The Design,Synthesis And Properties Of Multifunctional N-rich Porous Organic Polymers

Porous organic polymers?denoted as POPs?are highly cross-linked networks,consisted of light elements?such as C,H,O,N and B etc.?,connected by covalent bonds with low framework density and large BET specific surface area.Due to their characteristics of highly stability and high tunability of structural building blocks,the applications of POPs have been gradually extended from gas separation to catalysis,energy storage,sensing and biomedicine,etc.Therefore,there is more and more attention on the design and synthesis of new structures,and the development of new properties and applications.Technically,it can realize the controllable synthesis of POPs with novel structures and specific functions,based on the fully understanding of the structure-function relationship,controllable structural characteristics and synthetic strategies.In this thesis,we developed a series of POPs with specific functions through the control of structure units and condensation reaction.A triazine-base polymer connected by Tr?ger's base has been developed with good CO₂ separation and catalyzing properties,which broadens its synthesis strategies and develops its applications for the organic heterogeneous catalysis and the detection of hydrochloric acid vapor.A Tr?ger's base-connected porous polymer with strong fluorescence has been prepared with a tetraphenylethene unit,whose CO₂ adsorption property has been investigated and applications of the detection for Cu²⁺and picric acid have been explored.Two types of urea linked fluorescent polymers with the tetraphenylethylene units,which broadens the synthetic approaches of the polymer family and deepen the understanding of the coordination effect of ureido.Besides,a COF with novel structure using tetraphenylethylene unit has been synthesized,whose applications have been broadened for the organic heterogeneous catalysis.The main research results of this thesis are as follows:1.A facile strategy has been developed to synthesis a triazine polymer with Tr?ger's base?TB?structure at room temperature using trifluoroacetic acid as a solvent and a catalyst,which to a great degree reserved the functional groups for the polymer,different from the triazine materials prepared by ionothermal synthesis.The polymer has been a perfect candidate for CO₂ separation due to its high BET specific surface area and abundant N atoms in the frameworks.It shows high isosteric heat for CO₂ up to 33.7 kJ mol^-1 and good affinity to CO₂ molecule.Its unique structure endows this porous polymer high CO₂/N₂ and CO₂/CH₄ adsorption selectivity at 273K,the adsorption selectivity for the gas mixture of 15%CO₂ and 85%N₂,5%CO₂and 85%CH₄ were 55.3 and 9.2,respectively.Meanwhile,this polymer shows the application in naked eye detection of ppm level HCl gas based on the visible color change,which has potential in the detection of hydrochloric acid vapor.Besides,the polymer shows a productivity of 89-97%for Knovenagel reaction due to alkalinity itself.2.A strong fluorescent porous polymer with the structure units of tetraphenylethylene has been synthesized by the strategy of trifluoroacetic acid polymerization.Owing to the tetraphenylethylene structure units,which are rotation-confined by the polymer frameworks,the material has a good fluorescent property which has a strong green-emission under 380 nm.It has good performance in detection of picric acid and Cu²⁺,associated with the interactions between analyte and TB structure in the frameworks,whose the quenching constants reach up to 1.9 x 10⁵M^-1 and 2.6 x 10⁴ M^-1,respectively.Besides,the material has large BET specific surface area(484 m² g^-1)and excellent CO₂ isosteric heat(53.7 kJ mol^-1)which is higher than common materials.The separation factor for CO₂/N₂ was calculated 61.7by the initial slopes of the CO₂ and N₂ adsorption isotherms within low pressure using Henry's law constants.3.A facile strategy has been developed to synthesize two types of urea linked fluorescent polymers with the structure units of tetraphenylethylene by the urea-synthesizing way of CDI and 1,4-Phenylene diisocyanate without the catalyst.It has both good affinity to CO₂ and fluorescent property.Also it has a good performance in the detection of Fe³⁺and picric acid account of its ureido structure,whose quenching constants reach up to 2.32 x 10⁵ M^-1 and 1.37 x 10⁵ M^-1 for UOP-1,3.55 x 10⁵ M^-1 and 3.43 x 10⁵ M^-1 for UOP-2.4.A covalent organic framework based on Schiff base structure has been synthesized with TAPE and TFPB monomers,which is a micron-scale cube structure stacked by 2-dimensional layers in macroscopic.Two different micropores sized 0.92nm and 1.40 nm exist in the material with BET specific surface area as high as 992.2m² g^-1.At 273 K and 1 bar,the CO₂ adsorption amount is 76.0 cm³ g^-1,which indicates that the material has good CO₂ adsorption ability.Besides,catalyst has been prepared by using of the coordination of N atom and palladium acetate.This thesis is an expansion and development for the existing functional POPs by the introduction of specific property structure unit through the bottom-up strategy based on the fully understanding of POPs.Besides,it is an exploration for the synthesis of POPs with new structures and functions,which provides theoretic and experimental basis for further experimental design.