Copper(II) Ion Complexation by the Tetradentate Phosphorus-Nitrogen Ligand P2N2 at the Water/1,2-DCE Interface

The tetradentate ligand N,N?-bis[2-(diphenylphosphino)phenyl]propane-1,3-diamine (P2N2) has been synthesized and characterized by several analytical methods. The electrochemical properties of P2N2 and its coordination ability with transition metal ions at the water/1,2-dichloroethane interface have been studied by cyclic voltammetry. It was found that P2N2 can chelate copper(II) ion. The transfer of the Cu2+ facilitated by P2N2 has been observed in the presence of Cl-, Br-, or acetate anion in the aqueous phase. An interfacial reaction between the ligand and metal ion has been proposed. A unique selectivity of P2N2 toward copper(II) makes it possible to use this hydrophobic ligand as an extractant in separation processes.