Improving Confidence in Crystal Structure Solutions Using NMR Crystallography: The Case of β-Piroxicam

Tatton, Andrew S.; Blade, Helen; Brown, Steven P.; Hodgkinson, Paul; Hughes, Leslie P.; Lill, Sten O. Nilsson; Yates, Jonathan R.

Abstract

NMR crystallographic techniques are used to validate a structure of β-piroxicam determined from powder X-ray diffraction (PXRD) with a relatively poor R-factor. Geometry optimization of PXRD- and single-crystal XRD- derived structures results in convergence to the same energy of the structures, with minimal atomic displacements, and good agreement of gauge-included projector augmented wave (GIPAW) calculated and experimentally determined NMR 1H, 13C, and 15N chemical shifts, and 14N quadrupolar parameters. Calculations on isolated molecules combined with 2D magic-angle spinning (MAS) 1H double-quantum (DQ) and 14N–1H NMR experiments confirm the 3D packing arrangement of β-piroxicam. NMR crystallography is shown to be an effective means of validating crystal structures that might otherwise be considered sceptically on the basis of diffraction data alone.

Citation

Tatton, A. S., Blade, H., Brown, S. P., Hodgkinson, P., Hughes, L. P., Lill, S. O. N., & Yates, J. R. (2018). Improving Confidence in Crystal Structure Solutions Using NMR Crystallography: The Case of β-Piroxicam. Crystal Growth and Design, 18(6), 3339-3351. https://doi.org/10.1021/acs.cgd.8b00022

• Journal Article Type: Article
• Acceptance Date: Apr 10, 2018
• Online Publication Date: Apr 10, 2018
• Publication Date: Apr 10, 2018
• Deposit Date: Jun 28, 2018
• Publicly Available Date: Apr 10, 2019
• Journal: Crystal Growth and Design
• Print ISSN: 1528-7483
• Electronic ISSN: 1528-7505
• Publisher: American Chemical Society
• Peer Reviewed: Peer Reviewed
• Volume: 18
• Issue: 6
• Pages: 3339-3351
• DOI: https://doi.org/10.1021/acs.cgd.8b00022
• Public URL: https://durham-repository.worktribe.com/output/1323029