Synthetic Mn3Ce2O5-Cluster Mimicking the Structure and Function of the Oxygen-Evolving Center in Photosynthesis

Abstract

Abstract The photosynthetic oxygen-evolving center (OEC) is a unique Mn4CaO5-cluster that catalyses the water-splitting reaction in nature. It is a long-standing challenge to precisely mimic the structure and function of the OEC in the laboratory. Herein we report two synthetic Mn3Ce2O5-clusters that display unprecedented similarities to the OEC regarding the ten-atom core and the alkyl carboxylate peripheral ligands, as well as the catalytic capability of the water-splitting reaction in aqueous solution. In addition, it has been shown that the oxide bridge in the cluster can rapidly exchange with the isotopic oxygen of H218O in solution. These results, for the first time, demonstrate that cerium can structurally and functionally replace both the calcium and one manganese in the cluster. Our data provide chemical evidence that the oxide bridge could be directly involved in the O-O bond formation in its biological paragon and shed new light on the design of water-splitting catalysts in future.