A hybrid cyclic bisproline designed to adopt a β-fold: crystal structure of cyclo(ProNHCH2CH2NHProCOCH2CH2 CO)

Abstract

The crystal structure of 14-membered cyclo(ProNHCH₂CH₂NHProCOCH₂CH₂ CO) reveals the presence of an internal NH⋯OC bond dividing the molecule into two halves of 10-membered hydrogen-bonded rings; the molecules self-assemble into cyclic dimers through a symmetrical pair of intermolecular NH⋯OC hydrogen bonds; a layered structure is formed, alternating layers of cyclic dimers and layers of chloroform molecules, all of which make strong CH⋯O hydrogen bonds with the cyclic dimers.