Halogenated tetraphenylethylene derivative fluorescent probe as well as synthesis method and application thereof

Abstract

The invention discloses two halogenated tetraphenylethylene derivative fluorescent probes as well as a synthesis method and application thereof. The synthesis method of the halogenated tetraphenylethylene derivative fluorescent probes 2FH2L and 2BrH2L comprises the following steps: preparing a compound B from a compound A, dissolving the compound B in a mixed solvent of THF, methanol and water dissolved with LiOH for hydrolysis, acidizing, and carrying out suction filtration and drying on the precipitate to obtain the product 2FH2L. The preparation method comprises the following steps: brominating a compound C to prepare a compound D, dissolving the compound D in a mixed solvent of THF, methanol and water in which NaOH is dissolved, hydrolyzing, acidizing, and carrying out suction filtration and drying on the precipitate to obtain the product 2BrH2L. The fluorescence property of the halogenated tetraphenylethylene derivative shows a remarkable AIE effect under different solvent proportions, strong fluorescence emission is shown in a poor solvent, and the halogenated tetraphenylethylene derivative can be used as an efficient fluorescence probe capable of detecting Cu < 2 + > through the characteristics of the halogenated tetraphenylethylene derivative.

Description

Technical Field

[0001] The invention relates to one or two examples of fluorescent probes based on TPE and preparation thereof. The invention also relates to application of the copper ion fluorescent probe in identifying copper ions, belonging to the field of analysis and detection. Background Art

[0002] Copper, a key trace element, is not only an essential mineral for many organisms to maintain life activities, but also an indispensable metal raw material for industrial production. However, when the concentration of copper ions exceeds a certain threshold, it will pollute the environment and pose a threat to human health. Therefore, it is crucial to efficiently and accurately detect the copper ion content in the environment and organisms. In terms of the environment, factors such as industrial emissions, pesticide use and urbanization have caused copper to enter the natural environment, affecting water quality and soil quality. The application of fluorescent probe technology enables environmental protection departments to quickly identify excessive copper ions and take timely measures to effectively prevent environmental pollution. In the field of medicine and biology, copper, as an important element of cell activity, participates in a variety of physiological functions, but its abnormal accumulation or homeostasis imbalance can cause a variety of neurological diseases, such as Wilson's disease, Alzheimer's disease, Parkinson's disease and Menkes disease. Therefore, monitoring the excessive presence of copper in the environment and human body is of great significance to ensure our survival and development.

[0003] Traditional fluorescent materials are limited by the ACQ effect and are difficult to meet the needs of contemporary development. The discovery of the AIE phenomenon provides an important solution for this. In recent years, many fluorescent molecules with AIE properties, such as tetraphenylethylene (TPE), cyano, pyran, Schiff base and biphenyl derivatives, have been discovered and studied in depth. These AIE substances have been widely used in bioimaging, fluorescence sensing, LED, color-changing luminescent materials and other fields. In particular, tetraphenylethylene derivatives have attracted much attention due to their simple synthesis, easy modification and excellent luminescence properties. With their typical AIE characteristics, they have shown broad application prospects in the fields of fluorescence sensing analysis and cell imaging. There are various methods for detecting copper ions, including inductively coupled plasma mass spectrometry, UV-visible spectrophotometry, electrochemical analysis and fluorescence spectroscopy.

[0004] In view of the above situation, this scheme innovatively designed a fluorescent probe solution, using the fluorescence quenching mechanism to achieve the 2+ After in-depth study of their AIE properties, we found that these derivatives exhibited significant AIE effects in different solvent ratios, and the fluorescence emission was particularly strong in poor solvents. Through UV-visible absorption and fluorescence spectroscopy analysis, we revealed the intrinsic connection between the aggregation state of the material and the fluorescence properties. In addition, this study also developed an efficient Cu 2+ Fluorescent probe, even in the presence of multiple metal ions, the probe solution still shows Cu2+ The high selectivity and anti-interference ability of Cu 2+ The lower limit of detection. Summary of the invention

[0005] In order to solve the problems mentioned in the above background technology, the present invention provides a halogenated tetraphenylethylene derivative fluorescent probe and its synthesis method and application, which overcomes the problem that the probe solution is sensitive to Cu in the environment where multiple metal ions coexist. 2+ The selectivity and anti-interference ability are poor.

