Design,Preparation And Application Of AIE Fluorescent Probe With Multiple Recognition Sites

Fluorescent materials are often used as fluorescent probes or photoelectric functional devices.Traditional fluorescent sensors severely limited its application due to the aggregation of fluorescence quenching phenomenon（ACQ）in concentrated solution or solid state.In 2001,Tang et al discovered the aggregation induced emission（AIE）characteristics fluorescence system,making it widely used in the field of molecule,ion and biological macromolecules detection as fluorescent probes.Tetraphenylethylene（TPE）compounds based on easy modification and synthesis,high fluorescence quantum yields,have become the stars of AIE molecules.In current thesis reports the successful construction of AIE compounds with TPE fluorescent unit and carboxyl groups via click strategy.And explore the potential application of the AIE compounds in heavy metal ions detection and sensitively probing the phase transition of an AIE thermoresponsive supramolecular system.（1）Based on click chemistry,we combined the azide-TPE with propynoic acid ethyl esters with alkyne groups to design and synthesis a novel triazole bridged fluorescence probe（TPE-Triazole-COOH,TTC）.When the water fraction increases to96%,the solution of TTC becomes strongly emissive at 470 nm,indicating its AIE properties.TTC can act as an excellent selective turn-on fluorescence sensor for Al³⁺.In the low concentration range,the fluorescence emission intensity is enhanced rapidly upon addition of Al³⁺and a good linear response is found in the range of 1μM to 6μM（R²=0.94587）.After the Al³⁺concentration reaches 20μM,the fluorescence intensity levels off and remains unchanged.The Job^’s plot suggests that the complex of TTC with Al³⁺has a possible binding ratio of 1:1.Even a low Al³⁺concentration of 1μM can cause a distinct fluorescence intensity enhancement.Decipherment of the underlying mechanisms for the fluorescence enhancement phenomena,the test of DLS and TEM showed that Al³⁺caused aggregation of TTC.The fluorescence lifetime test showed that the addition of Al³⁺with longer life and confirmed that the TTC rotation was limited.（2）Thermoresponsive AIE supramolecular complexes were prepared on the basis of electrostatic attraction,hydrogen bonding interaction and host-guest interaction betweenamino-containingthermoresponsivehyperbranchedpolymers(HPEI-IBAm_0.7)and carboxylic acid–containing AIE molecules（TTC）.The fluorescence at 650 nm experienced an obvious emission boost with increasing temperature around phase transition temperature（PTT）,whereas the signal at 470 nm showed a emission reduction and then a decrease with increasing temperature around PTT.From these two different temperature-dependent emission responses,PTTs of these thermoresponsive AIE supramolecular complexes could be facilely read off even in dilute solution,where the traditional turbidimetry technique lose efficacy.Sensitively probing the phase transition of an AIE thermoresponsive supramolecular system in dilute solution was developed.Therefore,sensitively probing the phase transition of an AIE thermoresponsive supramolecular system in dilute solution was developed.In summary,new AIE molecules were prepared,and the AIE molecular system was extended to provide references for the development of AIE materials.