Directionality of Intrinsic Deuterium Isotope Effects in ~13C NMR Spectra of Molecules Containing One or Two Phenyl Groups

摘要

Intrinsic deuterium-induced isotope effects have been measured and analyzed for compounds having one or two phenyl groups spe- cifically labeled at different positions in a molecule. Some typical examples of directional and orientational dependence of the effects have been given. Different magnitudes of isotope effects that are transmitted in opposite directions have been observed. Thus, in p-~2H-cis-stilbene, the effect over six bonds at C-α of 8.7 ppb is found, while the corresponding effect in α-~2H-cis-stilbene at C-4 is only 1.4 ppb.