Catalytic Oxygenation of Hydrocarbons by Mono‐μ‐oxo Dicopper(II) Species Resulting from O−O Cleavage of Tetranuclear Cu(I)/Cu(II) Peroxo Complexes

One of the challenges of catalysis is the transformation of inert C−H bonds to useful products. Copper‐containing monooxygenases play an important role in this regard. Here we show that low‐temperature oxygenation of dinuclear copper(I) complexes leads to unusual tetranuclear, mixed‐valent μ(4)‐peroxo [Cu(I)/Cu(II)](2) complexes. These Cu(4)O(2) intermediates promote irreversible and thermally activated O−O bond homolysis, generating Cu(2)O complexes that catalyze strongly exergonic H‐atom abstraction from hydrocarbons, coupled to O‐transfer. The Cu(2)O species can also be produced with N(2)O, demonstrating their capability for small‐molecule activation. The binding and cleavage of O(2) leading to the primary Cu(4)O(2) intermediate and the Cu(2)O complexes, respectively, is elucidated with a range of solution spectroscopic methods and mass spectrometry. The unique reactivities of these species establish an unprecedented, 100 % atom‐economic scenario for the catalytic, copper‐mediated monooxygenation of organic substrates, employing both O‐atoms of O(2).