title: Increasing the size of an aromatic helical foldamer cavity by strand intercalation.
abstract: The postsynthetic modulation of capsules based on helical aromatic oligoamide foldamers would be a powerful approach for controlling their receptor properties without altering the initial monomer sequences. With the goal of developing a method to increase the size of a cavity within a helix, a single-helical foldamer capsule was synthesized with a wide-diameter central segment that was designed to intercalate with a second shorter helical strand. Despite the formation of stable double-helical homodimers (K(dim)>10(7) M(-1)) by the shorter strand, when it was mixed with the single-helical capsule sequence, a cross-hybridized double helix was formed with K(a)>10(5) M(-1). This strategy makes it possible to direct the formation of double-helical heterodimers. On the basis of solution- and solid-state structural data, this intercalation resulted in an increase in the central-cavity size to give a new interior volume of approximately 150 Å(3).
authors.affiliation: Université de Bordeaux, CBMN, UMR5248, Institut Européen de Chimie et Biologie, 2 rue Escarpit, 33600 Pessac (France); CNRS, CBMN, UMR5248 (France).
authors.forename: Michael L
authors.initials: ML
authors.lastname: Singleton
authors.forename: Geert
authors.initials: G
authors.lastname: Pirotte
authors.forename: Brice
authors.initials: B
authors.lastname: Kauffmann
authors.forename: Yann
authors.initials: Y
authors.lastname: Ferrand
authors.forename: Ivan
authors.initials: I
authors.lastname: Huc
mesh_terms: D003461:Crystallography / Q000379:methods*; D006860:Hydrogen Bonding; D007364:Intercalating Agents / Q000737:chemistry*; D046911:Macromolecular Substances; D008958:Models, Molecular; D008968:Molecular Conformation
chemical_list: D007364:Intercalating Agents; D046911:Macromolecular Substances
keywords: capsules; crystallography; foldamers; helical structures; supramolecular chemistry