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Abstract A new nonheme iron(II) complex, FeII(Me3TACN)((OSiPh2)2O) (1), is reported. Reaction of1with NO(g)gives a stable mononitrosyl complex Fe(NO)(Me3TACN)((OSiPh2)2O) (2), which was characterized by Mössbauer (δ=0.52 mm s−1, |ΔEQ|=0.80 mm s−1), EPR (S=3/2), resonance Raman (RR) and Fe K‐edge X‐ray absorption spectroscopies. The data show that2is an {FeNO}7complex with anS=3/2 spin ground state. The RR spectrum (λexc=458 nm) of2combined with isotopic labeling (15N,18O) reveals ν(N‐O)=1680 cm−1, which is highly activated, and is a nearly identical match to that seen for the reactive mononitrosyl intermediate in the nonheme iron enzyme FDPnor (ν(NO)=1681 cm−1). Complex2reacts rapidly with H2O in THF to produce the N‐N coupled product N2O, providing the first example of a mononuclear nonheme iron complex that is capable of converting NO to N2O in the absence of an exogenous reductant.
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Ultrafast Light‐Driven Electronic and Structural Changes in LaFeO 3 Perovskites Probed by Femtosecond X‐Ray Absorption Spectroscopy
Abstract Conducting real‐time, element‐specific studies of photo‐excited systems is a long‐standing challenge. The development of X‐ray free‐electron lasers (XFELs) has paved the way for the emergence of a promising technique: femtosecond X‐ray absorption spectroscopy (fs‐XAS). This powerful technique reveals electronic and geometric characteristics, providing unprecedented insight into their dynamic interactions under nonequilibrium conditions. Herein, the fs‐XAS technique is employed at PAL‐XFEL to unravel light‐driven ultrafast electronic and structural changes in epitaxial lanthanum iron oxide (LaFeO3) thin films. Density functional theory (DFT) and multiplet calculations are utilized to expound on the experimental results. The analyses reveal that photoexcitation initially induces high‐ and intermediate‐spin Fe2+states through ligand‐to‐metal charge transfer (LMCT), followed by polaron formation. It is demonstrated that the reduced overlap between the oxygen 2pand iron 3dorbitals accounts for all experimental observations, including 1) the XAS shifts to lower energies, 2) the decrease in the crystal field splitting, and 3) the relatively larger shifts observed in the oxygen 1sXAS.
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- Award ID(s):
- 2309000
- PAR ID:
- 10641091
- Publisher / Repository:
- Wiley Blackwell (John Wiley & Sons)
- Date Published:
- Journal Name:
- Advanced Materials
- Volume:
- 37
- Issue:
- 29
- ISSN:
- 0935-9648
- Format(s):
- Medium: X
- Sponsoring Org:
- National Science Foundation
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