Synthesis, spectroscopic, and antibacterial activity of tetraazamacrocyclic complexes of trivalent chromium, manganese, and iron

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⁻, NO₃⁻, CH₃COO⁻ for Cr(III), Fe(III) and X = CH₃COO⁻ for Mn (III), has been synthesized by condensation of benzil and succinyldihydrazide in the presence of metal salt. The complexes have been so formulated due to the 1:2 electrolytic nature of these complexes as shown by conductivity measurements. The complexes have been characterized with the help of various physicochemical techniques such as elemental analysis, molar conductance, electronic and infrared spectral studies, and magnetic susceptibility. 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 have been tested for their in vitro antibacterial activity. Some of the complexes show remarkable antibacterial activities against some selected bacterial strains. The minimum inhibitory concentrations shown by these complexes have been compared with those shown by some standard antibiotics such as linezolid and cefaclor.

Keywords::

• Macrocyclic complexes
• template
• infrared
• ligand
• antibacterial

Acknowledgements

D. P. Singh thanks the University Grants Commission, New Delhi, for financial support in the form of a Major Research Project. Thanks are also due to the authorities of NIT, Kurukshetra, for providing necessary research facilities.

Declaration of interest: The authors report no conflicts of interest.