Issue 9, 2022

Solid-state 17O NMR study of α-d-glucose: exploring new frontiers in isotopic labeling, sensitivity enhancement, and NMR crystallography

Abstract

We report synthesis and solid-state 17O NMR characterization of α-D-glucose for which all six oxygen atoms are site-specifically 17O-labeled. Solid-state 17O NMR spectra were recorded for α-D-glucose/NaCl/H2O (2/1/1) cocrystals under static and magic-angle-spinning (MAS) conditions at five moderate, high, and ultrahigh magnetic fields: 14.1, 16.4, 18.8, 21.1, and 35.2 T. Complete 17O chemical shift (CS) and quadrupolar coupling (QC) tensors were determined for each of the six oxygen-containing functional groups in α-D-glucose. Paramagnetic Cu(II) doping was found to significantly shorten the spin–lattice relaxation times for both 1H and 17O nuclei in these compounds. A combination of the paramagnetic Cu(II) doping, new CPMAS CryoProbe technology, and apodization weighted sampling led to a sensitivity boost for solid-state 17O NMR by a factor of 6–8, which made it possible to acquire high-quality 2D 17O multiple-quantum (MQ) MAS spectra for carbohydrate compounds. The unprecedented spectral resolution offered by 2D 17O MQMAS spectra permitted detection of a key structural difference for a single hydrogen bond between two types of crystallographically distinct α-D-glucose molecules. This work represents the first case where all oxygen-containing functional groups in a carbohydrate molecule are site-specifically 17O-labeled and fully characterized by solid-state 17O NMR. Gauge Including Projector Augmented Waves (GIPAW) DFT calculations were performed to aid 17O and 13C NMR signal assignments for a complex crystal structure where there are six crystallographically distinct α-D-glucose molecules in the asymmetric unit.

Graphical abstract: Solid-state 17O NMR study of α-d-glucose: exploring new frontiers in isotopic labeling, sensitivity enhancement, and NMR crystallography

Supplementary files

Article information

Article type
Edge Article
Submitted
02 Nov. 2021
Accepted
31 Dec. 2021
First published
03 Janv. 2022
This article is Open Access

All publication charges for this article have been paid for by the Royal Society of Chemistry
Creative Commons BY license

Chem. Sci., 2022,13, 2591-2603

Solid-state 17O NMR study of α-D-glucose: exploring new frontiers in isotopic labeling, sensitivity enhancement, and NMR crystallography

J. Shen, V. Terskikh, J. Struppe, A. Hassan, M. Monette, I. Hung, Z. Gan, A. Brinkmann and G. Wu, Chem. Sci., 2022, 13, 2591 DOI: 10.1039/D1SC06060K

This article is licensed under a Creative Commons Attribution 3.0 Unported Licence. You can use material from this article in other publications without requesting further permissions from the RSC, provided that the correct acknowledgement is given.

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