Neutralization of Reactive Oxygen Species at Dinuclear Cu(II)-Cores: Tuning the Antioxidant Manifold in Water by Ligand Design

Dinuclear Cu2(II,II)-cores stabilized by the N3O donorset of HL1 = (2-{[[di­(2-pyridyl)­methyl]­(methyl)­amino]­methyl}­phenol), HL2 = 2-({[di­(2-pyridyl)­methyl]­amino}­methyl)­phenol), and HL3 = 2-({[di­(2-pyridyl)­methyl]­amino}­methyl)-4-nitrophenol display a unique superoxide dismutase (SOD) combined with catalase (CAT)-like activity in water, at neutral pH. The Cu 2 L 1 2 < Cu 2 L 2 2 < Cu 2 L 3 2 structure–reactivity trend puts a spotlight on the electron-deficient core of Cu 2 L 3 2 that exhibits the highest SOD (log k cat(O2 •–) = 7.55) and CAT-like (k H2O2 = 0.66 M–1 s–1) performance. Time-lapse ESI-MS and EPR experiments indicate that a dimeric core is essential for oxygenic turnover upon H2O2 decomposition.