Design And Synthesis Of Porous Organic Framework Materials And Study Of Their Luminescent Properties

Porous organic materials are a new type of polymer materials with high specific surface area.Organic molecular cages are also a class of discrete molecular compounds.They have regular pore structures,permanent molecular cavities and windows,and can be dissolved in various solvents,which is beneficial to the recyclability and reprocessability of materials,etc.,making them useful in adsorption and separation,identification probes,loading Nanoparticles,and energy storage have good application prospects.Among many organic molecular cages,chiral molecular cages are favored.Because chirality increases the complexity and diversity of organic molecular cage structures,as well as functionality.In this thesis,a series of axially chiral organic molecular cage materials were constructed by a one-pot method with the help of Schiff base reaction by using rigid axially chiral organic ligands as building blocks through clever design,and their potential application properties in the direction of chiral luminescence and fluorescence sensing were explored.Details of the study are as follows.1.Three pairs of R/S-chiral enantiomeric organic molecular cage building units were synthesized from binaphthylamine as a chiral source:R/S-L-1;R/S-L-2;R/S-L-3.The three enantiomers were designed by the co-assembly of non-chiral luminescent molecules and chiral molecules,which inherited both the chirality of chiral molecules and the fluorescence properties of luminescent small molecules.2.The self-assembly of the chiral ligands L-1,L-2,and L-3 with the triformaldehyde methanetriol was achieved by a solvent-heated one-pot synthesis method,and three series of enantiomeric molecular cages,R/S-Cage1,R/S-Cage2,and R/S-Cage3,were obtained.The fluorescence and optical properties of the chiral organocages R/S-Cage1-3 were investigated.The results showed that the chiral organic cages R/S-Cage1-3 had maximum fluorescence emission at 400-500 nm in the single-molecule state,and almost no fluorescence properties in the aggregates.Thus,the chiral organic cages R/S-Cage1-3 can have good circularly polarized fluorescence properties only in the single-molecule state.In addition,the chiral organic cage R/S-Cage1-3 exhibits good fluorescence sensing properties for the explosive TNP with a detection limit at ppm level.3.We selectively investigated the recognition of the selective fluorescence response of the chiral organic cage R/S-Cage1 to metal ions.Interestingly,the chiral organic cage R/S-Cage1 not only selectively recognizes Cu²⁺among numerous ions,but also the recognition of Cu²⁺is time-dependent.The fluorescence intensity of the organic cage R/S-Cage1 for Cu²⁺recognition gradually decreases with time and finally stabilizes.4.In the process of exploring the properties and applications of chiral molecular cages,it was found that the fluorescence and chiral properties of each constructed ligand were able to be reflected on the chiral molecular cages.Moreover,the fluorescence properties and maximum emission wavelength of each chiral molecular cage are similar under the constraint of the[2+3]type of molecular backbone,which indicates that although the fluorescent molecules determine the fluorescence properties of the molecular cage,the bulky structure of the molecular cage also changes the emission principle of single molecule luminescence.