title: A short designed semi-aromatic organic nanotube--synthesis, chiroptical characterization, and host properties.
abstract: The first generation of an organic nanotube based on the enantiomerically pure bicyclo[3.3.1]nonane framework is presented. The helical tube synthesised is the longest to date having its aromatic systems oriented parallel to the axis of propagation (length ∼26 Å and inner diameter ∼11 Å according to molecular dynamics simulations in chloroform). The synthesis of the tube, a heptamer, is based on a series of Friedländer condensations and the use of pyrido[3,2-d]pyrimidine units as masked 2-amino aldehydes, as a general means to propagate organic tubular structures and the introduction of a methoxy group for modification toward solubility and functionalization are described. The electronic CD spectra of the tube and molecular intermediates are correlated with theoretical spectra calculated with time-dependent density functional theory to characterize the chirality of the tube. Both experimental (NMR-titrations) and theoretical (molecular dynamics simulations) techniques are used to investigate the use of the tube as a receptor for the acetylcholine and guanidinium cations, respectively.
authors.affiliation: Centre for Analysis and Synthesis, Department of Chemistry, Lund University, P.O. Box 124, SE-221 00, Lund, Sweden. kenneth.warnmark@chem.lu.se.
authors.forename: Torbjörn
authors.initials: T
authors.lastname: Wixe
authors.forename: Niels Johan
authors.initials: NJ
authors.lastname: Christensen
authors.forename: Sven
authors.initials: S
authors.lastname: Lidin
authors.forename: Peter
authors.initials: P
authors.lastname: Fristrup
authors.forename: Kenneth
authors.initials: K
authors.lastname: Wärnmark