[0006] To achieve the above objectives, in a first aspect, the present invention provides a halogenated tetraphenylethylene derivative fluorescent probe, wherein: the molecular structure of the fluorescent probe is specifically shown in the following structural formula (I) or formula (II):

[0007] (I)

[0008] (II).

[0009] In a second aspect, the present invention provides a method for synthesizing a halogenated tetraphenylethylene derivative fluorescent probe, comprising the following steps: (1) Synthesis of the structural formula (I) Step 1: 4,4′-difluorobenzophenone, 4,4′-dibromobenzophenone, zinc powder and THF that has been redispersed, dried and degassed are placed in a double-necked round-bottom flask. TiCl4 is slowly injected into the system in an ice-water bath under nitrogen protection, and then the reaction system is stirred for 2 hours. The reaction system is then refluxed at 80° C. overnight. After the reaction system is cooled, the reaction is quenched with a 10% K2CO3 aqueous solution, and then extracted with CH2Cl2. The extracted solution is dried with anhydrous Na2SO4 and then concentrated by a rotary evaporator. The concentrated product is purified by column purification using CH2Cl2 and petroleum ether as eluents. The obtained product is dissolved with CH2Cl2 and then precipitated with petroleum ether to obtain a white solid, which is filtered to obtain compound A; Step 2: Compound A, 4-(methoxycarbonyl)phenylboronic acid, K2CO3, and Pd(PPh3)4 are added to a two-necked round-bottom flask equipped with a magnetic stirring bar, and the flask is filled with a mixed solution of degassed toluene, ethanol and water, and then filled with nitrogen. Reflux at 95°C overnight, and observe the progress of the reaction by spot plate during the reaction. The mixed product obtained by the reaction is extracted with CH2Cl2 and dried, and then concentrated by rotary evaporation. The system uses a mixed solution of CH2Cl2 and petroleum ether as an eluent for column chromatography purification, and petroleum ether is poured into the CH2Cl2 solution to precipitate a solid and filter and dry to obtain compound B in the form of a white solid; Step 3: Dissolve compound B in a mixed solvent of THF, methanol and water containing LiOH, reflux the system at room temperature for 4 hours, and after cooling the system, perform rotary evaporation to appropriately remove some organic solvents such as THF and methanol, and then acidify the system with a diluted hydrochloric acid solution until the system is acidic as measured by a pH test paper, and a large amount of white flocculent precipitate is generated during the process. The precipitate is filtered and dried to obtain the product 2FH2L, which is a light yellow powder after filtration and drying; (2) Synthesis of the structural formula (II) Step 1: 4,4′-, (2,2-diphenylethylene-1,1-diyl) di(bromobenzene), 4-(methoxycarbonyl) phenylboronic acid, and Pd(PPh3)4 were placed in a three-necked round-bottom flask. A mixed solvent of degassed toluene, ethanol, and water was added to the flask, and a magnetic stirring bar was added. Then, the flask was filled with nitrogen and refluxed overnight at 95°C. The mixture was extracted with CH2Cl2, and the organic phase was washed with water and brine. The crude product was obtained by rotary evaporation, and purified by column chromatography using CH2Cl2 and petroleum ether as eluents to obtain compound C in the form of a white solid; Step 2: Dissolve compound C in CH2Cl2 and place in a round-bottom flask with a magnetic stirring bar. Then slowly add liquid bromine. Stir at room temperature for 12 hours, add an ethanol solution of Na2S2O3 to quench the reaction, and use NaOH solution to adjust the pH to a neutral range, then extract with CH2Cl2, dry the organic phase with anhydrous MgSO4, and after rotary evaporation, purify by column chromatography using a mixed solution of CH2Cl2 and petroleum ether as the eluent to obtain compound D; Step 3: Compound D was dissolved in a mixed solvent of THF, methanol and water containing NaOH, and the system was refluxed at 80°C for 4 hours. After the system was cooled, a portion of organic solvents such as THF and methanol were removed by rotary evaporation, and then diluted with 1 mol L -1 The system was acidified with hydrochloric acid solution until the system was acidic as measured by pH test paper, and a large amount of white flocculent precipitate was produced during the process. The precipitate was filtered and dried to obtain the product 2BrH2L.

