lee, Michel Bardet, Hiroki Takahashi, Sabine Hediger, Gaël De Paëpe, Service de Chimie Inorganique et Biologique (SCIB - UMR E3), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), and Centre National de la Recherche Scientifique (CNRS)
Subjects: 010405 organic chemistry, Chemistry, Abundance (chemistry), Analytical chemistry, General Medicine, General Chemistry, Fluorine-19 NMR, Nuclear magnetic resonance spectroscopy, 010402 general chemistry, 01 natural sciences, Catalysis, 0104 chemical sciences, Matrix (chemical analysis), Solid-state nuclear magnetic resonance, [CHIM]Chemical Sciences, Sample preparation, Polarization (electrochemistry), Two-dimensional nuclear magnetic resonance spectroscopy, ComputingMilieux_MISCELLANEOUS
Abstract: International audience
Published: 2012
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22. Dynamics property recovery of archaeological-wood fibers treated with polyethylene glycol demonstrated by high-resolution solid-state NMR

Author: Mathilde Giffard, Guillaume Gerbaud, Châu Doan, Sabine Hediger, Michel Bardet, Gaël De Paëpe, and Quôc-Khôi Trân
Subjects: chemistry.chemical_classification, Materials science, Polymers and Plastics, technology, industry, and agriculture, Polymer, Polyethylene glycol, Carbon-13 NMR, Archaeology, NMR spectra database, chemistry.chemical_compound, Molecular dynamics, Solid-state nuclear magnetic resonance, chemistry, PEG ratio, Cellulose
Abstract: We used high-resolution Solid-State 13C NMR to better understand and optimize the conservation process of archaeological waterlogged woods by polyethylene glycol (PEG) impregnation via the study of the molecular interactions between PEG and residual celluloses. By both deconvoluting NMR spectra and analyzing the behavior of 13C magnetization build-up under proton to carbon cross-polarization conditions, we were able to quantify PEG penetration and extract parameters sensitive to molecular dynamics such as proton spin lattice-relaxation-time constants in the rotating frame T1ρH and the cross-relaxation time constant TCH. By exploring a large range of PEG concentrations for the impregnating solutions we show that the PEG penetrates inside the fibers and interacts at a molecular level with the cellulose fibrils thus restoring the dynamics properties of the damaged molecular cell wall network. At high PEG concentration, the polymer accumulates in the remaining free volume with more and looser molecular interactions with the residual wood components. This feature explains the facility for these hydroscopic materials to exude from the wood and led to deleterious consequences for the restored artefacts.
Published: 2012
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23. Dynamics Characterization of Fully Hydrated Bacterial Cell Walls by Solid-State NMR: Evidence for Cooperative Binding of Metal Ions

Author: Thomas Kern, Bernard Joris, Nhat Khai Bui, Jean-Pierre Simorre, Sabine Hediger, Waldemar Vollmer, Mathilde Giffard, Catherine M. Bougault, Ana Maria Amoroso, and Cécile Giustini
Subjects: Staphylococcus aureus, Peptidoglycan, Biochemistry, Catalysis, Bacterial cell structure, Divalent, Cell wall, 03 medical and health sciences, chemistry.chemical_compound, Colloid and Surface Chemistry, Cell Wall, Escherichia coli, Magnesium, Nuclear Magnetic Resonance, Biomolecular, 030304 developmental biology, Ions, chemistry.chemical_classification, Manganese, 0303 health sciences, Teichoic acid, Binding Sites, Molecular Structure, 030306 microbiology, Water, Cooperative binding, General Chemistry, Nuclear magnetic resonance spectroscopy, Teichoic Acids, Solid-state nuclear magnetic resonance, chemistry, Biophysics, Thermodynamics, Bacillus subtilis
Abstract: The bacterial cell wall maintains a cell's integrity while allowing growth and division. It is made up of peptidoglycan (PG), a biopolymer forming a multigigadalton bag-like structure, and, additionally in gram-positive bacteria, of covalently linked anionic polymers collectively called teichoic acids. These anionic polymers are thought to play important roles in host-cell adhesion, inflammation, and immune activation. In this Article, we compare the flexibility and the organization of peptidoglycans from gram-negative bacteria (E. coli) with its counterpart from different gram-positive bacteria using solid-state nuclear magnetic resonance spectroscopy (NMR) under magic-angle sample spinning (MAS). The NMR fingerprints suggest an identical local conformation of the PG in all of these bacterial species. Dynamics in the peptidoglycan network decreases from E. coli to B. subtilis and from B. subtilis to S. aureus and correlates mainly with the degree of peptide cross-linkage. For intact bacterial cells and isolated cell walls, we show that (31)P solid-state NMR is particularly well adapted to characterize and differentiate wall teichoic acids of different species. We have further observed complexation with divalent ions, highlighting an important structural aspect of gram-positive cell wall architecture. We propose a new model for the interaction of divalent cations with both wall teichoic acids and carbonyl groups of peptidoglycan.
Published: 2010
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24. Investigation with 13C NMR, EPR and magnetic susceptibility measurements of char residues obtained by pyrolysis of biomass

Author: Sabine Hediger, Andrée Gadelle, Guillaume Gerbaud, Marie Françoise Foray, Michel Bardet, Jean Francois Jacquot, and Serge Gambarelli
Subjects: Chemistry, General Chemical Engineering, Organic Chemistry, Inorganic chemistry, Analytical chemistry, Energy Engineering and Power Technology, Biomass, Thermal treatment, Carbon-13 NMR, Magnetic susceptibility, law.invention, NMR spectra database, Fuel Technology, law, Char, Electron paramagnetic resonance, Pyrolysis
Abstract: Biomass pyrolysis for the production of fuels and chemicals is certainly one of the most promising strategies to replace petro-chemical polymers. Generally the biomass is first pyrolysed using temperature up to 700 °C to obtained vapors that are further cracked using catalysts. The catalyst can be poisoned by tars that are formed during the pyrolysis step and that are entrained with the vapor. In order to understand and model the behaviour of the biomass during such a process, a complete structural study of the chars was performed with high-resolution solid-state 13C, EPR, and susceptibility measurements. The origin of biomass does not affect the nature of the solid residues that are formed during the thermal treatment. They all loose their ligno-cellulosic structure and are transformed to polycyclic material with a preponderance of aromatic structures with proton amounts that decrease drastically as the temperature of treatment increases. The presence of unpaired electrons is undoubtedly indicated with EPR spectroscopy. Most of metallic compounds found in the solid residues are easily removed by a mild acidic treatment. It indicates that they are not intercalated inside the polycyclic plans. The occurrence of ferri/ferromagnetic parts has been clearly shown. Their origin is probably exogenous. The study has revealed some non-classical and unexpected features of the NMR spectra that are presented and discussed in relation to the structural properties of the pyrolysed biomass.
Published: 2007
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25. Nuclear depolarization and absolute sensitivity in magic-angle spinning cross effect dynamic nuclear polarization

