Generation and Reactivity of μ-1,2-Peroxo CuCu and Bis-μ-oxo CuCu Species and Catalytic Hydroxylation of Benzene to Phenol with Hydrogen Peroxide.

Tetradentate-N ligands stabilize dinuclear {Cu(μ-1,2-peroxo)Cu} and {Cu(μ-O)Cu} species, and Cu complexes of these ligands were reported to catalyze the oxidation of benzene with HO. Here, we report {Cu(μ-1,2-peroxo)Cu} and {Cu(μ-O)Cu} intermediates of dinucleating bis(tetradentate-N) ligands depending on the absence or presence of 6-methyl substituents on the terminal pyridine donors, respectively, generated either from {CuCu} precursors with O or from {CuCu} precursors with HO and NEt. Both intermediates are not stable even at low temperatures, but they show no electrophilic HAT reactivity with DHA.