Department of Chemistry, University of Kentucky, Lexington, KY 40506-0055, USA.
School of Chemistry, University of St Andrews, Fife, KY16 9ST, United Kingdom.
Acta Crystallogr C Struct Chem. 2023 Mar 1;79(Pt 3):77-82. doi: 10.1107/S2053229623001262. Epub 2023 Feb 15.
Crystal structures described as concomitant triclinic (I) and monoclinic (II) polymorphs of meso-(E,E)-1,1'-[1,2-bis(4-chlorophenyl)ethane-1,2-diyl]bis(phenyldiazene) [Mohamed et al. (2016). Acta Cryst. C72, 57-62] have been re-investigated. The published model for II was distorted due to forcing the symmetry of space group C2/c on an incomplete structure model. It is shown here to be a likely three-component superposition of S,S and R,R enantiomers with a lesser amount of the meso form. A detailed analysis of how the improbable distortion in the published model aroused suspicion and the subsequent construction of undistorted chemically and crystallographically plausible alternatives having the symmetry of Cc and C2/c is presented. For the sake of completeness, an improved model for the triclinic P-1 structure of the meso isomer I, revised to include a minor disorder component, is also given.
结构描述为伴随的三斜晶系（I）和单斜晶系（II）的中（E，E）-1,1'-[1,2-双（4-氯苯基）乙烷-1,2-二基]双（苯基亚肼）[Mohamed 等人。（2016）。结晶。C72,57-62]已重新研究。由于强制空间群 C2/c 的对称性在不完整的结构模型上，发布的 II 型模型发生了扭曲。这里显示它可能是 S，S 和 R，R 对映体的三组分叠加，其中含有较少的中间形式。详细分析了发布模型中不可能的扭曲如何引起怀疑，以及随后构建具有 Cc 和 C2/c 对称性的无扭曲的化学和结晶合理替代物。为了完整性，还给出了改进的中（E，E）-1,1'-[1,2-双（4-氯苯基）乙烷-1,2-二基]双（苯基亚肼）I 型三斜晶 P-1 结构的模型，修订后包括次要的无序成分。
