Synthesis and Characterization of Biologically Active 10-Membered Tetraazamacrocyclic Complexes of Cr(III), Mn(III), and Fe(III)

Abstract

A new series of macrocyclic complexes of type [M(TML)X]X2; where M = Cr(III), Mn(III), or Fe(III); TML is tetradentate macrocyclic ligand and X = Cl−1, NO3−1, CH3COO−1 for Cr(III), Fe(III), and X = CH3COO−1 for Mn(III) has been synthesized by template condensation of succinyldihydrazide and glyoxal. The complexes have been formulated as [M(TML)X]X2 due to 1:2 electrolytic natures of these complexes as shown by conductivity measurements. The complexes have been characterized with the help of elemental analyses, molar conductance, electronic, infrared, far infrared spectral studies and magnetic susceptibilities. On the basis of these studies, a five-coordinate distorted square-pyramidal geometry, in which two nitrogens and two carbonyl oxygen atoms are suitably placed for coordination toward the metal ion, has been proposed for all the complexes. The complexes were tested for their in vitro antibacterial activity. Some of the complexes showed remarkable antibacterial activities against some selected bacterial strains. The minimum inhibitory concentration shown by these complexes was compared with minimum inhibitory concentration shown by some standard antibiotics like linezolid and cefaclor.