Six-bond 1H,1H and 1H,19F spin coupling constants as indicators of geometry in aniline and p-fluoroaniline

Abstract

The long-range coupling constants between amino protons and the ring proton or fluorine nucleus in the para position of aniline and p-fluoroaniline imply that, in benzene solution, the geometry at the amino group is very similar in the two compounds. The ratio of the two coupling constants is consistent with potential functions for inversion at nitrogen derived from far infrared data, but inconsistent with microwave spectra which indicate that the angle defining the intersection of the amino and benzene planes differs by 9° in these two compounds.