| Autor: |
Contreras, RH, Giribet, CG, Natiello, MA, Perez, J, Rae, ID, Weigold, JA |
| Zdroj: |
Australian Journal of Chemistry; 1985, Vol. 38 Issue: 12 p1779-1784, 6p |
| Abstrakt: |
Calculations by the IPPP-INDO method give the spin-spin coupling constants for the side-chain carbons, 3JCF and 4JCF, as 4.97 and 6.86 Hz respectively with substantial contributions to through-space coupling from the pathway CO-C-H…F. The observed values for 1-(2- fluorophenyl ) ethanone , 3.3 and 7.2 Hz, and for 1-(2,5- difluorophenyl ) ethanone , 3.7 and 7.3 Hz, are in good agreement with these predictions. Two compounds, a dihydroindenone and a naphthalenone, in which this pathway cannot be effective, show no fluorine coupling to the aliphatic carbon next to the carbonyl and the values of 3JCF are reduced to 2.2 and 2.5 Hz, consistent with the loss of a through-space Fermi contact term of the kind described above. |
| Databáze: |
Supplemental Index |
| Externí odkaz: |
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