Increasing the complexity in breathing metal-organic frameworks using organic building units with conformational flexibility

该项目旨在合成新的金属有机框架（MOFs），结合内在柔性的有机建筑单元。因此，所得到的框架化合物有望表现出可逆的结构变化。最适合这一目的的有机建筑单元是烷二酸及其功能化衍生物，部分脂肪族二羧酸，也含有芳香苯核和二茂铁二羧酸。最重要的结构表征方法将是x射线粉末衍射。在期待新化合物发现的同时，也期待已知的基于刚性连接分子的mof的脂肪族类似物的出现。在这种情况下，柔性单元对化合物性能的影响可以通过与刚性单元的比较直接推导出来。因此，所研究的化合物对外界刺激（如压力、温度和客体分子）的灵活性也将通过x射线粉末衍射进行研究。新mof的预期结构灵活性将与基于刚性有机建筑单元的相关化合物进行比较。压力依赖性衍射实验将使用同步辐射和金刚石砧细胞进行。此外，将利用同步辐射原位研究客体分子从溶液中吸附时的相变，特别是它们的动力学。

This project aims at the synthesis of new metal-organic frameworks (MOFs) incorporating intrinsically flexible organic building units. Therefore the obtained framework compounds are expected to exhibit reversible structural changes. The organic building units best suited for this purpose are alkanedioic acids and their functionalised derivatives, partially aliphatic dicarboxylic acids which also contain an aromatic benzene core and ferrocenedicarboxylic acid. The most important structural characterisation method will be X-ray powder diffraction. While the discovery of new compounds is anticipated, it is also expected that aliphatic analogues of well-known MOFs based on rigid linker molecules will be obtained. In this case the influence of the flexible unit on the compounds properties can be directly deduced by comparison to its rigid counterpart. Thus the flexibility of the investigated compounds depending on external stimuli like pressure, temperature and guest molecules will be also investigated by means of X-ray powder diffraction. The expected structural flexibility of the new MOFs will be compared to related compounds based on rigid organic building units. Pressure dependent diffraction experiments will be conducted using synchrotron radiation and a diamond anvil cell. In addition the phase transitions upon adsorption of guest molecules from solution and especially their kinetics will be investigated in-situ using synchrotron radiation.