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&z.rad; − 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. Hydrogen peroxide functioned as a hydride donor and terminal reductant for the ruthenium-catalyzed reduction of radicals under biologically-relevant conditions.