Synthesis And Catalytic Performance Of RE-MOFs With Lewis Acid Sites

Rare earth organic framework materials(RE-MOFs)are a kind of new MOFs with rare earth metals ions as nodes.While rare earth MOFs can have many of the same characteristics common to all MOF families,namely,permanent porosity,tunable pore size/shape,and accessible Lewis acid centers,they can also exhibit unique structures and properties due to the high coordination number and different optical properties of rare earth metals.Due to the abundant energy level structure of rare earth ions,rare earth MOFs have great potential applications in multifunctional luminescent materials such as white light emission,chemical sensing and biological imaging.In addition,rare earth ions have different coordination number and coordination structure,and rare earth metals have unique hard sphere behavior,which makes them less selective in the formation of coordination bonds,and more likely to form stable MOFs with high coordination number.In this paper,two kinds of rare earth metal-organic frame materials synthesized by solvothermal method are introduced,and their structure,stability and catalytic performance are studied.The full text contains four chapters:In chapter one,we mainly introduce the research background of rare earth metal-organic framework materials in terms of synthesis strategy and structural characteristics,and then focus on the research progress of rare earth MOFs in the field of catalysis,mainly catalysis of carbon dioxide cycloaddition reaction and ring-opening reaction.In chapter two,a series of new rare earth MOFs,[NH₂(CH₃)₂][RE(2,5-Pydc)₂]4·DMF·x H₂O(RE=Y,Yb,Gd),were synthesized by solvothermal reaction with a dicarboxylic acid linear linearly(Pyridine-2,5-dicarboxylates)and three rare earth metal ions RE³⁺(RE=Y,Yb,Gd).This series of complexes exhibit an octa-linked three-dimensional structure,exhibit high chemical and thermal stability,and can effectively catalyze carbon dioxide cycloaddition reactions and styrene oxide ring opening reactions.In chapter three,we use 2,6-bis(3,5-dicarboxyphenyl)pyridine(H₄L)and three rare earth metal salts(RE(NO₃)₃,A series of three-dimensional framework structures containing trinuclear rare earth clusters were synthesized by solvothermal reaction:[H₂N(Me)₂[RE₃(L)₂(HCOO)₂(DMF)₂(H₂O)](1-RE-L),the catalytic performance of the three complexes on the cycloaddition reaction of carbon dioxide and the ring opening reaction of styrene oxide were tested.In chapter four,we summarized the two complexes synthesized and the catalyzed styrene oxide ring opening reaction and carbon dioxide ring opening reaction,which provided the basis for the application of rare earth metal MOFs in catalytic carbon dioxide ring opening reaction and catalytic ring opening reaction in the future.