[0010] Preferably, in the step 1, the volume ratio of CH2Cl2 to petroleum ether in the eluent is 1:5.

[0011] Preferably, the volumes of toluene, ethanol and water in step 2 of the synthesis of the structural formula (I) and step 1 of the structural formula (II) are 50 mL, 15 mL and 15 mL respectively.

[0012] Preferably, in step 2 of synthesizing the structural formula (I), the volume ratio of CH2Cl2 to petroleum ether is 1:1.

[0013] Preferably, the volume ratio of the mixed solvent of THF, methanol and water in step 3 of the synthesis of the structural formula (I) and the structural formula (II) is 1:1:1, and both are 20 mL

[0014] Preferably, in step 1 and step 2 of synthesizing the structural formula (II), the volume ratio of CH2Cl2 to petroleum ether is 1:1.

[0015] Preferably, the reaction route for synthesizing the structural formula (I) is:

[0016] Preferably, the reaction route for synthesizing the structural formula (II) is:

[0017] In a third aspect, the present invention provides the above-mentioned halogenated tetraphenylethylene derivative fluorescent probe for recognizing Cu 2+ ions, and the detection limit of the fluorescent probe for copper ions is determined by detecting the fluorescence emission levels of two fluorescent probe solutions in copper ion solutions of different concentrations.

[0018] Compared with the prior art, the present invention has the following beneficial effects: The present invention successfully synthesized and characterized two TPE derivatives, 2FH2L and 2BrH2L, and studied their AIE properties. The fluorescence properties of these derivatives in different solvent ratios showed significant AIE effects, and exhibited strong fluorescence emission in poor solvents. Through UV-visible absorption and fluorescence spectroscopy analysis, this scheme revealed the correlation between the aggregation state and fluorescence properties of these materials. An efficient method for detecting Cu 2+ of fluorescent probes. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0020] Figure 1 It is the H NMR spectrum of 2FH2L; Figure 2 It is the H NMR spectrum of 2BrH2L; Figure 3 The UV absorption spectra of 2FH2L (20 mol / L) in the mixed systems of DMF / H2O at different ratios; Figure 4 The fluorescence spectra of 2FH2L (20 mol / L) in the mixed systems of DMF / H2O with different ratios; Figure 5 The particle size distribution of 2FH2L (20 mol / L) in a mixed system of DMF / H2O = 1 / 99; Figure 6 The UV absorption spectra of 2BrH2L (20 mol / L) in the mixed systems of DMF / H2O at different ratios; Figure 7 The fluorescence emission of 2BrH2L (20 mol / L) in a mixed system of DMF / H2O at different ratios; Figure 8 The particle size distribution of 2BrH2L (20 mol / L) in a mixed system of DMF / H2O = 1 / 99; Fig. 9 Ion selectivity of 2FH2L fluorescent probe; Fig.10 Ion selectivity of 2BrH2L fluorescent probe; Fig.11 The anti-interference property of 2FH2L fluorescent probe in detecting copper ions; Fig.12 Anti-interference of 2BrH2L fluorescent probe in detecting copper ions; Fig.13 Fluorescence emission spectra of compound 2FH2L (10 mol / L) in copper ion solutions with different concentrations; Fig.14 Fluorescence emission spectra of compound 2BrH2L (10 mol / L) in copper ion solutions with different concentrations. DETAILED DESCRIPTION

[0021] The technical solution of the present invention will be clearly and completely described below in conjunction with the embodiments of the present invention. Obviously, the described embodiments are part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0022] Unless otherwise specified, the raw materials used in the present invention are all conventional products purchased from the market.

