A new bis(azine) tetradentate ligand and its transition metal complexes: Synthesis, characterisation, and extraction properties

A new bis(bidentate) azine ligand was prepared by linking (1Z,1′Z)-1,1′-{butane-1,4-diylbis[oxybenzene-4,1-diyl(1Z)ethyl-1-ylidene]}dihydrazine to salicylaldehyde. Two kinds of binuclear copper(II) and nickel(II) complexes with different stoichiometries were prepared. Reaction of bis(azine) ligand with Cu(II) and Ni(II) acetate at a 1: 1 mole ratio gave double-stranded binuclear bis(azine) complexes with stoichiometry [M(L)(H2O)2]2 containing [M(II)N2O2] centres while at a 2: 1 mole ratio, reaction of Cu(II) and Ni(II) chloride with bis(azine) resulted in dinuclear metal complexes with the general stoichiometry [M2(L)Cl2(H2O)2]. Structures of the bis(azine) ligand and its complexes were identified by elemental analysis, IR and UV-VIS spectra, magnetic susceptibility measurements, TGA, and powder XRD. Extraction properties of the bis(azine) ligand towards some transition metal cations and dichromate anions were also reported. It was found that the bis(azine) ligand does not extract cations but it has high extraction ability towards dichromate anions.