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Measurement of long-range heteronuclear coupling constants using the peak intensity in classical 1D HMBC spectra.
Journal article

Measurement of long-range heteronuclear coupling constants using the peak intensity in classical 1D HMBC spectra.

  • Bigler P Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, Berne, CH-3012, Switzerland.
  • Furrer J Departement für Chemie und Biochemie, Universität Bern, Freiestrasse 3, Berne, CH-3012, Switzerland.
  • 2018-01-17
Published in:
  • Magnetic resonance in chemistry : MRC. - 2018
13C
1H
HMBC
J-HMBC
NMR
cross-peak intensity
heteronuclear coupling constants
homonuclear couplings
product operator
English In this contribution, we show that the magnitude of heteronuclear long-range coupling constants can be directly extracted from the classical 1D HMBC spectra, as all multiplet lines of a cross-peak always and exclusively vanish for the condition Δ = k/n JCH . To the best of our knowledge, this feature of the classical HMBC has not yet been noticed and exploited. This condition holds true, irrespective of the magnitude and numbers of additional active and passive homonuclear n JHH' couplings. Alternatively, the n JCH value may also be evaluated by fitting the peak's intensity in the individual spectra to its simple sin(πn JCH Δ)exp(-Δ/T2eff ) dependence. Compared to the previously proposed J-HMBC sequences that also use the variation of the cross-peak's intensity for extracting the coupling constants, the classical HMBC pulse sequence is significantly more sensitive.
Language
  • English
Open access status
closed
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Persistent URL
https://sonar.ch/global/documents/215133
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