Synthesis, spectroscopic and antimicrobial properties of Co(II), Ni (II) and Cu(II) complexes of (&lt;i&gt;E&lt;/i&gt;)-N’-(2-hydroxy -5-nitrobenzylidene)isonicotinohydrazide)

Tolulope M Fasina,F Nneoma Idika,Cordelia U Dueke-Eze

doi:10.4314/jasem.v21i1.13

Abstract

The objective of this study is to investigate the antimicrobial activity of novel Schiff base metal complexes. The resistance of micro-organisms to classical antimicrobial compounds poses a challenge to effective management and treatment of some diseases. In line with this, copper (II), nickel (II) and cobalt (II) complexes of the Schiff base ligand ( E )-N’-(2- hydroxy-5-nitrobenzylidene) isonicotinohydrazide) were synthesized and characterized based on elemental analysis, conductivity measurements, infrared and electronic absorption spectroscopy. The results suggest a 1:2 [M:L] stoichiometry for the copper and cobalt complexes and a 1:1 [M:L] ratio for the nickel complex. The electronic absorption spectral data support octahedral geometry for cobalt(II) and copper(II) complexes and square planar for nickel (II). In-vitro antimicrobial properties of the compounds evaluated against five pathogenic bacteria using the agar-well diffusion method revealed that the activity was in the order Ni>Co>Cu. These compounds can be used as substrates for development of new antimicrobial agents. Keywords: isonicotinohydrazide, Schiff base metal complexes, in-vitro , antimicrobial activity, electronic spectra, 2-hydroxy-5-nitrobenzaldehyde

Highlights

Hydrazones are Schiff bases containing two adjacent nitrogen atoms in which both nitrogen atoms are nucleophilic and the azomethine carbon possesses both electrophilic and nucleophilic character
Salicyladehyde benzoylhydrazone has been shown to be a potent inhibitor of DNA synthesis and cell growth in some cultured human and rodent cells. (Johnson et al, 1982)
Hydrazones of isonicotinic hydrazide are used in treatment of iron overload and as pharmacophore in design of anticonvulsant drugs (Kim et al, 2010)

Summary

Introduction

Hydrazones are Schiff bases containing two adjacent nitrogen atoms in which both nitrogen atoms are nucleophilic and the azomethine carbon possesses both electrophilic and nucleophilic character These compounds have received much attention as a result of their interesting properties and important applications. Acyl and heteroacyl hydrazones are more versatile and flexible as a result of the carbonyl group present which introduces an additional donor site in the molecule These compounds exhibit high and selective antiproliferative activities (Ommis et al, 2016). Schiff bases of isonicotinic hydrazide (INH) a first line anti-tuberculosis drug, the isonicotincoyl hydrazones have been shown to form bioactive metal chelates with many bivalent ions (Chohan et al, 2006; Sharma et al, 2010). We report the synthesis, spectroscopic and antimicrobial properties of the cobalt, nickel and copper complexes of a Schiff base, (5-nitro-2hydroxybenzylidene) isonicotinoyl hydrazide derived from 5-nitro-isonicotinic hydrazide and 2-hydroxy-5nitrobenzyaldehyde

Objectives

Methods

Results