Tetraphenylethylene-based covalent organic framework material with high fluorescence quantum yield as well as preparation method and application of tetraphenylethylene-based covalent organic framework material

Abstract

The invention provides a tetraphenylethylene-based covalent organic framework material with high fluorescence quantum yield as well as a preparation method and application of the tetraphenylethylene-based covalent organic framework material. According to the material, due to the introduction of an aggregation-induced emission unit tetraphenyl ethylene, the conjugate interaction between a tetraphenyl ethylene element and a connecting group is weakened, so that the exciton kinetics among other connecting groups is changed, and the photoluminescence quantum yield is 73%; the material has a good light-emitting effect, is suitable for the field of photoelectric materials, and provides a thought for the design of similar materials. Meanwhile, the material has regular pore channels and rich active sites, the reaction activity of the imine connection site is high, phosphorus-chlorine bonds in the nerve poison stimulant diethyl chlorophosphate can be attacked in a nucleophilic mode, the conjugation relation of the connecting groups is changed, and the material has a good detection effect on the nerve poison stimulant diethyl chlorophosphate and can be used for detecting the nerve poison stimulant diethyl chlorophosphate. The method has the characteristics of simplicity and rapidness in operation, sensitive reaction, convenience in use and low cost, and can provide an effective technical means for detection of potential hazardous articles by related departments.

Description

Technical Field

[0001] The invention belongs to the technical field of optoelectronic materials, and in particular relates to a tetraphenylethylene-based covalent organic framework material with high fluorescence quantum yield, a preparation method and a use thereof. Background Art

[0002] Covalent organic framework (COF) materials are a class of crystalline porous materials formed by covalent cross-linking between organic monomers, with a highly ordered two-dimensional or three-dimensional network structure. Compared with other porous materials, COF not only has a large specific surface area, designable pore size and excellent thermochemical stability, but also exhibits unique fluorescence properties due to its rich conjugated system in the structure. By rationally designing the structure and connection mode of organic monomers, the luminescence properties of COF, including spectral wavelength, luminescence intensity and photostability, can be regulated, thereby giving the material fluorescence emission under specific conditions. Fluorescent COF materials are widely used in optical detection and sensing, bioimaging, information storage and anti-counterfeiting technology due to their excellent fluorescence properties. In addition, fluorescent COF materials show broad application prospects in the fields of fluorescence detection and optoelectronic devices, providing new ideas for the development and application of functional fluorescent materials.

[0003] Although fluorescent covalent organic framework (COF) materials have many advantages in the field of fluorescence applications, their current quantum yield is relatively low, which limits their further development in applications such as high-performance optoelectronics and bioimaging. This is mainly due to the structural characteristics of fluorescent COFs, including large non-radiative losses in the conjugated system and aggregation-induced quenching of luminophores. In order to improve the quantum yield of fluorescent COFs, researchers are exploring a variety of strategies, including optimizing the design of organic monomers, introducing conjugated units with high fluorescence quantum yields, and functionalizing the framework structure. These methods are expected to improve the radiative transition efficiency of COFs and reduce non-radiative losses, thereby improving fluorescence performance. At present, the improvement of quantum yield is still a key challenge in the research of fluorescent COFs and one of the core bottlenecks for achieving widespread application of this material. Summary of the invention

[0004] The purpose of the present invention is to solve the defects existing in the prior art, and the present invention provides a tetraphenylethylene-based covalent organic framework material with high fluorescence quantum yield, a preparation method and a use thereof. The material introduces the aggregation-induced emission unit tetraphenylethylene, which weakens the conjugated interaction between the tetraphenylethylene unit and the linking group, thereby changing the exciton dynamics between other linking groups, so that its photoluminescence quantum yield is 73%; the material has a good luminescent effect, is suitable for the field of optoelectronic materials, and provides ideas for the design of similar materials. At the same time, the material has regular pores and abundant active sites, and its imine connection site has high reactivity and can nucleophilically attack the phosphorus-chlorine bond in the nerve agent simulant diethyl chlorophosphate, change the conjugated relationship of its linking group, and has a good detection effect on the nerve agent simulant diethyl chlorophosphate. It has the characteristics of simple and rapid operation, sensitive reaction, convenient use and low cost, and can provide effective technical means for the relevant departments to detect potential dangerous goods.

