Dicopper μ‑Oxo, μ‑Nitrosyl Complex from the Activation of NO or Nitrite at a Dicopper Center

Treatment of a dicopper­(I,I) complex
with nitric oxide produces
a dicopper μ-oxo, μ-nitrosyl complex [LCu2(μ-O)­(μ-NO)]2+, representing
the first structurally characterized μ-oxo, μ-nitrosyl
metal complex. This compound can also be synthesized from the reaction
of nitrite with an [LCuIICuI]3+ synthon. Full characterization of the thermal-sensitive
[LCu2­(μ-O)­(μ-NO)]2+ complex with IR, EPR, and X-ray crystallography suggests
a localized mixed-valent CuIII, CuII, O2–, NO– formulation. The [Cu2(μ-O)­(μ-NO)]2+ core efficiently oxidizes exogenous
substrates, such as phosphine, cyclohexadienes, and isochroman to
afford phosphine oxide, benzene, and 1-isochromanone. Since both nitrite
and nitric oxide are proposed oxidants in denitrifying methane oxidation,
the oxidative reactivity of [Cu2(μ-O)­(μ-NO)]2+ core is potentially relevant to anaerobic methane oxidation
observed in methanotrophic archaea.