title: Watching the dynamics of electrons and atoms at work in solar energy conversion.
abstract: The photochemical reactions performed by transition metal complexes have been proposed as viable routes towards solar energy conversion and storage into other forms that can be conveniently used in our everyday applications. In order to develop efficient materials, it is necessary to identify, characterize and optimize the elementary steps of the entire process on the atomic scale. To this end, we have studied the photoinduced electronic and structural dynamics in two heterobimetallic ruthenium-cobalt dyads, which belong to the large family of donor-bridge-acceptor systems. Using a combination of ultrafast optical and X-ray absorption spectroscopies, we can clock the light-driven electron transfer processes with element and spin sensitivity. In addition, the changes in local structure around the two metal centers are monitored. These experiments show that the nature of the connecting bridge is decisive for controlling the forward and the backward electron transfer rates, a result supported by quantum chemistry calculations. More generally, this work illustrates how ultrafast optical and X-ray techniques can disentangle the influence of spin, electronic and nuclear factors on the intramolecular electron transfer process. Finally, some implications for further improving the design of bridged sensitizer-catalysts utilizing the presented methodology are outlined.
authors.affiliation: IFG Structural Dynamics of (Bio)chemical Systems, Max Planck Institute for Biophysical Chemistry, Am Fassberg 11, D-37077 Goettingen, Germany. sophie.canton@desy.de and FS-SCS, Structural Dynamics with Ultra-short Pulsed X-rays, Deutsches Elektronensynchrotron DESY, Notkestrasse 85, D-22607 Hamburg, Germany.
authors.forename: S E
authors.initials: SE
authors.lastname: Canton
authors.affiliation: X-ray Sciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: X
authors.initials: X
authors.lastname: Zhang
authors.affiliation: Department of Chemistry, Centre for Analysis and Synthesis, Lund University, S-22100 Lund, Sweden.
authors.forename: Y
authors.initials: Y
authors.lastname: Liu
authors.affiliation: School of Environmental and Chemical Engineering, Tianjin Polytechnic University, Tianjin 300387, China.
authors.forename: J
authors.initials: J
authors.lastname: Zhang
authors.affiliation: Wigner Research Centre for Physics, Hungarian Academy Sciences, PO Box 49, H-1525 Budapest, Hungary.
authors.forename: M
authors.initials: M
authors.lastname: Pápai
authors.affiliation: Department of Chemical Physics, Lund University, PO Box 124, S-22100 Lund, Sweden.
authors.forename: A
authors.initials: A
authors.lastname: Corani
authors.affiliation: Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, S-75120 Uppsala, Sweden.
authors.forename: A L
authors.initials: AL
authors.lastname: Smeigh
authors.affiliation: Paul Scherrer Institute, Villigen 5232, Switzerland.
authors.forename: G
authors.initials: G
authors.lastname: Smolentsev
authors.affiliation: Photon Science Directorate, Brookhaven National Laboratory, Upton, New York 11973-5000, USA.
authors.forename: K
authors.initials: K
authors.lastname: Attenkofer
authors.affiliation: X-ray Sciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: G
authors.initials: G
authors.lastname: Jennings
authors.affiliation: X-ray Sciences Division, Argonne National Laboratory, 9700 South Cass Avenue, Argonne, Illinois 60439, USA.
authors.forename: C A
authors.initials: CA
authors.lastname: Kurtz
authors.affiliation: State Key Laboratory of Fine Chemicals, Dalian University of Technology, Dalian 116024, China.
authors.forename: F
authors.initials: F
authors.lastname: Li
authors.affiliation: Department of Chemical Physics, Lund University, PO Box 124, S-22100 Lund, Sweden.
authors.forename: T
authors.initials: T
authors.lastname: Harlang
authors.affiliation: Department of Chemical Physics, Lund University, PO Box 124, S-22100 Lund, Sweden.
authors.forename: D
authors.initials: D
authors.lastname: Vithanage
authors.affiliation: Department of Chemical Physics, Lund University, PO Box 124, S-22100 Lund, Sweden.
authors.forename: P
authors.initials: P
authors.lastname: Chabera
authors.affiliation: Institut de Chimie Moléculaire et des Matériaux d'Orsay, Université Paris-Sud, UMR CNRS 8182, 15 rue Georges Clémenceau, 91405 Orsay Cedex, France.
authors.forename: A
authors.initials: A
authors.lastname: Bordage
authors.affiliation: Department of Chemistry, School of Chemical Science and Engineering, KTH Royal Institute of Technology, 10044 Stockholm, Sweden.
authors.forename: L
authors.initials: L
authors.lastname: Sun
authors.affiliation: Department of Chemistry-Ångström Laboratory, Uppsala University, Box 523, S-75120 Uppsala, Sweden.
authors.forename: S
authors.initials: S
authors.lastname: Ott
authors.affiliation: Department of Chemistry, Centre for Analysis and Synthesis, Lund University, S-22100 Lund, Sweden.
authors.forename: K
authors.initials: K
authors.lastname: Wärnmark
authors.affiliation: Department of Chemical Physics, Lund University, PO Box 124, S-22100 Lund, Sweden.
authors.forename: V
authors.initials: V
authors.lastname: Sundström
mesh_terms: D056831:Coordination Complexes / Q000737:chemistry; D004583:Electrons; D008958:Models, Molecular; D011789:Quantum Theory; D012428:Ruthenium / Q000737:chemistry; D012993:Solar Energy; D013472:Sunlight
chemical_list: D056831:Coordination Complexes; D012428:Ruthenium