手性硫醚功能化金属羧酸配位网络的设计合成及其性能研究

This proposal addresses the generic issues of assembly and systematic functionalization of homochiral metal-organic frameworks(MOFs), with the specific goal of achieving porous networks for high efficient enantioseparation. For this, we will take a crosscutting approach that integrates the knowledge of organic synthesis, crystal growth and coordination solid state chemistry. Our strategy here is to construct the frameworks from a class of rigid and symmetrical organic molecules containing two distinct sets of functional groups. One set is the chemically hard carboxylate groups at the terminal sites of the molecule as the primary group; the other is the thioether groups (-SR, with the soft S atom) at the central portion of the molecule as the seconday group. The crux is that chemically hard metal ions (such as Zn(II)) will selectively bond to the carboxylate groups to form a robust, porous MOF, while leaving the soft thioether groups free standing inside the established framework. By using a chiral thioether on the secondary group, we will be able to impose homochiral features on the framework. Moreover, we can also modify the secondary group to the provide accurate control over the local chiral environment of the pockets (e.g. hydrophobic or hydrophilic, the left- or right-handedness, binding sites for generating supramolecular interactions). Mostly, the efficiency of enantioseparation directly depends on the communication between host networks and guest molecules. We will then explore the separation test for racemic moleucles with the proposed network. To conclude, we will summarize the correlationship between the well-defined structures and their properties, in order to provide guidance for the design of new functional materials. In a broader perspective, this homochiral coordination network, combined with well-defined porosity, large surface area and free standing thioether group in the pockets, offer potential applications in heterocatalytic reaction, because the thioether side chains provide chiral bonding pockets for the incoming the catalytic metal centers such as Pd or Rh.

手性研究对于生命科学的探索、药物开发以及材料科学发展都有着极其重要的意义。本研究将综合利用有机合成化学、晶体生长和固态化学等多个学科领域的研究方法，通过手性配体设计合成，实现手性配位网络的构筑和手性孔道的修饰。本项目拟利用手性硫醚芳香羧酸作为手性配体，根据软硬酸碱理论，硬酸金属离子会选择跟羧基形成三维开放式配位网络，而硫醚游离在孔道中。使用手性硫醚可以赋予目标配合物的纯手性，还可以通过手性硫醚的修饰来调控手性孔道的局部环境。重点考察不同手性环境的多孔配位网络对特定有机分子的吸附分离性能，探索结构的变化对其分离性能的影响，总结构效关系的规律，为开发新型手性分离材料提供更多的科学依据。从长远来看，手性硫醚功能化的金属-羧酸配位网络可以吸附具有催化活性的金属(Pd或Rh)。因此，该多孔材料还可用作担体负载金属并应用于异相选择性催化中。

本研究对于无机固态化学、材料科学的发展有着重要的意义。本研究综合了利用有机合成化学、晶体生长和固态化学等多个学科领域的研究方法，通过配体设计合成，实现目标金属有机框架材料的构筑和孔道的修饰。本项目利用硫醚官能团作为侧链，芳香羧酸作为配体的主体，根据软硬酸碱理论，硬酸类金属离子会选择跟羧基形成三维开放式配位网络，而软碱类硫醚游离在孔道中。重点考察不同硫醚侧链功能化金属有机框架网络的性能，探索侧链的变化对其性能的影响，总结构效关系的规律，为开发新型金属有机框架材料提供更多的科学依据。此外，我们还基于联吡唑配体，合成出了两粒结构新颖、性能优异的Cu（I）配位聚合物，系统地研究了它们在吸附、催化及其导电性等性能的研究，还发展了利用共轭多孔高分子原位制备纳米银颗粒，并系统地研究了纳米颗粒在催化氢化中的应用。