Formic Acid Acting as an Efficient Oxygen Scavenger in Four-Electron Reduction of Oxygen Catalyzed by a Heterodinuclear Iridium−Ruthenium Complex in Water

A heterodinuclear iridium−ruthenium complex [IrIII(Cp*)(H2O)(bpm)RuII(bpy)2](SO4)2 (Cp* = η5-pentamethyl-cyclopentadienyl, bpm = 2,2′-bipyrimidine, bpy = 2,2′-bipyridine) acts as an effective catalyst for removal of dissolved O2 by the four-electron reduction of O2 with formic acid in water at an ambient temperature.