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Simplifying LR‐HSQC spectra using a triple‐quantum filter: The LR‐HTQC experiment
Author(s) -
Bigler Peter,
Furrer Julien
Publication year - 2021
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.5078
Subject(s) - heteronuclear single quantum coherence spectroscopy , heteronuclear molecule , chemistry , spectral line , range (aeronautics) , intensity (physics) , correlation , two dimensional nuclear magnetic resonance spectroscopy , molecular physics , nuclear magnetic resonance , atomic physics , computational physics , physics , optics , quantum mechanics , nuclear magnetic resonance spectroscopy , mathematics , stereochemistry , materials science , geometry , composite material
Long‐range heteronuclear single quantum correlation (LR‐HSQC) experiments may be applied for detecting long‐range correlations but suffer from two disadvantages, common to all heteronuclear long‐range correlation experiments: (i) The information density in LR‐HSQC spectra may be too high to be used directly without “filtering out” shorter range correlations, and (ii) often, substantial differences in intensity among cross peaks exist, potentially hampering the visualization of weak, often crucial cross peaks. In this contribution, we propose a modified LR‐HSQC experiment, the LR‐HTQC experiment ( L ong‐ R ange H eteronuclear T riple Q uantum C orrelation) that partially solves the problems aforementioned. We show theoretically and experimentally that the LR‐HTQC experiment removes the intense cross peaks of CH spin pairs, substantially reduces the medium intensity of cross peaks originating from CHH' spin systems, whereas the typically weak intensity of cross peaks of CHH'H″ and C(H) n , n > 3 spin systems is less affected. Consequently, the LR‐HTQC experiment affords simplified long‐range heteronuclear shift correlation spectra and scales down large intensity differences among different types of cross peaks, although a certain general reduction of signal intensities has to be accepted.