Near-infrared seven-membered fluorine-boron compounds and their applications

Abstract

The present invention discloses a near-infrared seven-membered fluoroborane compound and its application. The compound is prepared from a seven-membered fluoroborane dipyrrole derivative and a para-derivative of benzaldehyde via a piperidine- and acetic acid-catalyzed condensation reaction. The compound features a simple synthesis method, convenient separation and purification, and high yield. The compound can be used to monitor viscosity changes in solutions and as a practical viscosity probe to quantitatively measure viscosity values ​​in different regions within cells, thereby probing the intracellular microenvironment and providing important information for the early diagnosis and treatment of certain diseases.

Description

Technical Field

[0001] The present invention relates to a seven-membered fluorine-boron compound and its application, and more specifically to a near-infrared seven-membered fluorine-boron compound and its application. The compound has a certain response to viscosity. At low viscosity, the fluorescence is weak, and as the viscosity increases, the fluorescence increases. Background Art

[0002] Intracellular viscosity controls all diffusion processes, including mass transfer, signal transduction, biomolecular interactions, diffusion of metabolites, and electron transport. Viscosity plays a vital role in mitochondrial ATP production, and abnormal viscosity can reflect a dysfunctional state. For example, abnormal mitochondrial viscosity is associated with neurodegenerative diseases, diabetes, and cell malignancies. However, the complex internal environment of organisms makes real-time detection of in vivo viscosity a major challenge. Existing technologies have disadvantages such as difficulty in detecting in vivo viscosity and slow detection response. Therefore, it is very important to develop an easy-to-detect viscosity probe.

[0003] Near-infrared dyes can be used for imaging at different levels, from cells to tissues, and can also be used to visualize the viscosity of the microenvironment in zebrafish. At the same time, near-infrared dyes can be applied to cirrhosis models by inducing cirrhosis in mice and then performing bioimaging of cirrhotic liver tissue. The experiment observed that normal liver tissue samples showed a weak fluorescence signal, while the NIR fluorescence signal in cirrhotic liver tissue was significantly enhanced. These results show that near-infrared dyes can be successfully used for viscosity imaging of cirrhotic liver tissue, thereby distinguishing cirrhotic liver tissue from normal liver tissue.

[0004] The probe provided by the present invention is a near-infrared seven-membered fluorine-boron compound that responds to viscosity. Its own fluorescence is relatively weak, but as the viscosity increases, the fluorescence gradually increases. Summary of the Invention

[0005] The main purpose of the present invention is to provide a near-infrared seven-membered fluorine-boron compound and its application. The technical solution of the present invention is as follows:

[0006] A near-infrared seven-membered fluorine-boron compound and its application, wherein the chemical structural formula of the compound is:

[0007]

[0008] Wherein, the substituent R is any one selected from diphenylamine and cyano. As a preferred embodiment, the chemical structural formula of the dye is:

[0009]

[0010] Any one of .

[0011] The method for synthesizing the near-infrared seven-membered fluorine-boron compound comprises the following synthesis path:

[0012]

[0013] The method comprises the following steps:

[0014] (1) Add compound 1 and toluene to a reaction flask at room temperature, stir to dissolve, then add the para-derivative of benzaldehyde, piperidine, and acetic acid, and heat under reflux to obtain a reaction solution;

[0015] (2) The reaction solution in step (1) was subjected to rotary evaporation and then separated by silica gel column chromatography to obtain product I.

[0016] Compound 1 is a derivative of a seven-membered fluoroborane dipyrrole compound, which is condensed with a para-derivative of benzaldehyde to obtain compound I; the molar ratio of compound 1 to the para-derivative of benzaldehyde is 1:1-10.

[0017] The order of adding the materials in step (1) is compound 1, toluene, a para-derivative of benzaldehyde, piperidine, and acetic acid. Piperidine and acetic acid both act as activating reactants and need to be added last. The feeding ratio of compound 1 to piperidine is 1:1-10; the feeding ratio of compound 1 to acetic acid is 1:1-10.

