CN113788779B - A series of donor compounds based on diphenyl sulfone and indole derivatives and their preparation methods and applications - Google Patents

Abstract

The invention relates to the technical field of organic luminescent materials, in particular to a series of donor-acceptor type compounds based on diphenyl sulfone and indole derivatives, and a preparation method and application thereof. The invention takes indole derivatives as electron donor (D) and diphenyl sulfone as electron acceptor (A) to form D-A or D-A-D type compound; the series of compounds have the characteristics of torsion intramolecular charge transfer and aggregation-induced luminescence, and are sensitive to the existence of water in an organic solvent; the concrete steps are as follows: in a certain range, as the water content increases, the maximum emission peak position appears in a red shift of the law, the intensity ratio of the red shift gradually increases, and the red shift and the intensity ratio all show good linear relation; thus, the series of compounds of the present invention can be used as a novel fluorescence sensor for real-time detection of water content in organic solvents at an intensity ratio and wavelength.

Description

A series of donor compounds based on diphenyl sulfone and indole derivatives and their preparation Methods and applications

Technical field

The present invention relates to the technical field of organic light-emitting materials, in particular to a series of donor compounds based on diphenyl sulfone and indole derivatives and their preparation methods and applications.

Background technique

Organic fluorescent materials have a wide range of applications in fields such as fluorescence imaging, sensing, and organic light-emitting diodes due to their simple structure and stable luminescence. However, common organic fluorescent materials are all molecules with aggregation-induced quenching (ACQ). That is, although they have excellent luminescence properties in a dilute solution state, as the concentration increases, the degree of π-π stacking increases in the aggregated state. This results in a sharp weakening of the luminescence intensity or even fluorescence quenching, which greatly limits its development in related fields. In order to reduce the impact of ACQ, researchers such as Tang Benzhong proposed a series of luminescent molecules with aggregation-induced emission (AIE) and aggregation-induced enhanced emission (AIEE) properties (Y Hong, et al. Chem. Soc. Rev., 2011, 40,5361.), that is, the emission of molecules is enhanced in the aggregated state. In recent years, due to the broad development prospects of AIE molecules, many researchers have devoted themselves to studying the design principles, luminescence mechanisms, and the relationship between structure and properties of AIE molecules. Until now, AIE molecules with excellent properties still attract the attention of researchers (Q Wang et al, J. Mater. Chem. B., 2016, 4, 4033.).

Moreover, due to the characteristics of intramolecular charge conversion, in recent years, organic compounds composed of electron donors (D) and electron acceptors (A) have become popular materials in the field of optoelectronics (S Sasaki, et al, J. Mater. Chem .C.,2016,4,2731.). In polar environments, molecules with torsional intramolecular charge transfer undergo a rapid intramolecular charge transfer process from donor to acceptor, accompanied by a relaxed packing mode, in which, in addition to charge transfer from low energy, there is also charge transfer from high energy. The relaxation process of localized excited states is easily regulated by conditions such as molecular substituents and polarity. Therefore, molecules with torsional intramolecular charge transfer (TICT) properties are widely used in various fields of biochemistry. Therefore, more and more researchers have begun to focus on designing molecules with both AIE and TICT functions to construct TICT-AIE synergistic fluorescent materials. Since they can emit strongly in both dilute solutions and aggregated states, they have greatly promoted the development of fluorescent materials. Applications of such fluorescent molecules in fluorescence imaging and organic light-emitting diodes.

However, this molecule is not widely used in the detection of water content in organic solvents. Since water is the most common impurity in organic solvents, its detection and quantification is critical in both chemical reactions and industrial applications. There are currently some traditional techniques for detecting trace amounts of water, such as Karl Fischer titration, chromatography, and electrochemical methods (H Jung, Chem.Soc.Rev., 2016, 45, 1242.), but usually these methods are There are shortcomings such as high cost and long time, which greatly increases the operational requirements. Therefore, it is necessary to design organic fluorescent molecules with simple structure and obvious color development to replace traditional detection methods. Moreover, most of the existing water sensors only conduct quantitative analysis of water through the linear relationship between intensity and water content, which has certain errors in actual operation that may affect the measurement accuracy.

Combining the above research background, it is of great significance to develop a dual-parameter three-dimensional detection sensor that is sensitive to trace amounts of water in organic solvents and uses the change of intensity ratio and wavelength with water content. It can greatly improve the accuracy of quantification and is suitable for For quantitative detection of water in organic solvents in laboratory or industrial applications.

Contents of the invention

The purpose of the present invention is to provide a series of donor compounds based on diphenyl sulfone and indole derivatives and their preparation methods and applications, to overcome the shortcomings of the aforementioned prior art, and to use indole derivatives as electron donors (D) , diphenyl sulfone is a D-A or D-A-D compound formed by the electron acceptor (A). This series of compounds has the characteristics of torsional intramolecular charge transfer and aggregation-induced emission. It is relatively sensitive to the presence of water in organic solvents and can be used as a A new type of fluorescent water sensor that uses ratiometric intensity and emission wavelength to detect water content in organic solvents in real time. .

The technical solutions adopted by the present invention to solve the technical problems are:

A series of donor-type compounds based on diphenyl sulfone and indole derivatives are donor-type compounds formed by using indole derivatives as electron donors and diphenyl sulfone as electron acceptors. Their structural formulas are as follows: I or general formula II:

Where: R is hydrogen, or a halogen atom, or indole, or indoline

The donor compound based on diphenyl sulfone and indole derivatives of the present invention has the characteristics of reverse intramolecular charge transfer and aggregation-induced luminescence, and can be used as a sensor for detecting water in organic solvents.

