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1 H NMR and 19 F NMR chemical shifts of fluorinated retinals, Schiff bases and protonated Schiff bases
Author(s) -
Colmenares Leticia U.,
Liu Robert S. H.
Publication year - 1992
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.1260300606
Subject(s) - chemistry , chemical shift , protonation , fluorine 19 nmr , proton nmr , carbon 13 nmr , schiff base , nuclear magnetic resonance spectroscopy , carbon 13 nmr satellite , stereochemistry , organic chemistry , ion
Fluorine‐induced shifts of neighbouring protons were studied by comparing the 1 H NMR data of 20 fluorinated retinal isomers and their non‐fluorinated counterparts. Concurrent 19 F NMR data of various isomers, analysed with respect to those of the all‐ trans fluorinated isomers, showed an interactive effect between the γ‐protons and F. Successful application of the observed trends in 1 H NMR and 19 F NMR chemical shifts to retinylidene Schiff bases and protonated Schiff bases demonstrates their importance as practical aids in assigning configuration and predicting relative 1 H NMR and 19 F NMR resonances.