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首页> 外文期刊>Crystal growth & design >Hydrogen Bonding Is Not Everything: Extensive Polymorphism in a System with Conserved Hydrogen Bonded Synthons
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Hydrogen Bonding Is Not Everything: Extensive Polymorphism in a System with Conserved Hydrogen Bonded Synthons

机译：氢键结合并非全部：具有保守氢键合成子的系统中的广泛多态性

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摘要

A simple N,N'-diaryl urea derivative was found to form four different anhydrous crystal forms (I-IV degrees), which can be crystallized in pure form by several techniques from solution as well as from the melt. These polymorphs were characterized by thermomicroscopy, differential scanning calorimetry, Fourier-transform infrared spectroscopy and single crystal and powder X-ray diffraction. The polymorphs were found to be purely monotropically related with large differences in their heats of fusion (11.1 kJ mol(-1) for the least stable form 1, 34.5 kJ mol(-1) for the most stable form IV degrees). The crystal structures of all forms show the same conformer for forms I-III and a second conformer in form IV degrees. However, the hydrogen bonding motifs in all of the polymorphs are the same and thus the compound can be seen as a model for the importance of the entire crystal packing arrangement to the overall energy and stability of the crystal form, as opposed to just a few dominant interactions.
机译：发现一种简单的N，N'-二芳基脲衍生物可形成四种不同的无水晶体形式（I-IV度），可以通过多种技术从溶液以及从熔体中以纯净形式结晶。这些多晶型物通过热显微镜，差示扫描量热法，傅立叶变换红外光谱法以及单晶和粉末X射线衍射进行表征。多晶型物被发现与它们的熔化热有很大的差异（对于最不稳定的形式1，为11.1 kJ mol（-1），对于最稳定的形式IV度，为34.5 kJ mol（-1）），其纯单向相关。所有形式的晶体结构对于形式I-III显示相同的构象异构体，在形式IV度中显示第二构象异构体。但是，所有多晶型物中的氢键基序都相同，因此该化合物可以看作是整个晶体堆积排列对整体能量和晶型稳定性的重要性的模型，而不是几个主导相互作用。

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