Metalloporphyrinoids are utilized as efficient sensitizers and catalysts in photosynthesis and the reverse reaction that is respiration. Because metalloporphyrinoids show strong absorption in the visible region and redox active, metalloporphyrinoids are also suited as photoredox catalysts for photo-driven redox reactions using solar energy. In particular, metalloporphyrins are utilized as pivotal components to mimic the structure and function of the photosynthetic reaction center. Metalloporphyrins are used as photoredox catalysts for hydrogen evolution from electron and proton sources combining hydrogen evolution catalysts. Metalloporphyrins also act as thermal redox catalysts for photocatalytic reduction of CO2 with photoredox catalysts. Metalloporphyrins are also used as dual catalysts for a photoredox catalyst for oxygenation of substrates with H2O and a redox catalyst for O2 reduction when dioxygen is used as a two-electron oxidant and H2O as an oxygen source, both of which are the greenest reactants. Free base porphyrins can also be employed as promising photoredox catalysts for C-C bond formation reactions.
Bibliographical noteFunding Information:
The authors gratefully acknowledge the contributions of collaborators and co-workers mentioned in the references. The authors also appreciate financial supports provided by Japan Society for the Promotion of Science (Grant Numbers 16H02268 to S.F.), Japan Science and Technology Agency (JST), and Basic Science Research Program, Korea (2017R1D1A1B03029982 to Y.M.L. and 2017R1D1A1B03032615 to S.F.).
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- C-C bond formation
- carbon dioxide reduction
- cobalt complexes
- oxygen reduction
- photocatalytic reaction
- proton reduction
- proton-coupled electron-transfer catalysis