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

Abstract

Some ruthenium–hydride complexes react with O₂ to yield H₂O₂, therefore the principle of microscopic reversibility dictates that the reverse reaction is also possible, that H₂O₂ 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 O₂ from H₂O₂ following coordination to Ru. This demonstration that H₂O₂ can function as an H⁻ donor and reductant under biologically-relevant conditions provides the proof-of-concept that H₂O₂ may function as a reductant in living systems, ranging from metalloenzyme-catalyzed reactions to cellular redox homeostasis, and that H₂O₂ may be viable as an environmentally-friendly reductant and H⁻ source in green catalysis.