ISSN:
0030-4921
Keywords:
Chemistry
;
Analytical Chemistry and Spectroscopy
Source:
Wiley InterScience Backfile Collection 1832-2000
Topics:
Chemistry and Pharmacology
Notes:
Analyses of the 19F and 1H spectra of 1,2,3,4,5-pentafluoro-, 1-bromo-4,5,6,7,8-pentafluoro-, 1,2,3,4,5,6-hexafluoro-, and 1-bromo-3,4,5,6,7,8-hexafluoro-naphthalene are presented, and it is observed that the Fermi contact mechanism does not, simply, account for the long range couplings. Calculations of the carbon-carbon polarizability part of the Fermi contact term do, however, imply that inter-ring F,F couplings should be almost constant from difluoro- to heptafluoro-naphthalene. Within the limits of this study, the inter-ring F,F couplings, excluding peri F,F couplings, do not vary substantially. The steric effect of substituting an α-hydrogen with bromine, at a peri position and adjacent to fluorine, is to increase the F,F coupling at the opposed peri position by 20 Hz, an unusually high increase in J(FF)peri.
Additional Material:
3 Tab.
Type of Medium:
Electronic Resource
URL:
http://dx.doi.org/10.1002/mrc.1270180412
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