Uranium(VI) Complexes of Some Schiff Bases Derived from Hydroxyaromatic Aldehyde and Ketone

Abstract

Stable uranyl(II) complexes of some Schiff bases derived from 1,2-diaminoethane with bis-salicylaldehyde (H₂L₁) and/or bis-o-hydroxy-acetophenone (H₂L₂) as well as 2-aminophenol with salicylaldehyde (H₂L₃) and o-hydroxyacetophenone (H₂L₄) have been prepared. The complexes have been characterized by elemental analysis, spectral (UV-Visible, IR and ¹NMR) studies as well as magnetic measurements. IR specral data suggest that the neutral molecules (H₂L₃ and H₂L₄) are tridentate ligands coordinating to the central metal ions. The anions of H₂L₁ and H₂L₂ are tetradentate giving seven-coordination in the case of uranyl acetate and six-coordination in the nitrate. The labile EtOH molecule in UO₂L₁.C₂H₅OH is equatorially bonded to the uranium ion and its hydrogen is bonded to the axial oxygen of the uranyl moiety through hydrogen bonding and is easily substituted by polar solvents. The f_U-O (mdyn Å) and the length r_U-O(Å) of the UO bond are calculated from the IR data.