Organic NMR crystallography: enabling progress for applications to pharmaceuticals and plant cell walls.

The application of NMR crystallography to organic molecules is exemplified by two case studies. For the tosylate salt of the active pharmaceutical ingredient, Ritlectinib, solid-state NMR spectra are presented at a H Larmor frequency of 1 GHz and a magic-angle spinning (MAS) frequency of 60 kHz. Specifically, N-H heteronuclear multiple-quantum coherence (HMQC) and H-H double-quantum (DQ) single-quantum (SQ) correlation experiments are powerful probes of hydrogen bonding interactions.

Cl- H Heteronuclear correlation magic-angle spinning nuclear magnetic resonance experiments for probing pharmaceutical salts.

Heteronuclear multiple-quantum coherence (HMQC) pulse sequences for establishing heteronuclear correlation in solid-state nuclear magnetic resonance (NMR) between Cl and H nuclei in chloride salts under fast (60 kHz) magic-angle spinning (MAS) and at high magnetic field (a H Larmor frequency of 850 MHz) are investigated. Specifically, recoupling of the Cl- H dipolar interaction using rotary resonance recoupling with phase inversion every rotor period or the symmetry-based SR4 pulse sequences are compared. In our implementation of the population transfer (PT) dipolar (D) HMQC experiment, the satellite transitions of the Cl nuclei are saturated with an off-resonance WURST sweep, at a low nutation frequency, over the second spinning sideband, whereby the WURST pulse must be of the same duration as the recoupling time.

Isolated zirconium centres captured from aqueous solution: the structure of zirconium mandelate revealed from NMR crystallography.

Zirconium tetramandelate (2-hydroxy-2-phenylacetate) has been used for selective gravimetric analysis of zirconium for over 70 years. Herein its crystal structure is reported from synchrotron powder X-ray diffraction and C solid-state NMR. The complex is a rare example of isolated zirconium cations, rather than the clusters prevalent in aqueous solutions.

Investigating discrepancies between experimental solid-state NMR and GIPAW calculation: NC-N C and OH⋯O H chemical shifts in pyridinium fumarates and their cocrystals.

An NMR crystallography analysis is presented for four solid-state structures of pyridine fumarates and their cocrystals, using crystal structures deposited in the Cambridge Crystallographic Data Centre, CCDC. Experimental one-dimensional one-pulse H and C cross-polarisation (CP) magic-angle spinning (MAS) nuclear magnetic resonance (NMR) and two-dimensional N-H heteronuclear multiple-quantum coherence MAS NMR spectra are compared with gauge-including projector augmented wave (GIPAW) calculations of the H and C chemical shifts and the N shifts that additionally depend on the quadrupolar interaction. Considering the high ppm (>10 ​ppm) H resonances, while there is good agreement (within 0.

5-amino-2-methylpyridinium hydrogen fumarate: An XRD and NMR crystallography analysis.

Single-crystal X-ray diffraction structures of the 5-amino-2-methylpyridinium hydrogen fumarate salt have been solved at 150 and 300 K (CCDC 1952142 and 1952143). A base-acid-base-acid ring is formed through pyridinium-carboxylate and amine-carboxylate hydrogen bonds that hold together chains formed from hydrogen-bonded hydrogen fumarate ions. H and C chemical shifts as well as N shifts that additionally depend on the quadrupolar interaction are determined by experimental magic angle spinning (MAS) solid-state nuclear magnetic resonance (NMR) and gauge-including projector-augmented wave (GIPAW) calculation.