Characterization of a Dinuclear Copper(II) Complex and Its Fleeting Mixed‐Valent Copper(II)/Copper(III) Counterpart

The synthesis of a dinuclear copper(II) complex, supported by a 1,3‐diamino‐2‐propanol‐based tetraamide ligand, is reported. Structural properties in the solid state and in solution, by means of XRD analysis and NMR spectroscopy, respectively, provide evidence of a highly flexible complex that can display several conformations, leading to the image of the wings of a butterfly. The complex was fully characterized and the redox properties were investigated. Room‐temperature spectro‐electrochemistry was used to monitor the formation of a metastable mono‐oxidized product that displayed an absorption band centered at λ =463 nm. EPR investigation of the low‐temperature, chemically generated, mono‐oxidized product reveals the presence of an intermediate described as a mixed‐valent Cu II Cu III species, which is a model of the possible highly oxidizing intermediate in particulate methane monooxygenase.