Halogenated alkyl radicals

Biddles, I.; Cooper, J.; Hudson, Andrew; Jackson, Richard A.; Wiffen, J.T.

doi:10.1080/00268977300100211

Cited by 16 publications

(1 citation statement)

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“…The decrease in magnitude of 6~p F , C F on successive substitution to CH2F, CHF,, and CF, groups is expected if the group orbitals become successively lower in energy and interact to a lesser degree with the n: electron system (48,49).…”

Section: Long-range 19fc19~ Couplingsmentioning

confidence: 99%

Spin–spin coupling constants between side-chain and ring fluorine nuclei in some benzotrifluoride, benzal fluoride, and benzyl fluoride derivatives: coupling mechanisms

Schaefer¹,

Niemczura²,

Wong³

et al. 1979

Can. J. Chem.

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A complete analysis of the 1H and 19F nmr spectra of 2,5- and 3,4-difluorobenzotrifluoride, together with multiple resonance experiments, yields the signs and magnitudes of the long-range 19F,19F and 1H,19F spin–spin coupling constants. The coupling mechanisms are discussed. In particular, the coupling over six bonds, [Formula: see text], whose sign is interpretable in terms of a σ–π mechanism, is too large in magnitude when compared to [Formula: see text], and [Formula: see text] in the analogous compounds. These latter three couplings are consistent in sign and magnitude with what is known about hyperfine interaction constants. The magnitudes of [Formula: see text] are reported for 4-fluorobenzotrifluoride, 3-amino-4-fluorobenzotrifluoride, 3-nitro-4-fluorobenzotrifluoride, as are 6JpF,F values for p-fluorobenzal fluoride and p-fluorobenzyl fluoride. In contrast to 6JpH,CH and 6JpF,CH it seems unlikely that, unless its coupling mechanism becomes more precisely understood, 6JpF,CF will be a reliable indicator of conformational preferences.

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Section: Long-range 19fc19~ Couplingsmentioning

confidence: 99%