Conformational stability of a model macrocycle tetraamide: an ab initio study.

Ab initio calculations are carried out to investigate the conformational stability of a model macrocyle tetraamide. The four amide groups in the selected model are present in the sequence: -(O=CNH)-Ph-(NHC=O)-CH=CH-(O=CNH)-Ph-(NHC=O)-CH=CH-. In this sequence, two phenyl rings and two ethene groups act as bridges between the amide units.