title: Introducing Chirality into Nonionic Dendritic Amphiphiles and Studying Their Supramolecular Assembly.
abstract: Chiral head groups have been introduced into water-soluble hydroxyl-terminated nonionic amphiphiles and the impact of the head group stereochemistry on the supramolecular ultrastructures has been studied. Enantiomeric isomers were compared with the achiral meso form and the racemic mixture by means of cryogenic transmission electron microscopy and circular dichroism spectroscopy. Structurally, all amphiphiles are composed of the first-generation hydrophilic polyglycerol head group coupled to a single hydrophobic hexadecyl chain through an amide linkage and diaromatic spacer. The enantiomers aggregate to form twisted ribbons with uniform handedness, whereas the meso stereoisomer and racemic mixture produce elongated assemblies, namely, tubules and platelets, but without a chiral ultrastructure. Simulations on the molecular packing geometries of the stereoisomers indicate different preferential assembly routes that explain the individual supramolecular aggregation behavior.
authors.affiliation: Department of Chemistry, Deenbandhu Chhotu Ram University of Science & Technology, Murthal-, 131039, Haryana, India.|Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.
authors.forename: Sumit
authors.initials: S
authors.lastname: Kumar
authors.affiliation: Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstrasse 36a, 14195, Berlin, Germany.
authors.forename: Kai
authors.initials: K
authors.lastname: Ludwig
authors.affiliation: Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstrasse 36a, 14195, Berlin, Germany.
authors.forename: Boris
authors.initials: B
authors.lastname: Schade
authors.affiliation: Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstrasse 36a, 14195, Berlin, Germany.
authors.forename: Hans
authors.initials: H
authors.lastname: von Berlepsch
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.
authors.forename: Ilona
authors.initials: I
authors.lastname: Papp
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.
authors.forename: Rahul
authors.initials: R
authors.lastname: Tyagi
authors.affiliation: Department of Chemistry, Deenbandhu Chhotu Ram University of Science & Technology, Murthal-, 131039, Haryana, India.
authors.forename: Monika
authors.initials: M
authors.lastname: Gulia
authors.affiliation: Institut für Chemie und Biochemie, Freie Universität Berlin, Takustrasse 3, 14195, Berlin, Germany.
authors.forename: Rainer
authors.initials: R
authors.lastname: Haag
authors.affiliation: Forschungszentrum für Elektronenmikroskopie, Institut für Chemie und Biochemie, Freie Universität Berlin, Fabeckstrasse 36a, 14195, Berlin, Germany. christoph.boettcher@fzem.fu-berlin.de.
authors.forename: Christoph
authors.initials: C
authors.lastname: Böttcher
keywords: amphiphiles; chirality; helical structures; scanning probe microscopy; self-assembly