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Title: Calix[4]pyrrole: A New Ion-Pair Receptor As Demonstrated by Liquid-Liquid Extraction

Abstract

Solvent extraction studies provide confirming evidence that meso-octamethylcalix[4]pyrrole acts as an ion-pair receptor for cesium chloride and cesium bromide in nitrobenzene solution. The stoichiometry of the interaction under extraction conditions from water to nitrobenzene was determined from plots of the cesium distribution ratios vs. cesium salt and receptor concentration, indicating the formation of an ion-paired 1:1:1 cesium:calix[4]pyrrole:halide complex. The extraction results were modeled to evaluate the equilibria inherent to the solvent extraction system, either with chloride or bromide. The binding energy between the halide anion and the calix[4]pyrrole was found to be about 7 kJ/mol larger for cesium chloride than for the cesium bromide. The ion-pairing free energies between the calix[4]pyrrole-halide complex and the cesium cation are nearly the same within experimental uncertainty for either halide, consistent with a structural model in which the Cs+ cation resides in the calix bowl. These results are unexpected since nitrobenzene is a very polar solvent that generally leads to dissociated complexes in the organic phase when used as a diluent in extraction studies of univalent ions. Control studies involving nitrate revealed no evidence of ion-pairing for CsNO3 under conditions identical to those where it is observed for CsCl and CsBr.

Authors:
 [1];  [2];  [3];  [4];  [3]
  1. Ecole Nationale Superieure de Chimie de Paris
  2. Pacific Northwest National Laboratory (PNNL)
  3. ORNL
  4. University of Texas
Publication Date:
Research Org.:
Oak Ridge National Lab. (ORNL), Oak Ridge, TN (United States)
Sponsoring Org.:
USDOE Office of Science (SC)
OSTI Identifier:
972007
DOE Contract Number:  
DE-AC05-00OR22725
Resource Type:
Journal Article
Journal Name:
Journal of the American Chemical Society
Additional Journal Information:
Journal Volume: 130; Journal Issue: 12; Journal ID: ISSN 0002-7863
Country of Publication:
United States
Language:
English
Subject:
37 INORGANIC, ORGANIC, PHYSICAL AND ANALYTICAL CHEMISTRY; ANIONS; BINDING ENERGY; CATIONS; CESIUM; CESIUM BROMIDES; CESIUM CHLORIDES; CHLORIDES; DISTRIBUTION; HALIDES; NITRATES; NITROBENZENE; SOLVENT EXTRACTION; SOLVENTS; STOICHIOMETRY; STRUCTURAL MODELS; WATER; calixpyrrole; macrocycle; ion-pair extraction; anion receptor; anion binding; cesium; halide; chloride; bromide; nitrate

Citation Formats

Wintergerst, Mr. Matthieu, Levitskaia, Tatiana G., Moyer, Bruce A, Sessler, Jonathan L., and Delmau, Laetitia Helene. Calix[4]pyrrole: A New Ion-Pair Receptor As Demonstrated by Liquid-Liquid Extraction. United States: N. p., 2008. Web. doi:10.1021/ja7102179.
Wintergerst, Mr. Matthieu, Levitskaia, Tatiana G., Moyer, Bruce A, Sessler, Jonathan L., & Delmau, Laetitia Helene. Calix[4]pyrrole: A New Ion-Pair Receptor As Demonstrated by Liquid-Liquid Extraction. United States. https://doi.org/10.1021/ja7102179
Wintergerst, Mr. Matthieu, Levitskaia, Tatiana G., Moyer, Bruce A, Sessler, Jonathan L., and Delmau, Laetitia Helene. Tue . "Calix[4]pyrrole: A New Ion-Pair Receptor As Demonstrated by Liquid-Liquid Extraction". United States. https://doi.org/10.1021/ja7102179.
@article{osti_972007,
title = {Calix[4]pyrrole: A New Ion-Pair Receptor As Demonstrated by Liquid-Liquid Extraction},
author = {Wintergerst, Mr. Matthieu and Levitskaia, Tatiana G. and Moyer, Bruce A and Sessler, Jonathan L. and Delmau, Laetitia Helene},
abstractNote = {Solvent extraction studies provide confirming evidence that meso-octamethylcalix[4]pyrrole acts as an ion-pair receptor for cesium chloride and cesium bromide in nitrobenzene solution. The stoichiometry of the interaction under extraction conditions from water to nitrobenzene was determined from plots of the cesium distribution ratios vs. cesium salt and receptor concentration, indicating the formation of an ion-paired 1:1:1 cesium:calix[4]pyrrole:halide complex. The extraction results were modeled to evaluate the equilibria inherent to the solvent extraction system, either with chloride or bromide. The binding energy between the halide anion and the calix[4]pyrrole was found to be about 7 kJ/mol larger for cesium chloride than for the cesium bromide. The ion-pairing free energies between the calix[4]pyrrole-halide complex and the cesium cation are nearly the same within experimental uncertainty for either halide, consistent with a structural model in which the Cs+ cation resides in the calix bowl. These results are unexpected since nitrobenzene is a very polar solvent that generally leads to dissociated complexes in the organic phase when used as a diluent in extraction studies of univalent ions. Control studies involving nitrate revealed no evidence of ion-pairing for CsNO3 under conditions identical to those where it is observed for CsCl and CsBr.},
doi = {10.1021/ja7102179},
url = {https://www.osti.gov/biblio/972007}, journal = {Journal of the American Chemical Society},
issn = {0002-7863},
number = 12,
volume = 130,
place = {United States},
year = {2008},
month = {1}
}