Nitrogen-15 nuclear magnetic resonance spectra of ketenimines

Abstract

Nitrogen-15 NMR spectra of 11 ketenimines have been taken both at the natural-abundance level of ^(15)N and with the aid of ^(15)N-labeling. The nitrogen chemical shifts are substantially different from those of neutral imines and are upfield, more like those of protonated imines. The results are in accord with significant delocalization of the nitrogen lone-pair. Furthermore, there is a rough parallelism between the ^(13)C shifts of the terminal carbons and the ^(15)N shifts.

Additional details