Abstract: Currently, much attention is paid to improving the sensitivity of the NMR method. However, even with a very good sensitivity of the method, the interpretation of the spectra remains a priority. This problem is especially relevant for quadrupole nuclei. The successes achieved in recent decades in the NMR of quadrupole nuclei made it possible to develop NMR crystallography, a method for solving the problems of materials science and catalysis. NMR Crystallography combines state-of-the-art multinuclear Solid-State NMR with DFT computations. This method became a powerful tool for structure determination in biochemistry and in material science. As for catalysts, NMR crystallography has great potential since it could be served not only for characterization of the structure of surface sites, but also for characterization of their catalytic activity. NMR Crystallography is multistage investigation: the first step suggests verification NMR crystallography approach to the systems under study on the example of individual compounds. After that, it is possible to start the next step which consists of identifying NMR parameters of real catalysts by SSNMR experiments. In this presentation, we offer a lightweight version of the NMR crystallography approach, using as a test not the full set of all NMR parameters, but the NMR signatures of sites. This approach, consisting in the maximum similarity of experimental and theoretical spectra, will be demonstrated using vanadium and niobium catalysts as an example. Fig. 1 shows the experimental and theoretical 51V NMR spectra obtained during the preparation of vanadium catalysts on silica gel. It can be seen that at each stage there is good agreement between the spectra, although the individual NMR parameters do not prove to be so informative. For example, the use of high magnetic fields in NMR studies is increasingly leading to the characterization of systems based only on the isotropic shift value. However, theoretical calculations can not yet guarantee reliable information about the structure of the center based on the knowledge of only one parameter. Acknowledgements. Authors thank funding provided via RFBR projects No 17-03-00531 and No 17-53-150018.

Cite: Lapina O.B. , Shubin A.A. , Papulovskiy E.
Catalysts Structure Identification Using DFT-Confirmed NMR Signatures
In compilation Book of Abstracts of International Conference "Magnetic Resonance - Current State and Future Perspectives" and satellite XXI International Youth Scientific School "Actual problems of magnetic resonance and its application". 2019. – C.118.

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