Jenniefer Samson Jegan, Muthiah Packianathan Thomas
School of Chemistry, Bharathidasan University, Tiruchirappalli, Tamilnadu, India.
Acta Crystallogr C. 2011 Mar;67(Pt 3):m69-72. doi: 10.1107/S0108270111004227. Epub 2011 Feb 12.
Two isostructural uranyl complexes have been crystallized with different bipyridyl cations to yield the compounds hemi(4,4'-bipyridinium) tris(5-chlorothiophene-2-carboxylato)dioxidouranate(VI) monohydrate, (C(10)H(10)N(2))(0.5)[U(C(5)H(2)ClO(2)S)(3)O(2)]·H(2)O, (I), and hemi[4,4'-(ethane-1,2-diyl)dipyridinium] tris(5-chlorothiophene-2-carboxylato)dioxidouranate(VI) monohydrate, (C(12)H(14)N(2))(0.5)[U(C(5)H(2)ClO(2)S)(3)O(2)]·H(2)O, (II). In the UO(2)X(3) complexes (X is 5-chlorothiophene-2-carboxylate), the uranyl O atoms occupy the two axial positions and the equatorial positions are occupied by six O atoms of the three X ions so that each U atom is eight coordinated in a puckered hexagonal-bipyramidal structure. In both compounds, the metal centres are linked by classical O-H...O and N-H...O hydrogen bonds involving the coordinated ligands, the diprotonated organic linker cation (which rests on a centre of inversion at the mid-point of the central C-C bond) and water molecules. The crystal structures are further stabilized by weak C-H...O and π-π stacking interactions, forming similar three-dimensional supramolecular architectures, forming a two-dimensional network parallel to the (100) plane in (I) and a three-dimensional network in (II).
两种同构的铀酰配合物与不同的联吡啶阳离子结晶，得到化合物半（4,4'-联吡啶鎓）三（5-氯噻吩-2-羧基）二氧铀酰（VI）一水合物，(C₁₀H₁₀N₂)₀.₅[U(C₅H₂ClO₂S)₃O₂]·H₂O，（I），以及半[4,4'-（乙烷-1,2-二基）二吡啶鎓]三（5-氯噻吩-2-羧基）二氧铀酰（VI）一水合物，(C₁₂H₁₄N₂)₀.₅[U(C₅H₂ClO₂S)₃O₂]·H₂O，（II）。在[UO₂X₃]⁻配合物（X为5-氯噻吩-2-羧酸盐）中，铀酰O原子占据两个轴向位置，赤道位置被三个X离子的六个O原子占据，因此每个U原子以褶皱的六方双锥结构八配位。在这两种化合物中，金属中心通过涉及配位配体、双质子化有机连接阳离子（位于中心C-C键中点的对称中心上）和水分子的经典O-H...O和N-H...O氢键相连。晶体结构通过弱C-H...O和π-π堆积相互作用进一步稳定，形成相似的三维超分子结构，在（I）中形成平行于（100）平面的二维网络，在（II）中形成三维网络。
