Oxidation of aromatic compounds by hydrogen peroxide catalyzed by mononuclear iron(III) complexes

•Iron(III) complexes were studied as catalysts in aromatic hydrocarbons oxidation.•Toluene was oxidized in yields up to 30%, forming cresols as major products.•The reactivity against hydrogen peroxide was followed by UV–vis and ESI–MS.•Iron-hydroperoxide intermediate was proposed as the active catalytic species.•o-cresol and p-cresol interacts with the intermediate forming a yellow chromophore.