Nuclear Magnetic Resonance Spectroscopy. Magnetic Nonequivalence Due to Slow Inversion in Amines

Investigation of the low-temperature n.m.r. spectrum of N-benzyl-O,N-dimethylhydroxylamine has permitted a determination of the rate and activation energy for nitrogen inversion. The energy barrier to inversion has been found to be inversely proportional to the solvent dielectric constant in four rather nonpolar solvents. In n-hexane, E_ɑ was found to be 12.9 ± 0.3 kcal. while in methylene chloride a value of 9.4 ± 0.4 kcal. was obtained.