LAUSR

We use density functional theory (DFT) and ab initio molecular dynamics to study the conversion of H2O into H2O2 in water solution by the FeIVO2+ group under room-temperature and -pressure conditions. We compute the free energy of formation of an O(water)–O(oxo) bond using thermodynamic integration with explicit solvent and we examine the subsequent generation of H2O2 by proton transfer. We show that the O–O bond formation follows the standard reactivity pattern observed in hydroxylation reactions catalyzed by high-spin (S = 2) iron(IV)–oxo species, which is initiated by the transfer of one electron from the highest occupied molecular orbital of the moiety attacking the FeIVO2+ group, either a −C–H bonding orbital (hydroxylation) or a lone pair of a water molecule (water oxidation). The highly electrophilic character exhibited by the FeIVO2+ ion, which is related to the presence of an acceptor 3σ* orbital at low energy with a large contribution on the O end of the FeIVO2+ ion, is the crucial factor promot...