Synthesis And Properties Of Luminescent Porous Organic Polymers

Light-emitting porous organic polymer is a kind of material with good application prospects,and it has great applications in photoelectricity,photocatalysis,detection,etc.,which has attracted wide interest of researchers.Light-emitting porous organic polymers are generally classified into two types:crystalline and amorphous.For crystalline polymers such as covalent organic frameworks?COFs?,their structures are controllable,and they have the advantages of pore structure,high chemical and thermal stability,etc.,which is the basis for the subsequent development of various applications in gas storage and separation,energy storage,drug transport,catalysis and fluorescence sensing.However,compared with COFs,amorphous structure of covalent organicpolymers decreases the?-?interaction between the molecular layers and improves thefluorescence emission intensity of the polymer.By functionalizing the building blocks or changing the conjugated length of the polymers,the light-emitting performance and application effect of the polymers can be adjusted.In this paper,covalent organic frameworks and covalent organic polymers are firstly synthesized through condensation reaction.Then a series of characterizations are performed to analyze their properties.Finally,the fluorescence intensity of the polymer is changed by the interaction between the analyte and the organic polymer molecules,on which the polymer is based to detect the analyte.1.Synthesis,properties and application of luminescent covalent organic framework TAPT-BMTA-COFWe synthesized thioether-based fluorescent COF with electron-rich and electron-deficient structure through Schiff-base reaction between 2,5-bis?methylthio?terephthalaldehyde?BMTA?and 1,3,5-tris-?4-aminophenyl?triazine?TAPT?.TAPT-BMTA-COF has good crystallinity,porosity,high chemical and thermal stability,and outstanding solvatochromic behavior.The COF can be used to detect trace amount of water in organic solvents with the low detection limit?0.12%,v/v?because of the fluorescence quenching effect caused by the hydrogen bonding interaction between water and the COF.To further prove that interaction is formed between water molecules and the COF,we conducted a theoretical calculation.We synthesized TAPT-TP-COF possessing the similar structure with TAPT-BMTA-COF but without–SCH₃group as a reference.The results showed that COF with thioether had a better detection effect.TAPT-BMTA-COF has potential applications in fluorescent detection of trace water in organic solvents.2.Synthesis and properties of luminescent covalent organic polymer TAPE-BPDETAPE-BPDE was synthesized through Schiff base condensation reaction by using tetra-?4-aminophenyl?ethylene?TAPE?and 2,2'-bipyridine-5,5'-diformaldehyde?BPDE?as building blocks.TAPE-BPDE is an amorphous polymer,and the AIE property of the TAPE makes the polymer have good solid-state fluorescence properties.TAPE-BPDE is rich in nitrogen atoms,which can be protonated by H⁺to cause the fluorescence change of the polymer,so that the polymer is expected to have application prospects in pH detection.