[0023] Example 1 This embodiment provides a method for preparing a copper ion fluorescent probe based on TPE, comprising the following steps: Preparation steps of 2FH2L: 4,4′-(2,2-bis(4-bromophenyl)ethylene-1,1-diyl)bis(fluorobenzene) (Compound A) Preparation: 4,4′-, difluorobenzophenone, 4,4′-, dibromobenzophenone, zinc powder and THF after redispermation, drying and degassing are placed in a double-mouthed round-bottom flask, and the system is protected by nitrogen. TiCl4 is slowly injected into the system in an ice-water bath, and then the reaction system is stirred for 2 hours. The reaction system is then refluxed at 80°C overnight. After the system is cooled, the reaction is quenched with a 10% K2CO3 aqueous solution, and then extracted with CH2Cl2. The extracted solution is then dried with anhydrous Na2SO4 and concentrated by a rotary evaporator. The concentrated product is purified by column with CH2Cl2: petroleum ether as an eluent, and the obtained product is dissolved with CH2Cl2 and then precipitated with petroleum ether to obtain a white solid, which is filtered to obtain compound A.

[0024] 4′,4″′-(2,2-bis(4-fluorophenyl)ethylene-1,1-diyl)bis([1,1′-biphenyl]-4-carboxylic acid) dimethyl ester (Compound B) Synthesis: Compound A, 4-(methoxycarbonyl)phenylboronic acid, K2CO3, and Pd(PPh3)4 were added to a two-necked round-bottom flask equipped with a magnetic stirring bar, and the flask was filled with a mixed solution of degassed toluene, ethanol, and water. Then nitrogen was filled in and refluxed at 95°C overnight. During the reaction, the progress of the reaction was observed by a dot plate. When the reaction was relatively complete, the reaction was shut down and cooled. The mixed product obtained by the reaction was extracted with CH2Cl2 and dried, and then concentrated by rotary evaporation. The system used a mixed solution of CH2Cl2: petroleum ether as an eluent for column chromatography purification. Petroleum ether was poured into the CH2Cl2 solution to precipitate the solid and filtered and dried to obtain compound B in the form of a white solid.

[0025] 4′,4″′-(2,2-bis(4-fluorophenyl)ethylene-1,1-diyl)bis(([1,1′-biphenyl]-4-carboxylic acid))(2FH2L) Synthesis: Compound B is dissolved in a mixed solvent of THF, methanol and water containing LiOH. The system is refluxed at room temperature for 4 hours. After the system is cooled, a portion of organic solvents such as THF and methanol are appropriately removed by rotary evaporation, and then the system is acidified with a diluted hydrochloric acid solution until the system is acidic as measured by a pH test paper, and a large amount of white flocculent precipitate is produced during the process. The precipitate is filtered and dried to obtain the product 2FH2L, and the product after filtration and drying is in a light yellow powder state.

[0026] The synthetic route of this molecule is shown below

[0027] Preparation steps of 2BrH2L: 4′,4″′-(2,2-diphenylethylene-1,1-diyl)bis([1,1′-biphenyl]-4-carboxylic acid) dimethyl ester (Compound C) Preparation: 4,4′-, (2,2-diphenylethylene-1,1-diyl) di(bromobenzene), 4-(methoxycarbonyl) phenylboronic acid, and Pd(PPh3)4 were placed in a three-necked round-bottom flask, and degassed toluene, ethanol, and water were added to the flask. A magnetic stirring bar was also added. Then it was filled with nitrogen and refluxed at 95°C overnight. The mixture was extracted with CH2Cl2, and the organic phase was washed with water and brine. The crude product was obtained by rotary evaporation and purified by column chromatography using CH2Cl2: petroleum ether as the eluent to obtain compound C in the form of a white solid.

