Reaction Intermediates in Artificial Photosynthesis with Molecular Catalysts

Young Hyun Hong, Yong Min Lee, Wonwoo Nam, Shunichi Fukuzumi

Research output: Contribution to journalReview articlepeer-review

5 Scopus citations

Abstract

In nature, water oxidation is catalyzed by Mn4Ca clusters in the oxygen-evolving complex (OEC) of photosystem II (PSII), in which a manganese(V)-oxo species acts as an active reaction intermediate. Electrons and protons taken from water in PSII are used to reduce plastoquinone to plastoquinol via photoinduced charge separation in the photosynthetic reaction center. In photosystem I (PSI), NADP+coenzyme is reduced by plastoquinol via photoinduced charge separation in the photosynthetic reaction center to produce NADPH, which is used as a reductant to reduce CO2to carbohydrates in the Calvin cycle. Extensive efforts have so far been made to mimic functions of PSII and PSI for photocatalytic water oxidation and reduction to produce O2and H2, respectively. Characterization and reactivity of high-valent metal-oxo, -hydroperoxo, -peroxo, and -superoxo intermediates have been investigated to clarify the mechanisms of water oxidation. Metal hydride complexes have also been studied in relation with the catalytic reactivity for water reduction to produce H2as well as NAD+reduction to NADH. This Review is intended to provide an overview on the functional model reactions of PSII and PSI for the photocatalytic water oxidation and reduction, respectively. The roles of high-valent metal-oxo, -hydroperoxo, -peroxo, and -superoxo complexes as the reaction intermediates in photocatalytic water oxidation are focused in relation with the catalytic mechanisms of water oxidation. The roles of metal hydride complexes are also discussed in relation with the catalytic mechanisms of hydrogen evolution and NAD+reduction to NADH. The combination of functional model reactions of PSII and PSI leads to construct molecular artificial photosynthetic systems in which water is split to H2and O2in a 2:1 ratio, providing a way to realize artificial photosynthesis in molecular levels.

Original languageEnglish
Pages (from-to)308-341
Number of pages34
JournalACS Catalysis
Volume13
Issue number1
DOIs
StatePublished - 6 Jan 2023

Bibliographical note

Publisher Copyright:
© 2023 American Chemical Society. All rights reserved.

Keywords

  • artificial photosynthesis
  • molecular catalyst
  • photosystems I and II
  • reaction intermediate
  • reaction mechanism
  • water splitting

Fingerprint

Dive into the research topics of 'Reaction Intermediates in Artificial Photosynthesis with Molecular Catalysts'. Together they form a unique fingerprint.

Cite this