Peroxide Bond Cleavage of Nonheme Iron-(Hydro/Alkyl)Peroxo Complexes Induced by Endogenous and Exogenous Factors

The O–O bond cleavage of peroxide ligands such as hydroperoxide and alkylperoxide within metalloenzymes has been extensively investigated because this process constitutes the key step of dioxygen activation and cellular respiration in all forms of aerobic organisms. Herein, we have provided mechanistic insights into the O–O bond cleavage of iron-(hydro/alkyl)peroxo complexes that was promoted by endogenous and exogenous factors such as spin-state, axial ligand, and electron donors. It has been shown that these factors can effectively direct the O–O bond cleaving pathways (e.g., Fe–O bond cleavage vs O–O bond cleavage or homolysis vs heterolysis). These results support that the peroxide bond cleavage process might proceed via diverse pathways under biological reaction conditions. Understanding the mechanistic pathways for the formation of high-valent metaloxo intermediates has been of critical subjects in bioinorganic research because they have been proposed as key intermediates in dioxygen activation paradigm of O2-activating enzymes. In this review, we discuss the peroxide bond cleavage processes of iron-(hydro/alkyl)peroxo complexes induced by endogenous and exogenous factors.