Spectrometer for Dynamic Nuclear Polarization-NMR

• Subject Area: Process Engineering, Technical Chemistry
• Term: Funded in 2022
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 501130677

The application is for a DNP unit (Dynamic Nuclear Polarization) and spectrometer console to expand an existing 400 MHz solid-state spectrometer to increase the signal intensity (by a factor of 10 to 40) and thus drastically shorten the measurement times of NMR solid state spectroscopy. This is used for the molecular structure elucidation of solids, such as biomaterials, catalysts and proteins. However, it is characterized by low natural sensitivity and the associated long measurement times of up to several days. The DNP unit applied for is a microwave source (gyrotron) through which a sample located in the NMR magnet is irradiated with microwaves (263 GHz), allowing unpaired electron spins in the sample to be polarized. Interactions between electrons and atomic nuclei allow the electron polarization to be transferred to the nuclei and the nuclear magnetic resonance signal is amplified by two to three orders of magnitude. By intensifying the NMR signals, DNP-NMR spectroscopy enables the structural elucidation of very complex structures with many different functional units as well as the investigation of materials that have a low concentration of natural active centers. At the Chair of Carbon Sources and Conversion, carbon-containing biopolymers (e.g. lignin), surface species on heterogeneous catalysts as well as carbon-containing starting materials (e.g. carbonization products from the recycling of plastics) and carbon-based products (e.g. graphene) are to be investigated using this analytical method. By elucidating the underlying chemical structures, new processes for the use, conversion and production of these materials can be developed and optimized. In the other working groups (utilization share > 10%), the extended analysis method for the structure elucidation of proteins and peptides, of nanocarriers and antibacterial active molecules, of metal-organic equipment compounds, carbon-supported catalysts and nanoscale carbon materials is of extraordinary interest. The proposed DNP unit with control console is to be set up with the existing 400 MHz NMR magnet in the central NMR facility RUBiospek|NMR, whereby established organizational structures as well as the spatial infrastructure can be used. The centralized use of NMR spectrometers has proven itself over the past decades and allows interested groups easy access to the equipment. Since dynamic nuclear polarization enables a drastic reduction in measurement times, it is possible with the help of the proposed DNP unit to process an additional sample volume and offer extended analysis options despite the existing full utilization of the existing solid-state NMR spectrometer.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: Spektrometer für dynamische Kernpolarisations-NMR
• Instrumentation Group: 1740 Hochauflösende NMR-Spektrometer
• Applicant Institution: Ruhr-Universität Bochum
• Leader: Professor Dr. Thomas Ernst Müller