[0005] The present invention discloses a tetraphenylethylene covalent organic framework material with high fluorescence quantum yield. The unit structure of the material is a tetraphenylethylene covalent organic framework formed by the reaction of 4',4",4"',4""-(ethylene-1,1,2,2-tetrayl)tetra(([1,1'-biphenyl]-4-carboxaldehyde)) and trans-1,4-cyclohexanediamine, wherein the structural formula is (I):

[0006]

[0007] The method for preparing the tetraphenylethylene-based covalent organic framework material with high fluorescence quantum yield is carried out according to the following steps:

[0008] Preparation of organic mixed solvents:

[0009] a. Mix any two of o-dichlorobenzene, 1,4-dioxane and n-butanol, and perform ultrasonic treatment to obtain an organic mixed solvent;

[0010] b. Add 4',4",4"',4""-(ethylene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-carboxaldehyde)) and trans-1,4-cyclohexanediamine into a Pyrex tube and mix, then add the mixed solution obtained in step a, and perform ultrasonic treatment for 10 seconds to 5 minutes;

[0011] c. Add acetic acid, p-toluenesulfonic acid, benzoic acid, trifluoroacetic acid or benzenesulfonic acid at a concentration of 0.5M-6M to the mixed solution obtained in step b, and continue ultrasonic treatment for 5 minutes;

[0012] d. Remove dissolved gas from the mixed solution obtained in step c, use liquid nitrogen to perform three cycles of freezing-vacuuming-thawing to complete degassing, seal the Pyrex tube with a spray gun flame in a frozen and vacuumed state, react at a temperature of 70-140° C. for 70-168 hours, wait for the system to return to room temperature, and after the reaction is completed, filter to obtain a precipitate, then wash the precipitate with tetrahydrofuran, dichloromethane and ethanol for 3-6 times in sequence, and vacuum dry at a temperature of 45-80° C. for 6-24 hours to obtain a tetraphenylethylene covalent organic framework material.

[0013] The invention discloses a use of the tetraphenylethylene-based covalent organic framework material with high fluorescence quantum yield in preparing diethyl chlorophosphate, a neurotoxin simulant for fluorescence detection.

[0014] The tetraphenylethylene covalent organic framework material is dispersed in ethanol to obtain a probe solution, and then a diethyl chlorophosphate solution is added to the probe solution. When the excitation light wavelength is 365nm, the fluorescence changes from yellow-green to orange-red.

[0015] The invention discloses a tetraphenylethylene-based covalent organic framework material with high fluorescence quantum yield, a preparation method and a use thereof. The material is used to detect diethyl chlorophosphate, a neurotoxin simulant. The specific operation is performed according to the following steps:

[0016] Prepare detection reagents:

[0017] a. At room temperature, weigh 0.001-0.1 g of the obtained tetraphenylethylene covalent organic framework material and dissolve it in 2 mL of ethanol, and mix it by ultrasound until it is uniformly mixed to obtain a tetraphenylethylene covalent organic framework material detection reagent, and encapsulate the detection reagent in a brown reagent bottle;

[0018] b. Take 0.05M diethyl chlorophosphate solution and add it to the test bottle of the detection reagent obtained in step a at a volume ratio of 1:0.05. Due to the protonation of its imine linker, the photoinduced electron transfer effect between the imine group and the tetraphenylethylene group is changed, causing the fluorescence at 543nm to be gradually quenched, and the emission wavelength shifts to a longer wavelength, thereby determining the presence of diethyl chlorophosphate. BRIEF DESCRIPTION OF THE DRAWINGS

[0019] Figure 1 The powder X-ray diffraction spectrum of the tetraphenylethylene-based covalent organic framework material prepared in Example 1 of the present invention;

