Oxygen-promoted C-H bond activation at palladium

[Pd(P(Ar)(tBu)₂)₂] (1, Ar=naphthyl) reacts with molecular oxygen to form Pd^II hydroxide dimers in which the naphthyl ring is cyclometalated and one equivalent of phosphine per palladium atom is released. This reaction involves the cleavage of both C-H and O-O bonds, two transformations central to catalytic aerobic oxidizations of hydrocarbons. Observations at low temperature suggest the initial formation of a superoxo complex, which then generates a peroxo complex prior to the C-H activation step. A transition state for energetically viable C-H activation across a Pd-peroxo bond was located computationally.