title: Identification of a foldaxane kinetic byproduct during guest-induced single to double helix conversion.
abstract: An aromatic oligoamide sequence was designed and synthesized to fold in a single helix having a large cavity and to behave as a host for a dumbbell-shaped guest derived from tartaric acid. NMR, molecular modeling, and circular dichroism (CD) evidence demonstrated the rapid formation of this 1:1 host-guest complex and induction of the helix handedness of the host by the guest. This complex was found to be a long-lived kinetic supramolecular byproduct, as it slowly transformed into a 2:2 host-guest complex with two guest molecules bound at the extremities of a double helix formed by the host, as shown by NMR and CD spectroscopy and a solid-state structure. The guest also induced the handedness of the double helical host, but with an opposite bias. The chiroptical properties of the system were thus found to revert with time as the 1:1 complex formed first, followed by the 2:2 complex.
authors.affiliation: Université de Bordeaux, CBMN (UMR 5248), Institut Européen de Chimie Biologie, 2 rue Escarpit, 33607 Pessac, France.
authors.forename: Quan
authors.initials: Q
authors.lastname: Gan
authors.forename: Yann
authors.initials: Y
authors.lastname: Ferrand
authors.forename: Nagula
authors.initials: N
authors.lastname: Chandramouli
authors.forename: Brice
authors.initials: B
authors.lastname: Kauffmann
authors.forename: Christophe
authors.initials: C
authors.lastname: Aube
authors.forename: Didier
authors.initials: D
authors.lastname: Dubreuil
authors.forename: Ivan
authors.initials: I
authors.lastname: Huc
mesh_terms: D002942:Circular Dichroism; D007700:Kinetics; D008968:Molecular Conformation; D019906:Nuclear Magnetic Resonance, Biomolecular