Toward Highlighting the Ultrafast Electron Transfer Dynamics at the Optically Dark Sites of Photocatalysts.
Building a detailed understanding of the structure-function relationship is a crucial step in the optimization of molecular photocatalysts employed in water splitting schemes. The optically dark nature of their active sites usually prevents a complete mapping of the photoinduced dynamics. In this work, transient X-ray absorption spectroscopy highlights the electronic and geometric changes that affect such a center in a bimetallic model complex. Upon selective excitation of the ruthenium chromophore, the cobalt moiety is reduced through intramolecular electron transfer and undergoes a spin flip accompanied by an average bond elongation of 0.20 ± 0.03 Å. The analysis is supported by simulations based on density functional theory structures (B3LYP*/TZVP) and FEFF 9.0 multiple scattering calculations. More generally, these results exemplify the large potential of the technique for tracking elusive intermediates that impart unique functionalities in photochemical devices.
†Department of Synchrotron Radiation Instrumentation, P.O. Box 118, Lund University, 22100 Lund, Sweden.
Sophie E
SE
Canton
‡X-ray Sciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
Xiaoyi
X
Zhang
§Centre for Analysis and Synthesis, Department of Chemistry, Lund University, S-22100 Lund, Sweden.
Jianxin
J
Zhang
∥Centre for Molecular Movies, Department of Physics, Technical University of Denmark, DK-2800, Lyngby, Denmark.
Tim B
TB
van Driel
⊥Centre for Molecular Movies, Niels Bohr Institute, University of Copenhagen, DK-2100, Copenhagen, Denmark.
Kasper S
KS
Kjaer
∥Centre for Molecular Movies, Department of Physics, Technical University of Denmark, DK-2800, Lyngby, Denmark.
Kristoffer
K
Haldrup
#Chemical Physics Department, P.O. Box 118, Lund University, S-22100 Lund, Sweden.
Pavel
P
Chabera
#Chemical Physics Department, P.O. Box 118, Lund University, S-22100 Lund, Sweden.
Tobias
T
Harlang
†Department of Synchrotron Radiation Instrumentation, P.O. Box 118, Lund University, 22100 Lund, Sweden.
Karina
K
Suarez-Alcantara
§Centre for Analysis and Synthesis, Department of Chemistry, Lund University, S-22100 Lund, Sweden.
Yizhu
Y
Liu
§Centre for Analysis and Synthesis, Department of Chemistry, Lund University, S-22100 Lund, Sweden.
Jorge
J
Pérez
○Wigner Research Centre for Physics, Hungarian Academy Sciences, H-1525 Budapest, P.O.B. 49, Hungary.|▽Institut Néel, CNRS et Université Joseph Fourier, BP 166, F-38042 Grenoble Cedex 9, France.
Amélie
A
Bordage
○Wigner Research Centre for Physics, Hungarian Academy Sciences, H-1525 Budapest, P.O.B. 49, Hungary.
Mátyás
M
Pápai
○Wigner Research Centre for Physics, Hungarian Academy Sciences, H-1525 Budapest, P.O.B. 49, Hungary.
György
G
Vankó
‡X-ray Sciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
Guy
G
Jennings
‡X-ray Sciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, United States.
Charles A
CA
Kurtz
◆European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France.
Mauro
M
Rovezzi
◆European Synchrotron Radiation Facility, BP 220, F-38043 Grenoble, France.
Pieter
P
Glatzel
#Chemical Physics Department, P.O. Box 118, Lund University, S-22100 Lund, Sweden.
Grigory
G
Smolentsev
#Chemical Physics Department, P.O. Box 118, Lund University, S-22100 Lund, Sweden.
Jens
J
Uhlig
¶Department of Chemistry, Technical University of Denmark, DK-2800, Kgs. Lyngby, Denmark.
Asmus O
AO
Dohn
∥Centre for Molecular Movies, Department of Physics, Technical University of Denmark, DK-2800, Lyngby, Denmark.
Morten
M
Christensen
●European XFEL Facility, Albert-Einstein Ring 19, D-22 761 Hamburg, Germany.
Andreas
A
Galler
●European XFEL Facility, Albert-Einstein Ring 19, D-22 761 Hamburg, Germany.
Wojciech
W
Gawelda
●European XFEL Facility, Albert-Einstein Ring 19, D-22 761 Hamburg, Germany.
Christian
C
Bressler
◇SLAC National l Accelerator Laboratory, Linac Coherent Light Source, Menlo Park, California 94025, United States.
Henrik T
HT
Lemke
⊥Centre for Molecular Movies, Niels Bohr Institute, University of Copenhagen, DK-2100, Copenhagen, Denmark.
Klaus B
KB
Møller
∥Centre for Molecular Movies, Department of Physics, Technical University of Denmark, DK-2800, Lyngby, Denmark.
Martin M
MM
Nielsen
□Department of Chemistry-Ångström Laboratory, Box 523, Uppsala University, S-75120 Uppsala, Sweden.
Reiner
R
Lomoth
§Centre for Analysis and Synthesis, Department of Chemistry, Lund University, S-22100 Lund, Sweden.
Kenneth
K
Wärnmark
#Chemical Physics Department, P.O. Box 118, Lund University, S-22100 Lund, Sweden.
Villy
V
Sundström
electron transfer; excited-state structure; hydrogen evolution; photocatalysis; transient X-ray absorption spectroscopy; ultrafast structural dynamics