A 1H dynamic NMR study was carried out on N,N‐diethylmethacrylamide (1a), N,N,N′,N′‐tetraethylitaconamide (2), N,N,N′,N′‐tetraethylcitraconamide (3) and N,N,N′,N′‐tetraethylmesaconamide (4) over a wide temperature interval. Amide rotational barriers were determined from the coalescence temperatures. In 3 a second dynamic process was observed below 240 K, which made the geminal methylene protons non‐equivalent. The phenomenon is interpreted in terms of a non‐planar conformation caused by electrostatic and/or steric repulsion of the amide carbonyls. Homonuclear NOE experiments revealed an s‐cis, s‐cis′ conformation for the compounds studied.
- H and C dynamic NMR
- Low‐temperature conformational analysis
- Methylene proton non‐equivalence
- Vinylogous diamide rotational barriers
ASJC Scopus subject areas
- Materials Science(all)