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Cooperative Binding of Calix[4]pyrrole–Anion Complexes and Alkylammonium Cations in Halogenated Solvents
Author(s) -
Gross Dustin E.,
Schmidtchen Franz P.,
Antonius Wiebke,
Gale Philip A.,
Lynch Vincent M.,
Sessler Jonathan L.
Publication year - 2008
Publication title -
chemistry – a european journal
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 1.687
H-Index - 242
eISSN - 1521-3765
pISSN - 0947-6539
DOI - 10.1002/chem.200800899
Subject(s) - chemistry , isothermal titration calorimetry , pyrrole , dichloromethane , chloride , titration , inorganic chemistry , ion , affinities , selectivity , medicinal chemistry , organic chemistry , stereochemistry , solvent , catalysis
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.