A diphenyl ether compound with AEE properties, its preparation method and application

Abstract

This invention discloses a diphenyl ether compound with AEE (Average Energy Emission) properties, its preparation method, and its applications. The diphenyl ether compounds with AEE properties are 1,4-bis(2,2-bis(4-phenyletheryl)vinyl)benzene or 4,4'-bis(2,2-bis(4-phenyletheryl)vinyl)biphenyl. Both compounds exhibit excellent AEE effects, with improved fluorescence emission intensity compared to existing fluorescent detection substances. They show a fluorescence enhancement response to Trp that differs from other amino acids, specifically recognizing tryptophan without being affected by other amino acids. The detection luminescence effect is significant, with good sensitivity and a low detection limit. Furthermore, the short response time allows for instantaneous response to Trp, greatly shortening the detection time and effectively improving work efficiency. Experimental results show that the fluorescence emission intensities of the two compounds reach 5517 and 1781, respectively; the detection limits for specific recognition of tryptophan are 56.04 nM and 52.70 nM, respectively; and the sensitivities (Ksv) are 8710 M, respectively. ‑1 12610 M ‑1 .

Description

Technical Field

[0001] This invention belongs to the field of aggregation-induced enhanced luminescence (AEE) materials technology, and particularly relates to a diphenyl ether compound with AEE properties, its preparation method, and its application. Background Technology

[0002] Traditional organic light-emitting materials mostly emit strong fluorescence in the dispersed state, but once aggregated, they undergo aggregation-induced quenching (ACQ), limiting the application of luminescent molecules in the materials field. In 2001, Tang Benzhong's research group proposed the concept of aggregation-induced emission (AIE), where the luminogen does not emit light in solution but exhibits strong fluorescence in the aggregated state. Subsequently, Park's research group discovered that some luminogens exhibit weak emission in solution but show fluorescence enhancement (AEE) in the aggregated state. A large number of AIE / AEE macromolecules, with their advantages of good solubility, ease of processing, and high emission efficiency, have been widely used in fluorescent chemical sensors, bioimaging, organic light-emitting diodes (OLEDs), cell tracking, and clinical medicine.

[0003] Tryptophan (Trp) is an essential amino acid that is metabolized through a complex metabolic pathway. Its metabolites possess biological activity and play a central role in physiology and pathophysiology. Tryptophan deficiency can lead to neurotransmitter depletion and mental disorders, while excessive tryptophan intake may also cause some neurological diseases. Therefore, achieving simple, rapid, and selective detection of tryptophan is of great significance. Currently, methods for determining tryptophan mainly include spectrophotometry, fluorescence methods, high-performance liquid chromatography, capillary electrophoresis, atomic absorption spectrometry, and electrochemical methods. However, tryptophan detection is often affected by interference from other amino acids. Therefore, most existing detection methods suffer from drawbacks such as cumbersome equipment operation procedures, long detection cycles, and low accuracy, failing to meet the requirements for high-standard identification of amino acids. Summary of the Invention

[0004] The present invention aims to solve the above-mentioned technical problems existing in the prior art, and provides a diphenyl ether compound with AEE properties, its preparation method and application.

[0005] The technical solution of this invention is: a diphenyl ether compound with AEE properties, namely compound 1 or compound 2, wherein compound 1 is 1,4'-bis(2,2-bis(4-phenyletheryl)vinyl)benzene, and compound 2 is 4,4'-bis(2,2-bis(4-phenyletheryl)vinyl)biphenyl. The structural formulas of compound 1 and compound 2 are shown below:

[0006]

[0007] Compound 1

[0008]

[0009] Compound 2.

[0010] The preparation methods of the above-mentioned diphenyl ether compounds with AEE properties, and the synthetic routes of compound 1 and compound 2 are shown below:

[0011]

[0012] Synthetic route of compound 1

[0013]

[0014] Synthetic route of compound 2.

