600 MHz NMR spectrometer

• Subject Area: Molecular Chemistry
• Term: Funded in 2023
• Project identifier: Deutsche Forschungsgemeinschaft (DFG) - Project number 520306642

CeMSA@HHU (Center for Molecular and Structural Analytics @ Heinrich-Heine-Universität) is a central analytics center and consists of two departments. The department for NMR spectroscopy owns two spectrometers (300 MHz and 600 MHz) and provides measurement services for 25 groups in biology, chemistry and pharmacy. About 200 scientists (PhD students, postdocs, ...) use the NMR department per year. Currently, the NMR department can only handle the sample volume to a limited extent. So far there are no unacceptable waiting times, but due to the limited capacity we have to reject requests from users for time-consuming special measurements. This concerns mainly (i) 1D and 2D measurements of 15N (15N-{1H}, 15N-HSQC, 15N-HMBC) and (ii) 13C-{1H}-NMR of multiple fluorinated systems. (i) Nitrogen-containing heterocycles play a major role in various research groups at HHU. Often, especially the 2D methods (15N-HSQC, 15NHMBC) are essential to prove the expected structures and to elucidate the structure of unexpected reaction products or substances isolated from nature. Such measurements are only possible in exceptional cases due to long measurement times for 15N spectra in addition to routine operations. Therefore, the procurement of a modern spectrometer with a high signal-to-noise ratio is essential to provide a good service. Our choice therefore fell on a modern 600 MHz spectrometer with nitrogen (77 K) cooled coils and preamplifiers. The use of nitrogen cooling significantly reduces electronic noise and shortens the measurement time for 15N-{1H} compared to modern conventional probe heads to 1/4 of the time, for 15N-HSQC, 15NHMBC to 1/2 of the time. Thus, it should be possible in the future to measure the urgently needed 15N NMR spectra in the interest of many of our users. (ii) A number of our users regularly work with perfluorinated alkyl side chains. This leads to complex splitting in 13C-{1H}-NMR spectra, so that signals often disappear in the noise. A modern spectrometer in combination with a nitrogen cooled probe head reduces the measurement time for 13C to about 1/9 compared to modern probe heads. In addition, we are planning to procure a probe head that can decouple 1H and 19F simultaneously. This will then provide a special solution for particularly complex systems. In recent years, we have had several requests for exotic nuclei that are outside the measuring range of the spectrometers available in Düsseldorf. Therefore, we are planning to procure a probe head with a large measuring range (31P to 103Rh). As a further option, we are planning to procure an HRMS probe head for the investigation of viscous systems. This is particularly important with regard to the GRK 2482 ModISC, in which, among other things, aggregation-induced fluorescence plays a major role.

• DFG Programme: Major Research Instrumentation
• Major Instrumentation: 600 MHz-NMR-Spektrometer
• Instrumentation Group: 1740 Hochauflösende NMR-Spektrometer
• Applicant Institution: Heinrich-Heine-Universität Düsseldorf
• Leader: Professor Dr. Thomas J. J. Müller