Design,Assembly And Asymmetric Catalytic Properties Of Chiral Metal-Organic Frameworks Based On Metallosalen

Chiral metal-organic frameworks(MOFs)have received increasing attention due to their potential applications in diverse areas such as chiral recognition and separation,asymmetric catalysis,nonlinear optics.Here,a variety of carboxyl-and/or pyridylfunctionalized metallosalen ligands were synthesized and utilized to build a series of chiral MOFs with robust structures and unique properties.The structures and properties of these chiral MOFs were characterized by a variety of techniques including single crystal X-ray diffraction and their applications asymmetric catalysis were explored.This thesis includes the following five chapters.In Chapter 1,the background was introduced including the design and synthesis of chiral metal-organic frameworks histories,synthesis methods and their applications in asymmetric catalysis.The opportunities and challenges remained in thesis area together with overviews of the thesis topic and research progress were also discussed and presented.In Chapter 2,a chiral porous Cr(salen)-MOF based on a custom-designed Cr(salen)-ligand MOF was constructed.The chiral MOF can serve as an efficient and effective catalyst capable of catalyzing a series of important asymmetric transformations including Nazarov cyclization reaction,aminolysis reaction,DielsAlder and hetero Diels-Alder reactions with the highest ee up to 99%,outperforming the corresponding homogeneous systems.In addition,the chiral MOF maintains the original catalytic activity and crystal structure in the process of recycling.In Chapter 3,a core-shell MOF,with Al salen as core and Mn salen as shell,was assembled using pyridyl-functionalized chiral Al(salen)-ligand and Mn(salen)-ligand.As a heterogeneous catalyst,the core-shell MOF was used as an efficient and recyclable heterogeneous catalyst for asymmetric olefin epoxidation/epoxide aminolysis with an enantioselectivity up to 96.5%ee.In Chapter 4,a series of multiple,iso-structural MOFs(including five bicomponents MOFs and two tricomponents MOFs)were constucted using carboxyl-functionalized Cu(salen),V(salen),Cr(salen),Mn(salen),Fe(salen)and Co(salen)ligands.The bicomponents MOFs can serve as an efficient and effective catalyst capable of catalyzing a series of important asymmetric transformations including silylcyanation,aminolysis reaction,olefin epoxidation and Diels-Alder reaction.The tricomponents MOFs were used as an efficient and recyclable heterogeneous catalyst for asymmetric epoxidation of olefins/epoxide ring open with an enantioselectivity up to 99%ee,outperforming the corresponding homogeneous systems and hybrid system.In addition,these chiral MOFs maintains the original catalytic activity and crystal structure in the process of recycling.In Chapter 5,a briefly summary and prospect of this thesis were given.