Novel homo- and hetero-nuclear copper(II) complexes of tetradentate Schiff bases: Synthesis, characterization, solvent-extraction and catalase-like activity studies

Twelve homo- and hetero-nuclear copper(II) complexes of tetradentate Schiff base ligands containing N 4 donor sets have been prepared by employing several steps. The characterization and nature of bonding of the complexes have been deduced from elemental analysis, FT-IR, molar conductivity, magnetic moment measurements and thermal analysis. The three Schiff base ligands were further identified using 1H and 13C NMR spectra. All copper(II) complexes are 1:2 electrolytes as shown by their molar conductivities ( Λ M) in DMF and paramagnetic. The subnormal magnetic moment values of the di- and tri-nuclear complexes explained by a very strong anti-ferromagnetic interaction. The extraction ability of the ligands has been examined by the liquid–liquid extraction of selected transition metal (Mn 2+, Co 2+, Ni 2+, Cu 2+, Zn 2+, Pb 2+, Cd 2+, Hg 2+) cations. The ligands show strong binding ability toward copper(II) ion. Furthermore the homo- and hetero-nuclear copper(II) complexes were each tested for their ability to catalyse the disproportionation of hydrogen peroxide in the presence of the added base imidazole.