Author: Daniel Lee, Akiva Feintuch, Sabine Hediger, Subhradip Paul, Gaël De Paëpe, Frederic Mentink-Vigier, Shimon Vega, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Weizmann Institute of Science [Rehovot, Israël], ANR-11-LABX-0003,ARCANE,Grenoble, une chimie bio-motivée(2011), ANR-12-BS08-0016,CryoMAS4DNP,Polarisation dynamique nucléaire en rotation à l'angle magique à très basse température et à haut champ magnétique(2012), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: [PHYS]Physics [physics], Nitroxide mediated radical polymerization, C-13-C-13 Correlation Spectroscopy, Enhanced NMR, Chemistry, General Physics and Astronomy, Depolarization, Observable, Polarization (waves), Solid-state NMR, Rotating Solids, Nuclear magnetic resonance, Solid-state nuclear magnetic resonance, Magic angle spinning, Physical and Theoretical Chemistry, Atomic physics, C-13 NMR, Spinning, Microwave
Abstract: International audience; Over the last two decades solid state Nuclear Magnetic Resonance has witnessed a breakthrough in increasing the nuclear polarization, and thus experimental sensitivity, with the advent of Magic Angle Spinning Dynamic Nuclear Polarization (MAS-DNP). To enhance the nuclear polarization of protons, exogenous nitroxide biradicals such as TOTAPOL or AMUPOL are routinely used. Their efficiency is usually assessed as the ratio between the NMR signal intensity in the presence and the absence of microwave irradiation epsilon(on/off). While TOTAPOL delivers an enhancement epsilon(on/off) of about 60 on a model sample, the more recent AMUPOL is more efficient: >200 at 100 K. Such a comparison is valid as long as the signal measured in the absence of microwaves is merely the Boltzmann polarization and is not affected by the spinning of the sample. However, recent MAS-DNP studies at 25 K by Thurber and Tycko (2014) have demonstrated that the presence of nitroxide biradicals combined with sample spinning can lead to a depolarized nuclear state, below the Boltzmann polarization. In this work we demonstrate that TOTAPOL and AMUPOL both lead to observable depolarization at approximate to 110 K, and that the magnitude of this depolarization is radical dependent. Compared to the static sample, TOTAPOL and AMUPOL lead, respectively, to nuclear polarization losses of up to 20% and 60% at a 10 kHz MAS frequency, while Trityl OX63 does not depolarize at all. This experimental work is analyzed using a theoretical model that explains how the depolarization process works under MAS and gives new insights into the DNP mechanism and into the spin parameters, which are relevant for the efficiency of a biradical. In light of these results, the outstanding performance of AMUPOL must be revised and we propose a new method to assess the polarization gain for future radicals.
Published: 2015
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26. Frontispiece: Matrix-Free DNP-Enhanced NMR Spectroscopy of Liposomes Using a Lipid-Anchored Biradical

Author: Daniel Lee, Lionel Dubois, Alexandre Richard, Yves Chenavier, Sabine Hediger, Hiroki Takahashi, Gaël De Paëpe, Carlos Fernández‐de‐Alba, and Vincent Maurel
Subjects: Deuterium NMR, Liposome, Chemistry, Organic Chemistry, General Chemistry, Fluorine-19 NMR, Nuclear magnetic resonance crystallography, Nuclear magnetic resonance spectroscopy, Photochemistry, Catalysis, Matrix (chemical analysis), Membrane, Organic chemistry, Transverse relaxation-optimized spectroscopy
Published: 2015
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27. Matrix-Free DNP-Enhanced NMR Spectroscopy of Liposomes Using a Lipid-Anchored Biradical

Author: Sabine Hediger, Daniel Lee, Gaël De Paëpe, Vincent Maurel, Lionel Dubois, Yves Chenavier, Carlos Fernández‐de‐Alba, Alexandre Richard, Hiroki Takahashi, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Reconnaissance Ionique et Chimie de Coordination (RICC), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), ANR-11-LABX-0003,ARCANE,Grenoble, une chimie bio-motivée(2011), ANR-12-BS08-0016,CryoMAS4DNP,Polarisation dynamique nucléaire en rotation à l'angle magique à très basse température et à haut champ magnétique(2012), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Glycerol, Free Radicals, Propanols, Lipid Bilayers, Dynamic Nuclear-Polarization, chemical and pharmacologic phenomena, Fluorine-19 NMR, Photochemistry, C-13-C-13 Correlation, Catalysis, Solid-State NMR Spectroscopy, Cyclic N-Oxides, chemistry.chemical_compound, Abundance, Organic chemistry, Molecule, Lipid bilayer, Nuclear Magnetic Resonance, Biomolecular, Phospholipids, Spectroscopy, Dynamic Nuclear Polarization, [PHYS]Physics [physics], Liposome, Membranes, Chemistry, Dimethyl sulfoxide, Organic Chemistry, technology, industry, and agriculture, Proteins, General Chemistry, Nuclear magnetic resonance spectroscopy, NMR, Membrane, Solid-state nuclear magnetic resonance, Bilayers, Liposomes, Interdigitated Gel Phase, lipids (amino acids, peptides, and proteins), Signal Enhancement, Solid-State NMR
Abstract: International audience; Magic-angle spinning dynamic nuclear polarization (MAS-DNP) has been proven to be a powerful technique to enhance the sensitivity of solid-state NMR (SSNMR) in a wide range of systems. Here, we show that DNP can be used to polarize lipids using a lipid-anchored polarizing agent. More specifically, we introduce a C16-functionalized biradical, which allows localization of the polarizing agents in the lipid bilayer and DNP experiments to be performed in the absence of excess cryo-protectant molecules (glycerol, dimethyl sulfoxide, etc.). This constitutes another original example of the matrix-free DNP approach that we recently introduced.
Published: 2015
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28. A New Tool for NMR Crystallography: Complete C-13/N-15 Assignment of Organic Molecules at Natural Isotopic Abundance Using DNP-Enhanced Solid-State NMR

