H-1-CHEMICAL SHIFTS OF SOME DEHYDRO[12]ANNULENES AND DEHYDRO[14]-ANNULENES

The ring-current (RC) and local anisotropic (LA) contributions to the 1H-chemical shifts of the dehydro[12]- and dehydro[14]-annulenes 1-13 have been calculated. The calculated shifts are in very good accord with experiment. Only protons with distances <3 Å from a triple bond are obtained at too high a field. It is shown that only the consideration of the combined RC and LA effects can provide an explanation of the chemical shifts of inner and outer protons of annulenes. © 1979.