Calorimetric Investigation of the Complexation of Didodecylcalix[4]arene-crown-6 with Alkali Metal and Ammonium Cations in Acetonitrile |
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| Authors: | Erik G. Nelson Dusten M. Macdonald Tatiana G. Levitskaia |
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| Affiliation: | 1. Department of Chemistry and Biochemistry , Brigham Young University , Provo, UT, 84601;2. Oak Ridge National Laboratory, Bethel Valley Rd. , P. O. Box 2008, Building 4500 South, Mail Stop 6119, Oak Ridge, TN, 37831 |
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| Abstract: | Abstract The Cs+ selectivity of some calix-crown ligands makes them excellent candidates for use in separation systems such as liquid membranes. Separation performance can be understood and predicted from thermodynamic data for cation complexation. We have therefore determined the log K, ΔH and ΔS for the interaction of Na+, K+, Rb+, Cs+ and NH4 + with didodecyl-calix[4]arene-crown-6 in acetonitrile at 25°C by titration calorimetry. The ligand is strongly selective for Cs+, and the selectivity trend results entirely from the enthalpy contribution, with entropy effects opposing the trend. These results are discussed in light of some corresponding data obtained by other researchers with similar ligands. |
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| Keywords: | Calorimetry Calixarene Crown Metal ion complexation Cesium separation |
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