Synthesis, Characterization and Structural Assessment of Dioxouranium (VI) Complexes of Acetone Benzoylhydrazone

Abstract

Reaction of acetone benzoylhydrazone (ABH) or its deprotonated form (ABH-H) with dioxouranium (VI) salts in 2:1 molar ratio gives [UO₂(ABH)₃] (NO₃)₂, [UO₂(ABH)₂X₂] 72H₂O, [X = NCS, Cl], [UO₂(ABH) (SO₄) (H₂O)₂], [UO₂(ABH-H) (CH₃COO) (H₂O)₂] and [UO₂(ABH) (C₂O₄)] H₂O. The complexes have been characterized through elemental analyses, molar conductance, spectral data (IR, far IR and Raman). The ligand exhibits keto-enol tautomerism in the complexes and coordinates as a bidentate ligand through carbonyl oxygen and azomethine nitrogen. Nitrate ion retains its ionic character in the nitrate complex, while thiocyanate (through N) and chloride ions act as terminal monodentate ligand, sulphate and acetate ions act as bridging bidentate ligand and oxalate ion acts as a bridging tetradentate ligand. It is proposed that all complexes involve eight coordinate uranium atom with ligand atoms arranged around linear uranyl group in an equatorial plane perpendicular to the linear uranyl group.