Author: Katharina Märker, Morgane Pingret, Sabine Hediger, Jean-Marie Mouesca, Didier Gasparutto, Gaël De Paëpe, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Laboratoire Lésions des Acides Nucléiques (LAN), Service de Chimie Inorganique et Biologique (SCIB - UMR E3), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS)-Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), ANR-12-BS08-0016,CryoMAS4DNP,Polarisation dynamique nucléaire en rotation à l'angle magique à très basse température et à haut champ magnétique(2012), ANR-11-LABX-0003,ARCANE,Grenoble, une chimie bio-motivée(2011), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: [PHYS]Physics [physics], 010405 organic chemistry, Chemistry, Chemical shift, Resolution (electron density), Crystal-Structure Prediction, Natural abundance, General Chemistry, Fluorine-19 NMR, Nuclear magnetic resonance crystallography, Guanosine Derivatives, 010402 general chemistry, 01 natural sciences, Biochemistry, Catalysis, 0104 chemical sciences, Crystallography, Colloid and Surface Chemistry, Solid-state nuclear magnetic resonance, Dynamic nuclear-polarization, Molecule, C-13-C-13 correlation spectroscopy, Phosphorus-31 NMR spectroscopy
Abstract: International audience; NMR crystallography of organic molecules at natural isotopic abundance (NA) strongly relies on the comparison of assigned experimental and computed NMR chemical shifts. However, a broad applicability of this approach is often hampered by the still limited H-1 resolution and/or difficulties in assigning C-13 and N-15 resonances without the use of structure-based chemical shift calculations. As shown here, such difficulties can be overcome by C-13-C-13 and for the first time N-15-C-13 correlation experiments, recorded with the help of dynamic nuclear polarization. We present the complete de novo C-13 and N-15 resonance assignment at NA of a self-assembled 2'-deoxyguanosine derivative presenting two different molecules in the asymmetric crystallographic unit cell. This de novo assignment method is exclusively based on aforementioned correlation spectra and is an important addition to the NMR crystallography approach, rendering firstly H-1 assignment straightforward, and being secondly a prerequisite for distance measurements with solid-state NMR.
Published: 2015
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29. Is solid-state NMR enhanced by dynamic nuclear polarization?

Author: Sabine Hediger, Daniel Lee, Gaël De Paëpe, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), ANR-11-LABX-0003,ARCANE,Grenoble, une chimie bio-motivée(2011), ANR-08-CEXC-0003,DNP4NanoCarac,Polarisation Dynamique Nucléaire : amélioration de la sensibilité en RMN solide haute résolution pour l'étude structurale 3D de nanotubes fonctionnalisés et autres nano-objets(2008), ANR-12-BS08-0016,CryoMAS4DNP,Polarisation dynamique nucléaire en rotation à l'angle magique à très basse température et à haut champ magnétique(2012), European Project: 228664,EC:FP7:PEOPLE,FP7-PEOPLE-2007-2-3-COFUND,EUROTALENTS(2009), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])
Subjects: Nuclear and High Energy Physics, C-13-C-13 Correlation Spectroscopy, Analytical chemistry, Natural abundance, 010402 general chemistry, 01 natural sciences, Molecular physics, Solid-state NMR, Dynamic nuclear polarization, Cross-Polarization, Magic angle spinning, MAS-NMR, Hyperpolarization (physics), Spectral resolution, Spectroscopy, Instrumentation, Metal-Organic Frameworks, [PHYS]Physics [physics], Radiation, Zeolite, 010405 organic chemistry, Chemistry, General Chemistry, Polarization (waves), Polarizing Agents, 0104 chemical sciences, Amorphous solid, Solid-state nuclear magnetic resonance, Sn-Beta
Abstract: International audience; The recent trend of high-held (similar to 5-20 T), low-temperature (similar to 100 K) ssNMR combined with dynamic nuclear polarization (DNP) under magic angle spinning (MAS) conditions is analyzed. A brief overview of the current theory of hyperpolarization for so-called MAS-DNP experiments is given, along with various reasons why the DNP-enhancement, the ratio of the NMR signal intensities obtained in the presence and absence of microwave irradiation suitable for hyperpolarization, should not be used alone to gauge the value of performing MAS-DNP experiments relative to conventional ssNMR. This is demonstrated through a dissection of the current conditions required for MAS-DNP with particular attention to resulting absolute sensitivities and spectral resolution. Consequently, sample preparation methods specifically avoiding the surplus of glass-forming solvents so as to improve the absolute sensitivity and resolution are discussed, as are samples that are intrinsically pertinent for MAS-DNP studies (high surface area, amorphous, and porous). Owing to their pertinence, examples of recent applications on these types of samples where chemically-relevant information has been obtained that would have been impossible without the sensitivity increases bestowed by MAS-DNP are also detailed. Additionally, a promising further implementation for MAS-DNP is exampled, whereby the sensitivity improvements shown for (correlation) spectroscopy of nuclei at low natural isotopic abundance, facilitate internuclear distance measurements, especially for long distances (absence of dipolar truncation). Finally, we give some speculative perspectives for MAS-DNP. (C) 2015 Elsevier Inc. All rights reserved.
Published: 2015
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30. Third Spin-Assisted Recoupling in SSNMR

Author: Subhradip Paul, Hiroki Takahashi, Sabine Hediger, and Gaël De Paëpe
Subjects: Dipole, Magnetization, Nuclear magnetic resonance, Spins, Solid-state nuclear magnetic resonance, Chemistry, Quantum mechanics, Magic angle spinning, Biomolecular structure, Magnetic dipole–dipole interaction, Spin-½
Abstract: In solid-state nuclear magnetic resonance (SSNMR) under magic-angle spinning (MAS), the dipolar interactions (that contains distance information), averaged out by sample spinning, can be reintroduced by the application of carefully designed radiofrequency pulses called dipolar recoupling sequences. In this review, we will essentially focus on a recently introduced recoupling mechanism namely third spin-assisted recoupling (TSAR) which allows exchanging magnetization between two spins (say A and B) without relying on the reintroduction of the AB dipolar coupling. Instead, it uses a second-order effect driven by a cross-term between two dipolar terms (AH and BH) where H stands for an assisting spin (typically a proton). After a theory section delineating the principles of TSAR and of its related sequences (PAR and PAIN-CP), we will discuss some practical aspects of its experimental implementation (at moderate and ultra-high spinning frequencies) and its ability to provide structurally relevant C–C, N–C, and N–N distance information. Finally, recent applications of TSAR for structure determination of biomolecules will be overviewed.
Published: 2015
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31. Pushing NMR sensitivity limits using dynamic nuclear polarization with closed-loop cryogenic helium sample spinning

