Synthesis of novel silica gel immobilized-calix[4]arene amide ionophores and their anion binding abilities toward phosphate and chromate anions

This article describes the synthesis and characterization of four new calix[4]arene ionophores 5-7 and 9 and corresponding two new silica gel-immobilized calix[4]arene ionophores containing pyridine 10 and 11 via modification of calix[4]arene monoamide derivatives 5 and 6 with aminopropyl silica gel, respectively. The extraction studies have been performed using liquid-liquid extraction for receptors 5-7 and 9 and solid-liquid batchwise sorption procedures for receptors 10 and 11. Obtained extraction results showed that the immobilized-calix[4] arene ionophores 10 and 11 have high extraction ability toward chromate and phosphate anions as compared to their corresponding monomeric precursors 5 and 6. © 2011 Wiley Periodicals, Inc.