Synthesis And Ions Recognition Of Schiff Base Derivatives With Aggregation-Induced Emission Property

In recent years,it has been found that one kind of organic molecules not only does not exhibit a traditional concentration quenching affect,but rather a aggregation-induced emission enhancement phenomenon?AIE?.The AIE-active molecules have higher aggregation fluorescence efficiency,and therefore,it have a very broad prospects in novel luminescent materials,biosensors and other fields.In this paper,the salicylaldehyde-type Schiff base compounds with AIE properties found in the Tong group can form intramolecular hydrogen bonds to make up a six-member ring structure.So we design and synthesis of 2-hydroxyaldehydes and 2-hydroxyamines Schiff base derivatives,which also have excellent aggregation fluorescence enhancement properties,and have good ability to recognize CN-,Al³⁺,Zn²⁺,Mg²⁺,Fe³⁺,Cr³⁺,Cu²⁺ ions,some meaningful experimental results are obtained as follows:1.Schiff base L1 was synthesized by condensation of 1-naphthaldehyde and 2-aminothiophenol.Through observe the change of fluorescence signal,it can be found that the probe molecule L1 can efficiently recognize Fe³⁺ in the conditions of DMSO solvent,and has excellent anti-interference ability.2.Schiff base L2 was synthesized by condensation of 9-anthraldehyde and 2-amino-4-nitrophenol.The change of L2 fluorescence signal was measured in the solvent system with the different proportions of water content.The result shows that the molecule L2 has a good aggregation-induced emission property,and it was possible to efficiently identify CN-in a mixed system of ethanol and water?3:7?,which showed significant fluorescence enhancement,the detection limit is reach 1.02×10-4 M,and no interference from other ions,L2 has good selectivity for CN-.3.Schiff base compounds L3 and L4 was synthesized by condensation of 2-aminophenol with 5-chlorosalicylaldehyde and 5-bromosalicylaldehyde,respectively.Compare the fluorescence signal changes with different water content in solvent system,the results show that L3 and L4 have AIE properties.In the aqueous solvent system,L3 has a good ability to recognize Zn²⁺.Through 1:1 combination as an enhancement of the fluorescence signal.The detection limit reached 4.51×10-5 M.At the same time in the pure water system L4 has a good ability to identify Al³⁺ by fluorescence enhance,through 1: 1 combination,other ion have no interference effect,The detection limit reach 5.21×10-5 M.4.Schiff base compounds L5 and L6 was synthesized by condensation of 2-aminobenzimidazole with 5-methylsalicylaldehyde and 5-bromosalicylaldehyde,respectively.Test the fluorescence signal of the system with different water content.The results show that L5 and L6 have aggregation-induced emission enhance properties.And in the ethanol solvent system L5 has a good selectivity for Zn²⁺ that shows strong fluorescence.While in the DMSO system L6 can selectively identify Mg²⁺,by 1: 1 combination of binding,The detection limit reach 3.49×10-5 M.5.The Schiff base compounds L7 and L8 was synthesized by condensation of 2-hydroxy-1-naphthaldehyde with 2-?4-aminophenyl?benzothiazole and 2-?2-hydroxy-4-aminophenyl?benzothiazole,respectively.Studies the fluorescence changes of L7 and L8 in different water content,the results show L7 and L8 have AIE properties.In the DMSO solvent,L7 can efficiently identify trivalent ions(Al³⁺,Fe³⁺,Cr³⁺),through 1: 1 combination,and identify the trivalent ions without interference from other ions.The detection limit reach 1.49×10-5 M(Al³⁺),2.88×10-5 M(Cr³⁺),2.12×10-5 M(Fe³⁺).In the mixed solvent system of DMSO and water?1: 1?,L8 can effectively identify Cu²⁺ by 1: 1 combination and is not affected by other ions,L8 has good anti-interference ability for identify Cu²⁺.The detection limit reach 1.48×10^-6 M...