Design,Construction And Properties Of Benzothiadiazole Or Benzoselenadiazole Functionalized Metal-Organic Frameworks

Metal-organic frameworks?MOFs?,which are constructed by metal ions?metal-cluster nodes?and organic ligands via coordination bond,belong to the class of porous crystalline solid.It is widely used in gas adsorption and separation,heterogeneous catalysis,ion recognition and so on for its porous structure,high surface area and modifiable and adjustable property.In order to realize the functionalization of MOFs,it is feasible for us to change the metal node,synthesize the functionalized organic ligand and introduce metal nanoparticles into its pores.We sucessfully controled and improved the original physical and chemical properties of MOFs by mainly functionalizing the organic ligands.Therefore,some robust MOFs,which keep the original structures and embrace some specific performance,were obtained by the strategy of mixed ligands.Based on these,Zr-based UiO-68 typed MOF,as we all know,with good stability,high porosity and specific surface,large pore size and modified terphenyl dicarboxylic acid ligand,was used as a framework model in this thesis.We have incorporated some organic ligands with different functional groups into the model by the strategy of mixed ligand.These MOF materials with robust structure,high specific surface,thermal stability and prominent photophysical properties,showed potential applications in heterogeneous photocatalysis,gas adsorption,molecular recognition and other fields.In the first chapter,the concept,development process and research status of metal-organic frameworks are mainly introduced.Then,we summarized the main synthesis methods with each pros and cons.In the end,the superior performance of MOFs and potential applications in different fields are highlighted.In the second chapter,we designed and synthesized a benzothiadiazole functionalized TPDC ligand H₂-BTD?TPDC=terphenyl-4,4''-dicarboxylic acid?to construct the benzothiadiazole functionalized UiO-68 topological framework by the mix-and-match synthetic strategy.MOF UiO-68-S can serve as a highly active photocatalyst for visible light promoted aerobic oxidation reactions,including the selective oxygenation of sulfides and oxidative hydroxylation of arylboronic acids.In addition,it can be recycled at least 5 times without significant loss of catalytic activity and its framework is maintained following the catalytic reaction.In the third chapter,A zirconium?IV?-based UiO-topological metal-organic framework?UiO-68Se?containing benzoselenadiazole was synthesized by an approach of the mixed dicarboxylate struts,which show highly efficient and recycalable photocatalytic activity for aerobic crossdehydrogenative coupling reactions between tertiary amines and various carbon nucleophiles under visible light irradiation.In the fourth chapter,a photoactive moiety triazolobenzothiadiazole?TBTD?-conjuagted terphenyldicarboxylate?TPDC?linker was introduced into a porous and robust UiO-68 isoreticular zirconium metal-organic framework?MOF,denoted as UiO-68-TBTD?by the de novo synthetic approach of mixed TPDC struts.Under blue LED irradiation,UiO-68-TBTD can serve as a heterogeneous photocatalyst for highly efficient and selective oxidation of sulfur mustard simulant?2-chloroethyl ethyl sulfide?to the corresponding much less toxic sulfoxide product,with a half-life of only 3 min in the air atmosphere.In the fifth chapter,we demonstrated that a fluorescent benzothiadiazole?BTD?-conjugated terphenyldicarboxylate?TPDC?linker?denoted as H2-ostpdc?has been hybridized by a quinoxaline-2,3-?1H,4H?-dione?QD?moiety possessing lactam-lactim tautomerism,which was further integrated into a robust and porous UiO-68 type zirconium metal-organic framework?MOF UiO-68-osdm?by utilizing the mixed two dicarboxylate struts with the same ligand lengths.The resultant MOF UiO-68-osdm can work as a ratiometric luminescent sensor for visual and selective detection of alkyl amines.Furthermore,it can discriminate secondary alkylamines from other type amine species.In this dissertation,four kinds of functionalized terphenyl dicarboxylic acid organic ligands were designed and synthesized firstly.Then,they were merged into Zr-based UiO-68 framwork by solvothermal method to construct four different functionalized MOFs,inchuding UiO-68-S,UiO-68-Se,UiO-68-BTzTD,and UiO-68-osdm.Finally,we mainly studied their applications in heterogeneous catalysis and molecular recognition.In a word,based on the research results of this dissertation,we can draw a conclusion that the properties of metal organic framework materials can be controlled and improved effectively by rational design of ligands,which lay a foundation for further designing and constructing new high-performance MOFs materials and expanding their applications in other fields.