Effect of electron availability on selectivity of O2 reduction by synthetic monometallic Fe porphyrins.
Herein we report that biomimetic analogues of cytochrome c oxidase (CcO) couple reduction of O(2) to oxidation of a single-electron carrier, Ru(NH(3))(6)(2+), under steady-state catalytic turnover. Higher Ru(II) concentrations favor the 4-electron vs 2-electron O(2) reduction pathway. Our data indicate that the capacity of electrode-adsorbed Fe-only porphyrins to catalyze reduction of O(2) to H(2)O is due to high availability of electrons and is eliminated under the biologically relevant slow electron delivery.
Collman
James P
JP
Department of Chemistry, Stanford University, Stanford, California 94305, USA. jpc@stanford.edu
Shiryaeva
Irina M
IM
Boulatov
Roman
R
D002384:Catalysis; D004563:Electrochemistry; D003576:Electron Transport Complex IV / Q000737:chemistry*; D004583:Electrons; D005465:Fluorocarbon Polymers; D007202:Indicators and Reagents; D007501:Iron / Q000737:chemistry*; D018716:Molecular Mimicry; D010084:Oxidation-Reduction; D010100:Oxygen / Q000737:chemistry*; D011166:Porphyrins / Q000737:chemistry*
D005465:Fluorocarbon Polymers; D007202:Indicators and Reagents; D011166:Porphyrins; C040402:perfluorosulfonic acid; D007501:Iron; D003576:Electron Transport Complex IV; D010100:Oxygen