A5087144882- Advanced NMR Techniques and Applications
- Solid-state spectroscopy and crystallography
- Atomic and Subatomic Physics Research
- NMR spectroscopy and applications
- Fullerene Chemistry and Applications
- Crystallization and Solubility Studies
- X-ray Diffraction in Crystallography
- Molecular spectroscopy and chirality
- Quantum, superfluid, helium dynamics
- Graphene research and applications
- Nuclear Physics and Applications
- Astrophysics and Star Formation Studies
- Synthesis and Properties of Aromatic Compounds
- Advanced Chemical Physics Studies
- Advanced MRI Techniques and Applications
- High-pressure geophysics and materials
- Nonlinear Optical Materials Research
- Crystallography and molecular interactions
- Molecular Junctions and Nanostructures
- Liquid Crystal Research Advancements
- Protein Structure and Dynamics
- Physics of Superconductivity and Magnetism
- Metallurgical Processes and Thermodynamics
- Fuel Cells and Related Materials
- Glass properties and applications
Karlsruhe Institute of Technology
2021-2025
University of Southampton
2013-2019
Leipzig University
2009-2012
Helmholtz-Zentrum Dresden-Rossendorf
2012
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...
The water-endofullerene H2O@C60 provides a unique chemical system in which freely rotating water molecules are confined inside homogeneous and symmetrical carbon cages. spin conversion between the ortho para species of endohedral H2O was studied solid phase by low-temperature nuclear magnetic resonance. experimental data consistent with second-order kinetics, indicating bimolecular process. Numerical simulations suggest simultaneous presence diffusion process allowing neighbouring to...
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...
Abstract Water exists in two spin isomers, ortho and para , that have different nuclear states. In bulk water, rapid proton exchange hindered molecular rotation obscure the direct observation of isomers. The supramolecular endofullerene H 2 O@C 60 provides freely rotating, isolated water molecules even at cryogenic temperatures. Here we show dielectric constant this substance depends on / ratio, changes slowly time after a sudden temperature jump, due to conversion. attribution effect –...
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...
In dissolution-dynamic nuclear polarization, spins are hyperpolarized at cryogenic temperatures using radicals and microwave irradiation. The solid is dissolved with hot solvent the solution transferred to a secondary magnet where strongly enhanced magnetic resonance signals observed. Here we present method for transferring solid. A bullet containing frozen, sample ejected pressurized helium gas, shot into receiving structure in magnet, retained polarized rapidly. transfer takes...
Water exists in two forms, para and ortho, that have nuclear spin states with different symmetries. Here we report the conversion of fullerene-encapsulated water to ortho water. The enrichment at low temperatures is monitored via changes electrical polarizability material. Upon rapid dissolution material toluene excess converts In H_{2}^{16}O@C_{60} leads a slow increase NMR signal. H_{2}^{17}O@C_{60} gives rise weak signal enhancements attributed quantum-rotor-induced polarization. time...
For initial hit identification in fragment‐based drug design, NMR is one of the preferred methods, with well‐established ligand screening experiments T1ρ, waterLOGSY and STD. Here, we present a new, perfect echo‐based experiment superior binding sensitivity, PEARLScreen. The sensitivity enhancement based on longer relaxation delays as well active exchange broadening, enabled by echo scheme. This allowed reduction protein concentration up to order magnitude comparison conventional same setup...
For initial hit identification in fragment‐based drug design, NMR is one of the preferred methods, with well‐established ligand screening experiments T1ρ, waterLOGSY and STD. Here, we present a new, perfect echo‐based experiment superior binding sensitivity, PEARLScreen. The sensitivity enhancement based on longer relaxation delays as well active exchange broadening, enabled by echo scheme. This allowed reduction protein concentration up to order magnitude comparison conventional same setup...
We report on the design and successful testing (up to 55 T) of a 60 T long-pulse (LP) magnet with pulse duration 1500?ms at Hochfeld-Magnetlabor Dresden. This has capability producing magnetic fields time homogeneity characteristics suitable host specific-heat nuclear resonance (NMR) experiments. describe development probe for this magnet, which uses quasi-adiabatic heat-pulse method enables magnetocaloric-effect measurements. Furthermore, we implementation NMR setup, consisting home-built...
