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 big challenges of catalysis is the transformation of inert C-H bonds to useful products. Copper-containing monooxygenases play an important role in this regard, as exemplified by the enzyme pMMO which in methanotrophic bacteria converts methane to methanol. 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 the potent greenhouse gas N 2 O, demonstrating their extraordinary 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 .