Synthesis And Application Of Aggregation-Induced Emission Functional Molecules Containing Schiff Base And TPE Molecules

Fluorescent(FL)chemosensors are one of the most widely used molecules in environmental detection,molecular catalysis,and biological fluorescence imaging,due to their advantages in real-time analysis,high sensitivity,and remote detection capabilities.While conventional fluorescent chemosensors tend to form aggregates in aqueous solutions because of the hydrophobicity of their emitting centers(often aromatic rings),where aggregation-caused quenching(ACQ)effect may induce strong interference during the detection process.Aggregation-induced emission(AIE),a unique photophysical phenomenon observed for some novel FL chromophores,offers a new methodology to solve the above mentioned problems.Firstly,the molecules with AIE effect avoid aggregation induced FL quenching in solid states.Secondly,the FL spectra of mostly AIE molecules do not shift as the concentration increases.Finally,FL techniques by using AIE molecules as probes are more effective because they apply a turn on mechanism.To date,many AIE active molecules have been successfully used as fluorescent chemosensors for metal ions,temperature,p H,and biosensing system.Among them,the one for biosensing system has attracted particular attention on account of the critical roles of biomacromolecules in life.The following researches were carried out in this thesis:1.A dual functional AIE active amphiphilic molecule,sodium N,N'-bis[4-(3-sulfonatopropoxyl)]salicylidene(BSPS),was designed and synthesized.All the structures were confirmed by IR,1H NMR,13 C NMR,and ESI-MS.Due to its amphiphilic nature,BSPS could spontaneously enter into human serum albumin(HSA)cavities primarily promoted by hydrophobic forces,which restricted the rotation of N-N single bond through rigidifying the conformation of BSPS,thus making BSPS display intense fluorescence with a broad working range(0-100 ?g/m L)and a low detection limit(down to 6.11 ?g/m L)for HSA.Meanwhile,BSPS could also aggregate on chitosan(CS)through electrostatic interactions between negative sulphate moieties in BSPS and positive amine groups in CS,consequently resulting in a sharp increase in fluorescence intensity,with a linear relationship from 0 to 10 ?g/m L of CS and a detection limit of 0.58 ?g/m L.Moreover,the outstanding biocompatibility of BSPS makes it an attractive multiple functional sensor candidate for detecting biomacromolecules in biosystem.The structure of BSPS was as follows.2.For developing novel luminescent hydrogels with stimulating responsiveness,glycyrrhizic acid with broad bioactivity was introduced into tetraphenyl ethylene(TPE)structure by the rational design.The amphiphilic molecule,TPE-GL-4,contains a gelation factor of glycyrrhizic acid and a TPE moiety with AIE property.Due to TPE-GL-4 contains multiple carboxyl groups,the p H-responsive behavior of this hydrogel has be explored by using the fluorescence spectra.The structure of TPE-GL-4 is shown below.In conclusion,BSPS and TPE-GL-4 have been synthesized and characterized successfully.Among them,BSPS could quantify the protein HSA and biological macromolecule CS.Meanwhile,the luminescent hydrogel was prepared with TPE-GL-4,and their mechanical properties and stimuli response were experimented.All the above proved that our design was reasonable,which would provid a theoretical instruction for the development of probe molecules and luminescent hydrogels.