PROTON MAGNETIC RESONANCE STUDY FOR P-SUBSTITUTED N,N-DIMETHYLBENZAMIDES AND THEIR INTERACTION WITH SOME METAL CHLORIDES

The NCH3 chemical shifts and their separations (δν) of several p-substituted N,N-dimethylbenzamides in solution have been measured, and it has been assigned that NCH3 protons trans to the carbonyl group are more shielded than those of cis group. The free energies of activation (ΔG‡) for hindered internal rotation about the central CN bond of the amide have been calculated. Electron-releasing p-substituents decrease δν and ΔG‡. Tin tetrachloride, antimony pentachloride and titanium tetrachloride have been found to interact with the amide through carbonyl oxygen atom, and to increase δν or ΔG‡ by the coordination. On the other hand, silicon and germanium tetrachloride interact with the amides through nitrogen atom as well as carbonyl oxygen atom. © 1969.