1. LR-HSQMBC versus LR-selHSQMBC: Enhancing the Observation of Tiny Long-Range Heteronuclear NMR Correlations.
- Author
-
Motiram-Corral K, Nolis P, Saurí J, and Parella T
- Subjects
- Magnetic Resonance Spectroscopy methods, Molecular Structure, Protons, Biological Products chemistry, Nuclear Magnetic Resonance, Biomolecular methods
- Abstract
The detection of ultra-long-range (
4 JCH and higher) heteronuclear connectivities can complement the conventional use of HMBC/HSQMBC data in structure elucidation NMR studies of proton-deficient natural products, where two-bond and three-bond correlations are usually observed. The performance of the selHSQMBC experiment with respect to its broadband HSQMBC counterpart is evaluated. Despite its frequency-selectivity nature, selHSQMBC efficiently prevents any unwanted signal phase and intensity modulations due to passive proton-proton coupling constants typically involved in HSQMBC. As a result, selHSQMBC offers a significant sensitivity enhancement and provides pure in-phase multiplets, improving the detection levels for short- and long-range cross-peaks corresponding to small heteronuclear coupling values. This is particularly relevant for experiments optimized to smalln JCH values (2-3 Hz), referred to as LR-selHSQMBC, where key cross-peaks that are not visible in the equivalent broadband LR-HSQMBC spectrum can become observable in optimum conditions.- Published
- 2020
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