Homochiral and heterochiral associations observed in crystals of ArSO2-(Aib)5-OMe. Issue 48 (18th November 2020)

• Record Type: Journal Article
• Authors: Hikawa, Hidemasa; Takahashi, Ayaka; Kikkawa, Shoko; Suzuki, Ayaka; Takahashi, Yoshiki; Sato, Naruka; Okayasu, Misaki; Azumaya, Isao
• Is Part Of: CrystEngComm. Volume 22:Issue 48(2020)
• Page Start: 8353
• Page End: 8361
• Publication Date: 2020-11-18
• Subjects: Crystals -- Periodicals; Crystal growth -- Periodicals; Crystallography -- Periodicals; Cristaux -- Périodiques; Cristaux -- Croissance -- Périodiques; Cristallographie -- Périodiques; 548
• DOI: 10.1039/d0ce01267j
• Languages: English
• ISSNs: 1466-8033

Abstract

Abstract : We demonstrated two remarkably different types of network structures that consist of homochiral and heterochiral 1D chains of enantiomeric 310 -helices in the crystals of ArSO2-(Aib)5-OMe. Abstract : The molecular conformations, packing structures and intermolecular interactions of homopentapeptides from achiral α-aminoisobutyric acid (Aib), ArSO2 -(Aib)5 -OMe (Ar = p -tolyl, p -bromophenyl and p -methoxyphenyl), have been investigated by single-crystal X-ray diffraction analysis. The peptides were folded in 310 -helical conformations consisting of two or three consecutive ten-atom intramolecular hydrogen-bonded β-turns of type III or III′. In the packing mode, left-handed ( M ) and right-handed ( P ) 310 -helical molecules formed linear network structures with head-to-tail type intermolecular hydrogen bonds. Two types of network structures consisting of homochiral sequences (⋯ M ⋯ M ⋯ M ⋯ or ⋯ P ⋯ P ⋯ P ⋯) and heterochiral sequences (⋯ M ⋯ P ⋯ M ⋯ P ⋯) were obtained depending on the functional groups or substituents of the peptides. Interestingly, peptide 1a which has a p -tolyl group crystallized differently when using a different crystallization medium.