Re-examining Fenton and Fenton-like reactions

The Fenton and Fenton-like reactions are important in biology because they are a major source of oxidative stress. The reactions also feature in advanced oxidation technologies to remediate organic pollutants. Unfortunately, these reactions are often simplistically viewed as affording only OH˙ radicals as the active species. Indeed, a variety of additional oxidizing intermediates form, including OR˙, Mn+2Lm, MnLm−1(O2H−), MnLm−1(O2R−) and CO3˙−, depending on the system. Under physiological conditions, CO3˙− is probably the major oxidizing intermediate. The Fenton and Fenton-like reactions feature in oxidative stress and are central to advanced oxidation technologies to remediate organic pollutants. The reactions are often simplistically taught to afford only hydroxyl radical as the active oxidant. Yet, this is just one of many possible oxidants and is probably not the major oxidant formed under biological conditions.