[0018] The heating temperature in step (1) is 30 to 150° C., and the heating time is 2 to 18 hours. The reaction temperature and time vary depending on the para-substituent of the benzaldehyde. When the temperature rises above 120° C., the yield decreases; at lower temperatures, such as below 60° C., the reaction is difficult to proceed, resulting in increased reaction time.

[0019] The beneficial effects of the present invention are as follows:

[0020] (1) Some DAD-structured fluorophores, such as I-2, maintain a moderate dihedral angle between the benzothiadiazole core and triphenylamine. However, the large steric hindrance of the donor group inhibits intramolecular rotation, thus limiting sensitivity to viscosity. Taking the N,N-dimethylformamide-glycerol system as an example, the compounds of the present invention have a certain response to viscosity. The fluorescence of the compound itself is weak, but it gradually increases with increasing viscosity, and the maximum fluorescence enhancement with viscosity is 6.1 times.

[0021] (2) The synthesis reaction conditions of the present invention are easy to control, the product purification is simple, and it has universal applicability.

[0022] (3) The synthesis steps of the present invention are simple and the reaction conditions are mild. BRIEF DESCRIPTION OF THE DRAWINGS

[0023] Figure 1 This is the hydrogen spectrum of compound I-1 obtained in Example 1.

[0024] Figure 2 This is the hydrogen spectrum of compound I-2 obtained in Example 8.

[0025] Figure 3 1 is a fluorescence spectrum of compound I-1 obtained in Example 1 in DMF-glycerol mixtures of different proportions.

[0026] Figure 4 is the fluorescence intensity logI of compound I-1 obtained in Example 1 705nm Linear relationship with logη.

[0027] Figure 5 1 is a fluorescence spectrum of compound I-2 obtained in Example 8 in DMF-glycerol mixtures of different proportions.

[0028] Figure 6 is the fluorescence intensity logI of compound I-2 obtained in Example 8 733nm Linear relationship with logη. DETAILED DESCRIPTION

[0029] The present invention is further described below with reference to the following examples. However, the scope of protection claimed in the present invention is not limited to the scope described in the examples.

[0030] Example 1

[0031] Weigh compound 1 (541 mg, 1 mmol) of heptafluoroborane dipyrrole and dissolve it in 30.00 mL of toluene. Then add 4-cyanobenzaldehyde (131 mg, 1 mmol), piperidine (0.09 mL, 1 mmol), and acetic acid (0.06 mL, 1 mmol) in sequence. Heat and stir at 90 ° C for 8 hours until the reaction is complete. The reactant is rotary evaporated and purified by column chromatography to obtain a black solid I-1 (173.3 mg) with a yield of 26.5%.

[0032]

[0033] Example 2

[0034] Compound 1 (541 mg, 1 mmol) was weighed and dissolved in 30.00 mL of toluene. 4-cyanobenzaldehyde (262 mg, 2 mmol), piperidine (0.09 mL, 1 mmol), and acetic acid (0.06 mL, 1 mmol) were then added sequentially. The mixture was stirred at 90°C for 8 hours until complete. The reaction mixture was rotary evaporated and purified by column chromatography to obtain I-1 (312.0 mg), a black solid, with a yield of 47.7%. When the amount of 4-cyanobenzaldehyde was doubled compared to Example 1, the yield increased by 21.2%.

[0035]

[0036] Example 3

[0037] Compound 1 (541 mg, 1 mmol) was weighed and dissolved in 30.00 mL of toluene. 4-Cyanobenzaldehyde (131 mg, 1 mmol), piperidine (0.18 mL, 2 mmol), and acetic acid (0.12 mL, 2 mmol) were then added sequentially. The mixture was stirred at 90°C for 8 hours until complete. The reaction mixture was rotary evaporated and purified by column chromatography to obtain a black solid I-1 (179.2 mg) with a yield of 27.4%. When the amounts of piperidine and acetic acid were doubled relative to Example 1, the yield remained unchanged.

