Synthesis, characterization, crystal structure, superoxide dismutase and biological activities of nickel (II) complexes with bidentate ligands possessing N and O donor atoms

Two new Schiff bases 2-((E) -(4-bromo-2-chlorophenylimino)methyl)-4-bromophenol (HL1) and 1-((E)-(4-bromo-2-chlorophenylimino)methyl)naphthalene-2-ol (HL2) their new nickel (II) complexes [Ni(L1)2]·DMF(1) and [Ni(L2)2]·(2) have been synthesized and characterized by various physico-chemical and spectroscopic methods. The solid-state structures of complexes were determined by single crystal X-ray crystallography, which revealed square planar geometry around Ni (II) ion. Complex [Ni(L1)2]·DMF(1) crystallizes in the Triclinic system of the space group P-1, a = 8.9954(3) Å, b = 9.4593(4) Å, c = 13.2657(5) Å, α = 101.478°, β = 99.595°, γ = 117.651°and Z = 2. Complex [Ni(L2)2]·(2) crystallizes in the Monoclinic system of the space group P21/c, a = 9.301(9)Å, b = 12.149(8)Å, c = 13.792(10)Å, α = 90°, β = 106.35(4).°, γ = 90°and Z = 2.214