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Predicting the crystal structure of decitabine by powder NMR crystallography: influence of long-range molecular packing symmetry on NMR parameters
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SYSNO ASEP 0466691 Document Type J - Journal Article R&D Document Type Journal Article Subsidiary J Článek ve WOS Title Predicting the crystal structure of decitabine by powder NMR crystallography: influence of long-range molecular packing symmetry on NMR parameters Author(s) Brus, Jiří (UMCH-V) RID, ORCID
Czernek, Jiří (UMCH-V) RID
Kobera, Libor (UMCH-V) RID, ORCID
Urbanová, Martina (UMCH-V) RID, ORCID
Abbrent, Sabina (UMCH-V) RID, ORCID
Husak, M. (CZ)Source Title Crystal Growth & Design. - : American Chemical Society - ISSN 1528-7483
Roč. 16, č. 12 (2016), s. 7102-7111Number of pages 10 s. Language eng - English Country US - United States Keywords NMR crystalography ; decitabine ; drug delivery Subject RIV CD - Macromolecular Chemistry R&D Projects GA14-03636S GA ČR - Czech Science Foundation (CSF) GA16-04109S GA ČR - Czech Science Foundation (CSF) LO1507 GA MŠMT - Ministry of Education, Youth and Sports (MEYS) Institutional support UMCH-V - RVO:61389013 UT WOS 000389624200050 EID SCOPUS 85002745807 DOI 10.1021/acs.cgd.6b01341 Annotation Crystal structure determination in the absence of diffraction data still remains a challenge. In this contribution, we demonstrate a complete reconstruction of the crystal structure of decitabine exclusively from 1H and 13C solid-state NMR (ss-NMR) chemical shifts through comparison with the NMR parameters calculated for density functional theory-optimized, computer-generated crystal structure predictions. In particular, we discuss the previously unconsidered influence of long-range molecular packing symmetry on the NMR parameters and subsequent selection of the correct crystal structure. Symmetry operations considerably influenced the global molecular packing and unit cell parameters of the predicted crystal structures, while the conformations and short-range molecular arrangements were practically identical. Consequently, the NMR parameters calculated for NMR-consistent candidates were similar and barely distinguishable by the standard deviations of the experimental and calculated 1H and 13C chemical shifts. Therefore, to further refine the crystal structure selection, we simulated and analyzed the entire two-dimensional (2D) 1H–13C HETCOR and 1H–1H double-quantum/single-quantum NMR correlation spectra. By determining the covariance, which provides a quantitative measure of the differences between the experimental and calculated resonance frequencies of the correlation signals, the set of NMR-consistent candidates was additionally narrowed down, and the correct crystal structure was finally unambiguously identified. By applying the extended protocol including the comparative analysis of 2D ss-NMR correlation spectra, powder NMR crystallography can thus be used to describe the crystal structures differing in the long-range symmetry of molecular packing for which ss-NMR spectroscopy is otherwise less sensitive. Workplace Institute of Macromolecular Chemistry Contact Eva Čechová, cechova@imc.cas.cz ; Tel.: 296 809 358 Year of Publishing 2017
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