Superoxide Dismutase-like Activity of Zeolitic Imidazolate Framework Nanoparticles Comprising Biomimetic Imidazolato-bridged CuZn Units.

Nanoparticles exhibiting enzymatic functions have garnered considerable attention due to their structural robustness and the profusion of active sites that can be introduced to a single nanosized particle. Here we report that nanosized mixed-metal zeolitic imidazolate frameworks (ZIFs) show a superoxide dismutase (SOD)-like catalytic activity. We chose a ZIF composed of copper and zinc ions and 2-methylimidazole, CuZn-ZIF-8, in which the Cu and Zn ions are bridged by an imidazolato ligand. This coordination geometry closely mimics the active site of CuZn superoxide dismutase (CuZnSOD). The CuZn-ZIF-8 nanoparticles exhibit potent SOD-like activity, attributed to their porous nature and numerous copper active sites, and also possess exceptional recyclability.