A concerted approach for a better understanding and control of the polymorphism of benzamide molecular crystals - synthesis as well as experimental and theoretical characterisation

更好地理解和控制苯甲酰胺分子晶体多态性的协调方法 - 合成以及实验和理论表征

• 批准号: 140553152
• 负责人: Professor Dr. Josef Breu
• 金额: --
• 依托单位: Arbeitsgruppe Anorganische Chemie III
• 依托单位国家: 德国
• 项目类别: Priority Programmes
• 财政年份: 2009
• 资助国家: 德国
• 起止时间: 2008-12-31 至 2016-12-31
• 项目状态: 已结题
• 来源: https://gepris.dfg.de/gepris/projekt/140553152?language=en
• 关键词: concerted; approach; better; understanding; control

The aim of this project is to increase the understanding of polymorphism and nucleation of benzamide, which was developed during the first project period of the SPP 1415. Additionally, we strive to extend our studies to related molecular systems. During the first funding period we found to our surprise that benzamide exhibits a strong amphiphilic character. This opens up promising avenues for structurally similar molecules like pharmaceuticals and their precursors. Sodium benzoate was shown to display an unusual micelle like packing, indicating similar molecular interactions for benzamide and sodium benzoate. For the oncoming period we plan to focus our research efforts on heterogeneous nucleation processes for both systems. We intend to unravel specific structural motives of the pre-organisation of amphiphilic molecules at polar/unpolar interfaces as well as the influence of tensides and the formation of nuclei starting to grow from molecular monolayers at the interfaces. We also plan to investigate the potential of forming micellar aggregates as possible precursor and will follow their self-organisation into mesocrystals. In the case of sodium benzoate the experimentally observed transformation occurs in the solid-state and is slow allowing for easy access with in-situ analytics. We believe sodium benzoate to be an ideal system to study the hierarchical processes during the nucleation and growth mechanism. Therefore, we will use a coordinated approach combining synthesis, theory and experimental characterisation. As such the competence of all three groups involved is essential. The Breu group need to develop synthetic methods allowing for a nucleation which occurs at the interfaces as selectively as possible. The atomistic simulations carried out in the Zahn group will help to understand the relevant molecular interactions and is able to suggest possible scenarios of the selforganisation at the interfaces. The Senker group will contribute with NMR spectroscopic experiments, providing direct access to the molecular assembly at the interfaces and the micelles, respectively. They are also suited to validate the structural motives derived from the MD simulations. The thus derived insight into the nucleation phenomenon serves the long term goal to reach a general control of polymorphism in molecular crystals.

该项目的目的是增加对苯甲酰胺的多晶型和成核的理解，这是在SPP 1415的第一个项目期间开发的。此外，我们努力将我们的研究扩展到相关的分子系统。在第一个资助期间，我们惊讶地发现苯甲酰胺具有很强的两亲性。这为结构相似的分子（如药物及其前体）开辟了有希望的途径。苯甲酸钠显示出不寻常的胶束状堆积，表明苯甲酰胺和苯甲酸钠具有相似的分子相互作用。在接下来的一段时间里，我们计划把我们的研究工作集中在这两个系统的异质成核过程。我们打算解开特定的结构动机的预组织的两亲性分子在极性/非极性界面以及表面活性剂的影响和形成的核开始生长的分子单层在界面处。我们还计划研究形成胶束聚集体作为可能的前体的潜力，并将遵循它们的自组织成介晶。在苯甲酸钠的情况下，实验观察到的转化发生在固态中，并且是缓慢的，允许容易地进行原位分析。我们认为苯甲酸钠是一个理想的体系，研究在成核和生长机制的分级过程。因此，我们将采用综合、理论和实验表征相结合的协调方法。因此，所涉所有三个群体的能力至关重要。Breu小组需要开发合成方法，以允许尽可能选择性地在界面处发生成核。在Zahn小组中进行的原子模拟将有助于理解相关的分子相互作用，并能够提出界面自组织的可能方案。Senker小组将通过NMR光谱实验做出贡献，分别提供直接进入界面和胶束的分子组装。它们还适合验证从MD模拟中得出的结构动机。由此衍生的洞察成核现象服务的长期目标，以达到在分子晶体中的多晶型的一般控制。