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Hot Branching Dynamics in a Light-Harvesting Iron Carbene Complex Revealed by Ultrafast X-ray Emission Spectroscopy

Tatsuno, Hideyuki LU ; Kjær, Kasper S. LU ; Kunnus, Kristjan ; Harlang, Tobias C.B. LU ; Timm, Cornelia ; Guo, Meiyuan ; Chàbera, Pavel LU ; Fredin, Lisa A. LU ; Hartsock, Robert W. and Reinhard, Marco E. , et al. (2020) In Angewandte Chemie - International Edition 59(1). p.364-372
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 FeIINHC 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 3MLCT state, from the initially excited 1MLCT state, 30 % of the molecules undergo ultrafast (150 fs) relaxation to the 3MC state, in competition with vibrational relaxation and cooling to the relaxed 3MLCT state. The relaxed 3MLCT state then... (More)

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 FeIINHC 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 3MLCT state, from the initially excited 1MLCT state, 30 % of the molecules undergo ultrafast (150 fs) relaxation to the 3MC state, in competition with vibrational relaxation and cooling to the relaxed 3MLCT state. The relaxed 3MLCT state then decays much more slowly (7.6 ps) to the 3MC state. The 3MC state is rapidly (2.2 ps) deactivated to the ground state. The 5MC state is not involved in the deactivation pathway. The ultrafast partial deactivation of the 3MLCT 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.

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organization
publishing date
type
Contribution to journal
publication status
published
subject
keywords
femtochemistry, molecular dynamics, photochemistry, photophysics, X-ray spectroscopy
in
Angewandte Chemie - International Edition
volume
59
issue
1
pages
364 - 372
publisher
John Wiley and Sons
external identifiers
  • pmid:31602726
  • scopus:85074827405
ISSN
1433-7851
DOI
10.1002/anie.201908065
language
English
LU publication?
yes
id
94b8fa48-7d1a-41d5-b176-65f1d3aa1783
date added to LUP
2019-12-09 14:01:10
date last changed
2021-04-06 04:49:54
@article{94b8fa48-7d1a-41d5-b176-65f1d3aa1783,
  abstract     = {<p>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<sup>II</sup>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 <sup>3</sup>MLCT state, from the initially excited <sup>1</sup>MLCT state, 30 % of the molecules undergo ultrafast (150 fs) relaxation to the <sup>3</sup>MC state, in competition with vibrational relaxation and cooling to the relaxed <sup>3</sup>MLCT state. The relaxed <sup>3</sup>MLCT state then decays much more slowly (7.6 ps) to the <sup>3</sup>MC state. The <sup>3</sup>MC state is rapidly (2.2 ps) deactivated to the ground state. The <sup>5</sup>MC state is not involved in the deactivation pathway. The ultrafast partial deactivation of the <sup>3</sup>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.</p>},
  author       = {Tatsuno, Hideyuki and Kjær, Kasper S. and Kunnus, Kristjan and Harlang, Tobias C.B. and Timm, Cornelia and Guo, Meiyuan and Chàbera, Pavel and Fredin, Lisa A. and Hartsock, Robert W. and Reinhard, Marco E. and Koroidov, Sergey and Li, Lin and Cordones, Amy A. and Gordivska, Olga and Prakash, Om and Liu, Yizhu and Laursen, Mads G. and Biasin, Elisa and Hansen, Frederik B. and Vester, Peter and Christensen, Morten and Haldrup, Kristoffer and Németh, Zoltán and Sárosiné Szemes, Dorottya and Bajnóczi, Éva and Vankó, György and Van Driel, Tim B. and Alonso-Mori, Roberto and Glownia, James M. and Nelson, Silke and Sikorski, Marcin and Lemke, Henrik T. and Sokaras, Dimosthenis and Canton, Sophie E. and Dohn, Asmus O. and Møller, Klaus B. and Nielsen, Martin M. and Gaffney, Kelly J. and Wärnmark, Kenneth and Sundström, Villy and Persson, Petter and Uhlig, Jens},
  issn         = {1433-7851},
  language     = {eng},
  number       = {1},
  pages        = {364--372},
  publisher    = {John Wiley and Sons},
  series       = {Angewandte Chemie - International Edition},
  title        = {Hot Branching Dynamics in a Light-Harvesting Iron Carbene Complex Revealed by Ultrafast X-ray Emission Spectroscopy},
  url          = {http://dx.doi.org/10.1002/anie.201908065},
  doi          = {10.1002/anie.201908065},
  volume       = {59},
  year         = {2020},
}