Biomimetic mono- and dinuclear Ni(I) and Ni(II) complexes studied by X-ray absorption and emission spectroscopy and quantum chemical calculations

16th International Conference on X-ray Absorption Fine Structure

Schuth, N.^1 ; Gehring, H.^2 ; Horn, B.^2 ; Holze, P.^2 ; Kositzki, R.^1 ; Schrapers, P.^1 ; Limberg, C.^2 ; Haumann, M.^1

Department of Physics, Freie Universität Berlin, Berlin

14195, Germany^1

Department of Chemistry, Humboldt-Universität zu Berlin, Berlin

12489, Germany^2

关键词: Absorption transitions;    Core-to-valence excitation;    Dinuclear complex;    Emission transition;    Quantitative agreement;    Quantum chemical calculations;    Satellite emission;    X-ray absorption and emission spectroscopy;   

Others  :  https://iopscience.iop.org/article/10.1088/1742-6596/712/1/012134/pdf
DOI  :  10.1088/1742-6596/712/1/012134

来源: IOP

【 摘 要 】

Five biomimetic mono- or dinuclear nickel complexes featuring Ni(I) or Ni(II) sites were studied by X-ray absorption and emission spectroscopy and DFT calculations. Ni K-edge XANES spectra and Kβ main and satellite emission lines were collected on powder samples. The pre-edge absorption transitions (core-to-valence excitation) and Kβ2,5emission transitions (valence-to-core decay) were calculated using DFT (TPSSh/TZVP) on crystal structures. This yielded theoretical ctv and vtc spectra in near-quantitative agreement with the experiment, showing the adequacy of the DFT approach for electronic structure description, emphasizing the sensitivity of the XAS/XES spectra for ligation/redox changes at nickel, and revealing the configuration of unoccupied and occupied valence levels, as well as the spin-coupling modes in the dinuclear complexes. XAS/XES-DFT is valuable for molecular and electronic structure analysis of synthetic complexes and of nickel centers in H2or COxconverting metalloenzymes.