Synthesis,Characterization And Catalytic Performance Of The MIL-101(Cr)-FLP

Metal organic frameworks?MOFs?,also known as porous coordination polymers?PCPs?,are three-dimensional porous crystalline materials.It is a crystalline material composed of secondary building units?SBU?,metal ions or clusters and bridged polydentate organic ligands.It has the characteristics of adjustable pore size and structural diversity.It can be controlled by changing metal ions,bridging ligands and post-synthesis modification?PSM?.MOF has a higher specific surface area,which is much higher than zeolite and activated carbon.It is widely used in gas storage,energy conversion,chemical sensing,drug delivery,proton conductivity and catalysts.Due to its metal center,highly ordered porous structure,uniform pore size and pore environment,high specific surface area and functional organic ligands,MOFs have good application prospects in the field of catalysis.Frustrated Lewis pair?FLP?is a combination of Lewis acids and bases that are spatially prevented from forming classic Lewis acid-base adducts.It has Lewis acidity and a base that can interact with a third molecule.In this article,we incorporate Lewis acid-base pairs?FLP?into the MOF framework.Choose stable large pore size MOF,MIL-101?Cr?,Cr₃?OH?O?BDC?₃?BDC=1,4-benzenedicarboxylate?exposed to the solution of 1,4-diazabicyclo[2.2.2]octane?DABCO?,which causes the base to bind to open metal sites in the MOF pore and another nitrogen atom of the DABCO ligand exposed in the pores.Subsequent exposure to B?C₆F₅?₃ led to the incorporation of Lewis acid,thereby encapsulating FLP?DABCO?/B?C₆F₅?₃ into MOF,and obtained MIL-101?Cr?-FLP.It is characterized by X-ray powder diffraction,infrared spectroscopy,transmission electron microscopy,scanning electron microscopy,gas adsorption,elemental analysis,etc.The MIL-101?Cr?-FLP was used as a catalyst to catalyze the reaction of CO₂ and epoxide to produce propylene carbonate under normal temperature and pressure conditions.The effects of cocatalyst,reaction time and reaction substrate on the catalytic effect were investigated.The results showed that the catalyst exhibited excellent catalytic performance under mild conditions.