Synthesis And Properties Of Thiophene-based Fluorescent Probes

With the rapid development of the social industry,a large number of problems caused by toxic ions have brought serious harm to the environment and living organisms.Common ion detection methods include atomic absorption spectroscopy,atomic emission spectroscopy,ion selective electrode,and biochemical detection,but their disadvantages are also obvious:high cost,cumbersome operation process,large instrument and long time,which is not conducive to real-time monitoring on site.Fluorescence analysis has been widely used in the production and life fields of biology,medicine,agriculture,light industry and environmental protection because of its advantages of simple operation,high sensitivity,good selectivity,small size and real-time response.The work of this thesis is to design and synthesize several thiophene-based organic small molecule fluorescent probes,and to study their properties and sensing properties.Its outstanding properties include:fast real-time response,high selectivity,high sensitivity,high stability,strong anti-interference performance,wide pH response range,and successful application in various environmental water samples and foods.The detection of ions in the sample,more importantly,the design of fluorescent probes has also been successfully applied to detect ions in cells,which shows the potential application value of fluorescent probes in medicine.1.A new type of thiophene fluorescent probe TS was designed and synthesized.TS can rapidly detect aluminum(Al³⁺)and zinc(Zn²⁺)in aqueous solution,showing strong blue and green fluorescence,and enhancing the fluorescence intensity by 40 and 5 times,respectively.The properties of the probe were studied by fluorescence emission spectroscopy and ultraviolet absorption spectroscopy.The resul TS show that the probe has high selectivity,strong anti-interference ability,wide pH response range:(Al³⁺:4.0-12.0,Zn²⁺:4.0-11.0),high sensitivity(detection limi TS are Al³⁺:3.7 nM,Zn²⁺:30nM),high stability(binding constan TS respectively are Al³⁺:1.16*10⁴ M^-2,Zn²⁺:2.08*10⁴ M^-2).At the same time,we studied the sensing mechanism of TS by infrared spectroscopy and nuclear magnetic resonance.The resul TS show that the chemical binding stoichiometric ratio of TS-Al³⁺and TS-Zn²⁺is 1:1.At last,we have carried out the experimen TS of detecting ions with probes in various environmental water solutions,and confirmed that TS can be used to detect Al³⁺and Zn²⁺in actual water and food samples.More importantly,we have successfully realized the detection of ions by probe TS in cells.2.A new type of thiophene metal ion sensor TSA was designed and synthesized.TSA can rapidly detect aluminum(Al³⁺)and copper(Cu²⁺)in aqueous solution.When aluminium ion(Al³⁺)is detected,a strong blue fluorescence is displayed under 365 nm fluorescent lamp,which makes the fluorescence intensity more than 300 times stronger.The properties of the probe were studied by fluorescence emission spectroscopy.The resulTS show that the probe has high selectivity,strong anti-interference ability,wide pH response range?3.0-11.0?,high sensitivity?detection limit:8.36 nM?,and high stability(binding constant:1.2*10⁴ M^-2).When the copper ion(Cu²⁺)was detected,the discoloration was visible to the naked eye:from colorless to yellow.Ultraviolet absorption spectroscopy was used to study TSA properties.The resul TSA show that the sensor has high selectivity,strong anti-interference ability,wide pH response range?6-10?,high sensitivity?detection limit:4.87 nM?,and high stability(binding constant:9.8*10³ M^-2).At the same time,we studied the sensing mechanism of TSA by infrared spectroscopy and nuclear magnetic resonance.The resul TSA show that the stoichiometric ratio of TSA-Al³⁺and TSA-Cu²⁺is 1:1.Finally,we did the experimen TSA of detecting ions with TSA probe in various environmental water solutions,which proved that TSA can be used to detect aluminum ions(Al³⁺)and copper ions(Cu²⁺)in real water samples and food samples.In addition,we also carried out experimen TS.TSA was successfully used to detect aluminium ion(Al³⁺)in cells.3.Several novel thiophene metal ion probes TSB,TSC and TSD were designed and synthesized.TSB was detected by fluorescence method for Al³⁺,UV colorimetric method for Cu²⁺detection,TSC was detected by fluorescence detection method for Al³⁺,and TSD was detected by UV colorimetry.Cu²⁺.They all show excellent properties:high selectivity,strong anti-interference ability,wide pH response range,etc.