Superoxide-dependent reduction of some simple low molecular mass iron complexes.

Superoxide and hydrogen peroxide are often ascribed iron reducing roles in reactions leading to the formation of an aggressive oxidant by Fenton Chemistry. Hydrogen peroxide, however, does not appear to reduce iron in Fenton reactions, and we here show that several simple ferric complexes are not readily reduced to the ferrous state by superoxide generating systems. Our knowledge of low molecular mass iron complexes in vivo and their reactivity with superoxide radicals is at present insufficient for much of the chemistry proposed.