title: Anion-templated assembly of pseudorotaxanes: importance of anion template, strength of ion-pair thread association, and macrocycle ring size.
abstract: A wide range of pseudorotaxane assemblies containing positively charged pyridinium, pyridinium nicotinamide, imidazolium, benzimidazolium and guanidinium threading components, and macrocyclic isophthalamide polyether ligands have been prepared using a general anion templation procedure. In noncompetitive solvent media, coupling halide anion recognition by a macrocyclic ligand with ion-pairing between the halide anion and a strongly associated cation provides the driving force for interpenetration. Extensive solution 1H NMR binding studies, thermodynamic investigations, and single-crystal X-ray structure determinations reveal that the nature of the halide anion template, strength of the ion-pairing between the anion template and the cationic threading component, and to a lesser extent favorable second sphere pi-pi aromatic stacking interactions between the positively charged threading component and macrocyclic ligand, together with macrocyclic ring size, affect the efficacy of pseudorotaxane formation.
authors.affiliation: Department of Chemistry, Inorganic Chemistry Laboratory, University of Oxford, South Parks Road, Oxford, OX1 3QR, UK.
authors.forename: Mark R
authors.initials: MR
authors.lastname: Sambrook
authors.forename: Paul D
authors.initials: PD
authors.lastname: Beer
authors.forename: James A
authors.initials: JA
authors.lastname: Wisner
authors.forename: Rowena L
authors.initials: RL
authors.lastname: Paul
authors.forename: Andrew R
authors.initials: AR
authors.lastname: Cowley
authors.forename: Fridrich
authors.initials: F
authors.lastname: Szemes
authors.forename: Michael G B
authors.initials: MG
authors.lastname: Drew