Synthesis, structure, and solvent-extraction properties of tridentate oxime ligands and their cobalt(II), nickel(II), copper(II), zinc(II) complexes

Synthesis of four different types of ligands Ar[COC(NOH)R] (n) (Ar = biphenyl, n = 1, HL1; Ar = biphenyl, n = 2, H2L2; Ar = diphenylmethane, n = 1, HL3; Ar = diphenylmethane, n = 2, H2L4; R = furfurylamine in all ligands) and their dinuclear Co2+, Ni2+, Cu2+, and Zn2+ complexes is reported herein. These compounds were characterized by elemental analysis, ICP-OES, FT-IR spectra, and magnetic susceptibility measurements. The ligands were further characterized by H-1 NMR. The results suggest that dinuclear complexes of HL1 and HL3 have a metal to ligand mole ratio of 2: 2 and dinuclear complexes H2L2 and H2L4 have a metal to ligand mole ratio of 2: 1. Square pyramidal or octahedral structures are proposed for complexes of oxime ligands. Furthermore, extraction abilities of the four ligands were also evaluated in chloroform using selected transition metal picrates such as Mn2+, Co2+, Ni2+, Cu2+, Zn2+, Cd2+, Hg2+, Pb2+. The ligands show strong binding ability towards Hg2+ and Cu2+ ions.