Multivariate, flexible MOFs: The role of functionalized linkers, heterogeneity and defects

在For 2433第一阶段合作成果的基础上，项目S1将主要关注与材料功能相关的研究问题，即第二阶段资助中QF2可切换催化剂CATG@MOF的设计、合成和表征。CATG指的是催化活性客体，它包括结构定义的分子催化剂(由均相催化建立)以及表面活性剂稳定的金属纳米颗粒。潜在的研究问题(QP3)是缺陷、无序和异质性将如何影响母体柔性MOF的反应行为。因此，S1还将研究包含DEFG的更一般的影响，DEFG表示产生缺陷但催化不活跃的客体(例如，纳米级聚苯乙烯和硅珠等)。然而，解决QF2需要灵活的MOF候选者，它显示出在固体/液体和固体/气体情况下的多组分条件下的开关行为(QF1是基于对QP4的了解，具体的和非具体的吸附/开关)。这些混合吸附现象将在S1和S2提供的一系列柔性MOF上进行研究。然而，第二个相关的工作包将涉及阐明轻烃在fu-MOF家族的特殊晶型上的超高动力学选择性的机理，即蜂窝网状结构[Zn2(fu-bdc)2(Bipy)]体系。这种FU-MOF具有刚性的框架，在客体摄取/释放过程中不会经历相变。然而，在BDC主链上具有C3官能化的烷基醚侧基-OR(R：丙基、乙烯基、丙基)的情况下，我们观察到丙烯在丙烷和丙炔上的壮观选择吸附。将结合时间分辨多组分气/固吸附研究(包括与S2的突破实验)和固体核磁共振研究(使用具有P1的重氢烃客体分子)与理论模型(例如，迁移率和扩散，T2)一起进行。

Based on the collaboratively obtained results in FOR 2433 during the 1st period, the project S1 will primarily focus on research questions related to materials functions, namely on QF2 the design, synthesis and characterization of switchable catalysts catG@MOF in the 2nd period of funding. The notation catG refers to a catalytically active guest, which includes structurally defined molecular catalyst (established from homogeneous catalysis) as well as surfactant stabilized metal nanoparticles. The underlying research question (QP3) is how defects, disorder and heterogeneity will influence the responsive behavior of the parent flexible MOFs. Therefore S1 will also study the more general effects of inclusion of defG, which denotes defect generating but catalytically inactive guests (for example, nanoscale polystyrene and silica beads etc.). Addressing QF2, however, requires flexible MOF candidates, which show a switching behavior under multicomponent conditions in the solid/liquid and as well in the solid/gas situation (QF1 which is based on the knowledge about QP4, specific vs. non specific adsorption/switching). These mixed adsorption phenomena will be studied on a selection of flexible MOFs made available by S1 and S2. A second, however related work package will deal with the elucidation of the mechanistic origin of the ultrahigh kinetic selectivity in light hydrocarbon adsorption at special polymorphs of the fu-MOF family, namely the honeycomb net structures [Zn2(fu-bdc)2(bipy)] system. This fu-MOF features a rigid framework and does not undergo a phase transition during guest uptake/release. However, in case of C3 functional alkylether side groups -OR (R: propyl, vinyl, propinyl) at the bdc backbone we observed spectacular selective adsorption of propene over propane and propyne. A combined time–resolved multicomponent gas/solid adsorption study (including break-through experiments with S2) and solid-state NMR study (using deuterated hydrocarbon guest molecules with P1) will be performed together with theoretical modeling (e.g. mobility and diffusion, T2).