Abstract
To mimic the electron-donor side of photosystem II (PSII), three trinuclear ruthenium complexes (2, 2a, 2b) were synthesized. In these complexes, a mixed-valent dinuclear Ru2 II,III 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 Ru 2 II,III moieties in the complexes readily undergo reversible one-electron reduction and one-electron oxidation to give the Ru 2 II,III and Ru2 III,III states, respectively. This could allow for photo-oxidation 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 intra-molecular 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 (2a, 2b) to nanocrystalline TiO 2, and the desired electron transfer from the excited state of the [Ru-(bpy)3]2+ moiety to the conduction band of TiO 2 followed by intramolecular electron transfer from the dinuclear Ru2 II,III moiety to photogenerated RuIII was observed. The resulting long-lived Ru2 III,III state decays on the millisecond timescale.
| Original language | English |
|---|---|
| Pages (from-to) | 7305-7314 |
| Number of pages | 10 |
| Journal | Chemistry - A European Journal |
| Volume | 11 |
| Issue number | 24 |
| DOIs | |
| Publication status | Published - Dec 9 2005 |
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Keywords
- Electrochemistry
- Electron transfer
- Mixed-valent compounds
- Ruthenium cluster
- Sensitizers
ASJC Scopus subject areas
- Chemistry(all)
Cite this
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, Yunhua; Eilers, Gerriet; Borgström, Magnus; Pan, Jingxi; Abrahamsson, Maria; Magnuson, Ann; Lomoth, Reiner; Bergquist, Jonas; Polívka, Tomáš; Sun, Licheng; Sundström, Villy; Styring, Stenbjörn; Hammarström, Leif; Åkermark, Björn.
In: Chemistry - A European Journal, Vol. 11, No. 24, 09.12.2005, p. 7305-7314.Research output: Contribution to journal › Article
}
TY - JOUR
T1 - Synthesis and characterization of dinuclear ruthenium complexes covalently linked to RuII Tris-bipyridine
T2 - An approach to mimics of the donor side of photosystem II
AU - Xu, Yunhua
AU - Eilers, Gerriet
AU - Borgström, Magnus
AU - Pan, Jingxi
AU - Abrahamsson, Maria
AU - Magnuson, Ann
AU - Lomoth, Reiner
AU - Bergquist, Jonas
AU - Polívka, Tomáš
AU - Sun, Licheng
AU - Sundström, Villy
AU - Styring, Stenbjörn
AU - Hammarström, Leif
AU - Åkermark, Björn
PY - 2005/12/9
Y1 - 2005/12/9
N2 - To mimic the electron-donor side of photosystem II (PSII), three trinuclear ruthenium complexes (2, 2a, 2b) were synthesized. In these complexes, a mixed-valent dinuclear Ru2 II,III 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 Ru 2 II,III moieties in the complexes readily undergo reversible one-electron reduction and one-electron oxidation to give the Ru 2 II,III and Ru2 III,III states, respectively. This could allow for photo-oxidation 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 intra-molecular 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 (2a, 2b) to nanocrystalline TiO 2, and the desired electron transfer from the excited state of the [Ru-(bpy)3]2+ moiety to the conduction band of TiO 2 followed by intramolecular electron transfer from the dinuclear Ru2 II,III moiety to photogenerated RuIII was observed. The resulting long-lived Ru2 III,III state decays on the millisecond timescale.
AB - To mimic the electron-donor side of photosystem II (PSII), three trinuclear ruthenium complexes (2, 2a, 2b) were synthesized. In these complexes, a mixed-valent dinuclear Ru2 II,III 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 Ru 2 II,III moieties in the complexes readily undergo reversible one-electron reduction and one-electron oxidation to give the Ru 2 II,III and Ru2 III,III states, respectively. This could allow for photo-oxidation 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 intra-molecular 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 (2a, 2b) to nanocrystalline TiO 2, and the desired electron transfer from the excited state of the [Ru-(bpy)3]2+ moiety to the conduction band of TiO 2 followed by intramolecular electron transfer from the dinuclear Ru2 II,III moiety to photogenerated RuIII was observed. The resulting long-lived Ru2 III,III state decays on the millisecond timescale.
KW - Electrochemistry
KW - Electron transfer
KW - Mixed-valent compounds
KW - Ruthenium cluster
KW - Sensitizers
UR - http://www.scopus.com/inward/record.url?scp=29144520227&partnerID=8YFLogxK
UR - http://www.scopus.com/inward/citedby.url?scp=29144520227&partnerID=8YFLogxK
U2 - 10.1002/chem.200500592
DO - 10.1002/chem.200500592
M3 - Article
C2 - 16163754
AN - SCOPUS:29144520227
VL - 11
SP - 7305
EP - 7314
JO - Chemistry - A European Journal
JF - Chemistry - A European Journal
SN - 0947-6539
IS - 24
ER -