Cooperative Binding of Calix[4]pyrrole–Anion Complexes and Alkylammonium Cations in Halogenated Solvents

✍ Scribed by Dustin E. Gross; Franz P. Schmidtchen; Wiebke Antonius; Philip A. Gale; Vincent M. Lynch; Jonathan L. Sessler

• Book ID: 101834642
• Publisher: John Wiley and Sons
• Year: 2008
• Tongue: English
• Weight: 402 KB
• Volume: 14
• Category: Article
• ISSN: 0947-6539
• DOI: 10.1002/chem.200800899

✦ Synopsis

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 10^5^, 10^4^, and 10^2^ 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.