[0015] The preparation steps of compound 1 are as follows:

[0016] Step 1. Add the reactants 9,10-bis(dibromomethylene)-9,10-dihydroanthracene and 4-phenylether phenylboronic acid, the catalyst Pd(PPh3)4, and K2CO3 to provide an alkaline environment to a two-necked flask containing 1,4-dioxane and deionized water; the ratio of 9,10-bis(dibromomethylene)-9,10-dihydroanthracene, 4-phenylether phenylboronic acid, Pd(PPh3)4, K2CO3, 1,4-dioxane, and deionized water is 1.00 mmol:3.36 mmol:0.174 mmol:6.51 mmol:120 mL:24 mL;

[0017] Step 2. Place the double-necked flask into an oil bath and fix it in place. Turn on the magnetic stirrer under N2 protection and heat the oil bath to 90 °C. After reacting for 24 h, stop heating. After the reaction mixture cools to room temperature, extract and wash with dichloromethane / water.

[0018] Step 3. Using a petroleum ether / dichloromethane mixed solvent with a volume ratio of 5:1 as the eluent, the crude product was purified by silica gel column chromatography.

[0019] Step 4. Add dichloromethane dropwise to the crude product until it just dissolves, then add ethanol and recrystallize to obtain compound 1.

[0020] The preparation steps of compound 2 are as follows:

[0021] Step 1. Add the reactants 4,4'-bis(2,2-dibromovinyl)biphenyl, 4-phenyletherylphenylboronic acid, catalyst Pd(PPh3)4, and K2CO3 to provide an alkaline environment to a two-necked flask containing 1,4-dioxane and deionized water. The volume ratio of 4,4'-bis(2,2-dibromovinyl)biphenyl, 4-phenyletherylphenylboronic acid, Pd(PPh3)4, K2CO3, 1,4-dioxane, and 24 mL of deionized water is 0.674 mmol:3.36 mmol:0.174 mmol:6.51 mmol:120 mL:24 mL.

[0022] Step 2. Place the double-necked flask into an oil bath and fix it in place. Turn on the magnetic stirrer under N2 protection and heat the oil bath to 90 °C. After reacting for 24 h, stop heating. After the reaction mixture cools to room temperature, extract and wash with dichloromethane / water.

[0023] Step 3. Using a petroleum ether / dichloromethane mixed solvent with a volume ratio of 5:1 as the eluent, the crude product was purified by silica gel column chromatography.

[0024] Step 4. Add dichloromethane dropwise to the crude product until it just dissolves, then add ethanol and recrystallize to obtain compound 2.

[0025] The above-mentioned diphenyl ether compounds with AEE properties are used as fluorescent probes for recognizing small molecules, specifically as fluorescent probes for recognizing tryptophan.

[0026] The diphenyl ether compounds prepared in this invention exhibit excellent AEE (Anaerobic Emission Effect) and improved fluorescence emission intensity compared to existing fluorescent detection materials. They demonstrate a fluorescence enhancement response to Trp distinct from other amino acids, specifically recognizing tryptophan without being affected by other amino acids. The detection luminescence effect is significant, with good sensitivity and a low detection limit. Furthermore, the short response time allows for instantaneous response to Trp, greatly reducing the detection time and effectively improving work efficiency. Experimental results show that the fluorescence emission intensities of the two compounds reach 5517 and 1781, respectively; the detection limits for specific recognition of tryptophan are 56.04 nM and 52.70 nM, respectively; and the sensitivities (Ksv) are 8710 M, respectively. -1 12610 M -1 . Attached Figure Description

[0027] Figure 1 It is the compound prepared in Example 1 of this invention. 1 H NMR spectrum.

[0028] Figure 2 It is the compound prepared in Example 2 of this invention.1 H NMR spectrum.

[0029] Figure 3 This is a fluorescence spectrum of the compound prepared in the embodiments of the present invention interacting with different amino acids as a fluorescent probe.

[0030] Figure 4 This is a three-dimensional diagram showing the interaction between the compound prepared in the embodiments of the present invention as a fluorescent probe and different types of amino acids at different concentration gradients.

