(A) S = 1/2 PES (ΔH/ΔG at 288 K, with solvent correction, in kcal/mol) for the reaction of the LS [(N4Py)FeIII–OOH]2+ complex with xanthene. (B) Transition state structure of the direct H-atom abstraction reaction between the LS [(N4Py)FeIII–OOH]2+ complex and xanthene. Fe atom is in green, N atoms are in blue, C atoms are in black, O atoms are in red, H atom is in white. Only important H atoms are shown, others are omitted for clarity.