Light-induced spin crossover probed by ultrafast optical and X-ray spectroscopies
(2007) In Chimia 61(4). p.179-183- Abstract
The photoinduced energy and structural relaxation of aqueous iron(II)-tris-bipyridine ([FeII(bpy)3]2+), upon excitation into its singlet metal-to-ligand charge transfer (1MLCT) band, and the population of its short-lived (≤0.6 ns) high-spin excited state have been characterized by combined ultrafast optical and X-ray spectroscopies. Polychromatic femtosecond fluorescence up-conversion reveals a very short lived 1MLCT emission band, which decays in ≤20 fs by intersystem crossing to a 3MLCT, whose very weak emission is also observed. Transient absorption studies show that the latter decays in <150 fs, while the population of the lowest excited high spin quintet state... (More)
The photoinduced energy and structural relaxation of aqueous iron(II)-tris-bipyridine ([FeII(bpy)3]2+), upon excitation into its singlet metal-to-ligand charge transfer (1MLCT) band, and the population of its short-lived (≤0.6 ns) high-spin excited state have been characterized by combined ultrafast optical and X-ray spectroscopies. Polychromatic femtosecond fluorescence up-conversion reveals a very short lived 1MLCT emission band, which decays in ≤20 fs by intersystem crossing to a 3MLCT, whose very weak emission is also observed. Transient absorption studies show that the latter decays in <150 fs, while the population of the lowest excited high spin quintet state 5T 2 occurs in ∼1 ps. Subsequently it decays in ∼665 ps to the ground state. Therefore, we determined the structure of the high-spin excited state by picosecond X-ray absorption spectroscopy at the K edge of Fe. The structural analysis of both the transient difference and excited state X-ray spectra delivered an Fe-N bond elongation of 0.2 Å in the quintet state compared to the singlet ground state.
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- author
- Gawelda, Wojciech ; Cannizzo, Andrea ; El Nahhas, Amal LU ; Milne, Christopher J. ; Van Der Veen, Renske ; Bressler, Christian ; Chergui, Majed and Pham, Van-Thai LU
- publishing date
- 2007-05-21
- type
- Contribution to journal
- publication status
- published
- subject
- keywords
- Fluorescence, Iron (II) complexes, Optical absorption, Spin crossover, Ultrafast, X-ray absorption
- in
- Chimia
- volume
- 61
- issue
- 4
- pages
- 5 pages
- publisher
- Swiss Chemical Society
- external identifiers
-
- scopus:34248549685
- ISSN
- 0009-4293
- DOI
- 10.2533/chimia.2007.179
- language
- English
- LU publication?
- no
- id
- e3c8d03e-d1d9-41fe-b894-d281a1def0b8
- date added to LUP
- 2019-06-30 10:03:08
- date last changed
- 2022-01-31 23:00:53
@article{e3c8d03e-d1d9-41fe-b894-d281a1def0b8, abstract = {{<p>The photoinduced energy and structural relaxation of aqueous iron(II)-tris-bipyridine ([Fe<sup>II</sup>(bpy)<sub>3</sub>]<sup>2+</sup>), upon excitation into its singlet metal-to-ligand charge transfer (<sup>1</sup>MLCT) band, and the population of its short-lived (≤0.6 ns) high-spin excited state have been characterized by combined ultrafast optical and X-ray spectroscopies. Polychromatic femtosecond fluorescence up-conversion reveals a very short lived <sup>1</sup>MLCT emission band, which decays in ≤20 fs by intersystem crossing to a <sup>3</sup>MLCT, whose very weak emission is also observed. Transient absorption studies show that the latter decays in <150 fs, while the population of the lowest excited high spin quintet state <sup>5</sup>T <sub>2</sub> occurs in ∼1 ps. Subsequently it decays in ∼665 ps to the ground state. Therefore, we determined the structure of the high-spin excited state by picosecond X-ray absorption spectroscopy at the K edge of Fe. The structural analysis of both the transient difference and excited state X-ray spectra delivered an Fe-N bond elongation of 0.2 Å in the quintet state compared to the singlet ground state.</p>}}, author = {{Gawelda, Wojciech and Cannizzo, Andrea and El Nahhas, Amal and Milne, Christopher J. and Van Der Veen, Renske and Bressler, Christian and Chergui, Majed and Pham, Van-Thai}}, issn = {{0009-4293}}, keywords = {{Fluorescence; Iron (II) complexes; Optical absorption; Spin crossover; Ultrafast; X-ray absorption}}, language = {{eng}}, month = {{05}}, number = {{4}}, pages = {{179--183}}, publisher = {{Swiss Chemical Society}}, series = {{Chimia}}, title = {{Light-induced spin crossover probed by ultrafast optical and X-ray spectroscopies}}, url = {{http://dx.doi.org/10.2533/chimia.2007.179}}, doi = {{10.2533/chimia.2007.179}}, volume = {{61}}, year = {{2007}}, }