[Zurück]

C. Knoll, D. Müller, M. Seifried, Jan Welch, G. Giester, J. Ofner, B. Lendl, G. Steinhauser, P. Weinberger:
"Lanthanide complexes with 5,5´-Azobistetrazolate as ligand - astounding effects influencing the coordination behavior";
Vortrag: 43rd International Conference on Coordination Chemistry, Sendai (Japan); 30.07.2018 - 04.08.2018; in: "ICCC2018 Sendai Japan", Science Council of Japan (Hrg.); (2018), S. 39.

Different series of lanthanide complexes with 5,5´-azobistetrazolate (C₂N₁₀^2-; ZT) as a ligand were synthesized. An astounding effect for the Tb(III) complexes with ZT is the alteration of crystallization behavior due to only picomolar amounts of Am(III). Usually, the early Ln elements form complexes with a coordinative bond between the metal center and the ZT ligand, whereas the later Ln elements form salt-like compounds. In contrast, the Am-doped heavy [Tb(Am)(H₂O)₇ZT]₂ZT· 10 H₂O is isostructural to the light lanthanide (Ce-Gd) ZT compounds forming a coordinate bond. Another surprising effect was as example that super critical CO₂ proved to be a suitable desiccant enabling the synthesis of an unusually water-poor complex of Dy(III) under aqueous conditions. Usually, the ZT moiety is stabilized by H-bonds to lattice H₂O or coordination of an N-atom of the ZT to the lanthanide ion. The salt-like compound, [Dy(H₂O)₈]₂ZT₃, constitutes a unique exception to the above rule. Finally, based on the results from the series of aqueous Ln complexes with ZT as ligand, the formation of the corresponding carbonates was investigated. The carbonate ZT series of the lanthanides does not show any structural changes from coordinative to salt-like behavior, like the original complexes.

lanthanides; azo-bis-tetrazolate

https://publik.tuwien.ac.at/files/publik_271188.pdf