Characterization of a transient high-valent nonheme Fe(V)=O species by means of a combined time-resolved UV-Vis/XAS investigation

Selective C-H bond oxidation is one of the main goals in organic chemistry and the use of non-heme iron catalysts has emerged as one of its most promising approaches. Highly reactive Fe(V)=O intermediates are invoked as the key oxidizing species in enzymatic and bioinspired oxidations with H2O2 acting as the terminal oxidant, but their direct detection remains elusive. Recently, the generation of Fe(V)=O species from Fe(III)-OOH hydroperoxides has been allowed by the assistance of a strong acid, but the labile Fe(V) species has not yet been directly detected. Our project aims to fill in this gap by monitoring the reaction between an Fe(III)-OOH complex and triflic acid using coupled time-resolved UV-Vis/XAS spectroscopies. The resulting electronic and structural insights are expected to definitely disclose the nature of the key Fe(V)=O oxidizing intermediates allowing a rational design of highly efficient non-heme complexes better mimicking the natural reactivity of iron oxygenases.