A5068110288- Advanced NMR Techniques and Applications
- Atomic and Subatomic Physics Research
- Solid-state spectroscopy and crystallography
- Quantum, superfluid, helium dynamics
- Electron Spin Resonance Studies
- 3D Printing in Biomedical Research
- Hydrogels: synthesis, properties, applications
- DNA and Nucleic Acid Chemistry
- Advanced biosensing and bioanalysis techniques
- Catalysis for Biomass Conversion
- Asymmetric Hydrogenation and Catalysis
- Magnetism in coordination complexes
- Microfluidic and Capillary Electrophoresis Applications
- Catalysis and Hydrodesulfurization Studies
- NMR spectroscopy and applications
- Seaweed-derived Bioactive Compounds
- Polymer Surface Interaction Studies
- Membrane Separation Technologies
- Inorganic Fluorides and Related Compounds
- Diet, Metabolism, and Disease
- Cell Image Analysis Techniques
- Advanced Neuroimaging Techniques and Applications
- Nanomaterials for catalytic reactions
- Polysaccharides Composition and Applications
- Cyclopropane Reaction Mechanisms
RWTH Aachen University
2011-2024
DWI – Leibniz Institute for Interactive Materials
2019-2024
FH Aachen
2017-2020
Laboratoire de Chimie Moléculaire et Thioorganique
2019
University of California, Santa Barbara
2018
Signal Amplification by Reversible-Exchange (SABRE) is a method of hyperpolarizing substrates polarization transfer from para-hydrogen without hydrogenation. Here, we demonstrate that this can be applied to hyperpolarize small amounts all proteinogenic amino acids and some chosen peptides down the nanomole regime detected in single scan low-magnetic fields 0.25 mT (10 kHz proton frequency). An outstanding feature depending on chemical state used catalyst investigated acid or peptide,...
Signal amplification by reversible exchange (SABRE) is an inexpensive, fast, and even continuous hyperpolarization technique that uses para-hydrogen as source. However, current SABRE faces a number of stumbling blocks for translation to biochemical clinical settings. Difficulties include inefficient polarization in water, relatively short-lived 1H-polarization, limited substrate scope. Here we use water-soluble transfer catalyst hyperpolarize nitrogen-15 variety molecules with SABRE-SHEATH...
Abstract NMR signal amplification by reversible exchange (SABRE) has been observed for pyridine, methyl nicotinate, N ‐methylnicotinamide, and nicotinamide in D 2 O with the new catalyst [Ir(Cl)(IDEG)(COD)] (IDEG=1,3‐bis(3,4,5‐tris(diethyleneglycol)benzyl)imidazole‐2‐ylidene). During activation hyperpolarization steps, exclusively was used, resulting first fully biocompatible SABRE system. Hyperpolarized 1 H substrate signals were at 42.5 MHz upon pressurizing solution para hydrogen close to...
Abstract Rhodium nanoparticles immobilized on an acid‐free triphenylphosphonium‐based supported ionic liquid phase (Rh@SILP(Ph 3 ‐P‐NTf 2 )) enabled the selective hydrogenation and hydrodeoxygenation of aromatic ketones. The flexible molecular approach used to assemble individual catalyst components (SiO , liquid, nanoparticles) led outstanding catalytic properties. In particular, intimate contact between phosphonium is required for deoxygenation reactivity. Rh@SILP(Ph ) was active benzylic...
We report an observation of long-lived spin-singlet states in a 13C-1H spin pair zero magnetic field. In 13C-labeled formic acid, we observe lifetimes as long 37 s, about factor 3 longer than the T1 lifetime dipole polarization triplet state. contrast to common high-field experiments, observed coherence is singlet-triplet with T2 manifold. Moreover, demonstrate that heteronuclear singlet formed between 1H and 13C nucleus can exhibit respective even presence additional spins couple interest....
Fouling on filtration membranes is induced by the nonspecific interactions between membrane surface and foulants, effectively hinders their efficient use in various applications. Here, we established a facile method for coating of with dual stimuli-responsive antifouling microgel system enriched high polyzwitterion content. Different poly(sulfobetaine) (PSB) zwitterionic polymers defined molecular weights narrow dispersities were synthesized reversible addition–fragmentation chain transfer...
Advances with para-hydrogen induced polarization open up new fields of applications for portable low-field NMR. Here we report the possibility tracing drugs down to micromolar regime. We could selectively polarize nicotine quantities similar those found in one cigarette. Also less than 1 mg harmine, a drug used treatment Parkinson's disease, and morphine extracted from an opium solution were detectable after single-scan (1)H-experiments. Moreover, demonstrate enhance detect (1)H-signal...
We introduce two experiments that allow for the rapid production of hyperpolarized metabolites. More than 50%<sup>13</sup>C polarization in 50 mM concentrations is achieved. This can be translated to portable low field NMR devices.
The integrated one-pot synthesis of valuable allylamines and alkylamines from amines, formaldehyde, terminal alkynes is achieved using a single catalyst material. This multifunctional catalytic system composed silica support on which are jointly assembled ruthenium nanoparticles covalently functionalized copper N-heterocyclic carbene (NHC) complexes, introducing new generation immobilized molecularly modified surfaces. textural, structural, morphological, electronic properties the resulting...
