Synthesis and characterization of porphyrazines as novel extractants for the removal of Ag(I) and Hg(II) from aqueous solution

In this study, the synthesis and characterization of new metal-free and metallo-porphyrazines, peripherally and symmetrically derived from 1,3-alternate26,28-[34,37-dithia-29,32,40,43-tetraoxa-35-en]calix [4]arene-25,27-diol, were performed. Dicyano compound was prepared starting from cis-1,2-dicyano-12-ethylenedithiolate disodium salt and 1,3-alternate 26,28-bis[2-(2-iodoethoxy)ethoxy]calix[4]arene-25,27-diol, which was prepared by the conversion reaction of 26,28-bis[2-(2-chloroethoxy)ethoxy] calix [4]arene-25,27-diol with Nal. The demetalation of magnesium porphyrazine was achieved by the treatment with trifluoroacetic acid that resulted in the metal-free derivative. The solvent extraction of heavy metal cations such as Ag(I), Hg(II), Cu(II), Mn(II), Cr(III), Ni(II), Pb(II) and Zn(II) by the dicyano compounds and its derived metal-free and magnesium porphyrazines was investigated. From the results of two phase extraction studies on the novel compounds, one can conclude that the metal-free and metallo-porphyrazines show very high selectivity for silver and mercury ions when compared with other metal ions. The novel compounds were characterized using the techniques of UV-vis, H-1, C-13 NMR, IR, MS and elemental analysis. (C) 2012 Elsevier Ltd. All rights reserved.