Synthesis, spectral, electrochemical and antibacterial studies of copper(II) complexes with isatin derived bishydrazone and different co-ligands

Abstract

A potentially tridentate bishydrazone derived from isatin was prepared by condensing isatin monohydrazone and salicylaldehyde. This ligand is versatile in forming a series of copper(II) complexes in the presence of different coordinating anions. The ligand and metal complexes have been characterized on the basis of elemental analyses, molar conductance values, magnetic susceptibility data, NMR, UV-visible, IR and EPR spectral studies wherever possible and applicable. The spectral studies reveal that the bishydrazone is monobasic tridentate, coordinating through the deprotonated phenolate oxygen, azomethine nitrogen and carbonyl group of the isatin moiety. Analytical data indicate that the complexes possess 1 : 1 metal–ligand ratio. Molar conductance values support the non-electrolytic nature of the complexes and the complexes have been formulated as [Cu(IBS)X]; where X = Cl−, Br−, , OAc−, or and HIBS = [(2-hydroxybenzaldehyde)-3-isatin]-bishydrazone. Based on the electronic spectral data, and magnetic moment values, a distorted square planar geometry has been proposed for the complexes. The chloride complex [Cu(IBS)Cl] has been subjected to X-ray diffraction and cyclic voltammetric studies. In view of the biological activities of hydrazone derivatives, the ligand and the metallated compounds were screened for the antibacterial activities and the effect of co-ligands on the antibacterial property has also been discussed.