Controllability of dynamic double helices: quantitative analysis of the inversion of a screw-sense preference upon complexation. Issue 11 (19th August 2015)

• Record Type: Journal Article
• Authors: Katoono, Ryo; Kawai, Shunsuke; Fujiwara, Kenshu; Suzuki, Takanori
• Is Part Of: Chemical science. Volume 6:Issue 11(2015:Nov.)
• Page Start: 6592
• Page End: 6600
• Publication Date: 2015-08-19
• Subjects: Chemistry -- Periodicals; 540.5
• DOI: 10.1039/c5sc02614h
• Languages: English
• ISSNs: 2041-6520

Abstract

Abstract : We analyzed quantitatively the complexation-induced inversion of a screw-sense preference of dynamic double helices with CD and 1 H NMR spectroscopy. Abstract : We describe a quantitative analysis of the complexation-induced inversion of a screw-sense preference based on a conformationally dynamic double-helix structure in a macrocycle. The macrocycle is composed of two twisting units (terephthalamide), which are spaced by two strands (1, 3-bis(phenylethynyl)benzene), and is designed to generate a double-helix structure through twisting about a C 2 axis in a conrotatory manner. The attachment of chiral auxiliaries to the twisting units induces a helical preference for a particular sense of ( M )- or ( P )-helicity through the intramolecular transmission of chirality to dynamic double helices. The twisting unit can also act as a binding site for capturing a guest molecule, and, in a complexed state, the preferred screw sense of the dynamic double-helix structure is reversed to exhibit the contrary preference. We quantitatively monitored the complexation-induced inversion of the screw-sense preference using 1 H NMR spectroscopy, which enabled us to observe independently two species with ( M )- or ( P )-helicity in both the absence and presence of a guest molecule. Inversion of the screw-sense preference was induced upon complexation with an achiral guest as well as a chiral guest.