Uranyl Methacrylate Complexes with Carbamide and Methylcarbamide: Synthesis and Structure

Resumo

The synthesis and X-ray diffraction and IR spectroscopic study of (UO₂)₂(mac)₄(L)₃ · H₂O crystals, where mac^– is the methacrylate ion C₃H₅COO^– and L is carbamide (I) or methylcarbamide (II), have been performed. Complexes I and II have a homotypic structure: crystals contain two kinds of mononuclear uranium-containing complexes, i.e., cationic [UO₂(mac)(L)₃]⁺ and anionic [UO₂(mac)₃]^–. The crystallographic formula of complexes in structures I and II is AB⁰¹M₃¹ + AB₃⁰¹ (A =UO₂²⁺ B⁰¹ = mac^–, M¹ = L). The uranium-containing complexes in structures I and II are linked into a framework by means of electrostatic interactions and a system of hydrogen bonds. Despite the similar compositions and structures of the uranium-containing complexes, their packings into a three-dimensional framework appreciably differ from each other.