Metal (II) Complexes Derived from Naphthofuran-2-carbohydrazide and Diacetylmonoxime Schiff Base: Synthesis, Spectroscopic, Electrochemical, and Biological Investigation

M B Halli,R B Sumathi

doi:10.1155/2014/942162

Abstract

A new Schiff base and a new series of Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) complexes were synthesized by the condensation of naphthofuran-2-carbohydrazide and diacetylmonoxime. Metal complexes of the Schiff base were prepared from their chloride salts of Co(II), Ni(II), Cu(II), Cd(II), and Hg(II) in ethanol. The ligand along with its metal complexes have been characterized on the basis of analytical data, IR, electronic, mass, 1HNMR, ESR spectral data, thermal studies, magnetic susceptibility, and molar conductance measurements. The nonelectrolytic behaviour of the complexes was assessed from the measured low conductance data. The elemental analysis of the complexes confirm the stoichiometry of the type CuL2Cl2 and MLCl2 where M = Ni(II), Co(II), Cd(II), and Hg(II) and L = Schiff base. The redox property of the Cu(II) complex was investigated by electrochemical method using cyclic voltammetry. In the light of these results, Co(II), Ni(II), and Cu(II) complexes are assigned octahedral geometry, Cd(II), and Hg(II) complexes tetrahedral geometry. In order to evaluate the effect of metal ions upon chelation, both the ligand and its metal complexes were screened for their antibacterial and antifungal activities by minimum inhibitory concentration (MIC) method. The DNA cleaving capacity of all the complexes was analysed by agarose gel electrophoresis method.

Highlights

Oxime Schiff base ligand and their metal complexes are cutting-edge areas of research due to their wide variety of applications in bioinorganic chemistry
The enhanced activity of the metal complexes may be retained to the increased lipophilic nature of the complexes which arose from the chelation
It was noted that the toxicity of the metal complexes increases on increasing the metal ion concentration

Summary

Introduction

Oxime Schiff base ligand and their metal complexes are cutting-edge areas of research due to their wide variety of applications in bioinorganic chemistry. The chemistry involving oxime moiety is quite diverse [1,2,3]. Oxime based ligands and their metal complexes in coordination chemistry have been increasingly expanding for their highly valued physicochemical properties, plant growth regulatory activities, reactivity patterns, and potential applications in many significant chemical processes in the field of medicine, bioorganic systems, electrochemical, and electrooptical sensors [4]. Some of the oxime complexes have exhibited anti-carcinogenic properties [5]. It is known that oxime molecules exhibited greater potency as DNA cleavage agents [6]. Naphthofuran nuclei are key structural moieties found in a large number of biologically important natural products. Many of the natural naphthofurans, such as (±)-laevigatin [7], (+)-heritol [8, 9]

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Conclusion