Synthesis, DFT/TD-DFT theoretical studies, experimental characterization, electrochemical and antioxidant activity of Fe(III) complexes of bis (dimethylglyoximato) guanine

Abstract

A new series of Iron (III) complexes of general formula [Fe(Hdmg) 2 (Gua)X]nH 2 O where (Hdmg = dimethylglyoximato monoanion, Gua = Guanine, X = Cl, Br or I) have been prepared and characterized by elemental analysis, conductivity, infrared spectra and electronic spectra. The molar conductance data confirm that all the complexes are no electrolytic. The mode of bonding and geometry of the Fe(III) complexes have been inferred spectral data, an octahedral geometry is ascribed for all the Fe(III) complexes. In these compounds, two dimethylglyoximato monoanions bond to the metal in the equatorial plan have been formed. The two axial sites being occupied by the guanine and the halogen moieties. The thermal properties of the Fe(III) complexes were investigated using TG and TDA. The thermal behavior of the compounds illustrates the general decomposition patterns of the complexes. The voltammetry experiments have been performed on the complexes to evaluate the redox process of Fe(III)/Fe(II) couple. These compounds were screened for their in-vitro antioxidant properties using 2,2-diphenyl-1-picrylhydrazyl radical (DPPH.) free radical scavenging. The results obtained show that these complexes have a good antioxidant activity in comparison with ascorbic acid as positive control