Angewandte Chemie Interna... by Nicole Kindermann, Eckhard Bill, Sebastian Dechert, Serhiy Demeshko, Edward J. Reijerse, Franc Meyer / 5d // keep unread // hide // preview Abstract Copper enzymes play important roles in the binding and activation of dioxygen in biological systems. Key copper/dioxygen intermediates have been identified and studied in synthetic analogues of the metalloprotein active sites, including the μ-η 2 :η 2 -peroxodicopper(II) motif relevant to type III dicopper proteins. Herein, we report the synthesis and characterization of a bioinspired dicopper system that forms a stable μ-η 1 :η 1 -peroxo complex whose Cu-O-O-Cu torsion is constrained to around 90° by ligand design. This results in sizeable ferromagnetic coupling between the copper(II) ions, which is detected by magnetic measurements and HF-EPR spectroscopy. The new dicopper peroxo system is the first wit...