A computational study of oxidation of ruthenium porphyrins via ORuIV and ORuVIO species

Abstract

An unrestricted density functional theory (UDFT) was applied to study the oxidation of ruthenium porphyrins, [RuP], via an interaction with molecular oxygen. The important role of dimeric [RuP] complexes, i.e. [RuP]–O₂–[RuP], in the oxidation mechanism and particular in the cleavage of O–O bond of molecular oxygen has been studied. Geometries and relative Gibbs free energies of the intermediate Ru-complexes, i.e. dimeric oxo-Ru-porphyrins and O₂Ru^II–(or O₂⁻ Ru^III)-, ORu^IV- and ORu^VIO-porphyrins, were evaluated along the proposed reaction pathway. The detailed thermodynamic data of the oxidation reaction [Ru^IIP] → O[Ru^IVP] → O[Ru^VIP]O and important aspects of the vibrational spectra of an oxo-[RuP] has been presented.