Bioinspired molecular clusters for water oxidation

•The brief introduction of artificial photosynthesis and oxygen evolution complex (OEC) in PSII.•Synthetic Mn-based cubanes that mimic OEC have remarkable progress.•OEC-like cubanes and multi-nuclear clusters have extensively used for catalytic water oxidation. Water oxidation (2 H2O → 4H+ + 4 e- + O2) is a key step in utilization of solar energy for producing hydrogen of artificial photosynthetic system. Inspired by the oxygen evolution complex (OEC) in PSII, molecular catalysts are extensively studied and the progress both in biomimetic studies and the mechanistic understanding is truly remarkable. While research efforts in the earlier years focused on the Ru-, Mn- and Ir-based complexes, the focus has gradually changed to non-precious catalysts based on earth-abundant metals (Fe, Co, Ni, Cu). These studies have deepened our understanding on the mechanism of water oxidation, including both proton-coupled electron transfer and O-O bond formation. Herein, we briefly review the research progress surrounding the construction of the OEC-like catalytic systems as well as bioinspired multi-nuclear catalysts for water oxidation.