Dioxygen Binding at Ambient Temperature: Formation of a Novel Peroxodicopper(II) Complex with an Azole Macrocyclic Ligand

The protective pocket of hemocyanin is mimicked by the novel macrocyclic ligand MEPY22PZ (see schematic drawing on the right), which was used to make a Cu2O2 adduct. Proper design of a ligand with azole donors connected by ethylene spacers illustrates how metal–O2 adducts can be stabilized at ambient temperatures and in protic solvents. The purple trans-μ-1,2-CuII-O2-CuII species was obtained by oxygenation of the parent CuI compound and by addition of H2O2 and base to the dinuclear CuII complex.