Synthesis and Characterization a New Schiff Base Ligand Derived from O-vanillin with Some Transition Metal Complexes and Study of Antimicrobial Activity

A set newly complexes with the general formula [M(L)2(H2O)2] are resulting from the reaction of a new schiff base ligand (L) = "(E)-5-((2-hydroxy-3-methoxy benzylidene) amino)-2-phenyl-2,4-dihydro-3H-pyrazole-3-one". This ligand was derived from the reaction of the two substances amine 5-amino-2-phenyl-4,2-dihydro-3H-pyrazole-3-one with ortho-vanillin. Reaction the ligand with metal ions M= [Mn (II), Co (II), Ni (II), Cu (II), ‎Zn (II), Cd (II), Pt (IV), Hg (II)] afforded new complexes which are characterized by 1H, 13C-NMR, FT-IR, atomic absorption, elemental analysis and electronic spectra. These measurements indicate that the complexes have an octahedral geometry. It coordination with the metal ions through the nitrogen atom of the imine group and the ‎oxygen atom of the hydroxide group of the .pyrazoline ring.The new Schiff base ligand (L) was synthesized with a high yield (88%). The metal complexes were prepared and characterized. FT-IR spectra showed a shift in the (C=N) band from 1600 cm⁻¹ in the ligand to (1580-1595 cm⁻¹) in complexes. The antimicrobial results showed that the Hg(II) complex exhibited the highest inhibition zone (28 mm) against S. aureus, followed by the Cu(II) complex (24 mm), which is higher than the free ligand (14 mm). Standard drugs Ampicillin and Fluconazole were used as controls. The inhibition ability of the prepared compounds was tested against two types of selected bacteria (G-) Coli Escherichia & (G+) Staphylococcus aureus and fungi Candida albicans. The results showed that the ability of the metal complexes to inhibit selected types of microorganisms is higher than the Schiff base ligand.