Hydrogen peroxide as a hydride donor and reductant under biologically relevant conditions

Some ruthenium–hydride complexes react with O(2) to yield H(2)O(2), therefore the principle of microscopic reversibility dictates that the reverse reaction is also possible, that H(2)O(2) could transfer an H(–) to a Ru complex. Mechanistic evidence is presented, using the Ru-catalyzed ABTS˙(–) reduction reaction as a probe, which suggests that a Ru–H intermediate is formed via deinsertion of O(2) from H(2)O(2) following coordination to Ru. This demonstration that H(2)O(2) can function as an H(–) donor and reductant under biologically-relevant conditions provides the proof-of-concept that H(2)O(2) may function as a reductant in living systems, ranging from metalloenzyme-catalyzed reactions to cellular redox homeostasis, and that H(2)O(2) may be viable as an environmentally-friendly reductant and H(–) source in green catalysis.