A Demonstration of Anion Templation and Selectivity in Pseudorotaxane Formation We thank the EPSRC and the University of Reading for funds for the Image Plate System and the Natural Sciences and Engineering Research Council of Canada for financial support to Dr. Wisner.

Abstract

First‐ and second‐sphere coordination of a chloride anion templates the formation of a [2]pseudorotaxane (see picture) in which a pyridinium diamide threads through the annulus of a macrocyclic isophthalamide wheel. The formation of the pseudorotaxane depends on the nature of the anion involved: the use of a larger anion destabilizes the entire recognition motif.

Biomimetic macrocyclic receptors for carboxylate anion recognition based on C -linked peptidocalix[4]arenes

“…The presence of crosspeaks in the rotating-frame Overhauser effect spectroscopy spectra (see Fig. 4, which is published as supporting information) between the signals of protons 2, 4, and 6 of the isophthaloyl aromatic nucleus and the alanyl amide protons supports the second hypothesis, where the equilibrating conformations differ for the reciprocal orientation (Scheme 3) of the NH protons, which can be trans (a) or cis-outside (b) and cis-inside (c) (22)(23)(24)(25)(26).…”

“…6, which is published as supporting information), which prompted us to quantitatively evaluate the association constants by means of NMR methods. To overcome the conformational problems encountered in CDCl 3 (see above), the complexation properties of ligands 4 and 6 were studied in acetone-d6, which has been previously used in anion binding studies (9,23). In each binding experiment, a 1:1 stoichiometry was assumed for the complexation, which was generally supported by the good fit of the experimental data to the theoretical model and by the results of ESI-MS, which show the presence of only this species in different conditions.…”

Anion recognition as a method for templating pseudorotaxane formation

“…The syntheses of 1, 2, 3 (14), and 5b (16) have been reported. Compound 5a was obtained by extensive washing of a dichloromethane solution of 5b with aqueous NH 4 Cl (1 M).…”

“…4⅐Br was obtained by alkylation of n-hexyl nicotinamide with 1-bromohexane in refluxing chloroform over 3 days. The syntheses of 4a and 4b were accomplished by anion exchange methods reported previously (14). 1 H NMR spectra were recorded on Varian 300-MHz or 500-MHz spectrometers.…”

“…We have recently shown that pseudorotaxane formation can be templated selectively by chloride anions in acetone solution ( Fig. 1) (14). In this system, macrocycle 2 binds the pyridinium cation-chloride anion ion-pair thread 1a through a combination of first and second sphere coordination of the anion (i.e., complexation of the specific ion pair as a whole entity).…”