Tailoring the Oxidizing Intermediate in the Fenton Reaction, OH⋅ or FeIV=Oaq, by Modifying the pKa of the (H₂O)₅FeII(H₂O₂) Complex, and the Case of PDS – a DFT Study

A DFT analysis of the Fenton and Fenton‐like reactions points out that the pH effect on the nature of the oxidizing intermediate formed is due to a p K a of the peroxide when hydroperoxides are used. When S 2 O 8 2− is used, the pH effect is due to the p K a of one of the water ligands of the central iron cation. The results suggest that the choice of the hydroperoxide and the ligands present affects the pH at which the transition from the formation of hydroxyl radicals to the formation of Fe IV =O aq occurs.