Bioinspired artificial photosynthesis systems

In photosynthesis, the oxidizing equivalents generated by photoinduced charge separation in the photosynthetic reaction center in photosystem II (PSII) are used for four-electron oxidation of water to dioxygen, whereas the reducing equivalents are used to reduce two equivalents of plastoquinone in quinone pool to produce two equivalents of plastoquinol. Plastoquinol is used as a two-electron/two-proton reductant to reduce NADP⁺ regioselectively to NADPH in photosystem I (PSI). This review focuses on bioinspired artificial photosynthetic systems to mimic charge-separation processes in the photosynthetic reaction centers and also the functions of PSII to oxidize water, accompanied by reduction of plastoquinone to plastoquinol as well as PSI to reduce protons by plastoquinol to produce hydrogen. Simple photosynthetic reaction center model compounds, which undergo fast charge separation but slow charge recombination, are applied as effective photoredox catalysts to catalyze a variety of chemical transformations under photoirradiation including mimicry of the function of PSI.