600 MHz NMR spectrometer

点击翻译按钮获取中文摘要

A modern 600 MHz liquid NMR spectrometer with a nitrogen-cooled cryo probe head with a "normal" coil arrangement (X inside, 1H/19F outside) is proposed. The use of cryo technology improves the signal-to-noise ratio by a factor of three compared to room temperature probes. With a given amount of substance, not only can significant measurement time reductions be achieved, but more complex NMR measurement methods in the field of 2D NMR spectroscopy with significantly reduced measurement times can also be used. Due to the geometry of the probe head (internal 13C coil), this device will represent a significant gain, especially in the structural elucidation of highly substituted natural and active substances that are characterized by a high level of quaternary carbon atoms. Furthermore, polyaromatic systems, such as those used primarily in the field of materials science and which are also characterized by a large number of quaternary carbon atoms, can be characterized much better. Another method that is particularly useful in the field of biosynthesis elucidation of new natural products (here also using INADEQUATE), the metabolic degradation of active substances, as well as in the field of mechanism elucidation is based on the shifting of 13C signals by isotope labeling (e.g. 2H, 15N, 18O). Due to the high 13C sensitivity, which is achieved by the cryo probe head, not only isotope labels can be determined with exact position via 13C NMR spectra. Rather, the isotope content can also be quantified by integrating the 13C signals from labeled carbon atoms. Finally, the device opens up the possibility of direct measurement of a kinetic isotope effect, e.g. by 1H-13C polarization transfer measurements, which is complementary to the method described above.