Synthesis, characterization and superoxide dismutase activity of a series of copper(II) complexes containing NNO donor Schiff base and benzimidazole ligands

Abstract

Several mixed ligand copper(II) complexes, viz., [Cu(BPS)(ImH)](ClO4) (1), [Cu(BPS)(MeImH)](ClO₄) (2), [Cu(BPS) (EtImH)](ClO₄) (3), [Cu(BPS)(BenzImH)]ClO4.0.5H₂O (4) and [Cu(BPS)(MeBenzImH)]ClO₄ (5), where BPS = benzoylpyridine 4-phenylsemicarbazone, ImH = imidazole, MeImH = 2-methylimidazole, EtImH = 2-ethylimidazole, BenzImH = benzimidazole, MeBenzImH = 2-methylbenzimidazole have been synthesized and characterized by the elemental analysis, molar conductance measurements, magnetic susceptibility measurements, FAB mass, IR, electronic, EPR spectral and cyclic voltammetric studies. The BenzImH complex (4) is structurally characterized by single crystal X-ray crystallography. Complex (4) crystallizes in the triclinic space group P-1 with unit cell parameters: a = 10.104(3)Ǻ, b = 10.924(3)Ǻ, c = 13.128(3)Ǻ, ⍺ = 80.21(2)° , β = 70.63(3)°, ϒ = 89.61(2) and Z = 2. The one electron paramagnetic complexes show a d-d band near 700nm in DMSO and a cyclic voltammetric response due to Cu(II)/Cu(I) couple. The complexes show the presence of a distorted square planar CuN₂O₂ coordination geometry. Superoxide dismutase activity of the present complexes has also been studied.