Nitrogen nuclear magnetic resonance spectroscopy. Nitrogen‐15 and proton chemical shifts of methylanilines and methylanilinium ions

Abstract

AbstractNitrogen and carbon electron densities of the toluidines and xylidines have been recalculated by the INDO method; previously published errors have been corrected. Although the nitrogen‐15 chemical shifts of these compounds still display the earlier suggested correlation with σ and total electron densities, the calculated inverse correlation with proton electron densities has been shown to be incorrect. Methyl proton chemical shifts of these compounds display no meaningful correlation with the nitrogen shifts. The nitrogen chemical shifts of the toluidinium and xylidinium ions correlate moderately well with the 13C chemical shifts of the analogous di‐ and tri‐methylbenzenes.