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PSYCHE CPMG–HSQMBC: An NMR Spectroscopic Method for Precise and Simple Measurement of Long‐Range Heteronuclear Coupling Constants
Author(s) -
Timári István,
Szilágyi László,
Kövér Katalin E.
Publication year - 2015
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.201502641
Subject(s) - heteronuclear molecule , homonuclear molecule , pulse sequence , coupling constant , chemistry , nuclear magnetic resonance , j coupling , psyche , proton , physics , analytical chemistry (journal) , molecular physics , nuclear magnetic resonance spectroscopy , molecule , philosophy , organic chemistry , quantum mechanics , epistemology
Among the NMR spectroscopic parameters, long‐range heteronuclear coupling constants convey invaluable information on torsion angles relevant to glycosidic linkages of carbohydrates. A broadband homonuclear decoupled PSYCHE CPMG–HSQMBC method for the precise and direct measurement of multiple‐bond heteronuclear couplings is presented. The PSYCHE scheme built into the pulse sequence efficiently eliminates unwanted proton–proton splittings from the heteronuclear multiplets so that the desired heteronuclear couplings can be determined simply by measuring frequency differences between peak maxima of pure antiphase doublets. Moreover, PSYCHE CPMG–HSQMBC can provide significant improvement in sensitivity as compared to an earlier Zangger–Sterk‐based method. Applications of the proposed pulse sequence are demonstrated for the extraction of n J ( 1 H, 77 Se) and n J ( 1 H, 13 C) values, respectively, in carbohydrates; further extensions can be envisioned in any J ‐based structural and conformational studies.