title: The effect of isotopic substitution on the chirality of a self-assembled helix.
abstract: N,N',N″-trialkylbenzene-1,3,5-tricarboxamides (BTAs) self-assemble by means of strong, threefold α-helix-type intermolecular hydrogen bonding into well-defined, helical, one-dimensional columnar aggregates. When a stereogenic centre is introduced into the alkyl side chains of these BTAs, strong Cotton effects are observed in dilute apolar solutions, indicating the preference for one helical conformation over the other. Here, we report the creation of a helical sense preference in self-assembled BTAs by introducing deuterium/hydrogen isotope chirality into the alkyl side chains. We determine the relative stabilities of the left- and right-handed helical conformations of these deuterated supramolecular polymers by performing a conformational analysis. Our findings show that the results of deuterium/hydrogen substitution in BTA-based supramolecular polymers and helical polyisocyanates are very similar, although the formation mechanisms differ. The selectively deuterated BTAs discussed here represent the first example of supramolecular chirality resulting from isotope substitution.
authors.affiliation: Institute for Complex Molecular Systems and Laboratory of Macromolecular and Organic Chemistry, Eindhoven University of Technology, PO Box 513, 5600 MB Eindhoven, The Netherlands.
authors.forename: Seda
authors.initials: S
authors.lastname: Cantekin
authors.forename: Diederik W R
authors.initials: DW
authors.lastname: Balkenende
authors.forename: Maarten M J
authors.initials: MM
authors.lastname: Smulders
authors.forename: Anja R A
authors.initials: AR
authors.lastname: Palmans
authors.forename: E W
authors.initials: EW
authors.lastname: Meijer
mesh_terms: D000577:Amides; D002942:Circular Dichroism; D003903:Deuterium / Q000737:chemistry*; D008968:Molecular Conformation; D011108:Polymers / Q000138:chemical synthesis* / Q000737:chemistry; D013237:Stereoisomerism
chemical_list: D000577:Amides; D011108:Polymers; D003903:Deuterium