Synthesis, characterization, crystal structure and antibacterial activities of transition metal(II) complexes of the schiff base 2- [(4-methylphenylimino) methyl] -6-methoxyphenol

Abstract

Five transition metal(II) complexes, [ML2Cl2] 1∼5, were synthesized from the reaction of MCl2.nH2O (M = Mn, Co, Ni, Cu, Cd) and the Schiff base ligand 2-[(4methylphenylimino) methyl]-6-methoxyphenol (C15H15NO2, L), obtained by condensation of o-vanillin (2-hydroxy-3-methoxybenzaldehyde) with p-toluidine. They were characterized by elemental analysis, molar conductance, FT-IR spectra, thermal analysis. The structure of complex 1 was determined by single-crystal X-ray diffraction. Its crystal structure is of monoclinic system, space group P21/c with a = 9.0111(18) Å, b = 11.222(2) Å, c =28.130 (6) Å, α = 90 °, β = 92.29(3) °, γ = 90 °, V = 2867.6(10) Å3, Z = 4. The Mn atom is six-coordinate and displays distorted octahedral geometry. The Schiff base ligand and its complexes have been tested in vitro to evaluate their antibacterial activity against bacteria, viz., Escherichia coli, Staphylococcus aureus and Bacillus subtilis. It has been found that the complexes have higher activity than the corresponding free Schiff base ligand against the same bacteria.