A versatile approach toward chemosensor for Hg2+ based on para-substituted phenylazocalix[4]arene containing mono ethyl ester unit

In the present study, six new azocalix[4]arenes have been synthesized by reacting calix[4]arene with p-substituted aniline and ethyl bromoacetate. Characterization of these compounds has been used by elemental analyses, UV-Vis, FT-IR and 1H NMR spectroscopic studies. Their phase transfer studies have been performed by using liquid-liquid extraction procedure. With respect to the chromogenic behavior of hosts upon metal ion complexation, mono ethyl ester azocalix[4]arene derivatives have shown a significant selectivity toward Hg2+ and Hg+ over many other cations. It has been deduced that these new compounds are selective ionophores toward metal cations (Na +, K+, Sr2+, Ag+, Hg+, Hg2+, Co2+, Ni2+, Cu2+, Zn 2+, Cr3+, Al3+ and La3+). © 2014 Elsevier Ltd. All rights reserved