title: Inorganic chemistry. A synthetic Mn₄Ca-cluster mimicking the oxygen-evolving center of photosynthesis.
abstract: Photosynthetic splitting of water into oxygen by plants, algae, and cyanobacteria is catalyzed by the oxygen-evolving center (OEC). Synthetic mimics of the OEC, which is composed of an asymmetric manganese-calcium-oxygen cluster bound to protein groups, may promote insight into the structural and chemical determinants of biological water oxidation and lead to development of superior catalysts for artificial photosynthesis. We synthesized a Mn4Ca-cluster similar to the native OEC in both the metal-oxygen core and the binding protein groups. Like the native OEC, the synthetic cluster can undergo four redox transitions and shows two magnetic resonance signals assignable to redox and structural isomerism. Comparison with previously synthesized Mn3CaO4-cubane clusters suggests that the fourth Mn ion determines redox potentials and magnetic properties of the native OEC.
authors.affiliation: Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China. chunxizhang@iccas.ac.cn dhongxing@hrbeu.edu.cn holger.dau@fu-berlin.de.
authors.forename: Chunxi
authors.initials: C
authors.lastname: Zhang
authors.affiliation: College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China.
authors.forename: Changhui
authors.initials: C
authors.lastname: Chen
authors.affiliation: College of Materials Science and Chemical Engineering, Harbin Engineering University, Harbin 150001, China. chunxizhang@iccas.ac.cn dhongxing@hrbeu.edu.cn holger.dau@fu-berlin.de.
authors.forename: Hongxing
authors.initials: H
authors.lastname: Dong
authors.affiliation: Photosynthesis Research Center, Graduate School of Natural Science and Technology, Okayama University, Okayama 700-8530, Japan.
authors.forename: Jian-Ren
authors.initials: JR
authors.lastname: Shen
authors.affiliation: Department of Physics, Free University Berlin, Arnimallee 14, 14195 Berlin, Germany. chunxizhang@iccas.ac.cn dhongxing@hrbeu.edu.cn holger.dau@fu-berlin.de.
authors.forename: Holger
authors.initials: H
authors.lastname: Dau
authors.affiliation: Laboratory of Photochemistry, Institute of Chemistry, Chinese Academy of Sciences, Beijing, 100190, China.
authors.forename: Jingquan
authors.initials: J
authors.lastname: Zhao
mesh_terms: D002118:Calcium / Q000737:chemistry*; D008345:Manganese / Q000737:chemistry*; D018716:Molecular Mimicry; D010100:Oxygen / Q000737:chemistry*; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000737:chemistry*; D014867:Water / Q000737:chemistry*
chemical_list: D045332:Photosystem II Protein Complex; D014867:Water; D008345:Manganese; D010100:Oxygen; D002118:Calcium