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Long‐range carbon–proton couplings in strychnine
Author(s) -
Blechta Vratislav,
del RíoPortilla Federico,
Freeman Ray
Publication year - 1994
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.1260320214
Subject(s) - chemistry , strychnine , coupling constant , excitation , proton , polarization (electrochemistry) , pulse sequence , hadamard transform , range (aeronautics) , analytical chemistry (journal) , nuclear magnetic resonance , matrix (chemical analysis) , coupling (piping) , molecular physics , chromatography , physics , nuclear physics , particle physics , mechanical engineering , biochemistry , materials science , quantum mechanics , engineering , composite material
Long‐range 13 C,H NMR coupling constants were measured in strychnine at 400 MHz by a method that employs selective excitation of individual 13 C sites under decoupled conditions followed by polarization transfer to protons. The sensitivity was improved by performing eight simultaneous soft‐pulse experiments coded (±) according to a Hadamard matrix and later separated by reference to the same matrix. The antiphase 13 C,H splittings were measured by J ‐doubling performed in the frequency domain.