Abstract

Abbas Ali Salih Al-Hamdani¹ and Shayma A. Shaker²

The new hexadentate Schiff base ligand L [4,4‘(3Z,3‘Z)-3,3‘-(ethane-1,2-diylbis(azan-1-yl-1- ylidene))bis(1,5-dimethyl-2-phenyl-2,3-dihydro-1H-pyrazole-yl-3-ylidene)bis(diazene-2,1-diyl)bis(3- aminophenol)] has been synthesized from condensation of 4-(2-amino-4-hydroxy-phenylazo)-1,5- dimethyl-2-phenyl-1,2-dihydro-pyrazol-3-one (azo) with ethane-1,2- diamine. Monomeric complexes with the general formula [M(L)]Cl2 wher M = Co(II), Ni(II), Cu(II)and Zn(II) are reported. The structures of new ligand, mode of bonding and overall geometry of the complexes were determined through IR, UV-Vis, and NMR spectral studies, magnetic moment measurements, elemental analysis, metal content, and conductance. These studies revealed octahedral geometries for all complexes. Complex formation studies via molar ratio and continuous variation methods in DMF solution were consistent to those found in the solid complexes with a ratio of (M : L) as (1 : 1). Hyper Chem-6 program has been used to predict structural geometries of compounds in gas phase. The heat of formation (ΔHf î) and binding energy (ΔEb ) at 298 K for the free ligand and its metal complexes was calculated by PM3 method. Biological activity of the ligand and its metal complexes against several organisms, Escherichia coli and Staphylococcus aureus are reported. Compounds exhibited the high effect of activity. This may be attributed to the impact of both the chelate effect of Schiff base ligand and the role of the metal in these complexes.

Hexadentate ligand; Schiff base-Azo; Structural Studies and Biological Activity

[ View HTML Full Text]