Synthesis And Properties Of Two-dimensional COFs

Covalent organic frameworks(COFs)are formed from molecular organic building units linked by covalent bonds to form crystalline,porous,extended solids.They comprised light elements(such as H,B,C,N,O)and are connected by robust covalent bonds via reticular chemistry.Because of their well-defined structure,designable construction and tailored functionality,these materials have attracted considerable attention for diverse applications,including gas adsorption and separation,sensing,proton conductivity,catalysis,and many others.This article focuses on the new structure and catalysis of COF.?.Herein we report,for the first time,a new synthetic strategy that can generate new COFs via multicomponent one-pot in situ reactions.In total,12 ?-aminonitrile-and quinoline-linked COFs with high crystallinity and permanent porosity are successfully achieved by three-component one-pot in situ Strecker and Povarov reactions under solvothermal conditions in high yields.The obtained COFs feature the same structures as those obtained from the stepwise PSM approach on an established imine-linked COF.This in situ multicomponent assembly strategy,as a synthetic methodology parallel to PSM,might open a new route for constructing COFs that is not possible under PSM conditions.?.In this chapter,a urea-linked COF with higher crystallinity was synthesized and characterized by XRD,FTIR,BET,etc.Under the condition of no solvent filling,the framework of the synthesized does not collapse,and it still maintains a high degree of crystallinity.The connection of the urea group to the COF directly introduces new catalytic sites for the COF itself.The framework can be directly used as a high efficiency heterogeneous catalyst in Friedel-Crafts(F-C)reaction of indole and nitrostyrene.Furthermore,the urea-COF can catalyze the reaction at least for 10 cycles without significant loss of catalytic activity.In summary,we have made new breakthroughs in the one-pot multicomponent synthesis of COF and catalysis,and provided new ideas for the later synthesis of new COFs.