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Reduction of Quinones by NADH Catalyzed by Organoiridium Complexes


  • We thank the ERC (Award 247450 to P.J.S.), members of COST Action CM1105 for stimulating discussions, and the Magnetic Resonance Centre (Warwick University) for EPR support.


original image

One electron at a time: Half-sandwich organometallic cyclopentadienyl–IrIII complexes containing N,N-chelated ligands can catalyze the reduction of quinones (Q), such as vitamin K3, to semiquinones (Q.−) by coenzyme NADH (see picture). DFT calculations suggest that the mechanism involves hydride transfer followed by two one-electron transfers and the unusual IrII oxidation state as a key transient intermediate.