Why the Reactive Oxygen Species of the Fenton Reaction Switches from Oxoiron(IV) Species to Hydroxyl Radical in Phosphate Buffer Solutions? A Computational Rationale.

ABSTRACT: It has been shown that the major reactive oxygen species (ROS) generated by the aqueous reaction of Fe(II) and H₂O₂ (i.e., the Fenton reaction) are high-valent oxoiron(IV) species, whereas the hydroxyl radical plays a role only in very acidic conditions. Nevertheless, when the Fenton reaction is conducted in phosphate buffer solutions, the resulting ROS turns into hydroxyl radical even in neutral pH conditions. The present density functional theory (DFT) study discloses the underlying principle for this phenomenon. Static and dynamic DFT calculations indicate that in phosphate buffer solutions, the iron ion is highly coordinated by phosphoric acid anions. Such a coordination environment substantially raises the pK _a of coordinated water on Fe(III). A

SUBMITTER: Chen HY 

PROVIDER: S-EPMC6714542 | biostudies-literature | 2019 Aug

REPOSITORIES: biostudies-literature