Artificial Mn₄Ca Clusters with Exchangeable Solvent Molecules Mimicking the Oxygen‐Evolving Center in Photosynthesis

Abstract

The natural Mn4Ca cluster in photosystem II serves as a blueprint to develop artificial water‐splitting catalysts for the generation of solar fuel in artificial photosynthesis. Although significant advances have recently been achieved, it remains a great challenge to prepare robust artificial Mn4Ca clusters that precisely mimic the structure and function of the biological catalyst. Herein, we report the isolation and structural characterization of two Mn4CaO4 complexes with polar solvent molecules, acetonitrile or N,N‐dimethylformamide, which closely mimics the two water molecules on the calcium ion, as well as the oxidation states of the four manganese ions and the main geometric structure of the natural Mn4Ca cluster. These new artificial Mn4Ca complexes provide important chemical clues to understand the structure and mechanism of the biological system.

Chemistry of alkaline earth metals: It is not all ionic and definitely not boring!

“…Chemists are challenged to mimic its structure and function and have come up with a number of similar complexes (Fig. 8), of which some recent ones are cited here [47,48].…”

“…Crystal structure of an artificial mimic of the oxygen-evolving CaMn 4 -cluster of photosystem II (inspired with permission from[47]). …”

Redox Potential of the Oxygen-Evolving Complex in the Electron Transfer Cascade of Photosystem II

“…Chen et al reported artificial Mn 4 CaO 4 clusters with exchangeable solvent molecules, where O5 was present but O4 was absent. 11 They concluded that O5 was a structurally important component and O4 was a possible substrate site, which may also fit to the S 0 to S 1 mechanism involving proton release from O4 along the O4-water chain.…”

Tailored Synthesis of an Unprecedented Pb–Mn Heterometallic Halide Hybrid with Enhanced Emission

“…Heterometallic complexes, containing more than one kind of metal, are expected to show synergistic effects on the physical properties of the different metals. 19 Such compounds provide excellent platforms to design function-directed materials, which have been widely applied in catalysis, 20,21 small-molecule activation, 22 molecular magnetism, 23,24 and photoluminescence. 25−29 Particularly, heterometallic complexes comprising luminescent metals have been created as efficient and tunable bulk luminophors.…”