The nuclear magnetic resonance spectra of fluorobenzenes. Part III. o-Difluorobenzene and some 1-substituted 2,3-difluorobenzenes
- 1 January 1968
- journal article
- research article
- Published by Royal Society of Chemistry (RSC) in Journal of the Chemical Society B: Physical Organic
- p. 1094-1098
- https://doi.org/10.1039/j29680001094
Abstract
The AA′BB′XX′ spectrum of o-difluorobenzene and the ABCRX spectra of some 1-substituted 2,3-difluorobenzenes are completely analysed to give the magnitudes and signs of all the 1H and 19F coupling constants. The signs of these couplings agree with previous results. The HH and para-HF couplings in these molecules vary linearly with the electronegativity of the substituent in the same way as HH couplings in monosubstituted benzenes. This demonstrates the dominance of the σ-bond coupling mechanism for these couplings. The meta-HF couplings show a marked dependence on the substituent electronegativity, which is not linear, and the ortho-HF and ortho-FF couplings are suprisingly constant.Keywords
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