Application Of Catalytic Function-oriented Covalent Organic Frameworks In Thesynthesis Of 2-aminobenzothiazole Derivatives

As a new class of crystalline porous materials,covalent organic frameworks（COFs）have attracted much attention in recent years.It is composed of pre-designed organic building units orderly connected by covalent bonds to form a certain topological crystalline network structure.Compared with traditional materials,COFs materials show unique advantages due to their regular channels,excellent porosity,relatively high specific surface area,ultra-low density and excellent stability.At present,COFs have shown potential broad prospects in heterogeneous catalysis,gas adsorption and separation,biomedicine,molecular recognition,chemical sensing,energy storage and other applications.Pre-designed monomers and abundant modifiable nodes can flexibly load catalytic active sites,so that COFs materials show their unique advantages in heterogeneous catalysis.In addition,due to its excellent structural stability as an organic polymer,the regular channels also accelerate the transport of reactants and products,and can be recycled by simple filtration,realizing circular sustainable green chemistry.The concept has broad prospects for catalytic applications.1.This thesis summarizes the relevant research progress in recent years,the design of covalent organic framework materials（COFs）catalysts and their applications in chemical catalysis,photocatalysis,electrocatalysis and other fields,and further points out the significant role of COFs in traditional catalyst research.advantages,and discuss the challenges and prospects for the development of COF-based catalysts.2.Through the method of pre-synthesis,we pre-designed the hydrazide monomer L-Phen with o-phenanthroline as the functional unit,and successfully modified it to the COF framework through the Schiff base reaction to successfully synthesize a new hydrazone bonded COF-Phen.We used COF-Phen as a heterogeneous catalyst to successfully catalyze the cascade reaction of iodoaniline and phenylisothiocyanate derivatives in aqueous phase under mild conditions,and synthesized a series of related 2-aminobenzothiazole structures.product,the yield is as high as（82%-99%）.Moreover,it can be reused more than 7 times through simple filtration and drying,realizing the concept of green and sustainable environmental protection.So far,COF-Phen is the first COFs catalyst used in the tandem reaction of 2-iodoaniline and isothiocyanate,which will inspire the design and development of a series of widely used COFs materials based on o-phenanthroline functional units.3.Using the same design idea,we first designed and synthesized hydrazide monomers with short alkyl chain structures of quaternary ammonium salts through a four-step reaction,and synthesized a new case of quaternary ammonium salt covalent organic framework materials COF-QA;then,Cu Br₂was loaded in COF-QA by the post-modification method,and a new phase transfer catalyst Cu（II）@COF-QA with composite Cu²⁺and quaternary ammonium salt functional units was obtained.Through the synergistic effect of these two functional units,we used this heterogeneous catalyst to successfully catalyze the coupling ring formation reaction of iodoaniline and phenylisothiocyanate derivatives in the aqueous phase under mild conditions to produce The efficiency is as high as 88%-99%,realizing high-efficiency phase transfer catalysis and can be repeated more than 5 times.This catalyst is another example of COFs catalyst used in the series reaction of 2-iodoaniline and isothiocyanate,which expands the further application of COFs materials in catalyzing the series reaction of 2-iodoaniline and isothiocyanate.