Author: Sabine Hediger, Fabien Aussenac, G. De Paëpe, A. Purea, H. Takahashi, Michel Bardet, F. Engelke, Eric Bouleau, Daniel Lee, Pierre Saint-Bonnet, J.-F. Jacquot, Frederic Mentink-Vigier, Laboratoire de Calculs et Conception Cryogénique (L3C ), Service des Basses Températures (SBT ), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Cryogénie pour la Fusion (LCF ), Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Reconnaissance Ionique et Chimie de Coordination (RICC), SYstèmes Moléculaires et nanoMatériaux pour l’Energie et la Santé (SYMMES), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Bruker Biospin SA, Wissembourg, Bruker Elektronik GmbH, ANR-11-LABX-0003,ARCANE,Grenoble, une chimie bio-motivée(2011), European Project: 237646,EC:FP7:PEOPLE,FP7-PEOPLE-IEF-2008,DNP4NANOCARAC(2009), Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Laboratoire de Chimie de la Matière Condensée de Paris (site ENSCP) (LCMCP (site ENSCP)), Centre National de la Recherche Scientifique (CNRS)-Ecole Nationale Supérieure de Chimie de Paris- Chimie ParisTech-PSL (ENSCP)-Collège de France (CdF)-Université Pierre et Marie Curie - Paris 6 (UPMC), inconnu, Inconnu, Institut de biologie et chimie des protéines [Lyon] (IBCP), Université Claude Bernard Lyon 1 (UCBL), Université de Lyon-Université de Lyon-Centre National de la Recherche Scientifique (CNRS), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)-Institut de Chimie du CNRS (INC)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Diffraction, Magic angle, Analytical chemistry, chemistry.chemical_element, Lattice-Relaxation, 7. Clean energy, Biradicals, Cross-Polarization, [CHIM]Chemical Sciences, Spinning, Helium, ComputingMilieux_MISCELLANEOUS, [PHYS]Physics [physics], Temperatures, Spins, Nitroxide, General Chemistry, Polarization (waves), Computational physics, Surface, Chemistry, Efficient, chemistry, Solid-state nuclear magnetic resonance, Correlation Spectroscopy, High-Frequency, Two-dimensional nuclear magnetic resonance spectroscopy, Solid-State NMR
Abstract: The cooler the better. We report a strategy to push the limits of solid-state NMR sensitivity far beyond its current state-of-the-art., We report a strategy to push the limits of solid-state NMR sensitivity far beyond its current state-of-the-art. The approach relies on the use of dynamic nuclear polarization and demonstrates unprecedented DNP enhancement factors for experiments performed at sample temperatures much lower than 100 K, and can translate into 6 orders of magnitude of experimental time-savings. This leap-forward was made possible thanks to the employment of cryogenic helium as the gas to power magic angle sample spinning (MAS) for dynamic nuclear polarization (DNP) enhanced NMR experiments. These experimental conditions far exceed what is currently possible and allows currently reaching sample temperatures down to 30 K while conducting experiments with improved resolution (thanks to faster spinning frequencies, up to 25 kHz) and highly polarized nuclear spins. The impressive associated gains were used to hyperpolarize the surface of an industrial catalyst as well as to hyperpolarize organic nano-assemblies (self-assembling peptides in our case), for whom structures cannot be solved using diffraction techniques. Sustainable cryogenic helium sample spinning significantly enlarges the realm and possibilities of the MAS-DNP technique and is the route to transform NMR into a versatile but also sensitive atomic-level characterization tool.
Published: 2015
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32. Correlation of fast and slow chemical shift spinning sideband patterns under fast magic-angle spinning

Author: Lyndon Emsley, Sabine Hediger, and Bénédicte Elena
Subjects: Nuclear and High Energy Physics, Biophysics, Analytical chemistry, Biochemistry, Molecular physics, Omega, Magic angle spinning, Computer Simulation, Anisotropy, Nuclear Magnetic Resonance, Biomolecular, Spinning, Scaling, Carbon Isotopes, Sideband, Chemistry, scaling, Isotropy, chemical shift anisotropy, Dipeptides, Condensed Matter Physics, spinning sidebands, MAS, Solid-state nuclear magnetic resonance, Cyclosporine, solid-state NMR, Condensed Matter::Strongly Correlated Electrons
Abstract: A new two-dimensional solid-state NMR experiment, which correlates slow and fast chemical shift anisotropy sideband patterns is proposed. The experiment, dubbed ROSES, is performed under fast magic-angle spinning and leads to an isotropic spectrum in the directly detected omega(2) dimension. In the evolution dimension omega(1), the isotropic chemical shift is reduced by a factor S, and spinning sidebands are observed spaced by a scaled effective spinning speed omega(R)/S. These spinning sidebands patterns are not identical to those observed with standard slow magic-angle spinning experiments. Chemical shift anisotropy parameters can be accurately extracted with standard methods from these spinning sideband patterns. The experiment is demonstrated with carbon-13 experiments on powdered samples of a dipeptide and a cyclic undecapeptide, cyclosporin-A. (C) 2002 Elsevier Science (USA). All rights reserved.
Published: 2003
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33. Heteronuclear decoupling in NMR of Liquid Crystals using continuous phase modulation

Author: Paul Hodgkinson, Lyndon Emsley, Dimitris Sakellariou, Gaël De Paëpe, and Sabine Hediger
Subjects: Condensed Matter::Quantum Gases, Continuous phase modulation, Chemistry, Analytical chemistry, Phase (waves), General Physics and Astronomy, Pulse sequence, Molecular physics, NMR spectra database, Heteronuclear molecule, Liquid crystal, Physics::Atomic and Molecular Clusters, Physics::Atomic Physics, Physical and Theoretical Chemistry, Decoupling (electronics), Heteronuclear single quantum coherence spectroscopy
Abstract: In this Letter we present a framework for the use of continuously phase modulated radio-frequency pulses for heteronuclear decoupling in NMR of Liquid Crystals. Within this framework, we found new sets of heteronuclear decoupling sequences using numerical optimisation. These sequences and supercycles are tested experimentally on a model liquid crystal, and their performance is compared with standard heteronuclear decoupling sequences. (C) 2002 Elsevier Science B.V. All rights reserved.
Published: 2003
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34. A New NMR Method for the Study of Local Mobility in Solids and Application to Hydration of Biopolymers in Plant Cell Walls

Author: Lyndon Emsley, A. Lesage, and Sabine Hediger
Subjects: Polymers and Plastics, Proton, Hydrogen bond, Organic Chemistry, Isotropy, J-coupling, Inorganic Chemistry, chemistry.chemical_compound, Nuclear magnetic resonance, chemistry, Chemical physics, Materials Chemistry, Bound water, Molecule, Microfibril, Cellulose
Abstract: A new solid-state NMR experiment, J-WISE, is presented for studying local mobility in solids with atomic resolution. The experiment correlates the wide-line proton spectrum with the isotropic chemical shift of carbon-13 via the J coupling between both nuclei. The wide-line proton dimension contains information about the relative mobility of the directly bonded protons. The through-bond correlation to the isotropic chemical shift via J-coupling ensures a very selective detection of molecular motion. This experiment is notably particularly useful to distinguish between bonded and nonbonded interactions such as those involved in hydration or hydrogen bonding. This experiment is first demonstrated experimentally on the model system L-alanine. Finally, it is applied to onion cell wall material in order to localize water in the cell wall architecture. By comparison with complementary dipolar WISE spectra, we were able to attribute unambiguously some of the signal intensity in the latter experiments to bound water molecules, which must be intimately mixed with polysaccharide chains of the primary plant cell wall. A semi quantitative estimation of the hydrated cellulose part allowed us to discount oversimplified models of the structure of cellulose microfibrils in primary plant cell walls, which locate the hydrated cellulose only at the surface of the microfibril. The possibility to use faster sample spinning speeds for WISE-type experiments is demonstrated.
Published: 2002
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35. Ultra-Low Temperature Nuclear Magnetic Resonance

