TY  - JOUR
AU  - Ghodrati, Nahid
AU  - Eckert, Sebastian
AU  - Fondell, Mattis
AU  - Scherz, Andreas
AU  - Föhlisch, Alexander
AU  - Kuiken, Benjamin van
TI  - Identification of metal-centered excited states in Cr( iii ) complexes with time-resolved L-edge X-ray spectroscopy
JO  - Chemical science
VL  - 16
IS  - 15
SN  - 2041-6520
CY  - Cambridge
PB  - RSC
M1  - PUBDB-2025-01538
SP  - 6307 - 6316
PY  - 2025
AB  - 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.
LB  - PUB:(DE-HGF)16
C6  - pmid:40078607
UR  - <Go to ISI:>//WOS:001441340900001
DO  - DOI:10.1039/D4SC07625G
UR  - https://bib-pubdb1.desy.de/record/627066
ER  -