COLL 372 |
| Justin M. Notestein, Department of Chemical Engineering, University of California, Berkeley, MC-1462, Berkeley, CA 94720-1462 and Alexander Katz, Department of Chemical Engineering, University of California at Berkeley, MC 1462, Berkeley, CA 94720-1462. |
| Calixarenes are cyclic oligomers derived from condensation of phenols with formaldehyde, which can form host-guest complexes with neutral molecules. We have developed a single-step procedure for the rigid immobilization of isolated calix-[4]-arenes. The adsorption properties of these materials can be finely tuned via synthetic modifications of the carbonaceous upper rim and of the bridging groups in the calixarene macrocycles. For instance, materials prepared with tert-butyl functionalized upper rims are able to bind nitrobenzene from aqueous solution with a binding constant 2.5-fold higher than a similar material with a proton functionalized upper rim. Adsorption measurements for substituted aromatics from the gas phase and from various solvents led to measurements of adsorption enthalpies and entropies and to the isolation of solvation effects on the relevant supramolecular host-guest interactions. These results will be discussed in the context of the emerging applications of these materials as specific adsorbents in sensing and in chromatographic separations. |
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Surface Chemistry on Carbonaceous Materials
Division of Colloid and Surface Chemistry |