Author: Eric Bouleau, Sabine Hediger, Pierre Saint-Bonnet, Gaël De Paëpe, and Daniel Lee
Subjects: Free induction decay, Cryostat, Nuclear magnetic resonance, Materials science, Solid-state nuclear magnetic resonance, Spin echo, Nuclear magnetic resonance spectroscopy, Atmospheric temperature range, Ferromagnetic resonance, Nuclear magnetic resonance decoupling
Abstract: Because NMR spectroscopy requests more sensitivity and more resolution, high-frequency and high-power microwave irradiation of electron spins in a magnetic field, Dynamic Nuclear Polarization (DNP) is becoming a common partner for fast sample spinning NMR experiments. Currently, this technics is performed at minimum sample temperatures ~100 K, using cold nitrogen gas to pneumatically spin and cool the sample. The desire is to improve NMR by providing ultra-low temperatures, using cryogenic helium gas. It is shown that stable and fast spinning can be attained for sample temperatures down to 30 K using a cryostat developed in our laboratory. Using this cryostat to cool a closed-loop of helium gas results in spinning frequencies that can greatly surpass those achievable with nitrogen gas. It results in substantial sensitivity enhancements (~ 600) and according experimental time-savings by 2 to 4 orders of magnitude. Therefore, access to this temperature range is demonstrated to be both viable and highly pertinent.
Published: 2017
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36. Experimental observation of periodic quasi-equilibria in solid-state NMR

Author: Sabine Hediger, Lyndon Emsley, Dimitris Sakellariou, and Paul Hodgkinson
Subjects: Spin dynamics, Analytical chemistry, General Physics and Astronomy, Molecular physics, symbols.namesake, chemistry.chemical_compound, Solid-state nuclear magnetic resonance, Ferrocene, chemistry, Lattice (order), symbols, Magic angle spinning, Condensed Matter::Strongly Correlated Electrons, Physical and Theoretical Chemistry, Hamiltonian (quantum mechanics), Spinning
Abstract: We present the experimental observation of periodic quasi-equilibria in solid-state NMR. We observe these states in ordinary cross-polarization magic-angle spinning experiments on powder samples of ferrocene and alanine, and we compare our results with numerical simulations. The spin dynamics are explained by considering the coupling to the lattice as a coherent broadening of the eigenlevels of the Hamiltonian. (C) 1999 Elsevier Science B.V. All rights reserved.
Published: 1999
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37. Matrix-free dynamic nuclear polarization enables solid-state NMR 13C-13C correlation spectroscopy of proteins at natural isotopic abundance

Author: Sabine Hediger, Gaël De Paëpe, and Hiroki Takahashi
Subjects: Models, Molecular, Carbon Isotopes, Magnetic Resonance Spectroscopy, Chemistry, Metals and Alloys, Analytical chemistry, Proteins, Natural abundance, General Chemistry, Nuclear magnetic resonance spectroscopy, Polarization (waves), Correlation spectrum, Catalysis, Surfaces, Coatings and Films, Electronic, Optical and Magnetic Materials, Isotopic labeling, Solid-state nuclear magnetic resonance, Isotopes of carbon, Isotope Labeling, Materials Chemistry, Ceramics and Composites, Two-dimensional nuclear magnetic resonance spectroscopy
Abstract: We introduce a general approach for dynamic nuclear polarization (DNP) enhanced solid-state NMR that overcomes the current problems in DNP experiments caused by the use of frozen solutions. Notably, we report for the first time a 2D (13)C-(13)C correlation spectrum of a protein without the use of isotopic labeling.
Published: 2013

38. ChemInform Abstract: Solid-State NMR of the Bacterial Cell Wall

Author: Sabine Hediger, Jean-Pierre Simorre, and Catherine M. Bougault
Subjects: Solid-state nuclear magnetic resonance, Chemistry, Organic chemistry, General Medicine, Bacterial cell structure
Published: 2013
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39. Solid-state NMR on bacterial cells: selective cell wall signal enhancement and resolution improvement using dynamic nuclear polarization

Author: Sabine Hediger, Jean-Pierre Simorre, Michel Bardet, Hiroki Takahashi, Isabel Ayala, Gaël De Paëpe, Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), Institut de biologie structurale (IBS - UMR 5075 ), Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), ANR-12-BS08-0016,CryoMAS4DNP,Polarisation dynamique nucléaire en rotation à l'angle magique à très basse température et à haut champ magnétique(2012), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Centre National de la Recherche Scientifique (CNRS)
Subjects: Magnetic Resonance Spectroscopy, Propanols, Cell, Bacillus subtilis, Peptidoglycan, 010402 general chemistry, 01 natural sciences, Biochemistry, Models, Biological, Catalysis, Cell wall, Cyclic N-Oxides, chemistry.chemical_compound, MESH: Cell Wall, Colloid and Surface Chemistry, Nuclear magnetic resonance, Cell Wall, medicine, chemistry.chemical_classification, [SDV.BBM.BS]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Structural Biology [q-bio.BM], biology, Bacteria, MESH: Magnetic Resonance Spectroscopy, MESH: Peptidoglycan, 010405 organic chemistry, MESH: Propanols, MESH: Models, Biological, General Chemistry, Nuclear magnetic resonance spectroscopy, Polymer, biology.organism_classification, Polarization (waves), MESH: Cyclic N-Oxides, 0104 chemical sciences, MESH: Bacteria, medicine.anatomical_structure, Solid-state nuclear magnetic resonance, chemistry
Abstract: International audience; Dynamic nuclear polarization (DNP) enhanced solid-state nuclear magnetic resonance (NMR) has recently emerged as a powerful technique for the study of material surfaces. In this study, we demonstrate its potential to investigate cell surface in intact cells. Using Bacillus subtilis bacterial cells as an example, it is shown that the polarizing agent 1-(TEMPO-4-oxy)-3-(TEMPO-4-amino)propan-2-ol (TOTAPOL) has a strong binding affinity to cell wall polymers (peptidoglycan). This particular interaction is thoroughly investigated with a systematic study on extracted cell wall materials, disrupted cells, and entire cells, which proved that TOTAPOL is mainly accumulating in the cell wall. This property is used on one hand to selectively enhance or suppress cell wall signals by controlling radical concentrations and on the other hand to improve spectral resolution by means of a difference spectrum. Comparing DNP-enhanced and conventional solid-state NMR, an absolute sensitivity ratio of 24 was obtained on the entire cell sample. This important increase in sensitivity together with the possibility of enhancing specifically cell wall signals and improving resolution really opens new avenues for the use of DNP-enhanced solid-state NMR as an on-cell investigation tool.
Published: 2013
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40. Compensated second-order recoupling: application to third spin assisted recoupling

