Combining heteronuclear correlation NMR with spin-diffusion to detect relayed Cl–H–H and N–H–H proximities in molecular solids
Analysis of short-to-intermediate range intermolecular interactions offers a great way of characterizing the solid-state organization of small molecules and materials. This can be achieved by two-dimensional (2D) homo- and heteronuclear correlation NMR spectroscopy, for example, by carrying out expe...
Gespeichert in:
Veröffentlicht in: | Solid state nuclear magnetic resonance 2022-08, Vol.120, p.101808-101808, Article 101808 |
---|---|
Hauptverfasser: | , , , , , |
Format: | Artikel |
Sprache: | eng |
Schlagworte: | |
Online-Zugang: | Volltext |
Tags: |
Tag hinzufügen
Keine Tags, Fügen Sie den ersten Tag hinzu!
|
Zusammenfassung: | Analysis of short-to-intermediate range intermolecular interactions offers a great way of characterizing the solid-state organization of small molecules and materials. This can be achieved by two-dimensional (2D) homo- and heteronuclear correlation NMR spectroscopy, for example, by carrying out experiments at high magnetic fields in conjunction with fast magic-angle spinning (MAS) techniques. But, detecting 2D peaks for heteronuclear dipolar coupled spin pairs separated by greater than 3 Å is not always straightforward, particularly when low-gamma quadrupolar nuclei are involved. Here, we present a 2D correlation NMR experiment that combines the advantages of heteronuclear-multiple quantum coherence (HMQC) and proton-based spin-diffusion (SD) pulse sequences using radio-frequency-driven-recouping (RFDR) to probe inter and intramolecular 1H-X (X = 14N, 35Cl) interactions. This experiment can be used to acquire 2D 1H{X}-HMQC filtered 1H–1H correlation as well as 2D 1H-X HMQC spectra. Powder forms of dopamine·HCl and l-histidine·HCl·H2O are characterized at high fields (21.1 T and 18.8 T) with fast MAS (60 kHz) using the 2D HMQC-SD-RFDR approach. Solid-state NMR results are complemented with NMR crystallography analyses using the gauge-including projector augmented wave (GIPAW) approach. For histidine·HCl·H2O, 2D peaks associated with 14N–1H–1H and 35Cl–1H–1H distances of up to 4.4 and 3.9 Å have been detected. This is further corroborated by the observation of 2D peaks corresponding to 14N–1H–1H and 35Cl–1H–1H distances of up to 4.2 and 3.7 Å in dopamine·HCl, indicating the suitability of the HMQC-SD-RFDR experiments for detecting medium-range proximities in molecular solids.
[Display omitted]
•HMQC-SD-RFDR experiment is presented to analyze solid-state packing interactions.•Relayed 14N–1H–1H and 35Cl–1H–1H proximities are detected in dopamine·HCl.•Experiments are carried out at high fields (21.1 T and 18.8 T) with 60 kHz MAS.•NMR crystallography analysis is presented for dopamine·HCl. |
---|---|
ISSN: | 0926-2040 1527-3326 |
DOI: | 10.1016/j.ssnmr.2022.101808 |