Explanation of coupling with two neighbouring protons. Formation of a doublet and a triplet. The n+1 rule, quartets, quintets. Part of a set of videos giving an introductory course on proton NMR, aimed at around A-level or International Baccalaureate standard. Includes dicussion of integration, chemical shift and coupling.
From:jamesmungall
Views:7182
[U. of Ottawa NMR Facility Blog] Virtual Coupling
Virtual Coupling
When the chemical shift difference between two J coupled nuclei is of the same order as the coupling constant, second order spectra are obtained. See this and this. One, often unrecognized, second order effect is virtual coupling which is often misinterpreted as first order weak coupling. In a three-spin system, virtual coupling occurs when the observed nucleus appears to be coupled to both of the other two nuclei even though it is only coupled to one of them. This arises in AA'X and ABX spin systems when X (the observed nucleus) is coupled to only one of the other two...
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08-12-2011 02:30 AM
4ii. NMR spectroscopy - Coupling
4ii. NMR spectroscopy - Coupling
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4ii. NMR spectroscopy - Coupling
Visit www.chemistry.jamesmungall.co.uk for notes on this topic. Thanks for watching! Explanation of how coupling occurs. Specific example of formation of a doublet due to coupling of 2 non-identical protons. Part of a set of videos giving an introductory course on proton NMR, aimed at around A-level or International Baccalaureate standard. Includes dicussion of integration, chemical shift and coupling.
From:jamesmungall
Views:6379...
nmrlearner
NMR educational videos
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08-01-2011 12:07 AM
Improved accuracy in measuring one-bond and two-bond 15N,13Cα coupling constants in proteins by double-inphase/antiphase (DIPAP) spectroscopy
Improved accuracy in measuring one-bond and two-bond 15N,13Cα coupling constants in proteins by double-inphase/antiphase (DIPAP) spectroscopy
Abstract An extension to HN(CO-α/β-N,Cα-J)-TROSY (Permi and Annila in J Biomol NMR 16:221â??227, 2000) is proposed that permits the simultaneous determination of the four coupling constants 1 J Nâ?²(i)Cα(i), 2 J HN(i)Cα(i), 2 J Cα(iâ??1)Nâ?²(i), and 3 J Cα(iâ??1)HN(i) in 15N,13C-labeled proteins. Contrasting the original scheme, in which two separate subspectra exhibit the 2 J CαNâ?² coupling as inphase and antiphase splitting (IPAP), we...
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Journal club
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06-10-2011 01:41 AM
[NMR paper] Sensitivity enhanced NMR spectroscopy by quenching scalar coupling mediated relaxatio
Sensitivity enhanced NMR spectroscopy by quenching scalar coupling mediated relaxation: application to the direct observation of hydrogen bonds in 13C/15N-labeled proteins.
Related Articles Sensitivity enhanced NMR spectroscopy by quenching scalar coupling mediated relaxation: application to the direct observation of hydrogen bonds in 13C/15N-labeled proteins.
J Biomol NMR. 2000 May;17(1):55-61
Authors: Liu A, Hu W, Qamar S, Majumdar A
In this paper, we demonstrate that the sensitivity of triple-resonance NMR experiments can be enhanced...
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Journal club
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11-18-2010 09:15 PM
[Question from NMRWiki Q&A forum] J-Coupling In Proton NMR
J-Coupling In Proton NMR
I'm currently a college student taking Organic Chem and I've no idea how to figure out the J-coupling for H-NMR and neither my professor/TA's/book are being helpful. Does one apply the n+1 rule first to figure the number of peaks and then apply the various couplings to each peak?
I understand that if a single H has two non-equivalent neighboring protons, you'd get a doublet of doublets instead of a triplet. But say, for example, how would I figure out the signal for the hydrogens attached to the terminal C of the double bond in 1-pentene ( the first carbon in,...
4i. NMR spectroscopy - Coupling
Linear Mode
