A5003029312- Advanced NMR Techniques and Applications
- Solid-state spectroscopy and crystallography
- Atomic and Subatomic Physics Research
- NMR spectroscopy and applications
- X-ray Diffraction in Crystallography
- Crystallization and Solubility Studies
- Electron Spin Resonance Studies
- Molecular spectroscopy and chirality
- Advanced MRI Techniques and Applications
- Perovskite Materials and Applications
- Muon and positron interactions and applications
- Lanthanide and Transition Metal Complexes
- Photoreceptor and optogenetics research
- Photochemistry and Electron Transfer Studies
- Quantum, superfluid, helium dynamics
- Advanced Chemical Physics Studies
- Molecular Junctions and Nanostructures
- Advanced Condensed Matter Physics
- Spectroscopy and Quantum Chemical Studies
- Chemical Reactions and Isotopes
- Solar Radiation and Photovoltaics
- Chalcogenide Semiconductor Thin Films
- Building Energy and Comfort Optimization
- Magnetism in coordination complexes
- Nuclear physics research studies
École Polytechnique Fédérale de Lausanne
2016-2024
Universitätsmedizin Göttingen
2022-2024
Max Planck Institute for Multidisciplinary Sciences
2022-2023
University of Göttingen
2022-2023
University of Padua
2013-2023
Institut de Chimie
2018-2020
Charles Humbert 8
2018-2020
University of Southampton
2013-2018
Abstract Nuclear magnetic resonance (NMR) and imaging (MRI) are supremely important techniques with numerous applications in almost all branches of science. However, until recently, NMR methodology was limited by the time constant T 1 for decay nuclear spin magnetization through contact thermal molecular environment. Long‐lived states, which correlated quantum states multiple nuclei, have constants that may exceed large factors. Here we demonstrate a long‐lived state comprising two 13 C...
Substances containing rapidly rotating methyl groups may exhibit long-lived states (LLSs) in solution, with relaxation times substantially longer than the conventional spin-lattice time T1. The become through rapid internal rotation of CH3 group, which imposes an approximate symmetry on fluctuating nuclear spin interactions. In case very low rotational barriers, a hyperpolarized LLS is populated by thermal equilibration at liquid helium temperature. Following dissolution, cross-relaxation...
TinyPol binitroxides provide significantly higher DNP enhancement factors for solid-state NMR spectroscopy at high magnetic fields than today's reference radical AMPUPol.
Solid-state nuclear magnetic resonance under magic angle spinning (MAS) enhanced with dynamic polarization (DNP) is a powerful approach to characterize many important classes of materials, allowing access previously inaccessible structural and parameters. Here, we present the first DNP MAS experiments using 0.7 mm probe, which allows us reach frequencies 65 kHz, microwave irradiation, at 100 K. At highest field available for today (21.1 T), find that polarizing agent HyTEK2 provides...
Lead halide perovskites belong to a broad class of compounds with appealing optoelectronic and photovoltaic properties.
We have induced hyperpolarized long-lived states in compounds containing 13C-bearing methyl groups by dynamic nuclear polarization (DNP) at cryogenic temperatures, followed dissolution with a warm solvent. The give rise to enhanced antiphase 13C NMR signals solution, which often persist for times much longer than the and 1H spin–lattice relaxation under same conditions. DNP-induced effects are similar quantum-rotor-induced (QRIP) but observed wider range of because they do not depend...
NMR-based crystallography approaches involving the combination of crystal structure prediction methods, ab initio calculated chemical shifts and solid-state NMR experiments are powerful methods for determination microcrystalline powders. However, currently structural information obtained from is usually included only after a set candidate structures has already been independently generated, starting single-molecule conformations. Here, we show with case ampicillin that this can lead to...
The development of magic-angle spinning dynamic nuclear polarization (MAS DNP) has allowed atomic-level characterization materials for which conventional solid-state NMR is impractical due to the lack sensitivity. rapid progress MAS DNP been largely enabled through understanding rational design concepts more efficient polarizing agents (PAs). Here, we identify a new principle so far overlooked. We find that local geometry around unpaired electron can change enhancement by an order magnitude...
Abstract The metabolism of malignant cells differs significantly from that healthy and thus, it is possible to perform metabolic imaging reveal not only the exact location a tumor, but also intratumoral areas high activity. Herein, we demonstrate feasibility tumor using signal‐enhanced 1‐ 13 C‐pyruvate‐d 3 , which rapidly enhanced via para‐hydrogen, signal amplified by several orders magnitudes in less than minute. Using as model, human melanoma xenografts injected with C‐pyruvate‐d3, show...
Abstract Nuclear magnetic resonance (NMR) is widely applied from analytics to biomedicine although it an inherently insensitive phenomenon. Overcoming sensitivity challenges key further broaden the applicability of NMR and, for example, improve medical diagnostics. Here, we present a rapid strategy enhance signals 13 C‐labelled metabolites with para ‐hydrogen in particular, C‐pyruvate, important molecule energy metabolism. We succeeded obtain average 27 % C polarization 1‐ C‐pyruvate water...
