Synthesis And Catalytic Applications Of Small Organic Molecules And Metal-Modified Covalent Organic Frameworks

Designing and synthesizing chemical materials with ordered structures is a central topic in chemistry and materials science.It is a challenging goal to design and synthesize organic materials with ordered structures as expected.In this context,covalent organic frameworks(COFs)provide an irreplaceable platform.Because COFs can guide and integrate the topology of organic units into crystalline porous polymers to create periodic frameworks and ordered channels.As a typical class of polymer organic materials,COFs have the characteristics of good chemical stability,large specific surface area,high crystallinity,easy functionalization,and large inherent porosity.It has unlimited potential for applications in adsorption-separation,proton conduction,semiconductor,energy storage,drug delivery,sensing,and catalysis..More critically,COFs provide efficient channels for catalytic sites and accelerate the transport of reactants and products.These innate properties make it a great advantage in the field of heterogeneous catalysis.1.First,the synthesis method of COFs crystals is introduced.Secondly,the research progress of COFs in the field of application is introduced,and its research results in the field of catalysts are emphasized.2.The homogeneous catalytic system based on the Cu/TEMPO system has a good effect on the oxidation of aromatic alcohols.However,due to the pollution of metals to the environment,the high price of TEMPO,and the difficulty of recycling under homogeneous conditions,it has not been widely used in industry.Therefore,we obtained a novel heterogeneous catalyst Cu@MB-COF-TEMPO by orderly immobilizing TEMPO and Cu(II)on the COFs platform by one-pot and post-modification methods,respectively.And under mild conditions,aromatic alcohols are oxidized in a heterogeneous manner and still maintain good catalytic activity after the reaction.The results demonstrate that the COFs platform-based catalyst Cu@MB-COF-TEMPO can be easily recovered and reused for many times without loss of copper and expensive TEMPO.3.Bis(arylmethylene)cycloalkanones are a novel and versatile pharmacophore that plays an important role in organic synthesis and drug synthesis as precursors,but in the synthesis process,most reaction processes are relatively complex,or the presence of heavy metals,and most cannot be reused.However,in the synthesis process,most of the reaction processes are complicated,or there are heavy metals,and most of them cannot be reused.As one of the important asymmetric organic catalysts,chiral pyrrolidine derivatives are often used in the synthesis of complex molecules.In addition,water plays an important role in the field of green chemistry as a reaction solvent.Among them,the alkyl chain group has the role of a hydrophobic reaction field in water,and the presence of quaternary ammonium salt groups makes the active site of the catalyst in good contact with the reactants,which promotes the reaction in water.Therefore,we obtained COF-LA by "one-pot" modification of chiral pyrrolidine groups and long alkyl chain alkylamines onto COFs.We successfully synthesized bis(arylmethylene)cycloalkanone groups and their derivatives using this catalyst in aqueous phase at room temperature.Moreover,COF-LA has good reusability,and still maintains its structural stability after 7 times.