Iron(III) Schiff base complexes with asymmetric tetradentate ligands: synthesis, spectroscopy, and antimicrobial properties
ABSTRACT The synthesis and characterization is reported of four iron(III) complexes of general formula [Fe(pythsalX)(H2O)2]Cl2, derived from the NSNO-donor tetradentate Schiff base ligands pythsalHX ([5-X-N-(2-pyridylethylsulfanylethyl)salicylideneimine]
(X=OMe, N2Ph, I, NO2). The complexes were characterized by physico-chemical and spectroscopic methods. The thermal stabilities of both the free
Schiff bases and their complexes were studied by differential scanning calorimetry and thermogravimetric analyses. The spectroscopic
data suggest that the Schiff base ligands coordinate through deprotonated phenolic oxygen, imine, and pyridine-type nitrogens
and the thioether sulfur atoms to give an octahedral geometry around the iron(III) atom in all these complexes. The free Schiff
bases and their complexes have been screened for antimicrobial activities and the results show that the free Schiff bases
are more potent antibacterials than the complexes.