Canton, Sophie E.14; Zhang, Xiaoyi15; Zhang, Jianxin14; Brandt van Driel, Tim6; Kjaer, Kasper S.7; Haldrup, Martin Kristoffer1; Chabera, Pavel14; Harlang, Tobias14; Suarez-Alcantara, Karina14; Liu, Yizhu14; Pérez, Jorge14; Bordage, Amélie16; Pápai, Mátyás Imre2; Vankó, György16; Jennings, Guy15; Kurtz, Charles A.15; Rovezzi, Mauro17; Glatzel, Pieter17; Smolentsev, Grigory14; Uhlig, Jens14; Dohn, Asmus Ougaard10; Christensen, Morten1; Galler, Andreas11; Gawelda, Wojciech11; Bressler, Christian11; Lemke, Henrik T.12; Møller, Klaus Braagaard2; Nielsen, Martin Meedom1; Lomoth, Reiner13; Wärnmark, Kenneth14; Sundström, Villy14
1 Department of Physics, Technical University of Denmark2 Department of Chemistry, Technical University of Denmark3 Physical and Biophysical Chemistry, Department of Chemistry, Technical University of Denmark4 Lund University5 Argonne National Laboratory6 Risø National Laboratory for Sustainable Energy, Technical University of Denmark7 University of Copenhagen8 Hungarian Academy of Sciences9 European Synchrotron Radiation Facility10 Center for Atomic-scale Materials Design, Center, Technical University of Denmark11 European XFEL12 SLAC National Accelerator Laboratory13 Uppsala University14 Lund University15 Argonne National Laboratory16 Hungarian Academy of Sciences17 European Synchrotron Radiation Facility
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.
Journal of Physical Chemistry Letters, 2013, Vol 4, Issue 11, p. 1972-1976