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Jens Uhlig. Portrait.

Jens Uhlig

Senior lecturer

Jens Uhlig. Portrait.

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

Author

  • Robert H. Temperton
  • Meiyuan Guo
  • Giulio D’Acunto
  • Niclas Johansson
  • Nils W. Rosemann
  • Om Prakash
  • Kenneth Wärnmark
  • Joachim Schnadt
  • Jens Uhlig
  • Petter Persson

Summary, in English

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.

Department/s

  • MAX IV Laboratory
  • LINXS - Institute of advanced Neutron and X-ray Science
  • Chemical Physics
  • Synchrotron Radiation Research
  • Centre for Analysis and Synthesis
  • NanoLund: Centre for Nanoscience
  • eSSENCE: The e-Science Collaboration
  • Computational Chemistry

Publishing year

2021-12

Language

English

Publication/Series

Scientific Reports

Volume

11

Issue

1

Document type

Journal article

Publisher

Nature Publishing Group

Topic

  • Chemical Sciences
  • Atom and Molecular Physics and Optics
  • Physical Chemistry (including Surface- and Colloid Chemistry)

Status

Published

ISBN/ISSN/Other

  • ISSN: 2045-2322