[0020] Figure 2 This is a Fourier transform infrared spectrum of the tetraphenylethylene based covalent organic framework material prepared in Example 1 of the present invention;

[0021] Figure 3This is the fluorescence emission change spectrum of the tetraphenylethylene-based covalent organic framework material prepared in Example 2 of the present invention before and after the reaction with the nerve agent simulant diethyl chlorophosphate. DETAILED DESCRIPTION

[0022] Example 1

[0023] Preparation of organic mixed solvents:

[0024] a. Mix 0.8 mL of o-dichlorobenzene and 1.2 mL of n-butanol, and perform ultrasonic treatment for 10 minutes to obtain an organic mixed solvent;

[0025] b. Add 40 mg of 4',4",4"',4""-(ethylene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-carboxaldehyde)) and 10 mg of trans-1,4-cyclohexanediamine into a Pyrex tube, mix, add the mixed solution obtained in step a, and perform ultrasonic treatment for 5 min;

[0026] c. Add 0.2 mL of 6 M acetic acid as a catalyst to the mixed solution obtained in step b, and continue ultrasonic treatment for 5 minutes;

[0027] d. The mixed solution in step c is treated to remove dissolved gas, the Pyrex tube is connected to the double-row tube, and liquid nitrogen is used to perform three cycles of freezing-vacuuming-thawing to complete the degassing treatment. In the frozen and vacuumed state, the Pyrex tube is sealed with a blowtorch flame, and the reaction is carried out at a temperature of 70°C for 168h. After the system returns to room temperature, after the reaction is completed, the precipitate is filtered to obtain a precipitate, and the precipitate is washed three times with tetrahydrofuran, dichloromethane and ethanol in sequence, and the obtained solid is vacuum dried at a temperature of 80°C for 12 hours to obtain a tetraphenylethylene covalent organic framework material.

[0028] Example 2

[0029] Preparation of organic mixed solvents:

[0030] a. Mix 0.8 mL of 1,4-dioxane and 1 mL of o-dichlorobenzene, and perform ultrasonic treatment for 10 minutes to obtain an organic mixed solvent;

[0031] b. Add 40 mg of 4',4",4"',4""-(ethylene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-carboxaldehyde)) and 10 mg of trans-1,4-cyclohexanediamine into a Pyrex tube, mix, add to the mixed solution obtained in step a, and perform ultrasonic treatment for 10 seconds;

[0032] c. Add 0.1 mL of 6M p-toluenesulfonic acid as catalyst to the mixed solution obtained in step b, and continue ultrasonic treatment for 5 minutes;

[0033] d. The mixed solution in step c is treated to remove dissolved gas, the Pyrex tube is connected to the double-row tube, and liquid nitrogen is used to perform three cycles of freezing-vacuuming-thawing to complete the degassing treatment. In the frozen and vacuumed state, the Pyrex tube is sealed with a blowtorch flame, and the reaction is carried out at a temperature of 80° C. for 100 hours. After the system returns to room temperature, after the reaction is completed, the precipitate is filtered to obtain a precipitate, and the precipitate is washed three times with tetrahydrofuran, dichloromethane and ethanol in sequence, and the obtained solid is vacuum dried at a temperature of 70° C. for 20 hours to obtain a tetraphenylethylene covalent organic framework material.

[0034] Example 3

[0035] Preparation of organic mixed solvents:

[0036] a. Mix 1 mL of 1,4-dioxane and 1 mL of n-butanol, and perform ultrasonic treatment for 10 minutes to obtain an organic mixed solvent;

[0037] b. Add 40 mg of 4',4",4"',4""-(ethylene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-carboxaldehyde)) and 10 mg of trans-1,4-cyclohexanediamine into a Pyrex tube, mix, add the mixed solution obtained in step a, and perform ultrasonic treatment for 1 min;

[0038] c. Add 0.1 mL of 6M p-toluenesulfonic acid as catalyst to the mixed solution obtained in step b, and continue ultrasonic treatment for 5 minutes;