[0028] 4′,4″′-(2,2-bis(4-bromophenyl)ethylene-1,1-diyl)bis([1,1′-biphenyl]-4-carboxylic acid) dimethyl ester (Compound D) Preparation: Compound C was dissolved in CH2Cl2 and placed in a round-bottom flask with a magnetic stirring bar. Then, liquid bromine was slowly added. Stirring was continued at room temperature for 12 hours, and Na2SO3 and ethanol solution were added to quench the reaction, and the pH was adjusted to a neutral range using NaOH solution, and then extracted with CH2Cl2, and the organic phase was dried with anhydrous MgSO4. After rotary evaporation, column chromatography was performed with a mixed solution of CH2Cl2 and petroleum ether as the eluent to obtain compound D with a yield of about 90%.

[0029] 4′,4″′-(2,2-bis(4-bromophenyl)ethylene-1,1-diyl)bis(([1,1′-biphenyl]-4-carboxylic acid))(2BrH2L) Synthesis: Compound D was dissolved in a mixed solvent of THF, methanol and water containing NaOH. The system was refluxed at 80°C for 4 hours. After the system was cooled, a rotary evaporation was performed to remove some organic solvents such as THF and methanol. The system was then acidified with a diluted 1 molL-1 hydrochloric acid solution until the pH test paper showed that the system was acidic. A large amount of white flocculent precipitate was produced during the process. The precipitate was filtered and dried to obtain the product 2BrH2L. The synthetic route of this molecule is shown below. .

[0031] It should be noted that the characteristics of the copper ion fluorescent probe based on TPE are as follows: 1. AIE effect of copper ion probe DMF was selected as the good solvent and deionized water as the poor solvent. By changing the ratio of the poor solvent in the mixed solvent, the two molecules, namely 2FH2L and 2BrH2L, were used to prepare mixed solutions of DMF / H2O with different volume ratios (DMF / H2O=1 / 99, DMF / H2O=5 / 95, DMF / H2O=10 / 90, DMF / H2O=20 / 80, DMF / H2O=40 / 60, DMF / H2O=60 / 40, DMF / H2O=80 / 20, DMF / H2O=100 / 0) (the concentration of the solution was C=2*10 -5 mol / L), and studied the changes in UV absorption and fluorescence emission of the two compounds in a mixed solution of DMF / H2O with an excitation wavelength of 360nm. We also tested the particle size of the aggregate particles in the solution at DMF / H2O (V:V=1:99).

[0032] 2. UV absorption and fluorescence spectroscopy characterization of 2FH2L copper ion probe The fluorescence emission spectra and UV absorption spectra of 2FH2L molecules in mixed solutions of DMF / H2O with different volume ratios and the particle size distribution images of the mixed solutions at 99% water content are shown in the figure below. Figure 3 As shown, 2FH2L produces the maximum value of the ultraviolet absorption peak at around 320nm; Figure 4 As shown in the figure, when the volume fraction of water is less than 90%, the aggregation degree of the fluorescent molecules is very low and almost no fluorescence is generated; when the volume fraction of water is in the range of 90% to 99%, the aggregation degree of the fluorescent molecules gradually increases. This is due to the decrease in the solubility of the fluorescent molecules in the poor solvent system, which leads to the gradual increase in the molecular aggregation degree, and the 2FH2L molecule has good AIE properties. Figure 5 As shown, 20 mol / L compound 2FH2L exists as aggregates with a particle size of about 130 nm in a mixed system of DMF / H2O with a water volume fraction of 99%.

