Synthesis and characterization of three novel azocalix[4]arene Schiff base derivatives and their selective copper extraction

Abstract

The synthesis and characterization of three novel Schiff bases of azocalix[4]arene and their selective copper extraction are described. The preparation of azocalix[ 4]arenes (1c, 2c and 3c) has been achieved by the condensation of 2-hydroxy-3-methoxybenzaldehyde with the amine group of upper rim mono-, di- and tetra-(aminophenylazo) calix[4]arene in ethanol. The synthesized products (1c, 2c and 3c) are characterized by both 1H and 13C NMR techniques, IR spectroscopy and elemental analysis. Extraction capabilities of interested derivatives of azocalix[4]arene from aqueous phase into organic phase are also examined. While extraction of Ag +, Hg + and Hg 2+ cations gave strong complexes with azo groups, extraction of Cu 2+ cation is found to be highly effective with -CH=N- and neighboring -OH groups. © 2011 Iranian Chemical Society.