Remarkably high magnetic coupling and O(2)-activation ability analogous to that of catechol oxidase are characteristics of the first structurally defined, low-symmetry oligonuclear copper complexes of tridentate beta-oxoenamine ligands based on amino carbohydrates (the structure of a bis(acetylbutenonylaminoglucosidato)bis(µ-acetato)tricopper(II) complex is shown).