[0038]

[0039] Example 4

[0040] Compound 1 (541 mg, 1 mmol) was weighed and dissolved in 30.00 mL of toluene. 4-Cyanobenzaldehyde (131 mg, 1 mmol), piperidine (0.09 mL, 1 mmol), and acetic acid (0.06 mL, 1 mmol) were then added sequentially. The mixture was stirred at 120°C for 6 hours until complete. The reaction mixture was rotary evaporated and purified by column chromatography to obtain a black solid I-1 (408.1 mg) with a yield of 62.4%. When the reaction temperature was increased by 30°C relative to Example 1, the reaction time was reduced by 2 hours, resulting in a 35.9% increase in yield.

[0041]

[0042] Example 5

[0043] Compound 1 (541 mg, 1 mmol) was weighed and dissolved in 30.00 mL of toluene. 4-Cyanobenzaldehyde (131 mg, 1 mmol), piperidine (0.09 mL, 1 mmol), and acetic acid (0.06 mL, 1 mmol) were then added sequentially. The mixture was stirred at 140°C for 6 hours until complete. The product was then rotary evaporated and purified by column chromatography to afford I-1 (102.7 mg), a black solid, with a yield of 15.7%. When the reaction temperature was increased by 50°C relative to Example 1 and the reaction time was reduced by 2 hours, the yield decreased by 10.8%.

[0044]

[0045] Example 6

[0046] Compound 1 (541 mg, 1 mmol) was weighed and dissolved in 30.00 mL of toluene. 4-Cyanobenzaldehyde (131 mg, 1 mmol), piperidine (0.09 mL, 1 mmol), and acetic acid (0.06 mL, 1 mmol) were then added sequentially. The mixture was stirred at 60°C for 12 hours until complete. The reaction mixture was rotary evaporated and purified by column chromatography to obtain a black solid I-1 (123.6 mg) with a yield of 18.9%. When the reaction temperature was reduced by 30°C and the reaction time was increased by 4 hours relative to Example 1, the yield decreased by 7.6%.

[0047]

[0048] Example 7

[0049] Compound 1 (541 mg, 1 mmol) was weighed and dissolved in 60.00 mL of toluene. 4-Cyanobenzaldehyde (131 mg, 1 mmol), piperidine (0.09 mL, 1 mmol), and acetic acid (0.06 mL, 1 mmol) were then added sequentially. The mixture was stirred at 90°C for 8 hours until complete. The reaction mixture was rotary evaporated and purified by column chromatography to obtain a black solid I-1 (149.8 mg) with a yield of 22.9%. When the volume of toluene was doubled relative to Example 1, the yield decreased by 3.6%.

[0050]

[0051] Example 8

[0052] Compound 1 (541 mg, 1 mmol) was weighed and dissolved in 30 mL of toluene. 4-Diphenylaminobenzaldehyde (273 mg, 1 mmol), piperidine (0.09 mL, 1 mmol), and acetic acid (0.06 mL, 1 mmol) were added in sequence. The mixture was heated and stirred at 90 ° C for 8 hours until the reaction was complete. The reactant was rotary evaporated and purified by column chromatography to obtain a purple solid I-2 (244.4 mg) with a yield of 30.7%.

[0053]