In recent years, parahydrogen-induced polarization side arm hydrogenation (PHIP-SAH) has been applied to hyperpolarize [1-13C]pyruvate and map its metabolic conversion [1-13C]lactate in cancer cells. Developing on our MINERVA pulse sequence protocol, which we have achieved 27% carbon polarization, demonstrate the hyperpolarization of [1,2-13C]pyruvate (∼7% each 13C spin) via PHIP-SAH. By altering a single parameter sequence, enables signal enhancement C1 and/or C2 with opposite phase, allows...
Nuclear spin hyperpolarization enables real-time observation of metabolism and intermolecular interactions in vivo. 1-13C-pyruvate is the leading hyperpolarized tracer currently under evaluation several clinical trials as a promising molecular imaging agent. Still, quest for simple, fast, efficient technique ongoing. Here, we describe that continuous, weak irradiation audio-frequency range 13C at 121 μT magnetic field (approximately twice Earth's field) order transfer from parahydrogen to...
Long-lived nuclear spin states have a relaxation time much longer than the longitudinal T1. extend significantly scales that may be probed with magnetic resonance, possible applications to transport and binding studies, hyperpolarised imaging. Rapidly rotating methyl groups in solution support long-lived state, consisting of population imbalance between different exchange symmetries. Here, we expand formalism for describing behaviour groups, special attention hyperpolarisation effects...
Long-lived states exist far from magnetic equivalence when the local geometry is centrosymmetric.
Low sensitivity is the primary limitation to extending nuclear magnetic resonance (NMR) techniques more advanced chemical and structural studies. Photochemically induced dynamic polarization (photo-CIDNP) an NMR hyperpolarization technique where light used excite a suitable donor-acceptor system, creating spin-correlated radical pair whose evolution drives hyperpolarization. Systems that exhibit photo-CIDNP in solids are not common, this effect has, up now, only been observed for 13C 15N...
The intrinsic low sensitivity of nuclear magnetic resonance (NMR) experiments limits their utility for structure determination materials. Dynamic polarization (DNP) under magic angle spinning (MAS) has shown tremendous potential to overcome this key limitation, enabling the acquisition highly selective and sensitive NMR spectra. However, so far, DNP methods have not been explored in context inorganic lead halide perovskites, which are a leading class semiconductor materials optoelectronic...
Signal Amplification by Reversible Exchange (SABRE) is an attractive nuclear spin hyperpolarization technique capable of huge sensitivity enhancement in magnetic resonance (NMR) detection. The condition SABRE depends on coherent mixing, which can be achieved naturally at a low field. optimum transfer field to spin-1/2 heteronuclei technically demanding, as it requires strengths weaker than the earth's for efficient mixing. In this paper, we illustrate approach achieve strong 15N high radio...
We have recently demonstrated, in the context of para-hydrogen induced polarization (PHIP), conversion hyperpolarized proton singlet order into heteronuclear magnetisation can be efficiently achieved via a new sequence named S2hM (Singlet to Magnetisation). In this paper we give detailed theoretical description, supported by an experimental illustration, S2hM. Theory and experiments on thermally polarized samples demonstrate proposed method is robust frequency offset mismatches...
Gadolinium(III) complexes have recently been demonstrated to potential as polarizing agents for high-field dynamic nuclear polarization (DNP) NMR spectroscopy. By tailoring the ligand design reduce zero-field splitting (ZFS), we demonstrate a quadratic improvement in DNP through investigation of stable, water-soluble, narrow-line Gd(III) complex, [Gd(tpatcn)], doubling magic-angle-spinning enhancement previous state-of-the-art [Gd(dota)(H2O)]− at 9.4 T and 100 K.
Abstract The typical linewidths of 1 H NMR spectra powdered organic solids at 111 kHz magic‐angle spinning (MAS) are the order a few hundred Hz. While this is remarkable in comparison to tens observed static samples, it still key limit use solid‐state NMR, especially for complex systems. Here, we demonstrate novel strategy further improve spectral resolution. We show that anti‐z‐COSY experiment can be used reduce residual line broadening solids. Results obtained with sequence 100 MAS on...
Nuclear magnetic resonance suffers from an intrinsically low sensitivity, which can be overcome by dynamic nuclear polarization (DNP). Gd(III) complexes are attractive exogenous polarizing agents for magic angle spinning (MAS) DNP due to their high chemical stability in contrast nitroxide-based radicals. However, even the state-of-the-art have so far provided relatively signal enhancements of ca. 36 comparison standard biradicals, show over 200. Here, we report a series new and that observed...
Dissolution-dynamic nuclear polarization is implemented to hyperpolarize long-lived spin states in monodeuterated methyl groups.
Identifying and characterizing systems that generate well-defined states with large electron spin polarization is of high interest for applications in molecular spintronics, high-energy physics, magnetic resonance spectroscopy. The generation on free-radical substituents tethered to pentacene derivatives has recently gained a great deal its electronics. After photoexcitation the chromophore, pentacene–radical can rapidly form spin-polarized triplet excited through enhanced intersystem...