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Hot Branching Dynamics in a Light‐Harvesting Iron Carbene Complex Revealed by Ultrafast X‐ray Emission Spectroscopy
Author(s) -
Tatsuno Hideyuki,
Kjær Kasper S.,
Kunnus Kristjan,
Harlang Tobias C. B.,
Timm Cornelia,
Guo Meiyuan,
Chàbera Pavel,
Fredin Lisa A.,
Hartsock Robert W.,
Reinhard Marco E.,
Koroidov Sergey,
Li Lin,
Cordones Amy A.,
Gordivska Olga,
Prakash Om,
Liu Yizhu,
Laursen Mads G.,
Biasin Elisa,
Hansen Frederik B.,
Vester Peter,
Christensen Morten,
Haldrup Kristoffer,
Németh Zoltán,
Sárosiné Szemes Dorottya,
Bajnóczi Éva,
Vankó György,
Van Driel Tim B.,
AlonsoMori Roberto,
Glownia James M.,
Nelson Silke,
Sikorski Marcin,
Lemke Henrik T.,
Sokaras Dimosthenis,
Canton Sophie E.,
Dohn Asmus O.,
Møller Klaus B.,
Nielsen Martin M.,
Gaffney Kelly J.,
Wärnmark Kenneth,
Sundström Villy,
Persson Petter,
Uhlig Jens
Publication year - 2020
Publication title -
angewandte chemie international edition
Language(s) - English
Resource type - Journals
SCImago Journal Rank - 5.831
H-Index - 550
eISSN - 1521-3773
pISSN - 1433-7851
DOI - 10.1002/anie.201908065
Subject(s) - branching (polymer chemistry) , ultrashort pulse , spectroscopy , carbene , chemistry , materials science , chemical physics , photochemistry , physics , optics , laser , catalysis , organic chemistry , quantum mechanics
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.