Rational catalyst design and optimal solvent selection are key to advancing biorefining. Here, we explored the organocatalytic isomerization of d-fructose a valuable rare monosaccharide, d-allulose, as function solvent. The d-allulose competes with its d-glucose sugar degradation. In both water DMF, catalytic activity amines towards is correlated their basicity. Solvents impact selectivity significantly by altering tautomeric distribution d-fructose. Our results suggest that furanose...
Parahydrogen induced polarization (PHIP) is a hyperpolarization method for NMR signal enhancement with applications in spectroscopy and imaging. Although parahydrogen can be easily enriched up to nearly 95%, the detected on hydrogenated substrate substantially lower, where numerous loss mechanisms between start of hydrogenation reaction detection affect levels. The quality PHIP systems commonly determined by stating either degree or factor product at time detection. In this study, we present...
Enhancing NMR signals of biomacromolecules by hyperpolarization offers exciting opportunities for diagnostic applications. However, their via parahydrogen remains challenging as specific catalytic interactions are required, which difficult to tune due the large size biomolecule and its insolubility in organic solvents. Herein, we show unprecedented cancer-targeting DNA aptamer AS1411. By screening different molecular motifs an unsaturated label nucleosides oligomers, were able identify...
Hyperpolarization with parahydrogen (p-H2 ) is a fast developing field in NMR, which enables overcoming the inherent low sensitivity of this important technique. The hyperpolarization solvents, particularly water, offers wide range applications for structural investigations macromolecules and biomedical imaging. Until lately, only organic solvents could be polarized by means via coherent redistribution polarization (SABRE mechanism). In study, we investigate detail mechanism recently...
Rh nanoparticles prepared on hydrophobic molecularly modified silica act as effective catalysts for the hydrogenation of fluoroarenes to fluorocyclohexane derivatives.
A set of functionalized nanoparticles (PEGylated dendrimers, d = 2.8–11 nm) was used to probe the structural heterogeneity in Na+/K+ induced κ-carrageenan gels. The self-diffusion behavior these as observed by 1H pulsed-field gradient NMR, fluorescence recovery after photobleaching, and raster image correlation spectroscopy revealed a fast slow component, pointing toward microstructural gel network. faster could be modeled with obstruction coarse network (average mesh size <100 nm), while...
Abstract Rhodium nanoparticles immobilized on an acid‐free triphenylphosphonium‐based supported ionic liquid phase (Rh@SILP(Ph 3 ‐P‐NTf 2 )) enabled the selective hydrogenation and hydrodeoxygenation of aromatic ketones. The flexible molecular approach used to assemble individual catalyst components (SiO , liquid, nanoparticles) led outstanding catalytic properties. In particular, intimate contact between phosphonium is required for deoxygenation reactivity. Rh@SILP(Ph ) was active benzylic...
Tangential flow filtration (TFF) is a chemical unit operation used to purify and concentrate liquid suspensions of colloids, proteins, or cells. The solution flows tangentially across membrane, such that selective part the fluid permeates membrane while filtrated matter retained, increasing its concentration. TFF mild mechanical purification method does not interact chemically with filtrate. It applied in sensitive separation tasks protein chemistry, microbiology, immunology. fast...
The distinct folding accompanied by its polymorphic character renders DNA G-quadruplexes promising biomolecular building blocks to construct novel DNA-based and supramolecular assemblies. However, the highly polar nature of limits use water as a solvent. In addition, archetypical G-quadruplex fold needs be stabilized metal-cations, which is usually potassium ion. Here, we show that noncovalent PEGylation process enabled electrostatic interactions allows first metal-free in organic solvents....
Abstract Although micron‐sized microgels have become important building blocks in regenerative materials, offering decisive interactions with living matter, their chemical composition mostly significantly varies when network morphology is tuned. Since cell behavior simultaneously affected by the physical, chemical, and structural properties of gel network, variable but equivalence are interest. This work describes a new method to produce thermoresponsive defined mechanical properties,...
Abstract Although micron‐sized microgels have become important building blocks in regenerative materials, offering decisive interactions with living matter, their chemical composition mostly significantly varies when network morphology is tuned. Since cell behavior simultaneously affected by the physical, chemical, and structural properties of gel network, variable but equivalence are interest. This work describes a new method to produce thermoresponsive defined mechanical properties,...
Abstract The front cover artwork is provided by Dr. Meike Emondts, Daniel Schikowski, and Prof. Jürgen Klankermayer (RWTH Aachen University, Germany) as well Philipp Schleker (MPI CEC FZJ, Germany). image shows the hyperpolarization of HDO via new NEPTUN mechanism describing a chemical exchange/metathesis reaction between D 2 O parahydrogen. Read full text Communication at 10.1002/cphc.201800521 .
We report observation of long-lived spin-singlet states in a 13C-1H spin pair at zero magnetic field. In 13C-labeled formic acid, we observe lifetimes as long 37 seconds, about factor three longer than the T1 lifetime dipole polarization triplet state. also that singlet-triplet coherence, T2, is T1. Moreover, demonstrate this singlet formed by spins heteronucleus and 1H nucleus, can exhibit respective systems consisting more two nuclear spins. Although homonuclear have been extensively...
Abstract Enhancing NMR signals of biomacromolecules by hyperpolarization offers exciting opportunities for diagnostic applications. However, their via para hydrogen remains challenging as specific catalytic interactions are required, which difficult to tune due the large size biomolecule and its insolubility in organic solvents. Herein, we show unprecedented cancer‐targeting DNA aptamer AS1411. By screening different molecular motifs an unsaturated label nucleosides oligomers, were able...