[0033] 3. UV absorption and fluorescence spectroscopy characterization of 2BrH2L copper ion probe The UV absorption and fluorescence spectra of 2BrH2L molecules in DMF / H2O mixed solution, as well as the particle size distribution at high water content (99%), are shown in the figure below. Figure 6 As shown, 2BrH2L produces the maximum value of the ultraviolet absorption peak at around 320nm; Figure 7 As shown in the figure, when the volume proportion of water is less than 90%, the aggregation degree of fluorescent molecules is low and almost no fluorescence is generated; when the volume proportion of deionized water is between 90% and 99%, the increase of poor solvent water leads to a gradual increase in the aggregation degree of fluorescent molecules. This is because the solubility of fluorescent molecules in poor solvent systems gradually decreases, resulting in a gradual increase in the molecular aggregation degree, and 2BrH2L molecules have good AIE properties. Figure 8 As shown, 20 mol / L compound 2BrH2L exists as aggregates with a particle size of about 175 nm in a mixed system of DMF / H2O with a water volume fraction of 99%.

[0034] Example 2 Two AIE fluorescent probes for copper ion detection: When conducting the selectivity experiment of two compounds for copper ions, dilute the prepared different metal ion solutions into 100 mol / L solutions, take 9.9 mL of the diluted metal ion solution and add it to a 10 mL glass bottle, and finally take 0.1 mL of the 1.0 mmol / L sample stock solution and add it to a 10 mL glass bottle to mix with the metal ion solution. The total volume of the mixed solution is 10 mL. After mixing, measure the fluorescence spectrum of the sample in time.

[0035] Example 3 Method to test the anti-interference ability of three compounds: In a 10mL glass bottle, first inject 0.1mL of other metal ion solution with a concentration of 10.0mmol / L, then add 0.1mL of compound solution with a concentration of 1.0mmol / L, and finally adjust the total volume and make the solution volume constant to 10mL with deionized water. After the solution is mixed, the first fluorescence spectrum measurement of the sample is carried out in time. After the first fluorescence spectrum measurement, add 0.1mL of 10.0mmol / L copper ion solution to the mixed solution, and then carry out the second fluorescence spectrum measurement.

[0036] Example 4 Experimental method for the detection limit of copper ions by two compounds: The previously configured 10 -2 mol / L copper ion solution was diluted to 10-3 mol / L,10 -4 mol / L,10 - 5 mol / L,10 -6 mol / L,10 -7 mol / L, then add 0.1mL of 10.0mmol / L zinc ion solution to the diluted copper ion solution (the zinc ion is added to make the originally non-luminescent 2FH2L and 2BrH2L solutions emit light first, and then the detection limit of the two compounds for copper ions is determined by the effect of different concentrations of copper ions on the fluorescence intensity), and finally add 0.1mL of 1.0mmol / L compound solution, and the total volume of the final mixed solution is 10mL. After mixing, measure the fluorescence spectrum of the sample in time.

[0037] Specifically, the characteristics of the halogenated tetraphenylethylene derivative fluorescent probe in copper ion detection are as follows: 1. Selectivity of compounds 2FH2L and 2BrH2L for copper ion detection In order to explore the selectivity of compounds 2FH2L and 2BrH2L for copper ions, fluorescence spectroscopy was used to study the selectivity of the three compounds in the presence of different metal cations, such as Al 3+ , Ba 2+ 、Cd 2+ Cr 3+ , Fe 3+ , K + Mg 2+ 、Na + 、Zn 2+ The fluorescence intensity changes when Fig. 9 , Fig.10 The results show that when 10 equivalents of different metal cations are added to 10 mol / L solutions of the three compounds, except for copper ions, other metal cations can enhance the luminescence intensity of the compound solution, but with the addition of Cu 2+ The addition of , the fluorescence intensity of the compound solution is very small, or even no light. This fully demonstrates that these two compounds can be used as effective fluorescent probes to detect copper ions.

[0038] 2. Anti-interference of compounds 2FH2L and 2BrH2L on copper ion detection After exploring the selectivity of the three compounds for copper ions, we also need to explore the anti-interference ability of the fluorescent probe, which is also a key step. In addition to adding Cu 2+ In addition to the solution, a certain other metal cation was also added. Fig.11 , Fig.12As shown, most metal ions did not significantly interfere with the solution, but we found that chromium ions and iron ions had a weakening effect on the fluorescence quenching produced by the three compounds (2FH2L, 2BrH2L) after combining with copper ions.