Dissolution-dynamic nuclear polarization is implemented to hyperpolarize long-lived spin states in monodeuterated methyl groups.
In dissolution-dynamic nuclear polarization, a hyperpolarized solid is dissolved with jet of hot solvent. The solution then transferred to secondary magnet, where spectra can be recorded improved sensitivity. bullet-dynamic polarization this order reversed. Pressurized gas used rapidly transfer the and only upon arrival. A potential advantage approach that it may avoid excessive dilution associated signal loss, in particular for small sample quantities. Previously, we have shown liquid-state...
Hyperpolarized pyruvate is a widely used marker to track metabolism in vivo and benchmark molecule for hyperpolarization methods. Here, we show how combination of improved bullet-DNP instrumentation, an optimized sample preparation further sensitivity increase via
The many-body quantum dynamics of dipolar coupled nuclear spins $I=1/2$ on an otherwise isolated cubic lattice are studied with magnetic resonance. By increasing the signal-to-noise ratio by 2 orders magnitude compared previous reports for free induction decay (FID) $^{19}\mathrm{F}$ in ${\mathrm{CaF}}_{2}$ we obtain new insight into its long-time behavior. We confirm that tail FID is exponentially decaying cosine, but our measurements reveal a second mode comparable frequency twice...
The 17 O isotopomer of the water-endofullerene H2 O@C60 displays a remarkable proton NMR spectrum, with six well resolved peaks. These peaks are due to J-coupling between water protons and nucleus, which has spin-5/2. resolution these is enabled by suppression exchange fullerene cage. display an unusual pattern linewidths, we model Liouville-space treatment scalar relaxation quadrupolar nuclei. data consistent rotational diffusion molecules on sub-picosecond timescale.
Nuclear magnetic resonance (NMR) spectroscopy is a key method for the determination of molecular structures. Due to its intrinsically high (i.e., atomistic) resolution and versatility, it has found numerous applications investigating gases, liquids, solids. However, liquid-state NMR little application suspensions solid particles as resonances such systems are excessively broadened, typically beyond detection threshold. Herein, we propose route overcoming this critical limitation by enhancing...
A nuclear magnetic resonance apparatus for experiments in pulsed high fields is described. The field pulses created together with various magnet coils determine the requirements such an has to fulfill be operated successfully fields. Independent of chosen coil it desirable operate entire experiment at highest possible bandwidth that a correspondingly large temporal fraction pulse can used probe given sample. Our offers up 20 MHz and been tested Hochfeld-Magnetlabor Dresden, even very fast...
In dynamic nuclear polarization (DNP), radicals such as trityl provide a source for high spin polarization. Conversely, during the low-field transfer of hyperpolarized solids, radicals' dipolar or Non-Zeeman reservoir may act powerful sink. Here, we report low-temperature proton relaxation in pyruvic acid doped with trityl, fields from 5 mT to 2 T. We estimate heat capacity radical experimentally and show that recent formalism by Wenckebach yields parameter-free, yet quantitative model...
Abstract Fuel cells used for transport applications hold polymer membranes as a key element. Their efficiency can be significantly increased if structured ion channels are implemented at the molecular level into proton‐conducting membrane. New functional molecules with selective affinity ionomers needed to obtain such membrane design. This study presents method screen peptide binders perfluorinated sulfonic acid ionomers, e.g., Nafion using ultra‐high density arrays spot size of up 30 µm....
Noninvasive tracking of biochemical processes in the body is paramount diagnostic medicine. Among leading techniques spectroscopic magnetic resonance imaging (MRI), which tracks metabolites with an amplified (hyperpolarized) magnetization signal injected into subject just before scanning. Traditionally, brief enhanced period these agents limited clinical imaging. We propose a solution based on amalgamating two materials—one having diagnostic-metabolic activity and other characterized by...
It is shown that proton spins highly polarized by dynamic nuclear polarization (DNP) retain substantial upon the rapid transfer of frozen bullets from a polarizer to an NMR spectrometer. After injection in solution, resulting hyperpolarization aliphatic chains comprises population imbalances between singlet and triplet states geminal protons combinations thereof. These hyperpolarized long-lived (LLSs) can be reconverted into observable transverse magnetization polychromatic spin-lock-induced...