Ph.D. projects

Investigation of Early Actinide Properties by Utilizing Pyrrol based Ligands

Ph.D. student:
Luisa Köhler
Supervisor:
Dr. Juliane März,Prof. Dr. Thorsten Stumpf (HZDR)
Department:
Chemistry of the f-elements
Duration:
12/2018–11/2021

Schiff base ligands like Bis(salicyliden)ethylendiamin (salen) and its derivatives are vastly studied systems because of their ability to form stable complexes with a broad range of metals including actinides.1–4 Furthermore, their electronic and steric properties can be easily tuned to match the needs of e.g. different metal oxidation states. In comparison to the mixed N, O donor ligands of the salen type, pyrrol based ligands can be considered as structural relatives and only exhibit N donor functionalities. Thus the actinides’ binding properties to N atoms in different environments and aromaticity can be elucidated.

1,2-ethylenediamine-N,N’-bis(1H-pyrrol-2-yl)methylene (pyrenH2) L1H2 and 1,2-benzenediamine-N,N’-bis(1H-pyrrol-2-yl)methylene (pyrophenH2) L2H2 ©Copyright: Köhler, Luisa

The aim is the complexation of early actinides from Th to Pu with the pyrrol based ligands 1,2-ethylenediamine-N,N’-bis(1H-pyrrol-2-yl)methylene (pyrenH2) L1H2 and 1,2-benzenediamine-N,N’-bis(1H-pyrrol-2-yl)methylene (pyrophenH2) L2H2 with varying metal oxidation states (+III to +V). Characterization of the formed compounds is ought to be performed by standard methods in solid state (SCXRD, PXRD, IR, UV/Vis) and solution (NMR, UV/Vis). Furthermore, techniques like cyclic voltammetry (CV) and magnetic measurements (EPR) shall be applied to investigate the influence of different metal oxidation states on reactivity and binding. Quantum chemical calculations support the experimental work.

References

  1. B. E. Klamm, C. J. Windorff, M. L. Marsh, D. S. Meeker and T. E. Albrecht-Schmitt, Chem. Commun., 2018, 54, 8634–8636.
  2. A. N. Dame, M. S. Bharara, C. L. Barnes and J. R. Walensky, Eur. J. Inorg. Chem., 2015, 2015, 2996–3005.
  3. B. E. Klamm, C. J. Windorff, C. Celis-Barros, M. L. Marsh, D. S. Meeker and T. E. Albrecht-Schmitt, Inorg. Chem., 2018, 57, 15389–15398.
  4. T. Radoske, J. März, M. Patzschke, P. Kaden, O. Walter, M. Schmidt and T. Stumpf, Chem. – Eur. J., 2020, 26, 16853–16859.