Synthesis Of Salicylaldehyde Indole (2,3-a) Carbazole And Study Of Its Ion Recognition Propertie

Fluoride is one of the essential trace elements in human body and plays an important role in our life.Excessive intake of fluoride ion threatens our health.Therefore,researchers pay more and more attention to the detection of fluoride ions.Aluminum is one of the essential trace elements for human body,and it is closely related to our daily life.According to the World Health Report,the maximum daily human intake of aluminum is 7 mg,and long-term intake of high concentrations of aluminum may cause serious health problems.Therefore,the detection of Al³⁺is particularly important.Indole（2,3-a）carbazole was used as chromophore of fluorescent probe,using salicylaldehyde,N and O atoms on the Schiff base of salicylaldehyde and the protective group-Si-O bond of the hydroxyl group of salicylaldehyde were used as ion recognition response units,colorimetric and fluorescence sensors for detecting F^-and Al³⁺were constructed.The sensor has studied ion recognition,titration,interference,binding ratio and recognition mechanism in organic or mixed water and organic systems.A quick and convenient method to detect the fluoride ion concentration through smart phone and the accuracy of Al³⁺in water was tested through the recovery experiment and so on.The main research work is as follows:1.The advantages and disadvantages of F^-and Al³⁺in daily life and the significance of their detections are summarized.The composition and recognition mechanism of fluorescence sensor are introduced.The research status of F^-and Al³⁺probe,indole（2,3-a）carbazole derivatives in luminescence field and salicylaldehyde derivatives in ion recognition field are summarized.2.In theory,the recognition performance of fluorescence probe is closely related to the luminescence performance of the emitting group and the number of response units.Fluorescent sensors ICZ-o-1S and ICZ-o-2S were synthesized by using indolo（2,3-a）carbazole as the chromophore and regulating the number of salicylaldehyde as the recognition site.The sensors can recognize F^-with colorimetric and turning on fluorescence characteristics.The binding ratio of the sensor ICZ-o-1S to fluoride ions was 1:1 with a detection limit of 1.8×10^-7 M,and the binding ratio of the sensor ICZ-o-2S to fluoride was 1:2 with a detection limit of 6×10^-8 M.This indicates that the number of recognition units is closely related to the anion recognition performance of the probe,and sensors with multiple recognition sites show more advanced anion recognition capabilities.The F^-recognition mechanism for both sensors are the deprotonation process of the-OH unit in the salicylaldehyde group.Finally,the sensor can detect fluoride ions in actual ambient water,as well as the quick and convenient method to detect fluoride ion concentration through the smartphone.3.There are many fluorescence sensors to identify one ion reported in the literature,while dual channel ion recognition still faces challenges.A fluorescence sensor ICZ-o-XFJ was synthesized by Schiff base reaction between the aldehyde group on ICZ-o-1S and the amino group on aminophenol.A fluorescence sensor ICZ-o-XFJ that can recognize F^-and Al³⁺has been synthesized.The sensor shows good selectivity in recognizing fluoride ions,the sensor solution changes from colorless to brown,and the fluorescence of the solution changes from pink to bright green,which is characterized by colorimetric and fluorescence enhancement.The stoichiometric ratio of the sensor to fluoride ions was 1:1,and the detection limit for identifying fluoride ions was 4.5×10^-7M.The mechanism of fluoride ion recognition by the sensor may be the deprotonation of hydroxyl group.When the sensor recognizes Al³⁺,the solution of the sensor turns to yellow-green and the fluorescent color turns to yellow.This indicates that ICZ-o-XFJ can be used as colorimetric and fluorescence enhanced sensor for Al³⁺recognition.The chemical binding ratio of the sensor to Al³⁺is 1:1,and the detection limit for identifying Al³⁺is 3.2×10^-7 M.At the same time,the sensor can recognize Al³⁺in acidic and neutral water.The standard recovery method can well detect the content of metal Al³⁺in the actual environment.The test strip of the sensor can convenient,quickly detect fluoride ions and Al³⁺.4.To avoid the interference of the recognition of multiple ions by salicylaldehyde group,the high selectivity of the ion recognition by the probe is improved.The fluorine sensor ICZ-o-2Si O was synthesized by using indole（2,3-a）carbazole as the chromophore and introducing the protective group of hydroxyl group-Si-O unit on salicylaldehyde as the recognition site.When fluoride ions were added to the sensor solution,the solution turned to yellow-green and the fluorescence of the solution was quenched.The compound ICZ-o-2Si O can be used as colorimetric and fluorescence quenching sensor for F^-recognition.The binding ratio of sensor ICZ-o-2Si O to fluoride ions is 1:2,and the minimum detection limit for identifying fluoride ions is2.2×10^-7 M.Finally,through high-resolution mass spectrometry and nuclear magnetic resonance titration hydrogen spectroscopy,the sensor and the F^-recognition mechanism?Si?O bond were disconnected,and finally turned into ICZ-o-2Ph O^-.In UV-vis and PL spectra,a new absorption peak near 400 nm and an emission peak around 500 nm showed a decrease in fluorescence intensity,and the color of the solution changed to yellow-green and fluorescence quenched...