Helmholtz-Zentrum Dresden-Rossendorf

Chemistry of the f-elements

PD Dr. habil. Moritz Schmidt

Head Chemistry of the f-elements


+49 351 260 3156, +49 351 260 2536




ORCID: 0000-0002-8419-0811


Bautzner Landstraße 400 - 01328 Dresden
, 850/16.1

Scientific career

  • Current:
    Head of the department "Chemistry of the f-elements" Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology.
  • 2013 – 2018:
    Helmholtz Young Investigator group leader at the Helmholtz-Zentrum Dresden-Rossendorf (HZDR), Institute of Resource Ecology.
  • 2012 – 2013:
    Research associate at the Karlsruhe Institute of Technology (KIT), Institute for Nuclear Waste Disposal.
  • 2010 – 2012:
    Research Associate at Argonne National Laboratory (ANL), Chemical Sciences and Engineering Division.
  • 11/2009:
    PhD at the University of Heidelberg, Department of Chemistry, “Untersuchungen zum Einbaumechanismus von Actiniden und Lanthaniden in Calcium-haltige Sekundärphasen” (in German).
  • 2006 – 2009:
    PhD student at the Forschungszentrum Karlsruhe, Institute for Nuclear Waste Disposal.
  • 2006:
    Diplom (M.Sc.) in Chemistry at the University of Heidelberg

Research experience

  • Actinide chemistry
  • Geochemistry of the actinides in the context of nuclear waste storage
  • Mineral/water interface reactions
  • Structural incorporation of actinides into mineral phases
  • Site-selective time-resolved laser fluorescence spectroscopy with Cm(III) and Eu(III)
  • Surface X-ray diffraction

Newest Publication in the Department

The Hexacoordinate Si Complex SiCl₄(4-Azidopyridine)₂—Crystallographic Characterization of Two Conformers and Probing the Influence of SiCl₄-Complexation on a Click Reaction with Phenylacetylen

Riedel, S.; Gerwig, M.; Gerlach, D.; Brendler, E.; Gericke, R.; Kroke, E.; Wagler, J.

4-Azidopyridine (1) and SiCl₄ react with the formation of the hexacoordinate silicon complex SiCl₄(4-azidopyridine)₂ (2). Upon dissolving in warm chloroform, the complex dissociates into the constituents 1 and SiCl₄ and forms back upon cooling. Depending on the cooling, two different crystalline modifications of 2 were obtained, which feature two different trans-conformers. Slow cooling to room temperature afforded conformer 2′, which features coplanar pyridine rings. Rapid cooling to −39 °C afforded crystals of conformer 2′′, in which the planes of the pyridine ligands are nearly orthogonal to one another. Whereas 2′ resembles the molecular arrangement of various other known SiX₄(pyridine)₂ (X = halide) complexes, 2′′ represents the first crystallographically confirmed example of a SiX₄(pyridine)₂ complex in this conformation. Conformers 2′ and 2′′ were studied with ¹³C and ²⁹Si solid state NMR spectroscopy. Their differences in ²⁹Si chemical shift anisotropy, as well as energetic differences, were further investigated with computational analyses. In spite of the similar stabilities of the two conformers as isolated molecules, the crystal packing of 2′′ is less stable, and its crystallization is interpreted as a kinetically controlled effect of seed formation. (3+2)-cycloaddition of 1 and phenylacetylene in toluene at 110 °C yields a mixture of 1-(4-pyridyl)-4-phenyl-1,2,3-triazole (1,4-3) and 1-(4-pyridyl)-5-phenyl-1,2,3-triazole (1,5-3) in approximate 1:2 molar ratio. The crystal structures of the two isomers were determined via X-ray diffraction. In chloroform (at 60 °C), this reaction is slow (less than 2% conversion within 4 h), but the presence of SiCl₄ enhanced the rate of the reaction slightly, and it shifted the triazole isomer ratio to ca. 1:6 in favor of 1,5-3.

Keywords: chemical shift anisotropy; (3+2)-cycloaddition; Hirshfeld surface analysis; hypercoordination; packing efficiency; polymorphism; silicon; triazole


  • f-Char (02NUK059B), German Federal Ministry of Education and Research, 2019 - 2023.
  • SMILE (02E11668B), German Federal Ministry of the Economy, 2018 - 2022.
  • FENABIUM (02NUK046B), German Federal Ministry of Education and Research, 2016-2021.
  • Helmholtz Young Investigator Group “Structures and reactivity at the aqueous/mineral interface”, (VH-NG-942), Helmholtz Association, 2013 - 2018.