Synthesis and Catalytic Properties of Several Chiral Porous Metal-Oragnic Solids

Author:Li Zi Jian

Supervisor:cui yong

Database:Doctor

Degree Year:2018

Download:35

Pages:160

Size:8811K

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Chiral porous Metal-Organic Solids have attracted increasing attention due to their tunablity of the structures,high BET sufrace areas and potential applications in many areas,such as chiral recognition and separation,asymmetric catalysis and nonlinear optics.Here,a variety of porous chiral Metal-Organic Frameworks(MOFs)and Metal-Organic Cages(MOCs)have been designed and synthesized through several metallosalen ligands with C2-symmetric property and TEMPO-modified,MacMillan’s catalyst-functionalized tricarboxyl ligands with C3-pseudosymmetric property.Two chiral binary MOFs with precise active centers were constructed by the co-crystallization of dipyridine and dicarboxylate-functionalized M(salen)complexes.A chiral MOF catalyst decorated with TEMPO racidal was built by dipyridine-functionalized M(salen)complex and TEMPO-decorated tricarboxyl ligand.Three isostructural MOCs were synthesized by TEMPO or chiral MacMillan’s catalyst-functionalized tricarboxyl ligand with C4-symmetric calixarene.The structures of these chiral MOFs and MOCs were characterized by a variety of techniques,including single-crystal X-ray diffraction,and their applications in sequential asymmetric catalysis were explored.This thesis includes the following five chapters.In Chapter 1,the research background was introduced including the history,synthesis methods and their potential applications of chiral MOFs and chiral MOCs.The opportunities and challenges in thesis area as well as the overviews of the thesis topic and research progress were also discussed and presented.In Chapter 2,the dipyridyl-functionalized Fe(salen)/Mn(salen)ligands and dicarboxylate-functionalized VO(salen)were synthesized by five,eight-steps organic reactions,respectively.The co-crystallization of dipyridine-functionalized Fe(salen)/Mn(salen)complexes,dicarboxylate-functionalized VO(salen)complex with cadium ion produced two chiral prous binary MOFs 1/2 with precise active centers Fe(salen)/VO(salen)and Mn(salen)/VO(salen).Due to the periodical arrangement of a large mount of Fe/VO and Mn/VO sites,MOFs 1/2 can serve as the efficient and effective heterogeneous catalyst capable of catalyzing the sequential asymmetric epoxidation of olefins/epoxide aminolysis and epoxidation of olefins/epoxide hydrolysis,respectively,with the highest enantioselectivity up to 99%ee.In addition,the chiral MOFs 1/2 remains almost the original catalytic activity without negligible loss of efficiency and enantioselectivity and structurally intact after several recycling.In Chapter 3,the dipyridyl-functionalized VO(salen)ligands and the free radical TEMPO-decorated tricarboxylate ligand were synthesized by five,three steps organic reactions,respectively.The co-crystallization of dipyridine-functionalized VO(salen)complexe,TEMPO-decorated tricarboxylate ligand with cadium ion produced one chiral porous MOF 3.With the periodical arrangement of a large mount of Lewis acid VO(salen)and TEMPO radical,the resulting MOF 3 can serve as the efficient and effective heterogeneous catalyst capable of catalyzing the sequential alcohol oxidation/asymmetric cyanation with the highest enantioselectivity up to 87%ee,outperforming the corresponding homogeneous hybrid system.In addition,the chiral MOF 3 remains almost the original catalytic activity without negligible loss of efficiency and enantioselectivity and structurally intact after several recycling.In Chapter 4,the organic molecule MacMillan’s catalyst-functionalized tricarboxylate ligand H3L4 was synthesized through nine-steps organic reactions starting from the glycinemethylester hydrochloride while calixarene-based C4symmetric H4L5 was synthesized in two steps.Two isostructural MOCs 4/5 were constructed by H3L3、H3L4 with H4L5 and Zn2+,respectively.Mixing equivalent H3L3,H3L4 with H4L5,Zn2+generates another isostructural MOC 6 containing two catalytic centers.With the periodical arrangement of TEMPO radical and MacMillan’s catalyst,the resulting MOCs 4/5 can catalyze the primary alcohols oxidation and Diels-Alder reaction,respectively.The binary MOC 6 containing both of TEMPO and MacMillan’s catalyst can catalyze the sequential allyl alcohol oxidation/asymmetric intermolecular Diels-Alder reaction with up to 89%ee.The control experimental indicates these two catalysts are typically incompatible in a two-step/one-pot synthesis,because the oxoammonium species generated from TEMPO oxidizes the free amines of MacMillan’s catalyst.When the two catalyst heterogenized into one MOC,both of two catalysts remained their catalytic properties.Such MOCs are assembled into a two-dimensional metal-organic layered frameworks through the supramolecular interactions such as hydrogen bonding interactions.The layered frameworks can be further ultrasonated to get the corresponding nanosheet,in which two catalysts remained their catalytic properties.The reaction yield can be improved while the enantioselectivity remained because it can increase the possibility of reactant and catalysts meeting each other.In addition,the chiral MOC 6 nanosheet remains almost the original catalytic activity without negligible loss of efficiency and enantioselectivity after several recycling.In Chapter 5,a brief summary and prospect of this thesis were given.