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Extending the Light-Harvesting Properties of Transition-Metal Dendrimers

Larsen, Jane LU ; Puntoriero, Fausto; Pascher, Torbjörn LU ; McClenaghan, Nathan; Campagna, Sebastiano; Åkesson, Eva LU and Sundström, Villy LU (2007) In ChemPhysChem 8(18). p.2643-2651
Abstract
We report a study of the electronic energy-transfer dynamics within the transition-metal polypyridine complex OsRu3pyr6 (Os[(dpp)Ru(bpy{pyrene})2]38+, where dpp=2,3-bis(2-pyridyl)pyrazine and bpy=2,2-bipyridine) after excitation with UV light. By using a broadband visible femtosecond probe, we are able to simultaneously detect both the energy transfer from the peripheral aromatic ligands to the Os center and the sub-picosecond energy transfer from the initially excited Ru-bpy ligand-centered state to the Os triplet metal-to-ligand charge-transfer (MLCT) state. Pyrene energy transfer occurs from both the nonrelaxed and the relaxed S1 states on timescales of 6 and 45 ps, respectively. In both cases, the energy transfer is described by means... (More)
We report a study of the electronic energy-transfer dynamics within the transition-metal polypyridine complex OsRu3pyr6 (Os[(dpp)Ru(bpy{pyrene})2]38+, where dpp=2,3-bis(2-pyridyl)pyrazine and bpy=2,2-bipyridine) after excitation with UV light. By using a broadband visible femtosecond probe, we are able to simultaneously detect both the energy transfer from the peripheral aromatic ligands to the Os center and the sub-picosecond energy transfer from the initially excited Ru-bpy ligand-centered state to the Os triplet metal-to-ligand charge-transfer (MLCT) state. Pyrene energy transfer occurs from both the nonrelaxed and the relaxed S1 states on timescales of 6 and 45 ps, respectively. In both cases, the energy transfer is described by means of Förster energy transfer theory. Sub-picosecond energy transfer within the OsRu3 metal-ligand core most likely includes a direct energy transfer between the higher-lying ligand-centered states on Ru and Os, in addition to the transfer between the MLCT states. The absorption cross-sections in both the UV and the visible spectral regions are enhanced by attaching the aromatic pyrene ligands. Furthermore, energy transfer is directed only towards the Os core, which ultimately leads to an exclusive population of the Os-based triplet MLCT state, thus making the OsRu3pyr6 transition metal-polypyridine dendrimer an obvious candidate for artificial light-harvesting systems. (Less)
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author
organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
dendrimers • excitation energy transfer • light-harvesting systems • time-resolved spectroscopy • transition metals
in
ChemPhysChem
volume
8
issue
18
pages
2643 - 2651
publisher
John Wiley & Sons
external identifiers
  • wos:000252503700011
  • scopus:38049005852
ISSN
1439-7641
DOI
10.1002/cphc.200700539
language
English
LU publication?
yes
id
cbb9c5a5-97b4-48a6-8692-507a42120155 (old id 954006)
date added to LUP
2008-01-25 12:33:29
date last changed
2017-10-22 03:55:04
@article{cbb9c5a5-97b4-48a6-8692-507a42120155,
  abstract     = {We report a study of the electronic energy-transfer dynamics within the transition-metal polypyridine complex OsRu3pyr6 (Os[(dpp)Ru(bpy{pyrene})2]38+, where dpp=2,3-bis(2-pyridyl)pyrazine and bpy=2,2-bipyridine) after excitation with UV light. By using a broadband visible femtosecond probe, we are able to simultaneously detect both the energy transfer from the peripheral aromatic ligands to the Os center and the sub-picosecond energy transfer from the initially excited Ru-bpy ligand-centered state to the Os triplet metal-to-ligand charge-transfer (MLCT) state. Pyrene energy transfer occurs from both the nonrelaxed and the relaxed S1 states on timescales of 6 and 45 ps, respectively. In both cases, the energy transfer is described by means of Förster energy transfer theory. Sub-picosecond energy transfer within the OsRu3 metal-ligand core most likely includes a direct energy transfer between the higher-lying ligand-centered states on Ru and Os, in addition to the transfer between the MLCT states. The absorption cross-sections in both the UV and the visible spectral regions are enhanced by attaching the aromatic pyrene ligands. Furthermore, energy transfer is directed only towards the Os core, which ultimately leads to an exclusive population of the Os-based triplet MLCT state, thus making the OsRu3pyr6 transition metal-polypyridine dendrimer an obvious candidate for artificial light-harvesting systems.},
  author       = {Larsen, Jane and Puntoriero, Fausto and Pascher, Torbjörn and McClenaghan, Nathan and Campagna, Sebastiano and Åkesson, Eva and Sundström, Villy},
  issn         = {1439-7641},
  keyword      = {dendrimers • excitation energy transfer • light-harvesting systems • time-resolved spectroscopy • transition metals},
  language     = {eng},
  number       = {18},
  pages        = {2643--2651},
  publisher    = {John Wiley & Sons},
  series       = {ChemPhysChem},
  title        = {Extending the Light-Harvesting Properties of Transition-Metal Dendrimers},
  url          = {http://dx.doi.org/10.1002/cphc.200700539},
  volume       = {8},
  year         = {2007},
}