The phenol ortho-oxygenation by mononuclear copper(I) complexes requires a dinuclear (mu)-(eta)2: (eta)2-peroxodicopper(II) complex rather than mononuclear CuO2 species

The mononuclear complex [Cu(L)]+ performs the ortho-oxygenation of an exogeneous phenol through the formation of a dinuclear (mu)-(eta)2: (eta)2-peroxodicopper(II) intermediate, which is so far the only type of copper–dioxygen complex that mediates the tyrosinase monophenolase reaction.