Abstract

Synthesis, IR spectroscopic and X-ray structural studies of crystals [UO₂(C₄H₄O₄)(C₆H₅NO₂)₂] (I) and a new modification [UO₂(C₄H₄O₄)(H₂O)] (II), where C₄H₄O₄^2– are succinate ions, and C₆H₅NO₂ is isonicotinic acid. Structure I is formed by chains in which succinate ions play the role of bridging ligands Q⁰² and B², and isonicotinic acid molecules in the form of a zwitterion are monodentate ligands M¹. Chains I correspond to the crystal chemical formula АQ⁰²_0.5B²_0.5M¹₂, where = UO₂²⁺, Q⁰² and B² = C₄H₄O₄^2–, and M¹ = C₆H₅NO₂. The reasons of the change in the coordination type of half of the succinate ions in I from characteristic Q⁰² to rare B² 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 АQ⁴M¹, where A = UO₂²⁺, Q⁴ = C₄H₄O₄^2–, and M¹ = H₂O. 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 [UO₂(C₄H₄O₄)(H₂O)] registered in the CSD as {SUCCUR02}, are erroneous.

中文翻译：

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琥珀酸双氧铀与异烟酸配合物的合成与结构及琥珀酸双氧铀一水合物的新多晶型

摘要

合成，红外光谱和X射线晶体结构的研究[UO ₂（C ₄ H ^ ₄ ø ₄）（C ₆ H ^ ₅ NO ₂）₂ ]（我）和一个新的修改[UO ₂（C ₄ H ^ ₄ Ò ₄ )(H ₂ O)] ( II )，其中C ₄ H ₄ O ₄ ^2-是琥珀酸离子，C ₆ H ₅ NO ₂是异烟酸。结构一由链形成，其中琥珀酸离子起桥接配体Q ⁰²和B ²的作用，两性离子形式的异烟酸分子是单齿配体M ¹。链I对应于晶体化学式 АQ ⁰² _0.5 B ² _0.5 M ¹ ₂，其中 = UO ₂ ²⁺，Q ⁰²和 B ² = C ₄ H ₄ O ₄ ^2–，M ¹ = C ₆ H ₅ NO ₂. 从铀酰化合物中的18电子法则的角度解释了I中一半琥珀酸离子的配位类型从特征Q ⁰²变为稀有B ^{2 的}原因。结构II与已知的两个变体一样，对应于晶体化学式 АQ ⁴ M ¹，其中 A = UO ₂ ²⁺，Q ⁴ = C ₄ H ₄ O ₄ ^2–，M ¹ = H ₂O. 以琥珀酸铀酰一水合物多晶型物为例，发现与二氧化硅多晶型物一样，化学上相同的 3D 含铀酰骨架在拓扑结构（重构异构体）和骨架对称性（变形异构体）方面可能不同。结果表明，在≈180 K 区域内新的 γ 型II可逆地转变为已知的低温 β 型变体。使用 Voronoi-Dirichlet 多面体表明，在 CSD 中注册为 {SUCCUR02}的第四个多晶型物 [UO ₂ (C ₄ H ₄ O ₄ )(H ₂ O)]的可用数据是错误的。