Citation

Gross DE, Schmidtchen FP, Antonius W, Gale PA, Lynch VM, Sessler JL. Chemistry (Weinheim) 2008; 14(26): 7822-7827.

Copyright

(Copyright © 2008, John Wiley and Sons)

DOI

10.1002/chem.200800899

PMID

unavailable

Abstract

Calix[4]pyrrole–chloride interactions are affected not only by the choice of countercation in halogenated solvents, but show a specific dependence on the way in which these cations are bound within the electron rich, bowl-like calix[4]pyrrole cavity formed upon chloride anion complexation. In dichloromethane, the affinities of simple meso-octamethylcalix[4]pyrrole (1) for methyl-, ethyl-, and n-butylammonium chlorides are on the order of 105, 104, and 102 M−1, respectively, as determined from isothermal titration calorimetry (ITC) analyses. These cation-dependent anion affinity effects, while clearly evident, are less pronounced in other halogenated solvents, such as 1,2-dichloroethane. Support for the proposed cation complexation selectivity is provided by solid state X-ray crystallographic analyses.