molecular packings

  • 文章类型: Journal Article
    多孔分子材料由固态组装的分子构成,使得存在空腔或互连的孔网络。控制这些系统的组装具有挑战性,由于分子之间的相互作用通常很弱,分子结构的细微变化会导致分子间相互作用和随后不同的晶体堆积排列。同样,使用不同的溶剂进行结晶,或引入溶剂蒸气,可以导致形成不同的多晶型物和孔网络。很难唯一地描述形成的孔隙网络,因此,我们分析了多孔分子系统的1033晶体结构,以确定其空隙空间和潜在的客体扩散网络的潜在拓扑。应用与材料无关的拓扑定义。我们使用基础拓扑网来检查是否可以将等网状设计原理应用于多孔分子材料。总的来说,我们对大型数据集的自动分析提供了对分子拓扑结构及其孔隙网络拓扑网络之间关系的一般见解。我们表明,虽然多孔分子系统倾向于与非多孔分子类似地堆积,它们的孔隙分布的拓扑结构类似于更突出的多孔材料,例如金属-有机骨架和共价有机骨架。
    Porous molecular materials are constructed from molecules that assemble in the solid-state such that there are cavities or an interconnected pore network. It is challenging to control the assembly of these systems, as the interactions between the molecules are generally weak, and subtle changes in the molecular structure can lead to vastly different intermolecular interactions and subsequently different crystal packing arrangements. Similarly, the use of different solvents for crystallization, or the introduction of solvent vapour, can result in different polymorphs and pore networks being formed. It is difficult to uniquely describe the pore networks formed, and thus we analyse 1033 crystal structures of porous molecular systems to determine the underlying topology of their void spaces and potential guest diffusion networks. Material-agnostic topology definitions are applied. We use the underlying topological nets to examine whether it is possible to apply isoreticular design principles to porous molecular materials. Overall, our automatic analysis of a large dataset gives a general insight into the relationships between molecular topologies and the topological nets of their pore network. We show that while porous molecular systems tend to pack similarly to non-porous molecules, the topologies of their pore distributions resemble those of more prominent porous materials, such as metal-organic frameworks and covalent organic frameworks.
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  • 文章类型: Journal Article
    质子代表药物化合物中对NMR最敏感的核。因此,快速幻角旋转下的质子检测固态NMR技术是克服分析天然丰富药物和产品的低灵敏度挑战的少数解决方案之一。在这项研究中,我们报道了商业药物分子的晶体多晶型物的结构表征,泊沙康唑,分子量相对较大,为700.8g·mol-1,天然丰度。在100kHzMAS下增强的灵敏度和分辨率可以探索泊沙康唑I型中独特的分子间堆积,III,和γ。这些结果表明,质子检测的同源和异核相关方法可以探测药物多态性的结构细节。
    Protons represent the most NMR-sensitive nucleus in pharmaceutical compounds. Therefore, proton-detected solid-state NMR techniques under fast magic angle spinning are among the few solutions to overcome the challenge of low sensitivity to analyze natural abundant drug substances and products. In this study, we report the structural characterization of crystal polymorphs of a commercial drug molecule, posaconazole, with a relatively large molecular weight of 700.8 g·mol-1 and at the natural abundance. The enhanced sensitivity and resolution at 100 kHz MAS enables the exploration of the distinct intermolecular packing in posaconazole forms I, III, and γ. These results demonstrate that proton-detected homo- and heteronuclear correlation methods can probe the structural details of pharmaceutical polymorphism.
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