Preparation and crystal structure of tris(γ-aminobutanoic acid) dioxouranium(VI) diperchlorate

The title compound has been prepared and its crystal structure determined by X-ray crystallography. The compound is monoclinic,P21/m,Z=2, witha=9.842(5),b=22.136(6),c=5.939(4) A, and β=108.71(3)°. The complex is ionic and hasC s symmetry. The uranyl group is equatorially bonded to three bidentate acid molecules in a distorted hexagonal bipyramidal coordination geometry. Bond distances are: U-O(uranyl) 1.76(1) A, U-O(equatorial) 2.47–2.48 A, C-O 1.25–1.28 A, Cl-O 1.40–1.43 A. The amino acid is zwitterionic with the ionized carboxyl chelate to uranium and the amino terminus protonated. The structure is stabilized by hydrogen bonding.