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Shift reagent spectra. The automatic determination of relative bound shifts and the automatic assignment of signals in the parent spectrum. Effects of concentration, temperature and solvent on relative bound shifts
Author(s) -
ApSimon John W.,
Beierbeck Helmut,
Fruchier Alain
Publication year - 1976
Publication title -
organic magnetic resonance
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 0.483
H-Index - 72
eISSN - 1097-458X
pISSN - 0030-4921
DOI - 10.1002/mrc.1270080910
Subject(s) - reagent , chemistry , substrate (aquarium) , solvent , independence (probability theory) , molecule , analytical chemistry (journal) , spectral line , computational chemistry , chromatography , organic chemistry , mathematics , physics , astronomy , geology , oceanography , statistics
In the use of a shift reagent as an aid in the structural elucidation of organic compounds, it is shown that accurate measurements of the shift reagent and substrate concentrations are not needed to determine the relative bound shifts of the substrate and the chemical shifts of the free substrate spectrum with good precision. This is possible whenever the induced shift ratios of nuclei of a given molecule are independent of the shift reagent concentration. This independence has been verified for all the monofunctional compounds described in this paper. The effect of absolute substrate concentration, solvent, temperature and the presence of water on the relative bound shifts is studied using the eight methyl group signals of β‐amyrin. The method is demonstrated by its use for structural determinations in the ketoandrostane series.