Determining the crystal structures of peptide analogs of boronic acid in the absence of single crystals: intricate motifs of ixazomib citrate revealed by XRPD guided by ss-NMR

0499623 - FZÚ 2019 RIV US eng J - Journal Article
Hušák, M. - Jegorov, A. - Rohlíček, Jan - Fitch, A. - Czernek, Jiří - Kobera, Libor - Brus, Jiří
Determining the crystal structures of peptide analogs of boronic acid in the absence of single crystals: intricate motifs of ixazomib citrate revealed by XRPD guided by ss-NMR.
Crystal Growth & Design. Roč. 18, č. 6 (2018), s. 3616-3625. ISSN 1528-7483. E-ISSN 1528-7505
R&D Projects: GA ČR GA16-10035S; GA ČR(CZ) GA16-04109S; GA MŠMT(CZ) LO1507
Institutional support: RVO:68378271 ; RVO:61389013
Keywords : crystal structure * powder diffraction * NMR
OECD category: Condensed matter physics (including formerly solid state physics, supercond.); Polymer science (UMCH-V)
Impact factor: 4.153, year: 2018

We demonstrate successful solution of the crystal structures of two nonsolvated polymorphs of ixazomib citrate directly from synchrotron powder diffraction data, which is challenging because the two molecules in the asymmetric unit cell that exhibit 32 degrees of conformational freedom push the limits of current solution procedures. We used a novel two-step Rietveld refinement based on DFT-D restraints to improve information quality derived from powder diffraction data to be comparable with that of single crystal solutions. NMR crystallography was applied to verify the crystal structures, and the high potential value of using B-11 NMR parameters toward the solution of unknown structures was demonstrated.
Permanent Link: http://hdl.handle.net/11104/0291857