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Concomitant polymorphic forms of 3-cyclopropyl-5-(2-hydrazinylpyridin-3-yl)-1,2,4-oxadiazole.
Acta Crystallographica Section C ( IF 0.7 ) Pub Date : 2020-07-30 , DOI: 10.1107/s2053229620010414 Svitlana V Shishkina 1 , Irina S Konovalova 1 , Veronika R Karpina 2 , Svitlana S Kovalenko 2 , Sergiy M Kovalenko 3 , Natalya D Bunyatyan 4
Acta Crystallographica Section C ( IF 0.7 ) Pub Date : 2020-07-30 , DOI: 10.1107/s2053229620010414 Svitlana V Shishkina 1 , Irina S Konovalova 1 , Veronika R Karpina 2 , Svitlana S Kovalenko 2 , Sergiy M Kovalenko 3 , Natalya D Bunyatyan 4
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The dipharmacophore compound 3‐cyclopropyl‐5‐(2‐hydrazinylpyridin‐3‐yl)‐1,2,4‐oxadiazole, C10H11N5O, was studied on the assumption of its potential biological activity. Two concomitant polymorphs were obtained on crystallization from isopropanol solution and these were thoroughly studied. Identical conformations of the molecules are found in both structures despite the low difference in energy between the four possible conformers. The two polymorphs differ crucially with respect to their crystal structures. A centrosymmetric dimer formed due to both stacking interactions of the `head‐to‐tail' type and N—H…N(π) hydrogen bonds is the building unit in the triclinic structure. The dimeric building units form an isotropic packing. In the orthorhombic polymorphic structure, the molecules form stacking interactions of the `head‐to‐head' type, which results in their organization in a column as the primary basic structural motif. The formation of N—H…N(lone pair) hydrogen bonds between two neighbouring columns allows the formation of a double column as the main structural motif. The correct packing motifs in the two polymorphs could not be identified without calculations of the pairwise interaction energies. The triclinic structure has a higher density and a lower (by 0.60 kcal mol−1) lattice energy according to periodic calculations compared to the orthorhombic structure. This allows us to presume that the triclinic form of 3‐cyclopropyl‐5‐(2‐hydrazinylpyridin‐3‐yl)‐1,2,4‐oxadiazole is the more stable.
中文翻译：
3-环丙基-5-（2-肼基吡啶-3-基）-1,2,4-恶二唑的同时多晶型。
双药效团化合物3-环丙基-5-（2-肼基吡啶3-3-基）1,2,4-恶二唑，C 10 H 11 N 5O，是基于其潜在生物活性的假设进行研究的。从异丙醇溶液中结晶获得了两种伴随的多晶型物，并对其进行了深入研究。尽管四种可能的构象异构体之间的能量差很小，但在两种结构中都发现了分子的构象相同。两种多晶型物的晶体结构存在重大差异。由于“头到尾”型和N-H…N（π）氢键的堆叠相互作用而形成的中心对称二聚体是三斜结构中的构建单元。二聚体建筑单元形成各向同性填料。在斜方多晶型结构中，分子形成“头对头”类型的堆积相互作用，这导致它们在圆柱中的组织成为主要的基本结构基序。两个相邻柱之间的NH…N（孤对）氢键的形成允许形成双柱作为主要结构基序。如果不计算成对相互作用能，就无法确定两个多晶型物的正确堆积图案。三斜晶结构具有较高的密度和较低的密度（降低0.60 kcal mol-1）与正交结构相比，根据周期性计算得到的晶格能量。这可以让我们假设3-环丙基-5（2-肼基吡啶3-3-基）1,2,4-恶二唑的三斜晶形式更稳定。
更新日期：2020-07-30
中文翻译：
3-环丙基-5-（2-肼基吡啶-3-基）-1,2,4-恶二唑的同时多晶型。
双药效团化合物3-环丙基-5-（2-肼基吡啶3-3-基）1,2,4-恶二唑，C 10 H 11 N 5O，是基于其潜在生物活性的假设进行研究的。从异丙醇溶液中结晶获得了两种伴随的多晶型物，并对其进行了深入研究。尽管四种可能的构象异构体之间的能量差很小，但在两种结构中都发现了分子的构象相同。两种多晶型物的晶体结构存在重大差异。由于“头到尾”型和N-H…N（π）氢键的堆叠相互作用而形成的中心对称二聚体是三斜结构中的构建单元。二聚体建筑单元形成各向同性填料。在斜方多晶型结构中，分子形成“头对头”类型的堆积相互作用，这导致它们在圆柱中的组织成为主要的基本结构基序。两个相邻柱之间的NH…N（孤对）氢键的形成允许形成双柱作为主要结构基序。如果不计算成对相互作用能，就无法确定两个多晶型物的正确堆积图案。三斜晶结构具有较高的密度和较低的密度（降低0.60 kcal mol-1）与正交结构相比，根据周期性计算得到的晶格能量。这可以让我们假设3-环丙基-5（2-肼基吡啶3-3-基）1,2,4-恶二唑的三斜晶形式更稳定。
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