[0054] Example 9 - Response of Compounds I-1 and I-2 to Viscosity

[0055] Weigh compound I-1 (6.54 mg, 0.01 mmol) and dissolve it in 1 mL of DMF to prepare a 0.01 mol / L mother solution. Then, 10 μL of the mother solution was dissolved in 3 ml of a mixture of DMF and glycerol of different viscosities to prepare a 33.3 μmol / L test solution, wherein (DMF: glycerol = 10:0, such as 3 ml of DMF, the viscosity is 0.77 mPa·s), (DMF: glycerol = 9:1, such as the compound of 2.7 ml of DMF and 0.3 ml of glycerol, the viscosity is 1.5 mPa·s), (DMF: glycerol = 8:2, such as the compound of 2.4 ml of DMF and 0.6 ml of glycerol, the viscosity is 2.41 mPa·s), (DMF: glycerol = 7:3, such as the compound of 2.1 ml of DMF and 0.9 ml of glycerol, the viscosity is 4.22 mPa·s), (DMF: glycerol = 6:4, such as 1.8 ml The viscosity of the compound of DMF and 1.2 ml of glycerol is 7.36 mPa·s) (DMF: glycerol = 5:5, such as the viscosity of the compound of 1.5 ml of DMF and 1.5 ml of glycerol is 14.2 mPa·s), (DMF: glycerol = 4:6, such as the viscosity of the compound of 1.2 ml of DMF and 1.8 ml of glycerol is 19.9 mPa·s), (DMF: glycerol = 3:7, such as the viscosity of the compound of 0.9 ml of DMF and 2.1 ml of glycerol is 64.6 mPa·s), (DMF: glycerol = 2:8, such as the viscosity of the compound of 0.6 ml of DMF and 2.4 ml of glycerol is 127.5 mPa·s), (DMF: glycerol = 1:9, such as the viscosity of the compound of 0.3 ml of DMF and 2.7 ml of glycerol is 258.7 mPa·s) were detected respectively, and their fluorescence spectra were obtained. Figure 3 , and fitting the fluorescence intensity logI 705nm The linear relationship with logη gives Figure 4 The fluorescence of I-1 itself is weak, but with the increase of viscosity, the fluorescence gradually increases. The viscosity coefficient is 2.6, and the maximum fluorescence enhancement with viscosity is 9.7 times.

[0056] Compound I-1 (6.54 mg, 0.01 mmol) was weighed and dissolved in 1 mL of DME to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of DME and glycerol mixtures of varying viscosities to prepare 33.3 μmol / L test solutions. Fluorescence spectra of the following solutions were measured: (DME:glycerol = 10:0), (DME:glycerol = 9:1), (DME:glycerol = 8:2), (DME:glycerol = 7:3), (DME:glycerol = 6:4), (DME:glycerol = 5:5), (DME:glycerol = 4:6), (DME:glycerol = 3:7), and (DME:glycerol = 2:8). Fluorescence spectra increased with increasing viscosity. The detectable viscosity range was 0.1-260 mPa·s.

[0057] Compound I-1 (6.54 mg, 0.01 mmol) was weighed and dissolved in 1 mL of DMSO to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of DMSO and glycerol mixtures of varying viscosities to prepare 33.3 μmol / L test solutions. Fluorescence spectra of the following solutions were measured: (DMSO:glycerol = 10:0), (DMSO:glycerol = 9:1), (DMSO:glycerol = 8:2), (DMSO:glycerol = 7:3), (DMSO:glycerol = 6:4), (DMSO:glycerol = 5:5), (DMSO:glycerol = 4:6), and (DMSO:glycerol = 3:7). Fluorescence spectra of these solutions increased with increasing viscosity. The detectable viscosity range was 0.1-241 mPa·s.

[0058] Compound I-1 (6.54 mg, 0.01 mmol) was weighed and dissolved in 1 mL of ethylene glycol to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of a mixture of ethylene glycol and glycerol of varying viscosities to prepare a 33.3 μmol / L test solution. Fluorescence spectra of the following solutions were measured: (ethylene glycol:glycerol = 10:0), (ethylene glycol:glycerol = 9:1), (ethylene glycol:glycerol = 8:2), (ethylene glycol:glycerol = 7:3), (ethylene glycol:glycerol = 6:4), (ethylene glycol:glycerol = 5:5), and (ethylene glycol:glycerol = 4:6). Fluorescence gradually increased with increasing viscosity. The detectable viscosity range was 0.1-182 mPa·s.

