Journal Article

PUBDB-2025-01538

http://join2-wiki.gsi.de/foswiki/pub/Main/Artwork/join2_logo100x88.png Identification of metal-centered excited states in Cr( iii ) complexes with time-resolved L-edge X-ray spectroscopy

Ghodrati, N. ; Eckert, S. ; Fondell, M. ; Scherz, A. ; Föhlisch, A. ; Kuiken, B. v. (Corresponding author)XFEL.EU*

2025
RSC Cambridge

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Please use a persistent id in citations: doi:10.1039/D4SC07625G  doi:10.3204/PUBDB-2025-01538

Abstract: New coordination complexes of 3d metals that possess photoactive metal-centered (MC) excited states arepromising targets for optical applications and photocatalysis. Ultrafast spectroscopy plays an important rolein elucidating the photophysical mechanisms that underlie photochemical activity. However, it can bedifficult to assign transient signals to specific electronic excited states and mechanistic information isoften inferred from kinetics. Here it is demonstrated that 3d L-edge X-ray absorption spectroscopy ishighly selective for MC excited states. This is accomplished by probing the 2E spin-flip excited state inCr(acac)3 using synchrotron-based picosecond time-resolved XAS in solution. This excited state of Cr(III )has the property that its potential is nested with the ground state, which allows for the assessment ofpurely electronic changes upon excited state formation. Combining the measurements with ligand fieldand ab initio theory shows that the observed spectral changes between the 4 A2 ground state and 2Eexcited state are due to an intensity redistribution among the core-excited multiplets. Extrapolatingthese results to higher-lying MC excited states predicts that Cr L3-edge XAS can distinguish two statesseparated by ∼0.1 eV despite the L3-edge resolution being limited by the 0.27 eV lifetime width of the 2pcore-hole. This highlights the potential of L-edge XAS as a sub-natural linewidth probe of electronicstate identity.

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Contributing Institute(s):

1. SCS (XFEL_E2_SCS)

Research Program(s):

1. 6G13 - Accelerator of European XFEL (POF4-6G13) (POF4-6G13)

Experiment(s):

1. Experiments at XFEL

Appears in the scientific report 2025

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Database coverage:
; ; ; ; Chemical Reactions ; Clarivate Analytics Master Journal List ; Current Contents - Physical, Chemical and Earth Sciences ; DOAJ Seal ; Essential Science Indicators ; IF >= 5 ; Index Chemicus ; JCR ; National-Konsortium ; SCOPUS ; Science Citation Index Expanded ; Web of Science Core Collection

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