Claudia C. Gatto

Bis{diacetylpyridinebis(benzoylhydrazonato)}thorium(IV) – a novel thorium chelate with co-ordination number 10

Abstract The potentially five-dentate ligand diacetylpyridinebis(benzoylhydrazone), H2ac2py(benzhyd)2, reacts with Th(NO3)4·5H2O in methanol under formation of the neutral bis-chelate [Th{ac2py(benzhyd)2}2)]. The co-ordination polyhedron of the 10-coordinate metal ion can best be described to be intermediate between a bicapped cube and a bicapped square antiprism. Bond length between 2.390(3) and 2.398(3) A have been found for the Th–O bonds, whereas the Th–N distances are in the range between 2.644(3) and 2.781(4) A.

Dioxouranium complexes with `Jaeger-type¿ ligands

Abstract Azomethine ligands with electron-withdrawing groups such as bis{N,N′-(2-ethoxycarbonyl-3-oxo-but-1-en(1)yl)-1,2-diaminobenzene (H2L1) or N-(2-ethoxycarbonyl-3-oxo-but-1-en(1)yl)-2-aminophenol (H2L2) react with uranyl nitrate under deprotonation and formation of chelate complexes. The composition of the products can be controlled by the reaction conditions and the denticity of the ligands. Structure determinations have been performed on [NEt3H][UO2(L1)(OMe)], [UO2(L1)(DMSO)] and [NEt3H]2[{UO2(L2)}3(μ3-O)].

Syntheses and structures of 2-acetylpyridine-(2-amino-benzoylhydrazone) and its dioxouranium(VI) complex

We describe the synthesis and characterization of 2-acetylpyridine-(2-aminobenzoylhydrazone) (HL1) and its first dioxouranium complex. The single crystal X-ray structural analysis of the hydrazone, HL1, reveals an almost planar structure with intermolecular hydrogen bonds. The complex [UO2(L1)(dmf)2](NO3) is formed by refluxing a suspension of HL1 with uranyl nitrate in methanol in the presence of a small quantity of triethylamine. Recrystallisation from dmf results in single crystals suitable for X-ray crystallography. The single crystal X-ray study of the complex shows a distorted pentagonal-bipyramidal coordination geometry around the uranium(VI) center, determined by two axial oxo ligands, two nitrogen and one oxygen atoms from a chelating monodeprotonated hydrazone and the oxygen donor atoms of two dimethylformamide molecules.