Zimmermann Iwan, Keene Tony D, Hauser Jürg, Decurtins Silvio, Liu Shi-Xia
Department of Chemistry and Biochemistry, University of Bern, Freiestrasse 3, 3012 Bern, Switzerland.
Acta Crystallogr Sect E Struct Rep Online. 2014 Sep 10;70(Pt 10):178-82. doi: 10.1107/S1600536814019151. eCollection 2014 Oct 1.
The isostructural title compounds, {(C7H7N2)2[SnI4]} n , (1), and {(C7H5F2N2)2[SnI4]} n , (2), show a layered perovskite-type structure composed of anionic {SnI4} n sheets parallel to (100), which are decorated on both sides with templating benzimidazolium or 5,6-di-fluoro-benzimidazolium cations, respectively. These planar organic heterocycles mainly form N-H⋯I hydrogen bonds to the terminal I atoms of the corner-sharing [SnI6] octa-hedra (point group symmetry 2) from the inorganic layer, but not to the bridging ones. This is in contrast to most of the reported structures of related compounds where ammonium cations are involved. Here hydrogen bonding to both types of iodine atoms and thereby a distortion of the inorganic layers to various extents is observed. For (1) and (2), all Sn-I-Sn angles are linear and no out-of-plane distortions of the inorganic layers occur, a fact of relevance in view of the material properties. The arrangement of the aromatic cations is mainly determined through the direction of the N-H⋯I hydrogen bonds. The coherence between organic bilayers along [100] is mainly achieved through van der Waals inter-actions.
同构的标题化合物{(C₇H₇N₂)₂[SnI₄]}ₙ（1）和{(C₇H₅F₂N₂)₂[SnI₄]}ₙ（2）呈现出层状钙钛矿型结构，该结构由平行于(100)的阴离子{SnI₄}ₙ层组成，这些层的两侧分别由模板化的苯并咪唑鎓或5,6 - 二氟苯并咪唑鎓阳离子修饰。这些平面有机杂环主要与来自无机层的角共享[SnI₆]八面体（点群对称性2）的末端I原子形成N - H⋯I氢键，但不与桥连的I原子形成氢键。这与大多数报道的涉及铵阳离子的相关化合物结构形成对比。在那些结构中，观察到与两种类型的碘原子都形成氢键，从而导致无机层有不同程度的扭曲。对于(1)和(2)，所有的Sn - I - Sn角都是线性的，并且无机层没有发生面外扭曲，鉴于材料性质，这一事实具有重要意义。芳香族阳离子的排列主要由N - H⋯I氢键的方向决定。沿着[100]方向的有机双层之间的相干性主要通过范德华相互作用实现。