[0039] d. The mixed solution in step c is treated to remove dissolved gas, the Pyrex tube is connected to the double-row tube, and liquid nitrogen is used to perform three cycles of freezing-vacuuming-thawing to complete the degassing treatment. In the frozen and vacuumed state, the Pyrex tube is sealed with a blowtorch flame, and the reaction is carried out at a temperature of 100° C. for 120 hours. After the system returns to room temperature, after the reaction is completed, the precipitate is filtered to obtain a precipitate, and the precipitate is washed three times with tetrahydrofuran, dichloromethane and ethanol in sequence, and the obtained solid is vacuum dried at a temperature of 50° C. for 15 hours to obtain a tetraphenylethylene covalent organic framework material.

[0040] Example 4

[0041] Preparation of organic mixed solvents:

[0042] a. Mix 0.8 mL of 1,4-dioxane and 1 mL of o-dichlorobenzene, and perform ultrasonic treatment for 10 minutes to obtain an organic mixed solvent;

[0043] b. Add 40 mg of 4',4",4"',4""-(ethylene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-carboxaldehyde)) and 10 mg of trans-1,4-cyclohexanediamine into a Pyrex tube, mix, add the mixed solution obtained in step a, and perform ultrasonic treatment for 3 min;

[0044] c. Add 0.1 mL of 5M trifluoroacetic acid as catalyst to the mixed solution obtained in step b, and continue ultrasonic treatment for 5 minutes;

[0045] d. The mixed solution in step c is treated to remove dissolved gas, the Pyrex tube is connected to the double-row tube, and liquid nitrogen is used to perform three cycles of freezing-vacuuming-thawing to complete the degassing treatment. In the frozen and vacuumed state, the Pyrex tube is sealed with a blowtorch flame, and the reaction is carried out at a temperature of 140° C. for 70 hours. After the system returns to room temperature, after the reaction is completed, the precipitate is filtered to obtain a precipitate, and the precipitate is washed 6 times with tetrahydrofuran, dichloromethane and ethanol in sequence. Finally, the obtained solid is vacuum dried at a temperature of 45° C. for 24 hours to obtain a tetraphenylethylene covalent organic framework material.

[0046] Example 5

[0047] Preparation of organic mixed solvents:

[0048] a. Mix 0.8 mL of 1,4-dioxane and 1 mL of o-dichlorobenzene, and perform ultrasonic treatment for 10 minutes to obtain an organic mixed solvent;

[0049] b. Add 40 mg of 4',4",4"',4""-(ethylene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-carboxaldehyde)) and 10 mg of trans-1,4-cyclohexanediamine into a Pyrex tube, mix, add the mixed solution obtained in step a, and perform ultrasonic treatment for 4 min;

[0050] c. Add 0.1 mL of 5 M benzoic acid as catalyst to the mixed solution obtained in step b, and continue ultrasonic treatment for 5 minutes;

[0051] d. The mixed solution in step c is treated to remove dissolved gas, the Pyrex tube is connected to the double-row tube, and liquid nitrogen is used to perform three cycles of freezing-vacuuming-thawing to complete the degassing treatment. In the frozen and vacuumed state, the Pyrex tube is sealed with a blowtorch flame, and the reaction is carried out at a temperature of 120° C. for 130 hours. After the system returns to room temperature, after the reaction is completed, the precipitate is filtered out, and the precipitate is washed 4 times with tetrahydrofuran, dichloromethane and ethanol in sequence. The obtained solid is vacuum dried at a temperature of 60° C. for 10 hours to obtain a tetraphenylethylene covalent organic framework material.

[0052] Example 6

[0053] The crystal structure of any tetraphenylethylene covalent organic framework material obtained in Examples 1-5 was determined by X-ray crystal diffractometer. Figure 1 As shown, it can be seen that the tetraphenylethylene-based covalent organic framework material has an ordered crystal structure;

[0054] The chemical structure of any tetraphenylethylene covalent organic framework material obtained in Examples 1-5 was determined by infrared spectrometer. Figure 2 As shown in the figure, it can be seen that the characteristic peak of the monomer of the preparation raw material of tetraphenylethylene covalent organic framework material disappears, and the peak at 1640cm -1 The characteristic peak corresponding to the imine bond (-C=N-) appears at , proving that the organic monomer 4',4",4"',4""-(ethylene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-carboxaldehyde)) and the organic monomer trans-1,4-cyclohexanediamine in the tetraphenylethylene-based covalent organic framework material are connected by chemical bonds.

