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Resonant X-ray photo-oxidation of light-harvesting iron (II/III) N-heterocyclic carbene complexes

Temperton, Robert H. LU ; Guo, Meiyuan LU ; D’Acunto, Giulio LU ; Johansson, Niclas LU ; Rosemann, Nils W. LU ; Prakash, Om LU ; Wärnmark, Kenneth LU ; Schnadt, Joachim LU orcid ; Uhlig, Jens LU and Persson, Petter LU (2021) In Scientific Reports 11(1).
Abstract

Two photoactive iron N-heterocyclic carbene complexes [FeII(btz)2(bpy)]2+ and [FeIII(btz)3]3+, where btz is 3,3’-dimethyl-1,1’-bis(p-tolyl)-4,4’-bis(1,2,3-triazol-5-ylidene) and bpy is 2,2’-bipyridine, have been investigated by Resonant Photoelectron Spectroscopy (RPES). Tuning the incident X-ray photon energy to match core-valence excitations provides a site specific probe of the electronic structure properties and ligand-field interactions, as well as information about the resonantly photo-oxidised final states. Comparing measurements of the Fe centre and the surrounding ligands demonstrate strong mixing of the Fe t 2 g levels with occupied ligand π orbitals but weak mixing with the corresponding unoccupied ligand orbitals.... (More)

Two photoactive iron N-heterocyclic carbene complexes [FeII(btz)2(bpy)]2+ and [FeIII(btz)3]3+, where btz is 3,3’-dimethyl-1,1’-bis(p-tolyl)-4,4’-bis(1,2,3-triazol-5-ylidene) and bpy is 2,2’-bipyridine, have been investigated by Resonant Photoelectron Spectroscopy (RPES). Tuning the incident X-ray photon energy to match core-valence excitations provides a site specific probe of the electronic structure properties and ligand-field interactions, as well as information about the resonantly photo-oxidised final states. Comparing measurements of the Fe centre and the surrounding ligands demonstrate strong mixing of the Fe t 2 g levels with occupied ligand π orbitals but weak mixing with the corresponding unoccupied ligand orbitals. This highlights the importance of π-accepting and -donating considerations in ligand design strategies for photofunctional iron carbene complexes. Spin-propensity is also observed as a final-state effect in the RPES measurements of the open-shell Fe III complex. Vibronic coupling is evident in both complexes, where the energy dispersion hints at a vibrationally hot final state. The results demonstrate the significant impact of the iron oxidation state on the frontier electronic structure and highlights the differences between the emerging class of Fe III photosensitizers from those of more traditional Fe II complexes.

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author
; ; ; ; ; ; ; ; and
organization
publishing date
type
Contribution to journal
publication status
published
subject
in
Scientific Reports
volume
11
issue
1
article number
22144
publisher
Nature Publishing Group
external identifiers
  • pmid:34772983
  • scopus:85118957249
ISSN
2045-2322
DOI
10.1038/s41598-021-01509-7
language
English
LU publication?
yes
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Publisher Copyright: © 2021, The Author(s).
id
7f119bf4-b9a3-4cf5-9e11-b282d74a098e
date added to LUP
2021-12-02 17:08:43
date last changed
2024-08-11 02:48:50
@article{7f119bf4-b9a3-4cf5-9e11-b282d74a098e,
  abstract     = {{<p>Two photoactive iron N-heterocyclic carbene complexes [FeII(btz)2(bpy)]2+ and [FeIII(btz)3]3+, where btz is 3,3’-dimethyl-1,1’-bis(p-tolyl)-4,4’-bis(1,2,3-triazol-5-ylidene) and bpy is 2,2’-bipyridine, have been investigated by Resonant Photoelectron Spectroscopy (RPES). Tuning the incident X-ray photon energy to match core-valence excitations provides a site specific probe of the electronic structure properties and ligand-field interactions, as well as information about the resonantly photo-oxidised final states. Comparing measurements of the Fe centre and the surrounding ligands demonstrate strong mixing of the Fe t <sub>2 g</sub> levels with occupied ligand π orbitals but weak mixing with the corresponding unoccupied ligand orbitals. This highlights the importance of π-accepting and -donating considerations in ligand design strategies for photofunctional iron carbene complexes. Spin-propensity is also observed as a final-state effect in the RPES measurements of the open-shell Fe <sup>III</sup> complex. Vibronic coupling is evident in both complexes, where the energy dispersion hints at a vibrationally hot final state. The results demonstrate the significant impact of the iron oxidation state on the frontier electronic structure and highlights the differences between the emerging class of Fe <sup>III</sup> photosensitizers from those of more traditional Fe <sup>II</sup> complexes.</p>}},
  author       = {{Temperton, Robert H. and Guo, Meiyuan and D’Acunto, Giulio and Johansson, Niclas and Rosemann, Nils W. and Prakash, Om and Wärnmark, Kenneth and Schnadt, Joachim and Uhlig, Jens and Persson, Petter}},
  issn         = {{2045-2322}},
  language     = {{eng}},
  number       = {{1}},
  publisher    = {{Nature Publishing Group}},
  series       = {{Scientific Reports}},
  title        = {{Resonant X-ray photo-oxidation of light-harvesting iron (II/III) N-heterocyclic carbene complexes}},
  url          = {{http://dx.doi.org/10.1038/s41598-021-01509-7}},
  doi          = {{10.1038/s41598-021-01509-7}},
  volume       = {{11}},
  year         = {{2021}},
}