Light induced manganese oxidation and long-lived charge separation in a Mn-2(II,II)-Ru-II (bpy)(3)-acceptor triad
(2005) In Journal of the American Chemical Society 127(49). p.17504-17515- Abstract
- The photoinduced electron-transfer reactions in a Mn-2(II.II)-R-II-NDI triad (1) ([Mn-2(bpmp)(OAc)(2)](+), bpmp = 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methyiphenolate and OAc = acetate, R-II = trisbipyridine ruthenium(II), and NDI = naphthalenediimide) have been studied by time-resolved optical and EPR spectroscopy. Complex 1 is the first synthetically linked electron donor-sensitizer-acceptor triad in which a manganese complex plays the role of the donor. EPR spectroscopy was used to directly demonstrate the light induced formation of both products: the oxidized manganese dimer complex (Mn-2(II.III)) and the reduced naphthalenediimide (NDIcenter dot-) acceptor moieties, while optical spectroscopy was used to follow the kinetic... (More)
- The photoinduced electron-transfer reactions in a Mn-2(II.II)-R-II-NDI triad (1) ([Mn-2(bpmp)(OAc)(2)](+), bpmp = 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methyiphenolate and OAc = acetate, R-II = trisbipyridine ruthenium(II), and NDI = naphthalenediimide) have been studied by time-resolved optical and EPR spectroscopy. Complex 1 is the first synthetically linked electron donor-sensitizer-acceptor triad in which a manganese complex plays the role of the donor. EPR spectroscopy was used to directly demonstrate the light induced formation of both products: the oxidized manganese dimer complex (Mn-2(II.III)) and the reduced naphthalenediimide (NDIcenter dot-) acceptor moieties, while optical spectroscopy was used to follow the kinetic evolution of the [Ru(bpy)(3)](2+) intermediate states and the NDIcenter dot- radical in a wide temperature range. The average lifetime of the NDI- radical is ca. 600 mu s at room temperature, which is at least 2 orders of magnitude longer than that for previously reported triads based on a [Ru(bpy)(3)](2+) photosensitizer. At 140 K, this intramolecular recombination was dramatically slowed, displaying a lifetime of 0.1-1 s, which is comparable to many of the naturally occurring charge-separated states in photosynthetic reaction centra. It was found that the long recombination lifetime could be explained by an unusually large reorganization energy (lambda approximate to 2.0 eV), due to a large inner reorganization of the manganese complex. This makes the recombination reaction strongly activated despite the large driving force (-Delta G degrees = 1.07 eV). Thus, the intrinsic properties of the manganese complex are favorable for creating a long-lived charge separation in the "Marcus normal region" also when the charge separated state energy is high. (Less)
Please use this url to cite or link to this publication:
https://lup.lub.lu.se/record/151417
- author
- Borgström, Magnus ; shaikh, Nizamuddin LU ; Johansson, O ; Anderlund, MF ; Styring, Stenbjörn LU ; Akermark, B ; Magnuson, Ann LU and Hammarstrom, L
- organization
- publishing date
- 2005
- type
- Contribution to journal
- publication status
- published
- subject
- in
- Journal of the American Chemical Society
- volume
- 127
- issue
- 49
- pages
- 17504 - 17515
- publisher
- The American Chemical Society (ACS)
- external identifiers
-
- wos:000233917500075
- scopus:29044448014
- pmid:16332103
- ISSN
- 1520-5126
- DOI
- 10.1021/ja055243b
- language
- English
- LU publication?
- yes
- id
- 3e927973-d488-4998-bec6-23926e764ef8 (old id 151417)
- date added to LUP
- 2016-04-01 15:20:41
- date last changed
- 2022-04-22 07:09:41
@article{3e927973-d488-4998-bec6-23926e764ef8,
abstract = {{The photoinduced electron-transfer reactions in a Mn-2(II.II)-R-II-NDI triad (1) ([Mn-2(bpmp)(OAc)(2)](+), bpmp = 2,6-bis[bis(2-pyridylmethyl)aminomethyl]-4-methyiphenolate and OAc = acetate, R-II = trisbipyridine ruthenium(II), and NDI = naphthalenediimide) have been studied by time-resolved optical and EPR spectroscopy. Complex 1 is the first synthetically linked electron donor-sensitizer-acceptor triad in which a manganese complex plays the role of the donor. EPR spectroscopy was used to directly demonstrate the light induced formation of both products: the oxidized manganese dimer complex (Mn-2(II.III)) and the reduced naphthalenediimide (NDIcenter dot-) acceptor moieties, while optical spectroscopy was used to follow the kinetic evolution of the [Ru(bpy)(3)](2+) intermediate states and the NDIcenter dot- radical in a wide temperature range. The average lifetime of the NDI- radical is ca. 600 mu s at room temperature, which is at least 2 orders of magnitude longer than that for previously reported triads based on a [Ru(bpy)(3)](2+) photosensitizer. At 140 K, this intramolecular recombination was dramatically slowed, displaying a lifetime of 0.1-1 s, which is comparable to many of the naturally occurring charge-separated states in photosynthetic reaction centra. It was found that the long recombination lifetime could be explained by an unusually large reorganization energy (lambda approximate to 2.0 eV), due to a large inner reorganization of the manganese complex. This makes the recombination reaction strongly activated despite the large driving force (-Delta G degrees = 1.07 eV). Thus, the intrinsic properties of the manganese complex are favorable for creating a long-lived charge separation in the "Marcus normal region" also when the charge separated state energy is high.}},
author = {{Borgström, Magnus and shaikh, Nizamuddin and Johansson, O and Anderlund, MF and Styring, Stenbjörn and Akermark, B and Magnuson, Ann and Hammarstrom, L}},
issn = {{1520-5126}},
language = {{eng}},
number = {{49}},
pages = {{17504--17515}},
publisher = {{The American Chemical Society (ACS)}},
series = {{Journal of the American Chemical Society}},
title = {{Light induced manganese oxidation and long-lived charge separation in a Mn-2(II,II)-Ru-II (bpy)(3)-acceptor triad}},
url = {{http://dx.doi.org/10.1021/ja055243b}},
doi = {{10.1021/ja055243b}},
volume = {{127}},
year = {{2005}},
}