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

Abstract

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 [LCu^IICu^I]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 Cu^III, Cu^II, O^2-, 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.