[0059] Compound I-1 (6.54 mg, 0.01 mmol) was weighed and dissolved in 1 mL of ethanol to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of ethanol and glycerol mixtures of varying viscosities to prepare 33.3 μmol / L test solutions. Fluorescence spectra of the solutions were measured at (ethanol:glycerol = 10:0), (ethanol:glycerol = 9:1), (ethanol:glycerol = 8:2), (ethanol:glycerol = 7:3), (ethanol:glycerol = 6:4), (ethanol:glycerol = 5:5), and (ethanol:glycerol = 4:6). Fluorescence gradually increased with increasing viscosity. The detectable viscosity range was 0.1-180 mPa·s.

[0060] Compound I-1 (6.54 mg, 0.01 mmol) was weighed and dissolved in 1 mL of n-butanol to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of a mixture of n-butanol and glycerol of varying viscosities to prepare a 33.3 μmol / L test solution. Fluorescence spectra of the following solutions were measured: (n-butanol:glycerol = 10:0), (n-butanol:glycerol = 9:1), (n-butanol:glycerol = 8:2), (n-butanol:glycerol = 7:3), (n-butanol:glycerol = 6:4), (n-butanol:glycerol = 5:5), and (n-butanol:glycerol = 4:6). Fluorescence spectra increased with increasing viscosity. The detectable viscosity range was 0.1-187 mPa·s.

[0061] Compound I-1 (6.54 mg, 0.01 mmol) was weighed and dissolved in 1 mL of isopropanol to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of a mixture of isopropanol and glycerol of varying viscosities to prepare a 33.3 μmol / L test solution. Fluorescence spectra of the solutions were measured at (isopropanol:glycerol = 10:0), (isopropanol:glycerol = 9:1), (isopropanol:glycerol = 8:2), (isopropanol:glycerol = 7:3), (isopropanol:glycerol = 6:4), (isopropanol:glycerol = 5:5), and (isopropanol:glycerol = 4:6). Fluorescence gradually increased with increasing viscosity. The detectable viscosity range was 0.1-190 mPa·s.

[0062] Compound I-1 (6.54 mg, 0.01 mmol) was weighed and dissolved in 1 mL of PBS to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of PBS and glycerol mixtures of varying viscosities to prepare 33.3 μmol / L test solutions. Fluorescence spectra of the solutions were measured at (PBS:glycerol = 10:0), (PBS:glycerol = 9:1), (PBS:glycerol = 8:2), (PBS:glycerol = 7:3), (PBS:glycerol = 6:4), and (PBS:glycerol = 5:5). Fluorescence gradually increased with increasing viscosity. The detectable viscosity range was 0.1-150 mPa·s.

[0063] Weigh compound I-2 (7.96 mg, 0.01 mmol) and dissolve it in 1 mL of DMF to prepare a 0.01 mol / L mother solution. Then, 10 μL of the mother solution was dissolved in 3 ml of a mixture of DMF and glycerol of different viscosities to prepare a 33.3 μmol / L test solution, wherein (DMF: glycerol = 10:0, such as 3 ml of DMF, the viscosity is 0.77 mPa·s), (DMF: glycerol = 9:1, such as the compound of 2.7 ml of DMF and 0.3 ml of glycerol, the viscosity is 1.5 mPa·s), (DMF: glycerol = 8:2, such as the compound of 2.4 ml of DMF and 0.6 ml of glycerol, the viscosity is 2.41 mPa·s), (DMF: glycerol = 7:3, such as the compound of 2.1 ml of DMF and 0.9 ml of glycerol, the viscosity is 4.22 mPa·s), (DMF: glycerol = 6:4, such as 1.8 ml The viscosity of the compound of DMF and 1.2 ml of glycerol is 7.36 mPa·s) (DMF: glycerol = 5:5, such as the viscosity of the compound of 1.5 ml of DMF and 1.5 ml of glycerol is 14.2 mPa·s), (DMF: glycerol = 4:6, such as the viscosity of the compound of 1.2 ml of DMF and 1.8 ml of glycerol is 19.9 mPa·s), (DMF: glycerol = 3:7, such as the viscosity of the compound of 0.9 ml of DMF and 2.1 ml of glycerol is 64.6 mPa·s), (DMF: glycerol = 2:8, such as the viscosity of the compound of 0.6 ml of DMF and 2.4 ml of glycerol is 127.5 mPa·s), (DMF: glycerol = 1:9, such as the viscosity of the compound of 0.3 ml of DMF and 2.7 ml of glycerol is 258.7 mPa·s) were detected respectively, and their fluorescence spectra were obtained. Figure 5 , and fitting the fluorescence intensity logI 733nm The linear relationship with logη gives Figure 6 The fluorescence of I-2 itself is weak, but with the increase of viscosity, the fluorescence gradually increases. The viscosity coefficient is 3.46, and the maximum fluorescence enhancement with viscosity is 6.1 times.