Author: Sabine Hediger, Mathilde Giffard, Jean-Pierre Simorre, Michel Bardet, Gaël De Paëpe, Józef R. Lewandowski, and Robert G. Griffin
Subjects: Carbon Isotopes, Alanine, Nitrogen Radioisotopes, Proton, Nitrogen Isotopes, Chemistry, Phase (waves), General Physics and Astronomy, Proteins, Context (language use), Polarization (waves), Molecular physics, Article, Magnetic field, Dipole, Nuclear magnetic resonance, Heteronuclear molecule, Models, Chemical, Computer Simulation, Physical and Theoretical Chemistry, Protons, Spin (physics), Nuclear Magnetic Resonance, Biomolecular, Algorithms
Abstract: We consider the effect of phase shifts in the context of second-order recoupling techniques in solid-state NMR. Notably we highlight conditions leading to significant improvements for the Third Spin Assisted Recoupling (TSAR) mechanism and demonstrate the benefits of resulting techniques for detecting long-distance transfer in biomolecular systems. The modified pulse sequences of PAR and PAIN-CP, Phase-Shifted Proton Assisted Recoupling (AH-PS-PAR) and Phase-Shifted Proton-Assisted Insensitive Nuclei Cross Polarization (ABH-PS-PAIN-CP), still rely on cross terms between heteronuclear dipolar couplings involving assisting protons that mediate zero-quantum polarization transfer between low-γ nuclei ((13)C-(13)C, (15)N-(15)N, (15)N-(13)C polarization transfer). Using Average Hamiltonian Theory we show that phase inversion compensates off-resonance contributions and yields improved polarization transfer as well as substantial broadening of the matching conditions. PS-TSAR greatly improves on the standard TSAR based methods because it alleviates their sensitivity to precise RF settings which significantly enhances robustness of the experiments. We demonstrate these new methods on a 19.6 kDa protein (U-[(15)N, (13)C]-YajG) at high magnetic fields (up to 900 MHz (1)H frequency) and fast sample spinning (up to 65 kHz MAS frequency).
Published: 2012

41. NMR analysis of the transformation of wood constituents by torrefaction

Author: Guillaume Gerbaud, Michel Bardet, L. Le Pape, L. Bonnefois, S. Jacob, T. Melkior, Sabine Hediger, Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les nanomatériaux (LITEN), Institut National de L'Energie Solaire (INES), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS), Département Technique Conversion et Hydrogène (DTCH), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de L'Energie Solaire (INES), Service de Chimie Inorganique et Biologique (SCIB - UMR E3), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie et Biologie des Métaux (LCBM - UMR 5249), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: 020209 energy, General Chemical Engineering, Energy Engineering and Power Technology, Biomass, 02 engineering and technology, Thermal treatment, Lignocellulosic fuel, complex mixtures, Torrefaction, BIOMASS, chemistry.chemical_compound, [CHIM.ANAL]Chemical Sciences/Analytical chemistry, MAGNETIC-RESONANCE, 0202 electrical engineering, electronic engineering, information engineering, Organic chemistry, Lignin, Hemicellulose, Cellulose, C-13 NMR, SCOTS PINE, KINETICS, chemistry.chemical_classification, PYROLYSIS, THERMALLY MODIFIED WOOD, Organic Chemistry, HEAT-TREATMENT, Polymer, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Wood, SOLID-STATE NMR, GRINDABILITY, Fuel Technology, chemistry, Chemical engineering, CPMAS 13C NMR, [SPI.MECA.THER]Engineering Sciences [physics]/Mechanics [physics.med-ph]/Thermics [physics.class-ph], 0210 nano-technology, Pyrolysis
Abstract: International audience; The injection of biomass in a pressurised entrained flow reactor is challenging. Biomass preparation by torrefaction before gasification could be a suitable option to improve it. Transformation of the material induced by this treatment lead to interesting features: increased brittleness, improved fluidisation properties of the powder, hydrophobicity, higher energy content. The major biomass constituents, cellulose, hemicelluloses and lignin are variously affected by torrefaction, depending on their respective reactivity. The objective of this work is to investigate the transformation of the biomass constitutive polymers induced by this thermal treatment. For that purpose, both solid-state NMR and EPR investigations have been performed on wood samples (beech) torrefied at different temperatures ranging from 200 °C to 300 °C. The results of these investigations have been compared with data obtained on untreated wood. These characterizations have brought to light different transformations of the polymers: de-acetylation of hemicelluloses, demethoxylation of lignin, changes in the cellulose structure. Furthermore, the temperature at which depolymerisation of the different components begins to occur has been identified.
Published: 2012
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42. Study of liquid-liquid interfaces by an easily implemented localized NMR sequence

Author: Sabine Hediger, Claire Mantel, Claude Berthon, Pierre-Alain Bayle, and Michel Bardet
Subjects: Magnetic Resonance Spectroscopy, Spectrometer, Dynamic range, Chemistry, Analytical chemistry, Water, NMR tube, General Chemistry, Chemical Fractionation, Reference Standards, Spectral line, Diffusion, Kinetics, Plant Oils, General Materials Science, Diffusion (business), Pulsed field gradient, Olive Oil, Dissolution, Excitation
Abstract: To selectively extract heavy metals from solutions containing fission products, it is essential to optimize the liquid–liquid extraction processes. Such an objective requires improving the fundamental knowledge of the different mechanisms that are involved in these processes. In that respect, we propose a localized NMR sequence named LOCSY to assess the concentration profiles of different species involved in these processes. One of the goals of this sequence is to study the products as close as possible to the liquid–liquid interface with the help of a standard NMR spectrometer of chemistry labs. The one-dimensional spatial localization along the NMR tube is obtained by a discrete stepping of the frequency-selective excitation pulses under a pulsed field gradient. Specific data processing has been developed to obtain the 1D NMR spectra as a function of the vertical position in the NMR tube. The LOCSY sequence has been tested and evaluated on three different systems: (i) a cylindrical phantom inserted in the NMR tube containing 4-methylsalicylic acid solution, (ii) D2O/olive oil biphasic system, and (iii) the dissolution of solid saccharose in D2O. These examples illustrate potential applications of the LOCSY sequence, particularly the possibility to measure concentration profiles and to study phenomena such as diffusion, provided the dynamic range is compatible with NMR timescale and sensitivity. Copyright © 2010 John Wiley & Sons, Ltd.
Published: 2010
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43. ChemInform Abstract:13C High-Resolution Solid-State NMR for Structural Elucidation of Archaeological Woods

Author: Guillaume Gerbaud, L. Le Pape, Sabine Hediger, Mathilde Giffard, C. Doan, and Michel Bardet
Subjects: Solid-state nuclear magnetic resonance, Chemistry, High resolution, Nanotechnology, General Medicine
Published: 2010
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44. Spin-coated and PECVD low dielectric constant porous organosilicate films studied by 1D and 2D solid-state NMR

