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The NMR spectra of some iodo‐ and bromo‐fluorobenzenes. A novel solvent effect on ortho fluorine‐fluorine couplings
Author(s) -
Cooper M. Ashley
Publication year - 1969
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.1270010504
Subject(s) - substituent , fluorine , additive function , chemistry , solvent , solvent effects , computational chemistry , spectral line , fluorine 19 nmr , nuclear magnetic resonance spectroscopy , organic chemistry , physics , quantum mechanics , mathematics , mathematical analysis
The NMR spectral parameters for some bromo‐ and iodo‐substituted fluorobenzenes are presented, and the derived meta ‐ and para ‐ fluorine‐fluorine couplings are shown to be in accord with the predictions made by Abraham et al. , using an additive substituent constant scheme. While the approximation of additive substituent effects is quite good, it is shown, however, that with highly accurate experimental values there are small deviations from perfect additivity. The existence of a large solvent effect on 3 J FF is demonstrated and the mechanism of this effect is discussed. It is emphasized that certain discrepancies in the literature between various values of the same 3 J FF may be due to this large, hitherto unrecognized solvent dependence.