Resonant Stimulated X-ray Raman Spectroscopy of Mixed-Valence Manganese Complexes

J Phys Chem Lett. 2021 Jul 1;12(25):5925-5931. doi: 10.1021/acs.jpclett.1c01190. Epub 2021 Jun 22.

Abstract

Resonant stimulated X-ray Raman spectroscopy of the bimetallic [MnIIIMnIV(μ-O)2(μ-OAC)(tacn)2]2+ manganese complex is investigated in a simulation study. Essential biological processes, including water oxidation in photosynthesis, involve charge transfer between manganese sites of different oxidation states. We study a prototypical binuclear mixed-valence transition-metal complex with two Mn atoms in different oxidation states surrounded by ligand structures and employ a pump-probe sequence of resonant X-ray Raman excitations to follow the charge transfer occurring in the molecule. This allows us to generate and monitor valence-electron wave packets at selected regions in the molecule by exploiting element-specific core-excited states. A two-color protocol is presented, with pump and probe pulses tuned to the Mn and N K-edges. A natural orbital decomposition allows the visualization of the electron dynamics underlying the signal.

MeSH terms

  • Coordination Complexes / chemistry*
  • Electrochemistry
  • Ligands
  • Manganese / chemistry*
  • Oxygen / chemistry
  • Spectrum Analysis, Raman*
  • Water / chemistry
  • X-Rays

Substances

  • Coordination Complexes
  • Ligands
  • Water
  • Manganese
  • Oxygen