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Synthesis and Characterization of Dinuclear Ruthenium Complexes Covalently Linked to RuII Tris-bipyridine: An Approach to Mimics of the Donor Side of Photosystem II

Xu, Y; Eilers, G; Borgstrom, M; Pan, Jingxi LU ; Abrahamsson, M; Magnuson, A; Lomoth, R; Bergquist, J; Polivka, Tomas LU and Sun, L, et al. (2005) In Chemistry: A European Journal 11(24). p.7305-7314
Abstract
To mimic the electron-donor side of photosystem II (PSII), three trinuclear ruthenium complexes (2, 2 a, 2 b) were synthesized. In these complexes, a mixed-valent dinuclear moiety with one phenoxy and two acetato bridges is covalently linked to a RuII tris-bipyridine photosensitizer. The properties and photoinduced electron/energy transfer of these complexes were studied. The results show that the moieties in the complexes readily undergo reversible one-electron reduction and one-electron oxidation to give the and states, respectively. This could allow for photooxidation of the sensitizer part with an external acceptor and subsequent electron transfer from the dinuclear ruthenium moiety to regenerate the sensitizer. However, all trinuclear... (More)
To mimic the electron-donor side of photosystem II (PSII), three trinuclear ruthenium complexes (2, 2 a, 2 b) were synthesized. In these complexes, a mixed-valent dinuclear moiety with one phenoxy and two acetato bridges is covalently linked to a RuII tris-bipyridine photosensitizer. The properties and photoinduced electron/energy transfer of these complexes were studied. The results show that the moieties in the complexes readily undergo reversible one-electron reduction and one-electron oxidation to give the and states, respectively. This could allow for photooxidation of the sensitizer part with an external acceptor and subsequent electron transfer from the dinuclear ruthenium moiety to regenerate the sensitizer. However, all trinuclear ruthenium complexes have a very short excited-state lifetime, in the range of a few nanoseconds to less than 100 ps. Studies by femtosecond time-resolved techniques suggest that a mixture of intramolecular energy and electron transfer between the dinuclear ruthenium moiety and the excited [Ru(bpy)3]2+ photosensitizer is responsible for the short lifetimes. This problem is overcome by anchoring the complexes with ester- or carboxyl-substituted bipyridine ligands (2 a, 2 b) to nanocrystalline TiO2, and the desired electron transfer from the excited state of the [Ru(bpy)3]2+ moiety to the conduction band of TiO2 followed by intramolecular electron transfer from the dinuclear moiety to photogenerated RuIII was observed. The resulting long-lived state decays on the millisecond timescale. (Less)
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published
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in
Chemistry: A European Journal
volume
11
issue
24
pages
7305 - 7314
publisher
John Wiley & Sons
external identifiers
  • wos:000234038100017
  • scopus:29144520227
ISSN
1521-3765
DOI
10.1002/chem.200500592
language
English
LU publication?
yes
id
006ba7b7-f2f6-42a7-8b75-f02f4e5de49d (old id 157845)
date added to LUP
2007-07-04 09:05:14
date last changed
2017-08-27 05:13:55
@article{006ba7b7-f2f6-42a7-8b75-f02f4e5de49d,
  abstract     = {To mimic the electron-donor side of photosystem II (PSII), three trinuclear ruthenium complexes (2, 2 a, 2 b) were synthesized. In these complexes, a mixed-valent dinuclear moiety with one phenoxy and two acetato bridges is covalently linked to a RuII tris-bipyridine photosensitizer. The properties and photoinduced electron/energy transfer of these complexes were studied. The results show that the moieties in the complexes readily undergo reversible one-electron reduction and one-electron oxidation to give the and states, respectively. This could allow for photooxidation of the sensitizer part with an external acceptor and subsequent electron transfer from the dinuclear ruthenium moiety to regenerate the sensitizer. However, all trinuclear ruthenium complexes have a very short excited-state lifetime, in the range of a few nanoseconds to less than 100 ps. Studies by femtosecond time-resolved techniques suggest that a mixture of intramolecular energy and electron transfer between the dinuclear ruthenium moiety and the excited [Ru(bpy)3]2+ photosensitizer is responsible for the short lifetimes. This problem is overcome by anchoring the complexes with ester- or carboxyl-substituted bipyridine ligands (2 a, 2 b) to nanocrystalline TiO2, and the desired electron transfer from the excited state of the [Ru(bpy)3]2+ moiety to the conduction band of TiO2 followed by intramolecular electron transfer from the dinuclear moiety to photogenerated RuIII was observed. The resulting long-lived state decays on the millisecond timescale.},
  author       = {Xu, Y and Eilers, G and Borgstrom, M and Pan, Jingxi and Abrahamsson, M and Magnuson, A and Lomoth, R and Bergquist, J and Polivka, Tomas and Sun, L and Sundström, Villy and Styring, Stenbjörn and Hammarstrom, L and Akermark, B},
  issn         = {1521-3765},
  language     = {eng},
  number       = {24},
  pages        = {7305--7314},
  publisher    = {John Wiley & Sons},
  series       = {Chemistry: A European Journal},
  title        = {Synthesis and Characterization of Dinuclear Ruthenium Complexes Covalently Linked to RuII Tris-bipyridine: An Approach to Mimics of the Donor Side of Photosystem II},
  url          = {http://dx.doi.org/10.1002/chem.200500592},
  volume       = {11},
  year         = {2005},
}