Rational Design Assembly Of Chiral Functional Porous Frameworks

Chiral porous materials have attracted more and more attention due to their potential applications in diverse areas such as asymmetric catalysis and enantioselective adsorption and separation.In this dissertation,various crystalline chiral functional Covalent Organic Frameworks?COFs?and Metal-Organic Frameworks?MOFs?were synthesized.The structures of these COFs were characterized by Powder X-ray diffraction,IR spectra,N₂adsorption-desorption experiment and so on,their applications in asymmetric catalysis were explored;The structures of as-synthesized MOFs were characterized by X-ray diffraction,IR spectra,CO₂ adsorption-desorption experiment and so on.Their applications in chiral recognition and separation were examined.This dissertation includes five chapters as follows:In Chapter 1,the research background was introduced including the design and synthesis of COFs and chiral MOFs and their applications in catalysis,separation and fluorescent recognition.The challenges and opportunities remained in this area together with overviews of the topic and research progress were discussed and presented too.In Chapter 2,three chiral pyrrolidine functional building blocks and a chiral imidazolidin functional building block were synthesized,then chiral functional COFs were successfully constructed by using two-component or three-component strategies.The three-component COFs showed higher chemical stability and thermodynamic stability than those with two-component.These three-component chiral COFs could catalyze various asymmetric organic reactions including asymmetric?-aminooxylation reaction,asymmetric Aldol reaction and asymmetric Diels-Alder reaction with enantioselectivities up to 95%ee.In addition,these chiral solid catalysts can be recycled for five runs without significant loss in catalytic activity.In Chapter 3,six aldehyde or amine-based organic building blocks were synthesized.By using a bottom-up strategy,five[3+3]type imine-linked functional COFs were constructed.The DPI-functionalized COF was applied in the asymmetric Steglich rearrangement of O-acylated azlactones to their C-acylated isomers with good enantioselectivity and the pyrrolidine-functionalized COF carried the asymmetric Michael addition reaction with moderate enantioselectivity and stereoselectivity.These chiral solid catalysts can be recycled for five runs without significant loss in catalytic activity.In Chapter 4,an enantiopure dipyridyl functionalized DHIP bridging ligand was prepared.Two chiral 3D MOFs were obtaind by assembling this ligand and p-phthalic acid with Zn?NO₃?₂ and CdI₂,respectively.The unique structrual features of Zn-MOF make it a good candidate to adsorb and separate racemic sulfoxides in an enantioselective manner.The host material can be readily recycled and reused without any apparent loss of enantioselectivity.In Chapter 5,a briefly summary and prospect of this dissertation were given.