"Metal Complexes of Heterocyclic Hydrazone Schiff-Bases: Preparation, Spectral Characterisation and Biological Study"

Abstract

Abstract New isatinic hydrazone Schiff-base ligands, namely furan-2-carboxylic acid (2-oxo-1,2-dihydro-indol3-ylidene)-hydrazide (L1 ), thiophene-2-carboxylic acid (2- oxo-1,2-dihydro-indol-3-ylidene)-hydrazide (L2 ) and 2-(pyridine-2-yl-hydrazono)-1,2-dihydro-indol-3-one) (L3 ) are reported. The ligands were prepared by the condensation of furan-2-carboxylic acid hydrazide (L1 ), thiophene2-carboxylic acid hydrazide (L2 ), and 2-hydrazino pyridine (L3 ) with isatine. Monomeric complexes were prepared from the reaction of the corresponding metal chloride with the ligands. The ligands and their nine new complexes of the general formulae [M(Ln )2]Cl2 [where M = Co(II), Zn(II) and Cd(II); n = L1 , L2 and L3 ] were characterised by spectroscopic methods (FTIR, UV–Vis, 1 H, 13C NMR), elemental analysis, metal content, magnetic measurement and molar conductance. These studies revealed the formation of six coordinate complexes, in which the geometry about metal atom is a distorted octahedral. Biological activity of the ligands and their metal complexes against Gram-positive bacterial strain Bacillus (G?) and Gramnegative bacteria Ecoli (G-) are evaluated. The effects of prepared compounds depend on the type of tested bacteria. It is clear that the ligands and their metal complexes