Abstract
We synthesized a number of aniline derivatives containing acyl groups to compare their barriers of rotation around the N-CO groups. Geometry optimization for all the rotamers have been performed using density functional theory (DFT) at the B3LYP/6-31G** level of theory. For each stationary point we carried out vibrational frequency calculations at the same level to characterize their nature as minima or transition states. The methoxy group substituent on the benzene ring causes some changes in the C-C bond distances. We carried out potential energy surface scanning to find out all possible low-energy conformations, which would be used as the initial structure for further molecular calculations. There were only three kinds of conformations with local minimum potential energy and two transition states. The optimized bond lengths and bond angles are in better agreement with the experimental values.