title: Imidazolium or guanidinium/layered manganese (III, IV) oxide hybrid as a promising structural model for the water-oxidizing complex of Photosystem II for artificial photosynthetic systems.
abstract: Photosystem II is responsible for the light-driven biological water-splitting system in oxygenic photosynthesis and contains a cluster of one calcium and four manganese ions at its water-oxidizing complex. This cluster may serve as a model for the design of artificial or biomimetic systems capable of splitting water into oxygen and hydrogen. In this study, we consider the ability of manganese oxide monosheets to self-assemble with organic compounds. Layered structures of manganese oxide, including guanidinium and imidazolium groups, were synthesized and characterized by scanning electron microscopy, transmission electron microscopy, X-ray diffraction spectrometry, and atomic absorption spectroscopy. The compounds can be considered as new structural models for the water-oxidizing complex of Photosystem II. The overvoltage of water oxidation for the compounds in these conditions at pH = 6.3 is ~0.6 V. These compounds may represent the first step to synthesize a hybrid of guanidinium or imidazole together with manganese as a biomimetic system for the water-oxidizing complex of Photosystem II.
authors.affiliation: Department of Chemistry, Institute for Advanced Studies in Basic Sciences (IASBS), 45137-66731, Zanjan, Iran, mmnajafpour@iasbs.ac.ir.
authors.forename: Mohammad Mahdi
authors.initials: MM
authors.lastname: Najafpour
authors.forename: Mahmoud Amouzadeh
authors.initials: MA
authors.lastname: Tabrizi
authors.forename: Behzad
authors.initials: B
authors.lastname: Haghighi
authors.forename: Julian J
authors.initials: JJ
authors.lastname: Eaton-Rye
authors.forename: Robert
authors.initials: R
authors.lastname: Carpentier
authors.forename: Suleyman I
authors.initials: SI
authors.lastname: Allakhverdiev
mesh_terms: D055664:Electrochemical Techniques; D004566:Electrodes; D019791:Guanidine / Q000737:chemistry*; D007093:Imidazoles / Q000737:chemistry*; D017895:Manganese Compounds / Q000737:chemistry*; D046529:Microscopy, Electron, Transmission; D008958:Models, Molecular; D010084:Oxidation-Reduction; D010087:Oxides / Q000737:chemistry*; D010100:Oxygen / Q000378:metabolism; D010788:Photosynthesis; D045332:Photosystem II Protein Complex / Q000378:metabolism*; D014867:Water / Q000378:metabolism*; D014961:X-Ray Diffraction
chemical_list: D007093:Imidazoles; D017895:Manganese Compounds; D010087:Oxides; D045332:Photosystem II Protein Complex; D014867:Water; C027424:manganese oxide; D019791:Guanidine; D010100:Oxygen
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