[0039] 3. Detection limits of compounds 2FH2L and 2BrH2L for copper ions After exploring the selectivity and anti-interference of the two compounds for copper ions, we further explored the detection limits of the two fluorescent probes for copper ions, which is also an important indicator for evaluating the quality of their detection performance. We determined the detection limits of the fluorescent probes for copper ions by detecting the fluorescence emission levels of the two fluorescent probe solutions in copper ion solutions of different concentrations. The results are as follows: Fig.13 , Fig.14 As shown in the data image, it can be found that when the copper ion concentration is 10 -3 mol / L and 10 -4 mol / L, the fluorescence can be quenched. When the copper ion concentration is less than 10 -4 mol / L, concentration is 10 -5 mol / L,10 -6 mol / L,10 -7 mol / L, the fluorescence of the solution was enhanced. Therefore, we can conclude that the detection limit of the three fluorescent probes for copper ions is 10 -4 mol / L.

[0040] This study successfully synthesized and characterized two TPE derivatives, 2FH2L and 2BrH2L, and studied their AIE properties. The fluorescence properties of these derivatives in different solvent ratios showed significant AIE effects, and exhibited strong fluorescence emission in poor solvents. The correlation between the aggregation state and fluorescence properties of these materials was revealed through UV-visible absorption and fluorescence spectroscopy analysis. In addition, this study also discovered an efficient method for detecting Cu 2+ of fluorescent probes.

[0041] The above description is only a preferred specific implementation manner of the present invention, but the protection scope of the present invention is not limited thereto. Any technician familiar with the technical field can make equivalent replacements or changes according to the technical scheme and inventive concept of the present invention within the technical scope disclosed by the present invention, which should be covered by the protection scope of the present invention.

Claims

1. A halogenated tetraphenylethylene derivative fluorescent probe, characterized in that: The molecular structure of the fluorescent probe is shown in (1): Wherein: the molecular structure of the fluorescent probe is specifically shown in the following structural formula (I) or formula (II): （I） (II).