[0064] Compound I-2 (7.96 mg, 0.01 mmol) was weighed and dissolved in 1 mL of DME to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of a mixture of DME and glycerol of varying viscosities to prepare a 33.3 μmol / L test solution. Fluorescence spectra of the following solutions were measured: (DME:glycerol = 10:0), (DME:glycerol = 9:1), (DME:glycerol = 8:2), (DME:glycerol = 7:3), (DME:glycerol = 6:4), (DME:glycerol = 5:5), (DME:glycerol = 4:6), and (DME:glycerol = 3:7). Fluorescence spectra gradually increased with increasing viscosity. The detectable viscosity range was 0.1-250 mPa·s.

[0065] Compound I-2 (7.96 mg, 0.01 mmol) was weighed and dissolved in 1 mL of DMSO to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of DMSO and glycerol mixtures of varying viscosities to prepare 33.3 μmol / L test solutions. Fluorescence spectra of the following solutions were measured: (DMSO:glycerol = 10:0), (DMSO:glycerol = 9:1), (DMSO:glycerol = 8:2), (DMSO:glycerol = 7:3), (DMSO:glycerol = 6:4), (DMSO:glycerol = 5:5), (DMSO:glycerol = 4:6), and (DMSO:glycerol = 3:7). Fluorescence spectra of these solutions increased with increasing viscosity. The detectable viscosity range was 0.1-241 mPa·s.

[0066] Compound I-2 (7.96 mg, 0.01 mmol) was weighed and dissolved in 1 mL of ethylene glycol to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of a mixture of ethylene glycol and glycerol of varying viscosities to prepare a 33.3 μmol / L test solution. Fluorescence spectra of the following solutions were measured: (ethylene glycol:glycerol = 10:0), (ethylene glycol:glycerol = 9:1), (ethylene glycol:glycerol = 8:2), (ethylene glycol:glycerol = 7:3), (ethylene glycol:glycerol = 6:4), (ethylene glycol:glycerol = 5:5), and (ethylene glycol:glycerol = 4:6). Fluorescence gradually increased with increasing viscosity. The detectable viscosity range was 0.1-182 mPa·s.

[0067] Compound I-2 (7.96 mg, 0.01 mmol) was weighed and dissolved in 1 mL of ethanol to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of ethanol and glycerol mixtures of varying viscosities to prepare 33.3 μmol / L test solutions. Fluorescence spectra of the solutions were measured at (ethanol:glycerol = 10:0), (ethanol:glycerol = 9:1), (ethanol:glycerol = 8:2), (ethanol:glycerol = 7:3), (ethanol:glycerol = 6:4), (ethanol:glycerol = 5:5), and (ethanol:glycerol = 4:6). Fluorescence gradually increased with increasing viscosity. The detectable viscosity range was 0.1-180 mPa·s.

