Synthesis And Research On Cell Dynamic Imaging Of Fluorescent Adjustable AIE Materials

Traditional fluorescent materials that is under the aggregation state will produce a strongπ-πaccumulation due to the close accumulation,which will lead to aggregation and cause quenching（ACQ）phenomenon,and this seriously restricts their application in the field of luminescent materials.On the contrary,the phenomenon of aggregation-induced emission（AIE）is manifested that the molecules do not emit light in dilute solution or the fluorescence is weak,but the fluorescence is significantly enhanced under the aggregation state.Compared with ACQ material,AIE material has the advantages of low background,high sensitivity,high signal-to-noise ratio and strong anti-bleaching ability.Many studies have shown that traditional dyes have many valuable properties,unfortunately most of which have ACQ properties.After the functional modification of ACQ molecule,it can be transformed into AIE molecule,which provides a new way to solve the problems encountered in the application of traditional ACQ materials.Triphenylamine（TPA）is a typical ACQ molecule.Because the lone pair electrons on the nitrogen atom can form a p-πconjugated system with the three benzene rings,TPA,with low ionization potential,high hole mobility(typically around l0^-310^-4 cm²/（V·s）),good hole transmission performance and strong fluorescence properties as well as the advantages of light stability,can be applied to building materials with different properties.In the molecular structure of TPA,the nitrogen atom is sp3 hybridization,so that the molecule has a non-planar propeller structure;in solution,the spin of the C-N sigma bonding in TPA redounds to dissipate the excited state energy,meanwhile,its distorted molecular structure is conductive to reduce the formation ofπ-πstacking between molecules.In addition,due to its electron-rich nature,when the electron-deficient groups are introduced into the molecule,the D-A electronic system will be formed in the molecule,which will make the molecule possess the in-molecular charge transfer（ICT）property,and thus it is possible to convert triphenylamine（or derivatives of triphenylamine）into AIE molecule.In order to enrich the design ideas of AIE materials and further develop the application field of triphenylamine fluorescent materials,this thesis has developed a series of functional triphenylamine fluorescent materials with triphenylamine as the core skeleton.On the one hand,a series of different wavelengths of triphenylamine-based fluorescent compounds have been developed and applied in the field of cell imaging;On the other hand,based on the principle of forming white light with complementary colors of orange and blue,and through slight adjustment of the proportions of fluorescent monomers,a triphenylamine-based AIE white light emitting material was obtained.Based on this thesis is mainly composed of the following two parts:1.By the efficient organic synthesis method of C-C oxidative coupling reaction,Suzuki reaction,Vilsmeier-Haack reaction,Menshutkin reaction and so on,following the route of constructing D-A and D-π-A electronic systems in the molecule,regulating the electronic cloud density of the molecule,and enhancing the ability of Intersystem Crossing（ISC）of chemical compound,a series of triphenylamine fluorescent compounds（diTPAs）from blue（420 nm）to red（640nm）emission was developed.The main relationship between the optical properties and chemical structure of the compounds,which was applied in the field of biological imaging,was studied.The results showed that the electroneutral fluorescent probes indicated lipid drop targeting development in both living and fixed cells,and have a very high degree of overlap with the commercial lipid droplet stain（Nile Red）staining,which can be used as a kind of lipid droplet developer;and that ionic fluorescent probes can be used to dynamically monitor the state of cells due to its ability to visualize cell membranes in living cells and stain mitochondria in fixed cells;at the same time,it has also been found that there is a synergistic effect of exogenous substances during cell imaging.This section provides ideas for the development of different functional fluorescent materials.It has reference value in studying the different staining of cells in different states,the dynamic monitoring of cells,and the visual exploration of the interaction between organelles,as well as the correlation between different stimuli during biological imaging.2.Three molecules（TFBP-VB,TPA-Py-CVB and TPA-VPy-CVB）were synthesized with triphenylamine as the framework through such classical reactions as Suzuki reaction,Heck reaction and Menshutkin reaction.Triphenylamine white light emitting materials（P-Red&Blue）were successfully prepared by the free radical polymerization between two complementary color fluorescent monomers and n-isopropyl acrylamide.The Commission Internationale de l’éclairage（CIE）is（0.34,0.33）,which can realize white light emission in different states.Blue-emitting（P-Blue）and red-emitting（P-Red）polymers were prepared by radical polymerization of TFBP-VB and TPA-VPy-CVB with N-isopropylacrylamide,respectively.Regulate the ratio of two polymers,white light emission is achieved in both organic solvents and aqueous solutions.Through this part of research:（1）the fluorescence materials that can emit white light in different states were successfully developed,and it was also found that the emission intensity of the two complementary color fluorescence nuclei in the materials was equal,which was easy to produce white light materials,and it was guiding significance for the preparation of white light materials.（2）cationic fluorescence was used to verify the sensitivity of the polarity of the solvent,and it was used as the polarity indicator of different solvents and the electrical conductivity indicator of water phase to explore new application directions of triphenylamine fluorescent materials and enrich the application of triphenylamine fluorescent materials.