Mimicking the electron donor side of Photosystem II in artificial photosynthesis

Photosynth Res. 2006 Jan;87(1):25-40. doi: 10.1007/s11120-005-9005-0. Epub 2006 Jan 14.

Abstract

This review focuses on our recent efforts in synthetic ruthenium-tyrosine-manganese chemistry mimicking the donor side reactions of Photosystem II. Tyrosine and tryptophan residues were linked to ruthenium photosensitizers, which resulted in model complexes for proton-coupled electron transfer from amino acids. A new mechanistic model was proposed and used to design complexes in which the mechanism could be switched between concerted and step-wise proton-coupled electron transfer. Moreover, a manganese dimer linked to a ruthenium complex could be oxidized in three successive steps, from Mn (2) (II,II) to Mn (2) (III,IV) by the photo-oxidized ruthenium sensitizer. This was possible thanks to a charge compensating ligand exchange in the manganese complex. Detailed studies of the ligand exchange suggested that at high water concentrations, each oxidation step is coupled to a proton-release of water-derived ligands, analogous to the oxidation steps of the manganese cluster of Photosystem II.

Publication types

  • Research Support, Non-U.S. Gov't
  • Review

MeSH terms

  • Biomimetics*
  • Electrons*
  • Photosynthesis*
  • Photosystem II Protein Complex / chemistry*
  • Photosystem II Protein Complex / metabolism*
  • Tryptophan / chemistry
  • Tryptophan / metabolism
  • Tyrosine / chemistry
  • Tyrosine / metabolism

Substances

  • Photosystem II Protein Complex
  • Tyrosine
  • Tryptophan