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Unsymmetrical indirect covariance processing of hyphenated and long‐range heteronuclear 2D NMR spectra ‐ Enhanced visualization of 2 J CH and 4 J CH correlation responses
Author(s) -
Martin Gary E.,
Hilton Bruce D.,
Blinov Kirill A.,
Williams Antony J.
Publication year - 2008
Publication title -
journal of heterocyclic chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.321
H-Index - 59
eISSN - 1943-5193
pISSN - 0022-152X
DOI - 10.1002/jhet.5570450426
Subject(s) - heteronuclear molecule , homonuclear molecule , chemistry , spectral line , proton , covariance , nmr spectra database , chemical shift , fourier transform , two dimensional nuclear magnetic resonance spectroscopy , carbon 13 nmr , computational chemistry , nuclear magnetic resonance spectroscopy , nuclear magnetic resonance , analytical chemistry (journal) , stereochemistry , molecule , physics , organic chemistry , statistics , mathematics , quantum mechanics , astronomy
Recent reports have demonstrated the unsymmetrical indirect covariance combination of discretely acquired 2D NMR experiments into spectra that provide an alternative means of accessing the information content of these spectra. The method can be thought of as being analogous to the Fourier transform conversion of time domain data into the more readily interpreted frequency domain. Hyphenated 2D‐NMR spectra such as GHSQC‐TOCSY, when available, provide an investigator with the means of sorting proton‐proton homonuclear connectivity networks as a function of the 13 C chemical shift of the carbon directly bound to the proton from which propagation begins. Long‐range heteronuclear chemical shift correlation experiments establish proton‐carbon correlations via heteronuclear coupling pathways, most commonly across three bonds ( 3 J CH ), but in more general terms across two ( 2 J CH ) to four bonds ( 4 J CH ). In many instances 3 J CH correlations dominate GHMBC spectra. We demonstrate in this report the improved visualization of 2 J CH and 4 J CH correlations through the unsymmetrical indirect covariance processing of GHSQC‐TOCSY and GHMBC 2D spectra.