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X-ray absorption spectroscopy of ground and excited rhenium-carbonyl- diimine complexes : Evidence for a two-center electron transfer

El Nahhas, A. LU ; Van Der Veen, R. M. ; Penfold, T. J. ; Lima, F. A. ; Abela, R. ; Blanco-Rodriguez, A. M. ; Záliš, S. ; Vlček, A. ; Tavernelli, I. and Rothlisberger, U. , et al. (2013) In Journal of Physical Chemistry A 117(2). p.361-369
Abstract


Steady-state and picosecond time-resolved X-ray absorption spectroscopy is used to study the ground and lowest triplet states of [ReX(CO)
3
(bpy)]
n+
, X = Etpy (n = 1), Cl, or Br (n = 0). We demonstrate that the transient spectra at both the Re L
3
-and Br K-edges show the emergence of a pre-edge feature, absent in the ground-state spectrum, which is associated with the electron hole created in the highest occupied molecular orbital following photoexcitation. Importantly, these... (More)


Steady-state and picosecond time-resolved X-ray absorption spectroscopy is used to study the ground and lowest triplet states of [ReX(CO)
3
(bpy)]
n+
, X = Etpy (n = 1), Cl, or Br (n = 0). We demonstrate that the transient spectra at both the Re L
3
-and Br K-edges show the emergence of a pre-edge feature, absent in the ground-state spectrum, which is associated with the electron hole created in the highest occupied molecular orbital following photoexcitation. Importantly, these features have the same dynamics, confirming previous predictions that the low-lying excited states of these complexes involve a two-center charge transfer from both the Re and the ligand, X. We also demonstrate that the DFT optimized ground and excited structures allow us to reproduce the experimental XANES and EXAFS spectra. The ground-state structural refinement shows that the Br atom contributes very little to the latter, whereas the Re-C-O scattering paths are dominant due to the so-called focusing effect. For the excited-state spectrum, the Re-X bond undergoes one of the largest changes but still remains a weak contribution to the photoinduced changes of the EXAFS spectrum.

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publishing date
type
Contribution to journal
publication status
published
in
Journal of Physical Chemistry A
volume
117
issue
2
pages
9 pages
publisher
The American Chemical Society (ACS)
external identifiers
  • scopus:84872502704
ISSN
1089-5639
DOI
10.1021/jp3106502
language
English
LU publication?
no
id
0a0d86fc-3e86-459b-bf78-fdc6e26ccec8
date added to LUP
2019-06-30 09:46:59
date last changed
2020-10-07 06:35:53
@article{0a0d86fc-3e86-459b-bf78-fdc6e26ccec8,
  abstract     = {<p><br>
                            Steady-state and picosecond time-resolved X-ray absorption spectroscopy is used to study the ground and lowest triplet states of [ReX(CO) <br>
                            <sub>3</sub><br>
                            (bpy)]<br>
                            <sup>n+</sup><br>
                            , X = Etpy (n = 1), Cl, or Br (n = 0). We demonstrate that the transient spectra at both the Re L<br>
                            <sub>3</sub><br>
                            -and Br K-edges show the emergence of a pre-edge feature, absent in the ground-state spectrum, which is associated with the electron hole created in the highest occupied molecular orbital following photoexcitation. Importantly, these features have the same dynamics, confirming previous predictions that the low-lying excited states of these complexes involve a two-center charge transfer from both the Re and the ligand, X. We also demonstrate that the DFT optimized ground and excited structures allow us to reproduce the experimental XANES and EXAFS spectra. The ground-state structural refinement shows that the Br atom contributes very little to the latter, whereas the Re-C-O scattering paths are dominant due to the so-called focusing effect. For the excited-state spectrum, the Re-X bond undergoes one of the largest changes but still remains a weak contribution to the photoinduced changes of the EXAFS spectrum.</p>},
  author       = {El Nahhas, A. and Van Der Veen, R. M. and Penfold, T. J. and Lima, F. A. and Abela, R. and Blanco-Rodriguez, A. M. and Záliš, S. and Vlček, A. and Tavernelli, I. and Rothlisberger, U. and Milne, C. J. and Chergui, M.},
  issn         = {1089-5639},
  language     = {eng},
  month        = {01},
  number       = {2},
  pages        = {361--369},
  publisher    = {The American Chemical Society (ACS)},
  series       = {Journal of Physical Chemistry A},
  title        = {X-ray absorption spectroscopy of ground and excited rhenium-carbonyl- diimine complexes : Evidence for a two-center electron transfer},
  url          = {http://dx.doi.org/10.1021/jp3106502},
  doi          = {10.1021/jp3106502},
  volume       = {117},
  year         = {2013},
}