Preparation Of Porous Organic Polymers And Regulation Control To Its' Structure-Activity Relationship

Porous organic polymers(POPs)are series of macromolecular polymers constructed by covalent bonds,which has a dozen of superior properties such as high BET specific surface area,permanent porosity,low density,high stability,variously alternative synthetic methods,as well as the flexible designability of candidate blocks.Therefore,POPs are increasingly utilized as versatile platforms to be modified for specific requirement in various areas.On the past years,various POPs have been fabricated with eminent performance through the functionalization of building monomers or/and the post-modification for already synthetic POPs.Herein,this article mainly demonstrate two methods,one is the predesignated methodology toward the functional blocks,and another is the post-modification of POPs,which is utilized to controllably adjust the structure-activity relationship.In the meanwhile,the synthetic POPs were applied in several areas such as gas ad-desorption,heterogeneous catalysis.(1)By using the predesignated methodology,we synthesized a new three-dimensional conjugated microporous polymer(Fe-Por-N(CH3)2-CMP),which presented high specific surface area(550 m2 g-1)and high thermochemistry stability.It was performed to catalyze the formation of C-X(X ? N,S)bonds through carbine insertion reactions,with high efficiency,high selectivity,high cyclic stability,extensive scope of substrates,and high functional-group tolerance.Wherein,the catalytic performances were adjusted via control the methyl degree of amine group(primary amine and tertiary amine were discussed as comparison)of iron porphyrin blocks.(2)By using the post-modification methodology,we synthesized two kinds of ionic covalent organic frameworks(COFs),zwitterionic COFs([BE]X%-TD-COFs)and quaternary phosphonium salt COFs([P]X%-TD-COFs).Thereinto,the betaine and quaternary phosphonium salt were immobilized into the skeleton of COFs respectively,by Williamson ether reaction.We can control the density of ionic groups,which were introduced into the pore of COFs,by adjusting the proportion of hydroxyl blocks quantificationally.[BE]X%-TD-COFs were used to catalyze the hierarchical two-,four-,and six-electron reduction of CO2 with higher efficiency,milder reaction conditions,and considerable selectivity even better than its' homogeneous counterparts.The experiments indicated that the recovered catalyst still remained high activity after recycling for 4 times,which confirmed the excellent reusability of heterogeneous catalyst.[P]X%-TD-COFs were utilized to versatilely catalyse the chemical transformations of CO2.Among them,CO2 can be catalyzed into the corresponding products with 2,6 electrons reduction,when using the primary amines or second amines as substrates.In addition,the reaction between epoxides and CO2,which could be also catalyzed to afford cyclic carbonates efficiently.Similarly,the aziridines were transformed into corresponding oxazolidinones with high efficiency.The COFs and the immobilized catalytic sites are built up base on covalent bonds,which endows it considerable stability and thus possess perfect maintained catalytic activity after simply filtrating,washing,and desiccating when reuse it.