Calix[4]arene based chemosensor for selective complexation of Cd(II) and Cu(II)

The present article describes synthesis, characterization and a detailed complexation study of calix[4]arene based chemosensor (4) bearing two anthracenyl units as signaling groups on its coordination sphere. The complex formation ability of 4 toward selected transition metals such as Cd(II), Co(II), Cu(II), Ni(II) and Pb(II) has been investigated by UV-visible spectroscopy. Assessment of results reveal that the chemosensor is selective toward Cd(II) and Cu(II). The FT-IR spectroscopic method was applied for further confirmation of the complexation phenomenon. Besides this, a study regarding interference of other metals on complex formation in solution has also supported the efficient binding preference of 4 for Cd(II) and Cu(II). From the results it has been concluded that 4 has compatible coordination sphere to accommodate these metals. The similarities and differences revealed that being soft nature of both metals and because of diagonal relationship in the periodic table their coordination behavior toward N/O-donor ligand may be treated as a test on possibility of the Cu(II) ions to be displaced by Cd(II). The study certainly will help in understanding the hazards of Cd(II) in biological systems. (C) 2010 Elsevier B.V. All rights reserved.