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High resolution‐HMBC (HR‐HMBC), a new method for measuring heteronuclear long‐range coupling constants
Author(s) -
Furihata Kazuo,
Tashiro Mitsuru,
Seto Haruo
Publication year - 2010
Publication title -
magnetic resonance in chemistry
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0749-1581
DOI - 10.1002/mrc.2564
Subject(s) - pulse sequence , chemistry , heteronuclear molecule , coupling constant , pulse (music) , analytical chemistry (journal) , range (aeronautics) , resolution (logic) , nuclear magnetic resonance , stereochemistry , nuclear magnetic resonance spectroscopy , chromatography , physics , optics , materials science , particle physics , artificial intelligence , detector , computer science , composite material
A useful pulse sequence for measuring long‐range CH coupling constants ( J CH ) named high resolution‐HMBC (HR‐HMBC) has been developed. In this pulse sequence, the J ‐scaling pulse [( nt 1 )/2180° (H/C) − ( nt 1 )/2] is incorporated after the spin evolution period, and then followed by an 1 H 180° pulse to reverse the magnetization of J CH couplings. As a result, splittings of the cross peaks due to the long‐range J CH are realigned with separations of nJ CH along the F 1 dimension, and thus even the small long‐range J CH values can easily be determined. The efficiency of measuring the long‐range J CH using the proposed pulse sequences has been demonstrated in application to the complicated natural product, portmicin. Copyright © 2010 John Wiley & Sons, Ltd.