Effect of intramolecular interaction between polar and polarizable bonds on 13C shielding constants in different conformations of 2-methoxy- and 2-vinyloxynaphthalene molecules:: an ab initio study

Shielding constants of C-13 nuclei calculated for different conformations of 2-methoxynaphthalene and 2-vinyloxynaphthalene molecules by the GIAO ab initio method in the D95** basis set indicate a strong shielding effect of the intramolecular interaction between the polar O-C bond of the substituent and the polarizable pi-bond of the naphthyl moiety on the C atom in cis-position. The results obtained are in agreement with the experimentally found trends of changes in the chemical shifts of 13C nuclei and are in reasonable quantitative agreement with experimental data.