Author: Laurent Favennec, Olivier Gourhant, Sabine Hediger, Aziz Zenasni, Guillaume Gerbaud, Julien Beynet, Vincent Jousseaume, and Michel Bardet
Subjects: Solid-state nuclear magnetic resonance, Chemistry, Plasma-enhanced chemical vapor deposition, Analytical chemistry, General Physics and Astronomy, Deposition (phase transition), Nuclear magnetic resonance spectroscopy, Thermal treatment, Dielectric, Chemical vapor deposition, Physical and Theoretical Chemistry, Porosity
Abstract: In the research field of the sub-65 nm semiconductor industry, organosilicate SiOCH films with low dielectric constant (k2.4) need to be developed in order to improve the performance of integrated circuits [International Roadmap for Semiconductors (ITRS), San Jose, CA, 2004]. One way to produce SiOCH films of low dielectric constant is to introduce pores into the film. This is usually obtained in two steps. Firstly, co-deposition of a matrix precursor, with a sacrificial organic porogen, either by plasma enhanced chemical vapor deposition (PECVD) or spin-coating. Secondly, application of a specific thermal treatment to remove the porogen and create the porosity. This last step can be improved by adding to the thermal process a super-critical CO(2) treatment, an UV irradiation or an electronic bombardment (e-beam). In this study, the two deposition processes as well as the various treatments applied to eliminate the porogens were evaluated and compared using high-resolution solid-state NMR. For this purpose, hybrid (containing porogens) and porous films were extensively characterized on the basis of their (1)H, (13)C and (29)Si high-resolution NMR spectra. Information was obtained concerning the crosslinking of the Si skeleton. Spectral features could be correlated to the processes used. Isotropic chemical shift analyses and 2D correlation NMR experiments were used to show the existence and nature of the interactions between the matrix precursor and the organic porogen.
Published: 2009

45. 13C high-resolution solid-state NMR for structural elucidation of archaeological woods

Author: Sabine Hediger, Mathilde Giffard, L. Le Pape, C. Doan, Guillaume Gerbaud, Michel Bardet, Service de Chimie Inorganique et Biologique (SCIB - UMR E3), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie et Biologie des Métaux (LCBM - UMR 5249), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Nuclear and High Energy Physics, Materials science, Polyethylene glycol, CP/MAS NMR, [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, High resolution, 02 engineering and technology, 010402 general chemistry, ACETYLATED WOOD, 01 natural sciences, Biochemistry, Solid-state NMR, Analytical Chemistry, [SHS]Humanities and Social Sciences, chemistry.chemical_compound, SPECTROSCOPIC METHODS, CPMAS NMR, NUCLEAR-MAGNETIC-RESONANCE, Spectroscopy, ComputingMilieux_MISCELLANEOUS, Cellulose crystallinity, [PHYS]Physics [physics], [CHIM.ORGA]Chemical Sciences/Organic chemistry, Cross polarization, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, 0104 chemical sciences, MAS, CROSS POLARIZATION, Solid-state nuclear magnetic resonance, chemistry, Archaeology, BOND CARBON-CARBON, COMPLETE ASSIGNMENT, Physical chemistry, 0210 nano-technology, PLANT-CELL WALLS, CELLULOSE CRYSTALLINITY, Waterlogged wood
Abstract: International audience
Published: 2009
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46. Nuclear Magnetic Resonance and Electron Paramagnetic Resonance as Analytical Tools To Investigate Structural Features of Archaeological Leathers

Author: Michel Bardet, Nébia Boumlil, Quôc-Khôi Trân, Laurent Le Pape, Sabine Hediger, Guillaume Gerbaud, Service de Chimie Inorganique et Biologique (SCIB - UMR E3), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), Laboratoire de Chimie et Biologie des Métaux (LCBM - UMR 5249), Institut de Chimie du CNRS (INC)-Centre National de la Recherche Scientifique (CNRS)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA), 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), ARC-Nucleart CEA Grenoble (NUCLEART), Laboratoire d'Innovation pour les Technologies des Energies Nouvelles et les nanomatériaux (LITEN), Institut National de L'Energie Solaire (INES), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Institut National de L'Energie Solaire (INES), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-Centre National de la Recherche Scientifique (CNRS)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Savoie Mont Blanc (USMB [Université de Savoie] [Université de Chambéry])-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: DYNAMICS, [SHS.ARCHEO]Humanities and Social Sciences/Archaeology and Prehistory, Iron oxide, Solid-state, High resolution, PROTEIN, 02 engineering and technology, 010402 general chemistry, 01 natural sciences, Analytical Chemistry, law.invention, chemistry.chemical_compound, Nuclear magnetic resonance, law, Water environment, [SDV.BBM.BC]Life Sciences [q-bio]/Biochemistry, Molecular Biology/Biochemistry [q-bio.BM], Electron paramagnetic resonance, C-13 NMR, [PHYS]Physics [physics], SPECTROSCOPY, [CHIM.MATE]Chemical Sciences/Material chemistry, 021001 nanoscience & nanotechnology, Archaeology, COLLAGEN, 0104 chemical sciences, SOLID-STATE NMR, CONFORMATION, NMR spectra database, Solid-state nuclear magnetic resonance, chemistry, Trace analysis, EPR, POLYMERS, 0210 nano-technology
Abstract: International audience; Archaeological waterlogged leathers dated from the 13th to 17th century have been analyzed using carbon-13 high-resolution solid-state nuclear magnetic resonance (NMR) and electron paramagnetic resonance (EPR). The NMR and EPR spectra have been compared to modern vegetable-tanned leathers and crude hide. Both techniques allowed us to fully characterize the samples and better understand the changes occurring during aging in water environment. The main features of the archaeological leathers are the high contents in iron and the absence of residual vegetable tannins. Traces of lubricants could not be detected either. The accumulation of iron oxides may have played a role in the conservation of the archaeological objects and explain the surprising good conservation state of the leather samples as was observed in the NMR spectra. The absence of tannins and lubricants in the studied archaeological samples is also discussed. It may be a consequence of aging in water-rich environment. The analysis strategy described in this paper can be systematically applied to characterize archaeological or historical leather samples.
Published: 2009
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47. Synthesis and solid-state NMR study of chromium complexes of per(3,6-anhydro)-α-cyclodextrin based polymers

