Template-Engineered Trivalent Iron And Chromium Containing Macrocyclic Complexes: Characterization And In Vitro Studies

A novel series of tetraaza macrocyclic complexes of biological importance was synthesized by “in situ†template reaction between triethylenetetramine and dibenzoylmethane in the presence of trivalent Fe and Cr metal salts in 1:1:1 molar ratio. These complexes are represented by molecular formula [M(C21H26N4)X]X2; M=Fe(III) and Cr(III); X=Cl−, NO3−, −OAc; C21H26N4=macrocyclic ligand. The reported complexes were characterized by using various physicochemical and spectroscopic techniques including elemental analyses, molar conductance, thermo-gravimetric analysis, FTIR, UV–Visible and mass spectral studies. The results obtained from analytical techniques and spectroscopic techniques together suggested the complexes have a square pyramidal geometry. Various computational studies were performed including molecular docking and modeling. Further, macrocyclic complexes were also screened for their “in vitro†antimicrobial activity against selected bacterial and fungal strains. The antioxidant activity of these complexes was also evaluated. Some of the complexes were found to possess remarkable antimicrobial activity and antioxidant activity. However, complex [Fe(C21H26N4)(NO3)](NO3)2 was found to be most potent against selected bacterial and fungal strains. On the other hand, complex [Cr(C21H26N4)(NO3)](NO3)2 was found to show best antioxidant activity with lowest value of IC50.