[0055] Example 7

[0056] Any one of the tetraphenylethylene covalent organic framework materials obtained in Examples 1-5 was used to detect the nerve agent simulant diethyl chlorophosphate, and the specific operation was carried out according to the following steps:

[0057] Prepare detection reagents:

[0058] a. At room temperature, 0.01 g of the obtained tetraphenylethylene covalent organic framework material was weighed and dissolved in 2 mL of ethanol, and ultrasonically mixed until uniformly mixed to obtain a tetraphenylethylene covalent organic framework material detection reagent, and the detection reagent was packaged in a brown reagent bottle;

[0059] b. Take a 0.05M diethyl chlorophosphate solution at a volume ratio of 1:0.05 and add it to the test bottle containing the detection reagent obtained in step a, causing the fluorescence at 543nm to be gradually quenched and the emission wavelength to move to a longer wavelength, thereby determining the presence of diethyl chlorophosphate;

[0060] The fluorescence response of tetraphenylethylene covalent organic framework materials to nerve agent simulants was measured using a fluorescence spectrometer. Figure 3 As shown, the fluorescence peak intensity weakened and red-shifted to a longer wavelength, thereby confirming the presence of diethyl chlorophosphate.

Claims

1. A tetraphenylethylene-based covalent organic framework material with high fluorescence quantum yield, characterized in that The unit structure of the material is a tetraphenylethylene covalent organic framework formed by a Schiff base reaction of 4',4",4"',4""-(ethylene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-carboxaldehyde)) and trans-1,4-cyclohexanediamine, wherein the structural formula is (I):

2. The method for preparing a tetraphenylethylene-based covalent organic framework material with high fluorescence quantum yield according to claim 1, characterized in that: Follow these steps: Preparation of organic mixed solvents: a. Mix any two of o-dichlorobenzene, 1,4-dioxane and n-butanol, and perform ultrasonic treatment to obtain an organic mixed solvent; b. Add 4',4",4"',4""-(ethylene-1,1,2,2-tetrayl)tetrakis(([1,1'-biphenyl]-4-carboxaldehyde)) and trans-1,4-cyclohexanediamine into a Pyrex tube and mix, then add the mixed solution obtained in step a, and perform ultrasonic treatment for 10 seconds to 5 minutes; c. Add acetic acid, p-toluenesulfonic acid, benzoic acid, trifluoroacetic acid or benzenesulfonic acid at a concentration of 0.5M-6M to the mixed solution obtained in step b, and continue ultrasonic treatment for 5 minutes; d. Remove dissolved gas from the mixed solution obtained in step c, use liquid nitrogen to perform three cycles of freezing-vacuuming-thawing to complete degassing, seal the Pyrex tube with a spray gun flame in a frozen and vacuumed state, react at a temperature of 70-140° C. for 70-168 hours, wait for the system to return to room temperature, and after the reaction is completed, filter to obtain a precipitate, then wash the precipitate with tetrahydrofuran, dichloromethane and ethanol for 3-6 times in sequence, and vacuum dry at a temperature of 45-80° C. for 6-24 hours to obtain a tetraphenylethylene covalent organic framework material.

3. Use of a tetraphenylethylene-based covalent organic framework material with high fluorescence quantum yield as claimed in claim 1 in the preparation of diethyl chlorophosphate, a fluorescent detection simulant of nerve agents.

4. The use according to claim 3, characterized in that The tetraphenylethylene covalent organic framework material is dispersed in ethanol to obtain a probe solution, and then a diethyl chlorophosphate solution is added to the probe solution. When the excitation light wavelength is 365nm, the fluorescence changes from yellow-green to orange-red.

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