[0068] Compound I-2 (7.96 mg, 0.01 mmol) was weighed and dissolved in 1 mL of n-butanol to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of a mixture of n-butanol and glycerol of varying viscosities to prepare a 33.3 μmol / L test solution. Fluorescence spectra of the following solutions were measured: (n-butanol:glycerol = 10:0), (n-butanol:glycerol = 9:1), (n-butanol:glycerol = 8:2), (n-butanol:glycerol = 7:3), (n-butanol:glycerol = 6:4), (n-butanol:glycerol = 5:5), and (n-butanol:glycerol = 4:6). Fluorescence spectra increased with increasing viscosity. The detectable viscosity range was 0.1-187 mPa·s.

[0069] Compound I-2 (7.96 mg, 0.01 mmol) was weighed and dissolved in 1 mL of isopropanol to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of a mixture of isopropanol and glycerol of varying viscosities to prepare a 33.3 μmol / L test solution. Fluorescence spectra of the following solutions were measured: (isopropanol:glycerol = 10:0), (isopropanol:glycerol = 9:1), (isopropanol:glycerol = 8:2), (isopropanol:glycerol = 7:3), (isopropanol:glycerol = 6:4), (isopropanol:glycerol = 5:5), (isopropanol:glycerol = 4:6), and (isopropanol:glycerol = 3:7). Fluorescence spectra increased with increasing viscosity. The detectable viscosity range was 0.1-205 mPa·s.

[0070] Compound I-2 (7.96 mg, 0.01 mmol) was weighed and dissolved in 1 mL of PBS to prepare a 0.01 mol / L stock solution. 10 μL of each stock solution was then dissolved in 3 mL of PBS and glycerol mixtures of varying viscosities to prepare 33.3 μmol / L test solutions. Fluorescence spectra of the solutions were measured at (PBS:glycerol = 10:0), (PBS:glycerol = 9:1), (PBS:glycerol = 8:2), (PBS:glycerol = 7:3), (PBS:glycerol = 6:4), and (PBS:glycerol = 5:5). Fluorescence gradually increased with increasing viscosity. The detectable viscosity range was 0.1-150 mPa·s.

[0071] The above embodiments are merely preferred technical solutions of the present invention and should not be construed as limiting the present invention. The embodiments and features in the embodiments of this application may be arbitrarily combined with each other unless they conflict. The scope of protection of the present invention shall be the technical solutions described in the claims, including equivalent alternatives to the technical features of the technical solutions described in the claims. Equivalent alternatives and improvements within this scope are also within the scope of protection of the present invention.

Claims

1. Application of a near-infrared seven-membered fluorine-boron compound in detecting the viscosity of an organic solution, characterized in that: The chemical structural formula of the compound is: Wherein, the substituent R is selected from diphenylamino or cyano.

2. The use according to claim 1, characterized in that The synthesis of near-infrared seven-membered fluoroboron compounds includes the following synthesis routes: (1) Add compound 1 and toluene to a reaction flask at room temperature, stir and dissolve, then add the para-derivative of benzaldehyde, piperidine, and acetic acid, heat and reflux to react, and obtain a reaction solution. The para-derivative of benzaldehyde is 4-cyanobenzaldehyde or 4-diphenylaminobenzaldehyde; (2) The reaction solution in step (1) was subjected to rotary evaporation and then separated by silica gel column chromatography to obtain product I.

3. The use according to claim 2, characterized in that In the step (1), the molar ratio of compound 1 to the para-derivative of benzaldehyde is 1:1-10.

4. The use according to claim 2, characterized in that The order of feeding the materials in step (1) is compound 1, toluene, a para-derivative of benzaldehyde, piperidine, and acetic acid; the feeding ratio of compound 1, piperidine, and acetic acid is 1:1-10:1-10.

5. The use according to claim 1, characterized in that The organic solvent is one or more of glycerol, DMF, DME, DMSO, ethylene glycol, ethanol, n-butanol, isopropanol, and PBS.

6. The use according to claim 1, characterized in that The viscosity detection range is 0.1-300mPa·s.

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