Coordination chemistry of phosphorylated calixarenes and their applicationto separations science

Calixarenes are macrocyclic compounds with four to eight repeat units forme d by the condensation of p-alkylated phenols with formaldehyde. Substitutio n with ion-complexing ligands can allow for the synthesis of a wide array o f selective coordinating compounds. Phosphorus-containing ligands have been found to complex a large number of metal ions with selectivity being deter mined by the precise ligand structure. The coordination chemistry that resu lts when calixarenes are phosphorylated is reviewed to emphasize the unique potential of such molecules for selective metal ion separations and in ion sensor technology. The three sections of this review are (a) transition me tal complexes of phosphorylated calixarenes (e.g., phosphino, phosphinite, and phosphine-functionalized calixarenes), (b) application of phosphorylate d calixarenes as selective metal ion complexants, and (c) immobilization of calixarenes onto inorganic and organic polymers.