The substituent-induced chemical shifts (SCS) of C2 and C3 on the 13C NMR spectra of 1-aryl-3,3-difluoro-
2-halocyclopropenes were studied. The correlation between SCS and Hammett constants shows
that the tendency of effect by the substituents on the phenyl ring is BrC2( = 4.66) > ClC2( = 4.50) and
ClC3( = -1.63) > BrC3( = -1.41). The DSP treatment further confirms the SCS of C2 and C3 are the
main contribution of the resonance effect and field effect, respectively. Those results of the incremental
shifts reveals that the gem-difluorocyclopropenyl bearing the phenyl group possesses a triple bond character,
which is also observed in IR spectra with high C=C (1768-1945 cm-1).
Relation:
Journal of the Chinese Chemical Society, 53:915-921
