Variable Coordination of Peroxide in a Dinuclear Copper Mono‐Oxygenase Model Complex Supported by a Pyridazine‐Bridged Ligand

Copper‐oxygen intermediates play an important role in nature as active species of many copper‐containing enzymes. However, copper‐oxygen intermediates have a key function not only in nature, but also in industry, for example as catalysts. Herein a study on a dinuclear copper complex is presented based on the literature known ligand BPMPD . This ligand combines features of the previously investigated systems (octadentate N ‐donor, like the MO8 system and pyridine donors, like the bdpdz system). Oxygenation of the Cu(I)‐complex with O 2 at low temperature leads to the formation of a μ ‐1,2‐peroxo intermediate ( Cu 2 O 2 ), which is characterized with UV/Vis‐, rRaman‐ and X‐ray absorption spectroscopy (XAS), as well as by cryo‐UHR‐electrospray ionization mass spectrometry. The Cu 2 O 2 species can be reversibly converted into a μ ‐1,1‐hydroperoxo intermediate ( Cu 2 OOH ) by a reaction with lutidinium triflate and 1,8‐diazabicyclo[5.4.0]undec‐7‐ene (DBU), which can be monitored by UV/Vis and XAS. Furthermore, the reactivity of the Cu 2 O 2 species toward dihydroanthracene is investigated.