A very simple self-assembling system, which produces inclusion complexes with pseudorotaxane geometries, is described. The self-assembly of eight pseudorotaxanes with a range of stoichiometries-I : I , 1 :2, 2:1, and 2:2 (host:guest)-has been Keywords achieved. These pseudorotaxanes self-assemble from readily available componentscrown ethers -dialkylammonium well-known crown ethers, such as dibenzo [24]crown-8 and bis-p-phenylene[34lcrown-salts 9 hydrogen bonding -molecular 10, and secondary dialkylammonium hexafluorophosphate salts, such as (PhCH,),-recognition -pseudorotaxanes * NHiPF; and (nBu),NHlPF;-and have been characterized not only in the solid state, self-assembly but also in solution and in the "gas phase". The pseudorotaxanes are stabilized largely by hydrogen-bonding interactions and, in some instances, by aryl-aryl interactions.

A simple motif for molecular recognition—the binding of disubstituted ammonium salts, for example dibenzyl‐ and di‐n‐butylammonium hexaflurophosphate, with crown ethers like dibenzo[24]crown‐8—results in the self‐assembly of threaded 1:1 complexes 1. The superstructures of these complexes are stabilized by hydrogen bonds, electrostatic pole–dipole interactions, and dispersive interactions.

On account of its pivotal role in several essential chemical and biological processes, anion binding and recognition ['] is currently arousing considerable attention within the domain of supramolecular chemistry.['] Traditionally, supramolecular chemists have positioned anion recognition sites within covalent macro(po1y)cyclic framework^^^] in a preorganizedL4] manner, so as to achieve strong anion binding. However, the discovery of self-a~sembled[~~ superniolecules that are capable of binding anions has been accomplished,[61 as supramolecular science has developed. Nevertheless, to the best of our knowledge, there has been no report to date of a self-assembled anion receptor whose components are held together entirely by hydrogen bonds. We describe here the discovery of two novel supermoleculesself-assembled utilizing only hydrogen bonds-which display either partial or complete envelopment of PF, ions in the solid state.Recently, we reportedL7] that macrocyclic polyethers form inclusion complexes, termed pseudorotaxanes,[*I of varying stoichiometries with secondary dibenzylammonium ions. In these pseudorotaxanes the ammonium ions are threaded through the macrorings and are held in place by a combination of

Vier‐ und Fünfkomponenten‐Pseudorotaxane, die durch das Einfädeln von Dibenzylammoniumionen in makrocyclische Polyether entstehen, verhalten sich als Anionenrezeptoren. Die Präorganisation der positiv geladenen Erkennungsstellen in diesen Überstrukturen induziert im Festkörper die Komplexierung eines PF6−‐Anions. Dieses ist im dreisträngigen Vierkomponenten‐Pseudorotaxan nur teilweise eingelagert, in der größeren Bindungstasche des viersträngigen Fünfkomponenten‐Pseudorotaxans (siehe Bild rechts) hingegen völlig eingehüllt.

The self-assembly of three new rotaxanes-two[2]rotaxanes and a [3]rotaxane-formed by a "threading followed by stoppering" approach is described. These template-directed syntheses rely on the formation of pseudorotaxane intennediates, which self-assemble in solution from functionalized secondary dialkylammonium hewafluorophosphate threads and macrocyclic polyether rings (either dibenzo-[24]crown-8 or its asymmetric constitutional isomer). The stoppers-substituted 1,2,3-triazoles-were created by thermally allowed 1,3-dipolar cycloadditions between azido groups, which terminate the threads, and di-tert-butyl acetylenedicarboxylate. lar