[0031] Figure 5 The images show the fluorescence and ultraviolet absorption spectra of the compounds prepared in this invention as fluorescent probes in titration experiments with different concentrations of Trp.

[0032] Figure 6 The figure shows the Stern-Volmer curves and linear relationships of the compounds prepared in the embodiments of the present invention at different Trp concentrations.

[0033] Figure 7 The following is a fluorescence spectrum of the compound prepared in the embodiments of the present invention as a fluorescent probe and its interference with other amino acids and Trp.

[0034] Figure 8 These are fluorescence spectra of the compounds prepared in the embodiments of the present invention in response to Trp at different response times.

[0035] Figure 9 This is a Job's curve of the compound prepared in the embodiments of the present invention. Detailed Implementation

[0036] The present invention is described in detail below through specific embodiments, but this does not limit the scope of protection of the present invention. Unless otherwise specified, the experimental methods used in the present invention are all conventional methods, and the experimental equipment, materials, reagents, etc. used can all be obtained commercially. Example 1

[0037] The preparation method of the diphenyl ether compound 1 with AEE properties of the present invention is carried out in the following steps:

[0038] Step 1. Weigh the two reactants 9,10-bis(dibromomethylene)-9,10-dihydroanthracene (0.52 g, 1.00 mmol) and 4-phenyl ether phenylboronic acid (0.72 g, 3.36 mmol), then weigh the catalyst Pd(PPh3)4 (0.12 g, 0.174 mmol) and K2CO3 (0.9 g, 6.51 mmol) to provide an alkaline environment. Add the above four compounds to a double-necked flask containing 120 mL of 1,4-dioxane and 24 mL of deionized water.

[0039] Step 2. Place the double-necked flask into an oil bath, secure it with an iron stand, turn on the magnetic stirrer under N2 protection, heat the oil bath to 90°C, and start the Suzuki coupling reaction. Let it react completely for 24 hours, then stop heating. After the reaction mixture cools to room temperature, extract and wash it with dichloromethane / water.

[0040] Step 3. Purify the crude product by silica gel column chromatography using a petroleum ether / dichloromethane mixed solvent (5 / 1, v / v) as the eluent;

[0041] Step 4. Add dichloromethane dropwise to the crude product until it just dissolves, then add an appropriate amount of ethanol for recrystallization to obtain 0.4 g of product, with a yield of 74.8%.

[0042] The compound 1 H NMR spectrum as follows Figure 1 As shown, the structural formula is as follows:

[0043]

[0044] Compound 1. Example 2

[0045] Step 1. Weigh the two reactants, 4,4'-bis(2,2-dibromovinyl)biphenyl (0.3 g, 0.674 mmol) and 4-phenyl ether phenylboronic acid (0.72 g, 3.36 mmol), then weigh the catalyst Pd(PPh3)4 (0.12 g, 0.174 mmol) and K2CO3 (0.9 g, 6.51 mmol) to provide an alkaline environment. Add the above four compounds to a double-necked flask containing 120 mL of 1,4-dioxane and 24 mL of deionized water.

[0046] Step 2. Place the double-necked flask into an oil bath, secure it with an iron stand, turn on the magnetic stirrer under N2 protection, heat the oil bath to 90°C, and start the Suzuki coupling reaction. Let it react completely for 24 hours, then stop heating. After the reaction mixture cools to room temperature, extract and wash it with dichloromethane / water.

[0047] Step 3. Purify the crude product by silica gel column chromatography using a petroleum ether / dichloromethane mixed solvent (5 / 1, v / v) as the eluent;

[0048] Step 4. Add dichloromethane dropwise to the crude product until it just dissolves, then add an appropriate amount of ethanol and recrystallize to obtain 0.4 g of product, with a yield of 74.8%.

