New Monomeric (CoII, NiII, CuII and ZnII) Metal Complexes of a Bidentate Schiff-base Ligand; Synthesis, Characterisation and Biological Studies

Abstract

The new Co^II, Ni^II, Cu^II, Zn^II monomeric complexes with a bidentate Schiff-base ligand [(2-bromo-phenyl)-{3-[(2,4-dinitro-phenyl)-hydrazono]-1-methyl-butylidene}-amine] L are reported. The ligand L was derived from the condensation reaction of 2,4-dinitrophenylhydrazine and acetylacetone, which then reacted with o-bromoaniline. The complexes were prepared from the reaction of the corresponding metal chloride with the ligand. The ligand and its metal complexes were characterised by spectroscopic methods (FTIR, UV-Vis,¹H NMR, A.A), magnetic measurements, chloride content, conductance and melting point. These studies revealed complexes of the general formulae [M(L)₂]Cl₂ with tetrahedral geometries for Co^II and Zn complexes, while square planar geometries have been suggested for Ni^II and Cu^II complexes. Biological activity of the ligand and its metal complexes against gram positive bacterial strain Bacillus (G+) and gram negative bacteria Pseudomonase (G-) revealed that the metal complexes become less resistive to the microbial activities as compared to the free ligand.