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Beispielpublikationen aus der Actinoidenchemie

C.C. Gatto, E. Schulz Lang, A. Kupfer, A. Hagenbach, U. Abram

Mono-, Di- and Trinuclear Dioxo Complexes of Uranium Containing Hydrazonato and Azomethine Ligands

Z. Anorg. Allg. Chem. 2004, 630, 1286

Mono-, di or trinuclear dioxouranium complexes with benzoylhydrazonato or azomethine ligands were prepared by reactions of common dioxouranium precursors such as UO2(NO3)2 • 6 H2O or [NBu4]2[UO2Cl4] with vanillin benzoylhydrazone (H2L4), salicyl­alde­hyde benzoylhydrazone (H2L5), 2-hydroxyacetylbenzene salicylhydrazone (H3L6) or N-(2-ethoxycarbonyl-3-oxo-but-1-en(1)yl)-2-aminophenol (H2L7).

Spectroscopic and X-ray crystallographic studies on the complexes [NBu4]2[UO2Cl4] • 2 H2L4, [UO2(HL5)(H2L5)2](NO3), [HNEt3]2[{UO2(L6)}2] and [HNEt3]2[{UO2(L7}3O] confirm that the individual donor atom constellation, the size of the potential chelate rings and the acidity of the OH and NH functionalities of the proligands have a strong influence on the structure of the products.

C. C. Gatto, E. Schulz Lang,  A. Jagst, U. Abram

Dioxouranium(VI) Complexes with 2,6-Diacetylpyridinebenzoylhydrazones and semicarbazones

Inorg. Chim. Acta 347 (2004) 4405

Benzoylhydrazones and semicarbazones derived from 2,6-diacetylpyridine react with common dioxouranium(VI) compounds such as uranyl nitrate or [NBu4]2[UO2Cl4] to form air-stable complexes. 2,6-Diacetylpyridinebis(benzoylhydrazone) (H2L1), 2,6-diacetylpyridinebis(N4-phenylsemicarbazone) (H2L2) and the asymmetric proligand 2,6-diacetylpyridine(benzoylhydrazone)(N4-phenylsemicarbazone) (H2L3) give yellow products of the composition [UO2(L)]. The neutral compounds contain doubly deprotonated ligands and possess uranium atoms with distorted pentagonal-bipyramidal coordination spheres. The equatorial coordination spheres of the metal atoms can be extended by the addition of a monodentate ligand such as pyridine or DMSO. The uranium atoms in the resulting complexes have hexagonal-bipyramidal coordination environments with the oxo ligands in axial positions.

X-ray diffraction studies on [UO2(L1)(DMSO)], [UO2(L2)], [UO2(L2)(DMSO)] and [UO2(L3)] show relatively short U‑O bonds to the benzoylic oxygen atoms between 2.273(6) and 2.368(5) Å. This suggests a preference of these donor sites of the ligands over their imino and amine functionalities (U‑N bond lengths: 2.502(7) – 2.671(7) Å ). The addition of a sixth ligand to the equatorial coordination sphere results in a lengthening of the metal‑pyridine bonds.

C.C. Gatto, E. Schulz Lang, A. Kupfer, A. Hagenbach, D. Wille, U. Abram

Dioxouranium Complexes with Acetylpyridine Benzoylhydrazones and Related Ligands

Z. Anorg. Allg. Chem. 630 (2004) 735

Acetylpyridine benzoylhydrazone and related ligands react with common dioxouranium(VI) compounds such as uranyl nitrate or [NBu4]2[UO2Cl4] under formation of air-stable complexes. Reactions with 2,6-diacetylpyridinebis(benzoylhydrazone) (H2L1a) or 2,6-diacetylpyridinebis­(salicylhydrazone) (H2L1b) give yellow products of the composition [UO2(L1)]. The neutral compounds contain doubly deprotonated ligands and possess a distorted pentagonal-bipyramidal structure. The hydroxo groups of the salicylhydrazonato ligand do not contribute to the complexation of the metal. The equatorial coordination spheres of the complexes can be extended by the addition of a monodentate ligand such as pyridine or DMSO. The uranium atoms in the resulting deep-red complexes have hexagonal-bipyramidal coordination environments with the oxo ligands in axial positions. The sterical strains inside the hexagonal plane can be reduced when two tridentate benzoylhydrazonato ligands are used instead of the pentadentate 2,6-diacetylpyridine derivatives.

Acetylpyridine benzoylhydrazone (HL2) and bis(2-pyridyl)ketone benzoylhydrazone (HL3) deprotonate and form neutral, red [UO2(L)2] complexes. The equatorial coordination spheres of these complexes are puckered hexagons.

X-ray diffraction studies on [UO2(L1a)(pyridine)], [UO2(L1b)(DMSO)], [UO2(L2)2] and [UO2(L3)2] show relatively short U‑O bonds to the benzoylic oxygen atoms between 2.328(6) and 2.389(8) Å. This suggests a preference of these donor sites of the ligands over their imino and amine functionalities (U‑N bond lengths: 2.588(7) – 2.701(6) Å ).

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