Synthesis and Structure of Uranyl Succinate Complex with Isonicotinic Acid and New Polymorph of Uranyl Succinate Monohydrate

• Published in: Radiochemistry (New York, N.Y.) N.Y.), 2021-08, Vol.63 (4), p.428-438
• Main Authors: Serezhkina, L. B., Grigoriev, M. S., Rogaleva, E. F., Serezhkin, V. N.
• Format: Article
• Language: English
• Subjects: Chains; Chemistry; Chemistry and Materials Science; Chemistry/Food Science; Crystal structure; Dirichlet problem; Isomers; Ligands; Low temperature; Nuclear Chemistry; Silicon dioxide; Synthesis; Topology; Uranium dioxide; Zwitterions
• ISSN: 1066-3622; 1608-3288
• DOI: 10.1134/S1066362221040056

Synthesis, IR spectroscopic and X-ray structural studies of crystals [UO 2 (C 4 H 4 O 4 )(C 6 H 5 NO 2 ) 2 ] ( I ) and a new modification [UO 2 (C 4 H 4 O 4 )(H 2 O)] ( II ), where C 4 H 4 O 4 2– are succinate ions, and C 6 H 5 NO 2 is isonicotinic acid. Structure I is formed by chains in which succinate ions play the role of bridging ligands Q 02 and B 2 , and isonicotinic acid molecules in the form of a zwitterion are monodentate ligands M 1 . Chains I correspond to the crystal chemical formula АQ 02 0.5 B 2 0.5 M 1 2 , where = UO 2 2+ , Q 02 and B 2 = C 4 H 4 O 4 2– , and M 1 = C 6 H 5 NO 2 . The reasons of the change in the coordination type of half of the succinate ions in I from characteristic Q 02 to rare B 2 are explained from the standpoint of the 18-electron rule in uranyl compounds. Structure II , like the two already known modifications, corresponds to the crystal chemical formula АQ 4 M 1 , where A = UO 2 2+ , Q 4 = C 4 H 4 O 4 2– , and M 1 = H 2 O. By the example of uranyl succinate monohydrate polymorphs, it was found that, like silica polymorphs, chemically identical 3D uranyl-containing frameworks can differ both in topology (reconstructive isomers) and in the symmetry of the framework (deformation isomers). It was found that the new γ-form of II in the region of ≈180 K reversibly transforms into the already known low-temperature β-modification. It was shown using the Voronoi–Dirichlet polyhedra, that the available data for the fourth polymorph [UO 2 (C 4 H 4 O 4 )(H 2 O)] registered in the CSD as {SUCCUR02}, are erroneous.