Preparation Of Copper Catalyst Supported On Covalent Organic Frameworks And Its Application In C-N Coupling Reaction

Covalent organic frameworks(COFs)is a kind of organic porous material that runs through the disciplines of chemistry and materials.Because of its adjustable pore size and high orderliness,the covalent organic framework material has become a leader in many fields,including catalysis,adsorption,drug loading and photoelectric sensing.Because covalent organic framework materials are connected by covalent bonds,such as C-N,C-C,C-O,O-B,etc.,it has good thermal stability and can exist stably in high temperature environments.In view of the above advantages,this paper designed and synthesized a covalent organic framework material BPy-COF containing bipyridine sites,and used copper of different valence states to catalyze the cross-coupling reaction.The synthesized covalent organic framework material contains bipyridine sites and provides good catalytic activity sites,so copper can complex with the existing nitrogen atoms to form a nitrogen-copper complex,and the copper is uniformly loaded on the surface of the material.It is more conducive to the continuous progress of the coupling reaction.Compared with other inorganic porous nanomaterials and organic porous nanomaterials,the covalent organic framework material has a more uniform pore size,and it exhibits its unique size and structure as a catalyst.This thesis aims to use copper of different valences as coordinating ions to coordinate with the synthesized BPy-COF ligands containing bipyridine sites to catalyze different coupling reactions,and to screen and optimize the reaction conditions.These mainly included the following two aspects:(1)Preparation of CuCuIBPy-COF and its application in Chan-Lam coupling reactionIn this chapter,we first synthesized a BPy-COF rich in bipyridine sites.The preparation process was to first synthesize COF monomer from 5-acetyl-2-bromopyridine as raw material,and then generate the target product BPy-COF from COF monomer through cyclotrimerization.Then,this chapter carried out the first metal loading on the synthesized BPy-COF containing bipyridine sites to realize the functionalization of COF and catalyze the Chan-Lam coupling reaction.Among them,the catalyst is copper acetate,which is cheap and easy to obtain.The divalent copper ion complexes with the nitrogen atom in bipyridine to form an N-Cu complex,which maked the catalyst uniformly dispersed on the surface of the carrier,which is beneficial to the continuous progress of the coupling reaction.Under mild conditions,the catalyst CuCuIBPy-COF was added to the Chan-Lam coupling reaction of arylboronic acid and amines.By optimizing the reaction conditions such as solvent,catalyst dosage and time,it was found that the reaction effect is best when methanol is used.When the amount of catalyst is 1 mol%,the reaction time can be shortened to 1 h to complete the reaction,and the yield was as high as 90%.Moreover,this catalyst can be recovered by filtration and used in the next experiment.And can be used repeatedly.(2)Preparation of CuICuIBPy-COF and its application in Ullmann coupling reactionThis chapter still used 5-acetyl-2-bromopyridine as the raw material to synthesize BPy-COF.Similarly,in this chapter,the synthesized BPy-COF is supported.The catalyst was cuprous iodide(CuI).The monovalent copper ion complexes with the bipyridine site in the BPy-COF to form a supported catalyst.Catalyzes Ullmann coupling reaction.The results showed that the aryl halide and the nucleophile imidazole were catalyzed by the catalyst CuI@BPy-COF,and the C-N coupling was successfully carried out at a high temperature of100°C.It has been found through experiments that when different aryl halides have different reaction effects.The overall order is PhI>PhBr>PhCl.