单一手性金属有机框架的制备与不对称催化1,3偶极环加成反应研究

Metal–organic frameworks (MOFs) are hybrid solids with infinite network structures that built from organic bridging ligands and inorganic connecting nodes. Recent progress in MOF based asymmetric catalysis has proved that these emerging catalysts provide a new exciting opportunity for the synthesis of enantiopure compounds, including chiral drugs and fine chemicals. The 1,3-dipolar cycloaddition of azomethine ylides with electron-deficient olefins is an extremely versatile process to form highly substituted chiral pyrrolidines, which provide an important motif with widespread applications to the synthesis of biologically active compounds and natural products. To minimize the metal trace in the product and to avoid the waste of the expensive chiral catalytic addictives, our project provided an approach to incorporate chiral metal complexes that are able to generate a metallodipole within the nodes of frameworks, resulting in efficient catalytic activity with the catalysts being recyclable and reusable. This approach is based on the chiral induced homochiral crystallization of enantiomeric metal-based MOFs from achiral tripdol ligands and metal ions that enables the application of the metal intrinsically asymmetric catalysis. The distorted tetrahedral coordinated metal atoms acted as lattice nods to connect the ligands in a controllable fashion. The twist configurations of the three aromatic rings attached to one atom exhibit atropisomeric chirality in the solid state, facilitating the chiral transfer between the metal centers and finally leading to the formation of chiral MOFs. The role of the assembly processes and the influence factors on the catalytic reaction are modified, and highly efficient homochiral MOF-based materials are achieved by further matching the chirality of the confined space in the porous of the MOF-based materials and the chiral configuration of the metal ions for the asymmetric 1,3-dipolar cycloaddition. The structural simplicity of the building blocks and the ability to control the assembly process through conformational chiral adducts make this system a promising one for the development of a wide range of homochiral materials.

手性金属有机框架是一类优越的非均相不对称催化材料。探索新型的手性金属有机框架催化剂应用于药物中间体的合成具有巨大的应用价值。本项目针对通过1,3-偶极环加成反应形成杂螺环结构产物的构型控制等科学问题，拟通过自组装的方式将过渡金属离子(Ag+、Au+、Cu+)与具有潜在构型手性的三臂双齿有机配体形成手性的金属-有机多孔框架结构，以期利用手性多孔框架结构的空间限域与金属中心本征催化功能的协同与复合，实现对1,3-偶极环加成反应产物的构型控制，获取构型单一对映体产物；探索不同手性多孔金属有机框架结构在1,3-偶极环加成反应中的催化规律，考察非手性配体通过自发拆分和手性诱导过程构筑单一手性多孔框架结构的影响因素，制备并优化出系列新型高选择性、高效率非均相不对称催化材料,为新型催化剂的制备提供新的研究思路。

金属有机框架结构作为一种新型的多孔晶态材料展现出多样化的拓扑结构与优越的结构性能，在非均相不对称催化领域具有广泛的应用前景，本项目针对手性催化剂均相催化过程中存在的贵金属流失、催化剂昂贵等问题，通过配位自组装的方式得到系列具有限域空腔孔道的金属-有机限域结构。通过模拟酶的催化活性和催化环境的耦合，实现对模拟酶催化反应过程的控制和产物的构型选择具有极高的科学意义。 利用三芳胺特殊的结构特征，通过与四面体配位的金属银离子作用，建立了通过自发拆分与手性诱导构筑单一手性金属有机框架的新方式，为实现高产率、高立体选择性的催化剂的制备提供了新的拓展模型。 金属-有机限域八面体内部空腔对有机染料的包合作用，构筑超分子体系，调控光敏剂和催化剂件的电子转移途径，提升光催化分解水制氢体系的效率和稳定性。利用限域区间内部和外部的空间隔离效应，实现内部还原反应，外部氧化反应的耦合。上述体系为金属-有机限域体系在光催化分解水方面的研究提供了新的思路。.资助期间发表SCI收录论文5篇。分别发表在Accounts of Chemical Research、Angewandte Chemie International Edition、ACS Catalysis、Chem. Sci等高影响力期刊。