Use of long-range C-H (nJ n>3) heteronuclear multiple bond connectivity in the assignment of the 13C NMR spectra of complex organic molecules
Author
dc.contributor.author
Araya Maturana, Ramiro
Author
dc.contributor.author
Delgado Castro, Tomás
Author
dc.contributor.author
Cardona,
Author
dc.contributor.author
Weiss López, Boris
Admission date
dc.date.accessioned
2018-12-20T15:09:10Z
Available date
dc.date.available
2018-12-20T15:09:10Z
Publication date
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2001
Cita de ítem
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Current Organic Chemistry, Volumen 5, Issue 3, 2018, Pages 253-263
Identifier
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13852728
Identifier
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10.2174/1385272013375634
Identifier
dc.identifier.uri
https://repositorio.uchile.cl/handle/2250/157959
Abstract
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The structural elucidation of complex organic molecules relies heavily on the application of proton detected heteronuclear NMR. Among these techniques, the HMBC NMR experiment is probably the most useful 2D NMR method. The HMBC (C-H) experiment allows the assignment of structural fragments through correlations between protons and carbons separated by more than one bond, usually two or three bonds (2JCH and 3JCH) via 1H, 13C-coupling constants. It is also possible to obtain valuable information through longer correlations, nJCH n>3, performing several HMBC experiments with different long-range delays and using a deeper threshold in the contour plot. There have been several attempts to improve the results of the HMBC experiment, mainly focused on the question of optimization of the long-range delay, Δ2. The D-HMBC, 3D-HMBC, CT-HMBC, ACCORD-HMBC, IMPEACH-MBC and CIGAR-HMBC experiments which provide much better experimental access to sample long-range couplings are briefly discussed. These