Synthesis and structural characterization of bisazocalix[4]arene with melamine: Metal ion extraction studies

Abstract

In this study, the synthesis and characterization of novel bisazocalix[4]arene [2-amino-4,6-bis(5-azo-25,26,27- tribenzoyloxy-28-hydroxycalix[4]arene)-1,3,5-triazine] (5), symmetrically derived from the diazo coupling of 2,4,6-triamino-1,3,5-triazine (melamine), were carried out. This compound was prepared by reacting 25,26,27- tribenzoyloxy-28-hydroxycalix[4]arene (3) and melamine (4) in nitrosyl sulfuric acid and DMF. Purified product was characterized by elemental analyses, FT-IR, 1 H-NMR, MS and thermogravimetric analysis (TGA) techniques. Complexation properties of synthesized compound were studied by the liquid-liquid extraction of selected metal cations (Na + , K + , Sr 2+ , Ag + , Hg + , Hg 2+ , Co 2+ , Ni 2+ , Cu 2+ , Cd 2+ , Pb 2+ , Zn 2+ , Cr 3+ , Al 3+ ). It has been observed that bisazocalix[4]arene shows high affinity to Hg + and Hg 2+ ions, whereas almost less affinity to other metals. This sensor therefore present a very significant advantage in that it allows for determination of mercury ion in environmental and industrial wastewater. © 2014 Elsevier B.V. All rights reserved.