415 Polymeric Systems Containing Supramolecular Receptors for Molecular Recognition

Friday, November 6, 2009: 9:30 AM
Rio Grande (Camino Real Hotel)
Brett M. Rambo , Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX
Sung Kuk Kim , Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX
Christopher W. Bielawski , Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX
Jonathan L. Sessler , Department of Chemistry and Biochemistry, University of Texas at Austin, Austin, TX
Supramolecular polymers represent an exciting and expanding area of polymer science.  These systems utilize noncovalent interactions to define material assembly and behavior.  Described herein, is the development of covalent polymeric systems containing supramolecular receptors as pendant side-chains.  Specifically, these systems contain receptors (i.e., calix[4]pyrrole, calixarenes, and crown ether moieties) with high affinity for ionic species (i.e., CsNO3, KF and KCl, as well as H2PO4-).  Ionic species play a vital role in a number of biological processes, but often these species play less than salubrious roles in both the environment and the human body.  For example, a key problem in kidney dialysis is the removal of ions from the blood.  The accumulation of potassium in blood can lead to a disease state know as hyperkalemia (meaning literally “high potassium”).  Typically, supramolecular receptors display a weak affinity for ions in water; however, their incorporation into polymeric structures, serving as a solid support, can help address this issue.  First generation systems containing poly(methylmethacrylate) with pendant anionic and cationic recognition units have been generated.  These materials demonstrate the ability to extract potassium fluoride and chloride salts out of aqueous media.  Recently, a second generation of polymers have been developed that display a high affinity for cesium nitrate.  Removal of Cs+ is a problem in the cleanup of radioactive waste.  The binding and extraction properties of these systems will be described as well as progress towards utilizing ionic species in supramolecular cross-linking.