C-H Bond Activation by Air-Stable [(Diimine)MII(μ2-OH)]22+ Dimers (M = Pd, Pt)

Air- and water-tolerant C−H activation is observed in reactions of [(diimine)Pt(μ_2-OH)]_2^(2+) dimers with allylic and benzylic C−H groups. The reactions proceed in good yields under mild conditions. Mechanistic studies indicate that the active species is the monomeric [(diimine)Pt(OH_2)]^(2+) dication. The related palladium species, [(diimine)Pd(μ_2-OH)_2]^(2+), exhibit similar stoichiometric activations and also effect catalytic oxidation of cyclohexene to benzene with molecular oxygen as the terminal oxidant.