Pendrill R, Sørensen OW, Widmalm G. Suppressing one-bond homonuclear 13C,13C scalar couplings in the J-HMBC NMR experiment: application to 13C site-specifically labeled oligosaccharides.
MAGNETIC RESONANCE IN CHEMISTRY : MRC 2014;
52:82-86. [PMID:
24395678 DOI:
10.1002/mrc.4038]
[Citation(s) in RCA: 4] [Impact Index Per Article: 0.4] [Reference Citation Analysis] [Abstract] [Key Words] [MESH Headings] [Track Full Text] [Subscribe] [Scholar Register] [Received: 08/26/2013] [Revised: 10/10/2013] [Accepted: 12/04/2013] [Indexed: 06/03/2023]
Abstract
Site-specific (13)C isotope labeling is a useful approach that allows for the measurement of homonuclear (13)C,(13)C coupling constants. For three site-specifically labeled oligosaccharides, it is demonstrated that using the J-HMBC experiment for measuring heteronuclear long-range coupling constants is problematical for the carbons adjacent to the spin label. By incorporating either a selective inversion pulse or a constant-time element in the pulse sequence, the interference from one-bond (13)C,(13)C scalar couplings is suppressed, allowing the coupling constants of interest to be measured without complications. Experimental spectra are compared with spectra of a nonlabeled compound as well as with simulated spectra. The work extends the use of the J-HMBC experiments to site-specifically labeled molecules, thereby increasing the number of coupling constants that can be obtained from a single preparation of a molecule.
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