Computational and DNMR Analysis of the Conformational Isomers and Stereodynamics of Secondary 2,2′-Bisanilides

The conformational preference of 2,2′-bisanilides was investigated by variable-temperature NMR spectroscopy, NMR titration and diffusion experiments, IR spectroscopy, computational analysis, and X-ray crystallography. The formation of a conformation having the two amide moieties linked by an intramolecular hydrogen bond was detected at low temperatures. The interconversion kinetics of the two conformational species of bisanilide 2 were determined by NMR line shape analysis. The formation of a supramolecule linked by intermolecular hydrogen bonds was ruled out by means of DMSO titration, DOSY experiments, and steric considerations.