[0049] The 1H NMR spectrum of this compound is as follows: Figure 2 As shown, the structural formula is as follows:

[0050]

[0051] Compound 2

[0052] Experiment 1: AEE performance test of two diphenyl ether compounds

[0053] To demonstrate that the two compounds exhibit the AEE effect, they were dissolved separately in tetrahydrofuran (THF) to prepare solutions. THF was used as a benign solvent and water as a poor solvent. The concentrations of the two compounds in their solutions (10⁻⁶ ppm) were measured. -4 The fluorescence intensity in (mol / L) was determined. The excitation wavelength of the fluorescence spectrum was set to 300 nm, the slit width to 5:5, and the voltage to 550 V. By changing the volume fraction of water, (f w Absorption and emission spectra were obtained from 0% to 90% in a THF / H2O mixture, and the intensity change of the solution (fw) from 0% to 90% was observed visually under a UV lamp (365 nm).

[0054] Experimental results show that the fluorescence intensity of compound 1 in pure THF solution is 296.3. When the water content increases to 60%, the fluorescence intensity reaches a maximum of 5517, which is 18.62 times higher than that in pure THF solution. Correspondingly, the emission wavelength blue shifts from 402.4 nm to 395.0 nm.

[0055] For compound 2, the fluorescence intensity was 483.2 in pure THF solution. When the water content increased to 70%, the fluorescence intensity reached a maximum of 1781, which was 3.68 times higher than that in pure THF solution. Correspondingly, the emission wavelength blue-shifted from 438.2 nm to 467.8 nm.

[0056] The data above indicate that both compounds exhibit typical AEE characteristics and belong to AEE-property compounds.

[0057] Experiment 2: Selectivity of two diphenyl ether compounds for amino acids

[0058] To confirm the specific recognition of amino acids by the two compounds, the compounds prepared in Examples 1 and 2 of this invention were used as fluorescent probes to interact with different amino acids. Specifically, 2 ml of compounds 1 and 2 were added to 100 μM of 12 amino acids (Val, Thr, Ccp, Ala, Leu, Met, Pro, Ser, Cys, Lys, Glu, Trp), respectively. The fluorescence spectra are shown below. Figure 3 As shown in (a) and (b). From Figure 3It can be seen that other amino acids did not show a significant response, and the fluorescence intensity changed only slightly. Only when Trp was added did the fluorescence intensity change dramatically, which indicates that the two compounds specifically recognize tryptophan.

[0059] Experiment 3: Fluorescent Titration Test of Amino Acids

[0060] The compounds prepared in Examples 1 and 2 of this invention were used as fluorescent probes to interact with different types of amino acids at different concentration gradients. Specifically, 2 ml of each compound was taken, and 0-100 μM of the above 12 amino acids were added sequentially for fluorescence titration. The three-dimensional graph is shown below. Figure 4 As shown in (a) and (b). From Figure 4 It can be seen that the fluorescence intensity of both compounds increases dramatically with the increase of Trp concentration, while the fluorescence intensity of the compounds remains almost unchanged as the concentration of other amino acids gradually increases. Only the addition of Ccp, Ala, and Val amino acids shows a slight increasing trend.

[0061] Experiment 4: Titration of Tryptophan Concentration

[0062] Using the compounds prepared in Examples 1 and 2 of this invention as fluorescent probes, titration experiments were conducted on different concentrations of Trp. Specifically, 0-100 μM Trp was added sequentially to the two compounds, and their respective fluorescence emission spectra and ultraviolet absorption spectra were obtained, as shown below. Figure 5 As shown in (a) and (b), the fluorescence emission spectra show that the emission wavelengths of both compounds undergo a significant blue shift and the fluorescence intensity increases dramatically; the ultraviolet absorption spectra show that the absorbance of both compounds decreases.

