Original Articles: 2013 Vol: 5 Issue: 5
Synthesis and structural characterization studies of cobalt(III), manganese(III) and iron(III) schiff base complexes
Abstract
Coordination behaviour of the ligands towards trivalent metal ions has been investigated by IR, molar conductance,
magnetic moments and electronic spectral measurements. The ligands employed are TAA, PAA, ISA and IDA. The
ligands and their metal complexes have been investigated with particular reference to the structure and bonding of
the ligand moiety in the metal complexes. All the complexes are intensely coloured and are insoluble in water and
methanol and soluble in DMSO. They possess 1:2 metal-ligand stoichiometry and formulation of the complexes has
been made on the basis of their analytical data and magnetic susceptibility measurements. Molar conductance
values were in the range expected for a 1:1 electrolytic species. The bonding nature of the ligands to the metal ion
has been determined by careful comparison of the IR spectra of the complexes and the ligands. All the ligands
function as neutral tridentate/bidentate, in all the complexes utilizing the carbonyl oxygen atoms and azomethine
nitrogen atoms for coordination. IR spectra together with molar conductance values adequately confirmed the ionic
nature of acetate group. The cyclic voltammogram of [Fe(PAA)2Cl2]Cl showed the quasi-reversible reduction
nature. The indexing of the X-ray diffraction pattern obtained for the [Fe(TAA)2]Cl3 complex indicated that it has an
orthorhombic crystal lattice. The Schiff base ligands and their metal complexes were tested against four pathogenic
bacteria (Staphylococcus aureus, Bacillus substilis) as Gram-positive bacteria, and (Escherichia coli, Klebsiella
pneumonia) as Gram-negative bacteria. All the metal complexes exhibit higher antibacterial activity than the free
ligand. Iron(III) complexes have higher bacterial activity than the other complexes.