2. A method for synthesizing a halogenated tetraphenylethylene derivative fluorescent probe as claimed in claim 1, characterized in that: The following steps are involved: (1) Synthesis of the structural formula (I) Step 1: 4,4'-difluorobenzophenone, 4,4'-dibromobenzophenone, zinc powder and THF that has been redispersed, dried and degassed are placed together in a double-necked round-bottom flask. TiCl4 is slowly injected into the system in an ice-water bath under nitrogen protection, and then the reaction system is stirred for 2 hours. The reaction system is then refluxed at 80°C overnight. After the reaction system is cooled, the reaction is quenched with a 10% K2CO3 aqueous solution, and then extracted with CH2Cl2. The extracted solution is dried with anhydrous Na2SO4 and then concentrated by a rotary evaporator. The concentrated product is purified by column purification using CH2Cl2 and petroleum ether as eluents. The obtained product is dissolved with CH2Cl2 and then precipitated with petroleum ether to obtain a white solid, which is filtered to obtain compound A; Step 2: Compound A, 4-(methoxycarbonyl)phenylboronic acid, K2CO3, and Pd(PPh3)4 are added to a two-necked round-bottom flask equipped with a magnetic stirring bar, and the flask is filled with a mixed solution of degassed toluene, ethanol and water, and then filled with nitrogen. Reflux at 95°C overnight, and observe the progress of the reaction by spot plate during the reaction. The mixed product obtained by the reaction is extracted with CH2Cl2 and dried, and then concentrated by rotary evaporation. The system uses a mixed solution of CH2Cl2 and petroleum ether as an eluent for column chromatography purification, and petroleum ether is poured into the CH2Cl2 solution to precipitate a solid and filter and dry to obtain compound B in the form of a white solid; Step 3: Dissolve compound B in a mixed solvent of THF, methanol and water containing LiOH, reflux the system at room temperature for 4 hours, and after cooling the system, perform rotary evaporation to appropriately remove some organic solvents such as THF and methanol, and then acidify the system with a diluted hydrochloric acid solution until the system is acidic as measured by a pH test paper, and a large amount of white flocculent precipitate is generated during the process. The precipitate is filtered and dried to obtain the product 2FH2L, which is a light yellow powder after filtration and drying; (2) Synthesis of the structural formula (II) Step 1: 4,4'-, (2,2-diphenylethylene-1,1-diyl) di(bromobenzene), 4-(methoxycarbonyl) phenylboronic acid, and Pd(PPh3)4 were placed in a three-necked round-bottom flask. A mixed solvent of degassed toluene, ethanol, and water was added to the flask, and a magnetic stirring bar was added. Then, the flask was filled with nitrogen and refluxed overnight at 95°C. The mixture was extracted with CH2Cl2, and the organic phase was washed with water and brine. The crude product was obtained by rotary evaporation, and purified by column chromatography with CH2Cl2 and petroleum ether as eluents to obtain compound C in the form of a white solid; Step 2: Dissolve compound C in CH2Cl2 and place in a round-bottom flask with a magnetic stirring bar. Then slowly add liquid bromine. Stir at room temperature for 12 hours, add an ethanol solution of Na2S2O3 to quench the reaction, and use NaOH solution to adjust the pH to a neutral range, then extract with CH2Cl2, dry the organic phase with anhydrous MgSO4, and after rotary evaporation, purify by column chromatography using a mixed solution of CH2Cl2 and petroleum ether as the eluent to obtain compound D; Step 3: Compound D was dissolved in a mixed solvent of THF, methanol and water containing NaOH, and the system was refluxed at 80°C for 4 hours. After the system was cooled, a portion of organic solvents such as THF and methanol were removed by rotary evaporation, and then diluted with 1 mol L -1 The system was acidified with hydrochloric acid solution until the system was acidic as measured by pH test paper, and a large amount of white flocculent precipitate was produced during the process. The precipitate was filtered and dried to obtain the product 2BrH2L.

3. The method for synthesizing a halogenated tetraphenylethylene derivative fluorescent probe according to claim 2, characterized in that: In the step 1, the volume ratio of CH2Cl2 to petroleum ether in the eluent is 1:

5.

4. The method for synthesizing a halogenated tetraphenylethylene derivative fluorescent probe according to claim 2, characterized in that: In the step 2 of synthesizing the structural formula (I) and the step 1 of the structural formula (II), the volumes of toluene, ethanol and water are 50 mL, 15 mL and 15 mL respectively.

5. The method for synthesizing a halogenated tetraphenylethylene derivative fluorescent probe according to claim 2, characterized in that: In step 2 of synthesizing the structural formula (I), the volume ratio of CH2Cl2 to petroleum ether is 1:

1.

6. The method for synthesizing a halogenated tetraphenylethylene derivative fluorescent probe according to claim 2, characterized in that: In the synthesis of the structural formula (I) and the structural formula (II) in step 3, the volume ratio of the mixed solvent of THF, methanol and water is 1:1:1, and both are 20 mL.

7. The method for synthesizing a halogenated tetraphenylethylene derivative fluorescent probe according to claim 2, characterized in that: In the steps 1 and 2 of synthesizing the structural formula (II), the volume ratio of CH2Cl2 to petroleum ether is 1:

1.

8. The method for synthesizing a halogenated tetraphenylethylene derivative fluorescent probe according to claim 2, characterized in that: The reaction route for synthesizing the structural formula (I) is: 。 9. The method for synthesizing a halogenated tetraphenylethylene derivative fluorescent probe according to claim 2, characterized in that: The reaction route for synthesizing the structural formula (II) is: 。 10. A fluorescent probe of a halogenated tetraphenylethylene derivative as claimed in claim 1 for recognizing Cu 2+ Application in ions.

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