Hot Branching Dynamics in a Light‐Harvesting Iron Carbene Complex Revealed by Ultrafast X‐ray Emission Spectroscopy
- Division of Chemical Physics Department of Chemistry Lund University Box 124 Lund SE-22100 Sweden
- Division of Chemical Physics Department of Chemistry Lund University Box 124 Lund SE-22100 Sweden, Theoretical Chemistry Division Department of Chemistry Lund University Box 124 Lund SE-22100 Sweden
- PULSE Institute SLAC National Accelerator Laboratory Stanford University Menlo Park California 94025 USA
- Theoretical Chemistry Division Department of Chemistry Lund University Box 124 Lund SE-22100 Sweden
- Centre for Analysis and Synthesis Department of Chemistry Lund University Box 124 Lund SE-22100 Sweden
- Division of Chemical Physics Department of Chemistry Lund University Box 124 Lund SE-22100 Sweden, Centre for Analysis and Synthesis Department of Chemistry Lund University Box 124 Lund SE-22100 Sweden
- Department of Physics Technical University of Denmark DK-2800 Lyngby Denmark
- PULSE Institute SLAC National Accelerator Laboratory Stanford University Menlo Park California 94025 USA, Department of Physics Technical University of Denmark DK-2800 Lyngby Denmark
- Wigner Research Centre for Physics Hungarian Academy of Sciences P.O. Box 49 H-1525 Budapest Hungary
- LCLS SLAC National Accelerator Laboratory Menlo Park California 94025 USA
- LCLS SLAC National Accelerator Laboratory Menlo Park California 94025 USA, SwissFEL Paul Scherrer Institut Villigen PSI 5232 Switzerland
- SSRL SLAC National Accelerator Laboratory Menlo Park California 94025 USA
- FS-ATTO Deutsches Elektronen-Synchrotron (DESY) Notkestrasse 85 22607 Hamburg Germany, ELI-ALPS, ELI-HU Non-Profit Ltd. Dugonics ter 13 Szeged 6720 Hungary
- Department of Chemistry Technical University of Denmark DK-2800 Lyngby Denmark, Faculty of Physical Sciences and Science Institute University of Iceland 107 Reykjavik Iceland
- Department of Chemistry Technical University of Denmark DK-2800 Lyngby Denmark
Abstract
Iron N‐heterocyclic carbene (NHC) complexes have received a great deal of attention recently because of their growing potential as light sensitizers or photocatalysts. We present a sub‐ps X‐ray spectroscopy study of an Fe II NHC complex that identifies and quantifies the states involved in the deactivation cascade after light absorption. Excited molecules relax back to the ground state along two pathways: After population of a hot 3 MLCT state, from the initially excited 1 MLCT state, 30 % of the molecules undergo ultrafast (150 fs) relaxation to the 3 MC state, in competition with vibrational relaxation and cooling to the relaxed 3 MLCT state. The relaxed 3 MLCT state then decays much more slowly (7.6 ps) to the 3 MC state. The 3 MC state is rapidly (2.2 ps) deactivated to the ground state. The 5 MC state is not involved in the deactivation pathway. The ultrafast partial deactivation of the 3 MLCT state constitutes a loss channel from the point of view of photochemical efficiency and highlights the necessity to screen transition‐metal complexes for similar ultrafast decays to optimize photochemical performance.
- Sponsoring Organization:
- USDOE
- Grant/Contract Number:
- AC02-76SF00515
- OSTI ID:
- 1572579
- Journal Information:
- Angewandte Chemie, Journal Name: Angewandte Chemie Journal Issue: 1 Vol. 132; ISSN 0044-8249
- Publisher:
- Wiley Blackwell (John Wiley & Sons)Copyright Statement
- Country of Publication:
- Germany
- Language:
- English
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