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Interfacial Catalysis at Oil/Water Interfaces
Published in Alexander G. Vdlkdv, Interfacial Catalysis, 2002
The molecular organization of a thylakoid membrane is shown in Fig. 5. The spectral characteristics of PS II indicate that the primary electron donor is the dimer of chlorophyll P680 with absorption maxima near 680 and 430nm. Water can be oxidized by an oxygen-evolving complex (OEC) composed of several chlorophyll molecules, two molecules of pheophytin, plastoquinol, several plastoquinone molecules, and a manganese-protein complex containing four manganese ions. The OEC is a highly ordered structure in which a number of polypeptides interact to provide the appropriate environment for cofactors such as manganese, chloride, and calcium, as well as for electron transfer within the complex. Figure 6 shows the electronic equivalent circuit of PS I and PS II.
Vibrational spectroscopy of free di-manganese oxide cluster complexes with di-hydrogen
Published in Molecular Physics, 2023
Sandra M. Lang, Thorsten M. Bernhardt, Joost M. Bakker, Bokwon Yoon, Uzi Landman
The direct conversion of solar energy into storable and renewable fuels is one of the main challenges of modern catalysis research. Inspired by natural photosynthesis, sun-light driven water oxidation followed by the hydrogen evolution reaction (HER, i.e. proton reduction) has attracted much interest and huge research efforts have been invested in this direction during the past decade (see e.g. Ref. [1–7] for recent review articles). Among the various processes involved in artificial photosynthesis the catalysis of the energy demanding water oxidation (reaction 1) represents one of the main challenges (see e.g. Ref. [1,6–10]). In nature, this half-reaction (i.e. the oxidative part of the water plus carbon dioxide redox reaction) is catalysed by the oxygen evolving complex (OEC), which is embedded in the protein structure of photosystem II (PS II). X-ray diffraction studies revealed that the OEC consists of an inorganic CaMn4O5 cluster surrounded by a network of amino acid residues and water molecules [11,12].