Gate opening behaviour of structurally flexible porous coordination polymers - characterization by combined X-ray diffraction and sorption studies

在多孔性配位聚合物(金属有机骨架，MOF)之外，一些MOF表现出所谓的开门行为，这取决于客体分子在孔道中的负载程度。在这些结构灵活的材料中，晶体结构对外部刺激(如某些气体的存在差异)做出响应，因此它们被认为是具有各种潜在应用的有前途的可开关材料。然而，到目前为止，只有几个例子是已知的，它们的结构是如何变化的。该项目的目的之一是对结构变化进行详细调查，以了解大门打开效应的起源和后果。为此，将根据在吸附研究条件下收集的X射线粉末衍射图，进行一系列吸附实验，包括纯和混合气体吸附研究和突破实验，以及结构确定研究。此外，该项目的中心任务是改进我们实验室衍射仪的自制原位(吸收/X射线衍射)样品夹持器，以便扩大研究结构柔性材料的实验可能性--不依赖于访问同步加速器光束线。拟议的项目需要有关研究小组及其在吸附和结构表征方面的个人专长的密切合作。

Out of the class of porous coordination polymers (metal-organic frameworks, MOFs) some MOFs exhibit so-called gate opening behaviour which is dependent on the degree of loading of the pores with guest molecules. In these structurally flexible materials the crystal structure responds on external stimuli such as differences in presence of certain gases, and therefore they are regarded as promising switchable materials with various potential applications. However, up to now only for a few examples it is known, how their structures change. One aim of this project are detailed investigations of structural changes in order to understand origin and consequences of the gate opening effect. For that purpose a combination of sorption experiments, including pure and mixed gas sorption studies and break through experiments, and structure determination studies will be performed based on X-ray powder diffraction patterns collected at the conditions of the sorption studies. Besides that, it is an central task within the project, to improve the home-built in situ (sorption / X-ray diffraction) sample holder for our laboratory diffractometer in order to extend the experimental possibilities for investigation of structurally flexible materials - independent of access to synchrotron beam lines. The proposed project requires a close cooperation of the involved research groups with their individual expertise in sorption and structural characterization.