Synthesis, crystal structure, and spectra of the Np(V) terephthalate [C(NH2)3]3[NpO2(C6H4(COO)2)2]·5H2O and An(VI) terephthalates [AnO2(C6H4(COO)2)] (An = U, Np, Pu)

Abstract

The structure and spectra of the Np(V) terephthalate [C(NH 2 ) 3 ] 3 [NpO 2 (C 6 H 4 (COO) 2 ) 2 ]·5H 2 O (I) and An(VI) terephthalates [AnO 2 (C 6 H 4 (COO) 2 )] (II), where An = U, Np, or Pu, were studied. The crystal structure of I is build of NpO 2 + cations and terephthalate anions linked with each other in infinite anionic chains [NpO 2 (C 6 H 4 (COO) 2 ) 2 ] n 3-, with the water molecules and guanidinium cations arranged between them. The Np atom has the coordination surrounding in the form of a hexagonal bipyramid whose equatorial plane is formed by the O atoms of three [C 6 H 4 (COO) 2 ] 2-anions. There are two independent [C 6 H 4 (COO) 2 ] 2-anions in the structure. One of them is bidentate chelating, and the other is chelating and bridging, with both of its carboxylate groups bonded to the NpO 2 + cations in the anionic chains in the bidentate fashion. Five crystallographically independent water molecules are localized in the structure of I. Together with the [C(NH 2 ) 3 ] + cations, these water molecules form a three-dimensional system of hydrogen bonds. The crystal structure of II is built of neutral [AnO 2 (C 6 H 4 (COO) 2 )] n layers formed by the AnO 2 2+ cations and terephthalate anions. The An(VI) atom has the coordination surrounding in the form of a tetragonal bipyramid whose equatorial plane is formed by the O atoms of four [C 6 H 4 (COO) 2 ] 2-anions. The IR and electronic absorption spectra of the compounds are presented.Synthesis of new organometallic compounds of f elements with the framework structure is a promising line of the modern chemistry. According to the results of recent studies, such compounds exhibit unique physicochemical properties, in particular, high porosity and high specific surface area, and are therefore promising for use, e.g., in catalysis, in gas treatment, for hydrogen storage, etc. Relatively successful attempts to summarize the results obtained and use them for passing to directional synthesis of compounds with preset properties have been made for d elements [1]. Numerous papers on the synthesis, structure, and properties of complexes of actinyl ions with different isomers of benzenedicarboxylic acid have been published recently. The behavior of Pu(V) in aqueous solutions containing anions of benzene-1,2-dicarboxylic (phthalic) acid has been studied in detail [2]. Also, new

Secondary Role of Aliphatic and Heterocyclic Amines in the Formation of Low-Temperature Amine-Bearing U, Np, and Pu(VI) Chromates

“…The chains of the same topology were found in the crystal structure of derriksite , Cu 4 [UO 2 (SeO 3 ) 2 ]­(OH) 6 . Similar chains are also observed in the crystal structures of compounds with different organic bridging ligands including phenylphosphinate, diethylphosphate, benzoate, and their derivatives. − Moreover, such chains can act as building blocks for 2D structural units as, for example, in the uranyl and neptunyl aromatic dicarboxylates. − …”

Synthesis of Coordination Polymers of Tetravalent Actinides (Uranium and Neptunium) with a Phthalate or Mellitate Ligand in an Aqueous Medium

“…In fact, the crystal chemistry of Np IV is poorly investigated even to date. To the best of our knowledge, only a small number of publications have reported the crystal structure of neptunium­(IV) carboxylates, such as oxalates, − formate, and tribromoacetate, while there are several studies reporting the carboxylate complexes with other oxidation states of Np, such as Np V − and Np VI . − The present study reports the hydrothermal syntheses of U IV and Np IV with phthalate and mellitate. The crystal structures of the obtained compounds were determined by single-crystal X-ray diffraction (SC-XRD), and the results are compared between U IV and Np IV .…”