Modeling of Antioxidant Complex Particles Based on Ions of 3d Elements and the Active Site of Cytochrome c

The paper presents the computer simulation results of electron transfer process from the superoxide ion to model particles. The model particles are constructed by replacing the iron ion in the active site of cytochrome c with ions of other 3d metals with valence (III), like chromium, manganese, cobalt, and nickel. Bader’s topological analysis of electron density is conducted to analyze model complex particles and characterize the interactions of bonds between central atom and ligands. Using the Marcus theory, the reorganization energies, activation energies, and rate constants of electron transfer from a superoxide ion to a metal complex in a continuum dielectric medium are calculated. The calculations are preformed using the ORCA 5.0.2 software package and the CPCM continuum solvent model with the PBE density functional in the def2-TZVPD basis for the superoxide ion and def2-SVP basis for the active center models. It is shown that iron (III)-and nickel (III)-based complex particles have potential antioxidant properties with respect to the superoxide ion. The iron(III)-based complex particles demonstrate the most pronounced antioxidant properties.