79/81Br nuclear quadrupole resonance spectroscopic characterization of halogen bonds in supramolecular assemblies
Articolo
Data di Pubblicazione:
2018
Abstract:
Despite the applicability of solid-state NMR to study the halogen bond, the direct NMR detection of 79/81Br covalently bonded to carbon remains impractical due to extremely large spectral widths, even at ultra-high magnetic fields. In contrast, nuclear quadrupole resonance (NQR) offers comparatively sharp resonances. Here, we demonstrate the abilities of 79/81Br NQR to characterize the electronic changes in the C–Br⋯N halogen bonding motifs found in supramolecular assemblies constructed from 1,4-dibromotetrafluorobenzene and nitrogen-containing heterocycles. An increase in the bromine quadrupolar coupling constant is observed, which correlates linearly with the halogen bond distance (dBr⋯N). Notably, 79/81Br NQR is able to distinguish between two symmetry-independent halogen bonds in the same crystal structure. This approach offers a rapid and reliable indication for the occurrence of a halogen bond, with experimental times limited only by the observation of 79/81Br NQR resonances.
Tipologia CRIS:
03A-Articolo su Rivista
Keywords:
Chemistry (all), NMQ, SSNMR, Halogen bond, cweak interactions, crystal engineering
Elenco autori:
Cerreia Vioglio, P.; Szell, P.M.J.; Chierotti, M.R.; Gobetto, R.; Bryce, D.L.*
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