[0063] Experiment 5: Sensitivity and detection limit for Trp

[0064] The formula for calculating the detection limit of a compound is: detection limit = 3σ / k;

[0065] Where σ is the standard deviation of the measurement of the blank compound, and k is the slope of the linear relationship between fluorescence intensity and Trp concentration. The linear relationship between the two compounds is shown in the figure below. Figure 6 As shown in (a) and (b), the correlation coefficient R between the two compounds is... 2 As shown in Table 1, the values ​​are 0.98613 and 0.98462, respectively, indicating a good linear relationship. The k values ​​are 61.56 and 35.59, respectively. The corresponding detection limits calculated using σ are 56.04 nM and 52.70 nM, respectively. Compound 2 has a lower detection limit, which is beneficial for detecting Trp.

[0066] To investigate compound detection

[0067] Where I0 is the initial fluorescence intensity of the added compound, I is the corresponding fluorescence intensity when different concentrations of Trp are added, and [Q] is the molar concentration of Trp. The Stern-Volmer curve is shown below. Figure 6 As shown in (a) and (b), the correlation coefficient R between compounds 1 and 2 is... 2 As shown in Table 2, the values ​​are 0.98928 and 0.99270 respectively, indicating a good linear relationship. The sensitivity (Ksv) is 8710 MHz. -1 12610 M -1 Both compounds exhibit high sensitivity, thus showing a better response to tryptophan.

[0068] Table 1. Detection limits of the two compounds

[0069]

[0070] Table 2. Sensitivity of the two compounds

[0071]

[0072] Experiment 6: Interference Experiment

[0073] To investigate whether the presence of other amino acids would affect the detection of tryptophan by the compounds of this invention, an interference experiment was conducted using the compounds prepared in Examples 1 and 2 of this invention as fluorescent probes against other amino acids and Trp. Specifically, 10 μM of other amino acids and tryptophan were added alternately, and their fluorescence intensity was measured (twice for each). The results are as follows: Figure 7 As shown in (a) and (b), the experimental results show that the fluorescence intensity changes only slightly when other amino acids are added, while it increases rapidly when tryptophan is added. Repeated addition of 10 μM of other amino acids also has no significant effect on the fluorescence intensity. This demonstrates that the two compounds of this invention are not affected by other amino acids when detecting tryptophan, and can specifically recognize tryptophan. The addition of equal amounts of other amino acids has virtually no impact on the fluorescence intensity, and the trends are similar.

[0074] Experiment 7: Response Time Test

[0075] To investigate the fluorescence intensity of two compounds in response to different Trp response times, this experiment used a Trp solution with a maximum titration concentration of 100 μM, which was directly added to the compounds. The fluorescence spectra are shown below. Figure 8 As shown in (a) and (b), the results indicate that the fluorescence intensity of the solution increases rapidly immediately upon the addition of Trp to both compounds, and then the change in fluorescence intensity becomes weak with increasing response time. This demonstrates that the two compounds can provide an instantaneous response to Trp, significantly shortening the detection time and improving efficiency.

[0076] Experiment 8: Job's Curve Analysis

[0077] To investigate the optimal binding ratio of the two compounds to Trp, Job's curves were used. The total concentration of the compounds and Trp was controlled at 100 μM, thus varying the ratio of the compounds to Trp. Figure 9 (a) and (b) can be observed through linear fitting that the fluorescence intensity of [compounds] / [compounds+Trp] is the highest at around 0.5, indicating that the two compounds are most effective when they bind to Trp in a 1:1 ratio.

Claims

1. A diphenyl ether compound with AEE properties, characterized in that... Compound 1 or Compound 2, wherein Compound 1 is 1,4-bis(2,2-di(4-phenyletheryl)vinyl)benzene and Compound 2 is 4,4'-bis(2,2-di(4-phenyletheryl)vinyl)biphenyl, and the structural formulas of Compound 1 and Compound 2 are shown below: Compound 1; Compound 2.

2. A method for preparing a diphenyl ether compound with AEE properties as described in claim 1, characterized in that... The synthetic routes for compounds 1 and 2 are as follows: Synthetic route of compound 1; Synthetic route of compound 2.

3. The application of a diphenyl ether compound with AEE properties as described in claim 1 as a fluorescent probe for recognizing small molecule substances, characterized in that... Application as a fluorescent probe for recognizing tryptophan.

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