Selective Four-Electron Reduction of Oxygen by a Nonheme Heterobimetallic CuFe Complex

We report herein the first nonheme CuFe oxygen reduction catalyst ([CuII(bpbp)(mu-OAc)2FeIII]2+, CuFe-OAc), which serves as a functional model of cytochrome c oxidase and can catalyze oxygen reduction to water with a turnover frequency of 2.4x103 s-1 and selectivity of 96.0 % in the presence of Et3NH+. This performance significantly outcompetes its homobimetallic analogues (2.7 s-1 of CuCu-OAc with %H2O2 selectivity of 98.9 %, and inactive of FeFe-OAc) under the same conditions. Structure-activity relationship studies, in combination with density functional theory calculation, show that the CuFe center efficiently mediates O-O bond cleavage via a CuII(mu-eta 1 : eta 2-O2)FeIII peroxo intermediate in which the peroxo ligand possesses distinctive coordinating and electronic character. Our work sheds light on the nature of Cu/Fe heterobimetallic cooperation in oxygen reduction catalysis and demonstrates the potential of this synergistic effect in the design of nonheme oxygen reduction catalysts. We have successfully developed the first nonheme CuFe oxygen reduction catalyst, which serves as a functional model of cytochrome c oxidase. This catalyst demonstrates exceptional selectivity (96.0 %) and an impressive turnover frequency (2.4x103 s-1) in the reduction of O2 to water. These outstanding catalytic properties are attributed to the collaborative efforts of copper and iron, as they work together to efficiently break the O-O bond via the CuII(mu-eta 1 : eta 2-O2)FeIII intermediate.image

Automated summary

We report the first nonheme CuFe oxygen reduction catalyst, which shows exceptional selectivity and turnover frequency in the reduction of oxygen to water. The collaborative efforts of copper and iron play a crucial role in achieving these outstanding catalytic properties.