Author: Andrée Gadelle, Guillaume Gerbaud, Michel Bardet, Sabine Hediger, Service de Chimie Inorganique et Biologique (SCIB - UMR E3), Institut Nanosciences et Cryogénie (INAC), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Centre National de la Recherche Scientifique (CNRS), 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), Centre National de la Recherche Scientifique (CNRS)-Université Claude Bernard Lyon 1 (UCBL), and Université de Lyon-Université de Lyon-École normale supérieure - Lyon (ENS Lyon)-Institut de Chimie du CNRS (INC)
Subjects: chemistry.chemical_classification, Polymers and Plastics, Cyclodextrin, Organic Chemistry, chemistry.chemical_element, 02 engineering and technology, Polymer, 010402 general chemistry, 021001 nanoscience & nanotechnology, 01 natural sciences, 0104 chemical sciences, [CHIM.THEO]Chemical Sciences/Theoretical and/or physical chemistry, Molecular dynamics, Chromium, chemistry, Solid-state nuclear magnetic resonance, Computational chemistry, Sequestrant, Materials Chemistry, Moiety, Organic chemistry, Chelation, 0210 nano-technology
Abstract: International audience; This work presents the synthesis strategy, the structural characterization and the molecular dynamic properties of decontaminant polymers based on modified cyclodextrins. The polymers were made of per(3,6-anhydro)-α-cyclodextrin with either 2,4-diisocyanatotolylene, 1,4-diisocynatophenylene, 1,6-diisocyanatohexane or 1,12-diisocyanatododecane to bridge the modified cyclodextrin moiety. On the starting polymers and their metal complexes, the structural studies were carried out using classical 1D and 2D solid-state NMR experiments such as 2D WISE, along with the measurements of the time constants TCH, T1ρH and T1C. Information obtained on the changes in mobility of these different starting polymers gives insights into their ability to extract dichromate. The molecular sites of interactions between the oxoanions and the polymers could be also determined from these experiments and appear to be dependant upon the nature of the cross-linking agents.
Published: 2008
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48. Toward the characterization of peptidoglycan structure and protein-peptidoglycan interactions by solid-state NMR spectroscopy

Author: Bernard Joris, Sabine Hediger, Jean-Pierre Simorre, Patrick Müller, Cécile Giustini, Catherine M. Bougault, Thomas Kern, and Waldemar Vollmer
Subjects: Peptidoglycan metabolism, Carbon Isotopes, Magnetic Resonance Spectroscopy, Nitrogen Isotopes, Stereochemistry, Proteins, General Chemistry, Nuclear magnetic resonance spectroscopy, Peptidoglycan, medicine.disease_cause, Biochemistry, Catalysis, Characterization (materials science), carbohydrates (lipids), NMR spectra database, chemistry.chemical_compound, Colloid and Surface Chemistry, Solid-state nuclear magnetic resonance, chemistry, medicine, Escherichia coli, Spectroscopy
Abstract: Solid-state NMR spectroscopy is applied to intact peptidoglycan sacculi of the Gram-negative bacterium Escherichia coli. High-quality solid-state NMR spectra allow atom-resolved investigation of the peptidoglycan structure and dynamics as well as the study of protein-peptidoglycan interactions.
Published: 2008

49. Well-Defined Surface Tungstenocarbyne Complexes through the Reaction of [W(⋮C t Bu)(CH 2 t Bu) 3 ] with Silica

Author: Jean Thivolle-Cazat, Damien Alcor, Sabine Hediger, Anne Baudouin, Mathieu Chabanas, Anne Lesage, Lyndon Emsley, Christophe Coperet, Mostafa Taoufik, Jean-Marie Basset, Erwan Le Roux, 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 méditerranéen de médecine moléculaire (C3M), Université Nice Sophia Antipolis (... - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Université Côte d'Azur (UCA)-Institut National de la Santé et de la Recherche Médicale (INSERM), 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), Magnetic Resonance (RM ), Modélisation et Exploration des Matériaux (MEM), Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Direction de Recherche Fondamentale (CEA) (DRF (CEA)), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Université Grenoble Alpes [2016-2019] (UGA [2016-2019]), 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), Université Nice Sophia Antipolis (1965 - 2019) (UNS), COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-COMUE Université Côte d'Azur (2015-2019) (COMUE UCA)-Institut National de la Santé et de la Recherche Médicale (INSERM)-Université Côte d'Azur (UCA), 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), Université Grenoble Alpes [2016-2019] (UGA [2016-2019])-Institut de Recherche Interdisciplinaire de Grenoble (IRIG), and Commissariat à l'énergie atomique et aux énergies alternatives (CEA)-Commissariat à l'énergie atomique et aux énergies alternatives (CEA)
Subjects: Reaction conditions, Olefin metathesis, 010405 organic chemistry, Chemistry, Stereochemistry, Organic Chemistry, Alkane metathesis, [CHIM.CATA]Chemical Sciences/Catalysis, 010402 general chemistry, 01 natural sciences, Tautomer, 0104 chemical sciences, Catalysis, Inorganic Chemistry, chemistry.chemical_compound, Polymer chemistry, [CHIM.COOR]Chemical Sciences/Coordination chemistry, Physical and Theoretical Chemistry, Well-defined, Organometallic chemistry, ComputingMilieux_MISCELLANEOUS
Abstract: The molecular complex [W(&3bond; CtBu)(CH(2)tBu)(3)], 1, reacts with SiO2-(700) to give as major species 2a, [(&3bond; SiO)W(CtBu)(CH(2)tBu)(2)], while a bisgrafted surface species 3a, [(&3bond; SiO)(2)W-(&3bond; CtBu)(CH(2)tBu)], is obtained on SiO2-(200). As in molecular organometallic chemistry, the alkylalkylidyne tautomeric form is favored. Despite these structural features, these surface organometallic complexes are very active olefin metathesis catalysts, as reported earlier, and it is very likely that the necessary metallocarbene intermediates are generated under the reaction conditions.
Published: 2005
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50. Multi-dimensional magnetic resonance imaging in a stray magnetic field

Author: Jay H. Baltisberger, Lyndon Emsley, Sabine Hediger, 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), 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: stray field imaging MRL, Nuclear and High Energy Physics, magic-angle spinning, Field (physics), Biophysics, Magnetic resonance force microscopy, Superconducting magnet, 010402 general chemistry, 01 natural sciences, Biochemistry, 030218 nuclear medicine & medical imaging, 03 medical and health sciences, 0302 clinical medicine, Nuclear magnetic resonance, Optics, Electromagnetic Fields, Imaging, Three-Dimensional, Magic angle spinning, Image Processing, Computer-Assisted, [CHIM]Chemical Sciences, Image resolution, spatial resolution, ComputingMilieux_MISCELLANEOUS, Physics, Magnetic resonance microscopy, business.industry, Demagnetizing field, Condensed Matter Physics, inhomogeneous magnetic fields, Magnetic Resonance Imaging, 0104 chemical sciences, Magnetic field, business
Abstract: Stray field imaging has been extensively utilized in the last 10 wars to perform very high resolution imaging of samples in a single dimension using the massive field gradient present in the fringe of a superconducting magnet. By spinning the sample around the magic-angle, the stray field gradient is successively reoriented along three orthogonal directions in the sample reference frame, allowing the acquisition of a full three-dimensional Fourier image, thereby providing the possibility to perform multi-dimensional very high-resolution imaging with standard nuclear magnetic resonance spectroscopy equipment. Here, we show multi-dimensional images demonstrating the feasibility of this technique. (C) 2004 Elsevier Inc. All rights reserved.
Published: 2005
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