Structure of complexes of uranyl succinate with carbamide and dimethylurea

Abstract

Three new succinate-containing complexes of uranyl with carbamide (Urea) and N,N'-dimethylurea (s-Dmur) are synthesized and studied by IR spectroscopy and X-ray diffraction. Structures of the same type, [UO₂(Urea)₄(H₂O)][(UO₂)₂(C₄H₄O₄)3] · 3H₂О and [UO₂(Urea)₄(H₂O)][(UO₂)₂(C₄H₄O₄)3] · 2Urea contain two sorts of uranium-containing complex groups, namely, mononuclear [UO₂(Urea)₄(H₂O)]²⁺ cations and two-dimensional [(UO₂)₂(C₄H₄O₄)₃]^2– anions described by crystal-chemical formulas AМ₅¹ and A₂Q₃⁰², respectively (A = UO₂²⁺, M¹ = Urea or H₂O, Q⁰² = C₄H₄O₄^2-), and differ only in the nature of noncoordinated molecules—water and carbamide. The main structural groups of the [(UO₂)₂(C₄H₄O₄)₂(s-Dmur)₃] crystals are [(UO₂)₂(C₄H₄O₄)₂(s-Dmur)₃] chains belonging to the А₂Q₂⁰²M₃¹ (A = UO₂²⁺, Q⁰² = C₄H₄O₄^2-, M¹ = s-Dmur) crystal-chemical group. Specific features of intermolecular interactions in the crystal structures are revealed using the Voronoi–Dirichlet method of molecular polyhedra.