Crystal Structure of An(VI) Complexes with Succinate Anions, [PuO2(C4H4O4)(H2O)] and Cs2[(AnO2)2(C4H4O4)3]·H2O (An = U, Np, Pu)

Abstract

Actinide(VI) complexes with succinate anions [PuO₂(succ)(H₂O)] and Cs₂[(AnO₂)₂(succ)₃]·H₂O (An = U, Np, Pu), where succ = [C₄H₄O₄]^{2 −}, were synthesized and studied by single crystal X-ray diffraction. The compound [PuO₂(succ)(H₂O)] is isostructural with [UO₂(succ)(H₂O)] [1] and forms a three-dimensional electrically neutral framework in the crystal. The equatorial plane of the Pu(VI) pentagonal bipyramid is constituted by the O atoms of four [C₄H₄O₄]²⁻ anions and one water molecule. The [C₄H₄O₄]²⁻ anions are bridging; each anion is bound in the monodentate fashion with four Pu atoms. The structure of the complexes Cs₂[(AnO₂)₂(succ)₃]·H₂O is based on an anionic framework. The equatorial plane of the An(VI) hexagonal bipyramid is constituted by O atoms of three [C₄H₄O₄]²⁻ anions, with each anion acting as a chelating and bridging ligand binding two An(VI) atoms. The electronic absorption spectra of [PuO₂(succ)(H₂O)] and Cs₂[(PuO₂)₂(succ)₃]·H₂O were measured.