FENABIUM - Structure-activity relationships between f-elements and organic ligand systems with natural product-based binding functions in view of possible mobilization in the environment. Final report

The focus of FENABIUM comprises the investigation of the coordination of actinides and their lanthanide homologues with biologically relevant organic ligands and the interaction between f-elements and biological matrices. For this purpose, detailed studies on the complex formation properties of substituted glucosamine, the monomer of chitin, and 4-phosphorylpyrazolone as a ligand system with a phosphoryl group were carried out at the TU Dresden. The experimental results using La(III), Ce(III), and Ce(IV), the actinides Th, U, and Np in the +IV oxidation state, and uranyl ions indicate a coordination pattern for both systems in solution that is comparable to the crystal structure. The coordination of the uranium ions by glucosamine derivatives leads to the formation of complexes in a 3:3 stoichiometry with a bridging μ-oxo ligand, while mononuclear complexes for the lanthanides and actines could be isolated and characterized in detail for the 4-phosphorylpyrazolone ligand. The metal ions are coordinated by the N- and O- or O-donor atoms of the ligand systems. Diatom biosilicate and the protein-rich biomass spent grains were examined as biomatrices for the adsorption of f-elements. While cathode luminescence experiments show a coordination of Eu${}^{3+}$ by the SiOH groups, especially for freshly extracted diatom biosilicate, different characteri zation methods such as FT-IR, ${}^{13}$C-CP / MAS-NMR, SEM-EDX and STA-GC-MS were used to characterize both chemically and specifically thermally modified spent grains. Furthermore, the adsorption mechanisms was elucidate and the thermodynamic data of the absorption process were determined. The analyses show that, in addition to oxygencontaining functional groups, nitrogen-containing functional groups also contribute to the coordination of the absorbed ions La(III), Eu(III), Yb(III) and U(VI) and achieve a very high adsorption capacity of 297 mg/g, especially for uranyl ions. In addition, young scientists were trained in Radiochemistry through the project work. Furthermore, other measures such as a workshop, a special session at an international conference and an autumn school were organised within the project for their advance training.