Premium
BIRD‐ J ‐resolved HMBC and BIRD‐high‐resolution HMBC pulse sequences for measuring heteronuclear long‐range coupling constants and proton–proton spin coupling constants in complicated spin systems
Author(s) -
Furihata Kazuo,
Tashiro Mitsuru,
Seto Haruo
Publication year - 2011
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.2702
Subject(s) - heteronuclear molecule , chemistry , coupling constant , proton , pulse sequence , protonation , range (aeronautics) , proton spin crisis , spin (aerodynamics) , pulse (music) , coupling (piping) , analytical chemistry (journal) , nuclear magnetic resonance , molecular physics , atomic physics , stereochemistry , crystallography , nuclear magnetic resonance spectroscopy , ion , physics , optics , nuclear physics , thermodynamics , organic chemistry , materials science , particle physics , composite material , metallurgy , detector
Efficient pulse sequences for measuring long‐range CH coupling constants ( J CH ) and proton‐proton spin coupling constants ( J HH ), named BIRD‐ J ‐resolved HMBC and BIRD‐high‐resolution HMBC, respectively, have been developed. In spin systems possessing a secondary methyl group positioned between protonated carbons (e.g.CH 2 CH(CH 3 )CH 2 ), the methine proton splits in a complicated fashion, resulting in difficulty in the determination of its spin coupling constants. For easy and accurate measurements of the long‐range J CH and J HH in such a spin system, the BIRD pulse [90° x (H)− 180° x (H/C)− 90° (− x )(H)] or [90° x (H)− 180° x (H/C)− 90° (− x )(H)180° x (C)] is incorporated into the J ‐resolved portion of the pulse sequence. As a result, the above secondary methyl group can be selectively decoupled, providing simplified cross‐peak patterns, which are suitable for the accurate measurements of the long‐range J CH and J HH . Copyright © 2010 John Wiley & Sons, Ltd.