The preparation method of a series of donor compounds based on diphenyl sulfone and indole derivatives includes the following steps: adding indole, 4,4'-difluorodiphenyl sulfone and potassium carbonate to a reaction vessel, indole, The molar mass ratio of 4,4'-difluorodiphenyl sulfone and potassium carbonate is 0.9-1.1mmol: 1.8-2.2mmol: 0.9-1.1mmol. Under nitrogen protection, inject 2-12ml N-methylpyrrolidone at 100°C. The reaction was carried out for 0.5 hours, the reaction solution was poured into ice water, extracted three times with ethyl acetate, washed with saturated brine, the organic phase was rotary evaporated to remove the solvent, and separated and purified by column chromatography to obtain the product 4-fluoro-4'- Indoxyl phenyl sulfone, 4-fluoro-4'-indolyl phenyl sulfone, is a compound represented by the general formula I.

The preparation method of a series of donor compounds based on diphenyl sulfone and indole derivatives includes the following steps: adding indole, 4,4'-difluorodiphenyl sulfone and potassium carbonate to a reaction vessel, indole, The molar mass ratio of 4,4'-difluorodiphenyl sulfone and potassium carbonate is 2-2.4mmol: 0.9-1.1mmol: 9-11mmol. Under nitrogen protection, inject 2-12ml N-methylpyrrolidone at 160°C. React for 4 hours, then naturally cool down to room temperature. Pour the reaction solution into ice water while stirring, extract three times with ethyl acetate, wash with saturated brine, rotary evaporate the organic phase to remove the solvent, and separate and purify by column chromatography to obtain the product. Bis(4-indolebenzene)sulfone, the product bis(4-indolebenzene)sulfone is a compound represented by general formula I.

A method for preparing a series of donor compounds based on diphenyl sulfone and indole derivatives, including the following steps: adding indoline, 4,4'-difluorodiphenyl sulfone and potassium carbonate to a reaction vessel, indole The molar mass ratio of phosphine, 4,4'-difluorodiphenyl sulfone and potassium carbonate is 0.9-1.1mmol: 2-2.4mmol: 9-11mmol. Under nitrogen protection, inject 2-12ml N-methylpyrrolidone at 160 The reaction was carried out for 2 hours at ℃, the reaction solution was added to cold water, extracted three times with ethyl acetate, washed with saturated brine, the organic phase was rotary evaporated to remove the solvent, and separated and purified by column chromatography to obtain the product 4-fluoro-4'- Indoline phenyl sulfone, 4-fluoro-4'-indoline phenyl sulfone, is a compound represented by general formula II.

A method for preparing a series of donor compounds based on diphenyl sulfone and indole derivatives, including the following steps: adding indoline, 4,4'-difluorodiphenyl sulfone and sodium hydride, indole in a reaction vessel The molar mass ratio of phosphine, 4,4'-difluorodiphenyl sulfone and sodium hydride is 4-4.8mmol: 0.9-1.1mmol: 4-4.8mmol. Under nitrogen protection, inject 2-12mlN,N dimethylformamide in, react at 100°C for 10 hours, then naturally cool down to room temperature. Pour the reaction solution into ice water while stirring, extract it three times with ethyl acetate, wash with saturated brine, rotary evaporate the organic phase to remove the solvent, and pass through the column layer Through analytical separation and purification, the product bis(4-indolylbenzene)sulfone is obtained, and bis(4-indolylbenzene)sulfone is a compound represented by general formula II.

The synthetic routes of the above four preparation methods are as follows:

4-Fluoro-4'-indolebenzene sulfone is compound C-1 in the above reaction formula, and bis(4-indolebenzene)sulfone is compound C-2 in the above reaction formula, 4-fluoro-4' -Indoline phenyl sulfone is the compound C-3 in the above reaction formula, and bis(4-indoline phenyl) sulfone is the compound C-4 in the above reaction formula.

A series of donor-type compounds based on diphenyl sulfone and indole derivatives are used as fluorescent sensors to detect the water content of organic solvents.

Preferably, the application of a series of donor compounds based on diphenyl sulfone and indole derivatives includes the following steps:

(1) Dissolve the compound of general formula I or general formula II in a mixed solution of water and tetrahydrofuran;

(2) Measure the change in luminescence of the system caused by changes in water volume fraction to detect the water content in the organic solvent.

The fluorescence spectrum changes regularly with changes in water content.

The invention synthesizes a series of donor-type compounds based on diphenyl sulfone and indole derivatives, which are D-A or D-A-D formed by using the indole derivative as the electron donor (D) and diphenyl sulfone as the electron acceptor (A). type compounds; research has shown that this series of compounds has the characteristics of torsional intramolecular charge transfer and aggregation-induced emission, and is relatively sensitive to the presence of water in organic solvents; the specific performance is: within a certain range, as the water content increases, The maximum emission peak position shows a regular red shift, and its intensity ratio also gradually increases, and all show a good linear relationship; therefore, this series of compounds can be used as a real-time detection of water content in organic solvents based on intensity ratio and wavelength. New fluorescent sensor.

The beneficial effects of the present invention are: compared with the existing technology, the series of donor compounds based on diphenyl sulfone and indole derivatives of the present invention and their preparation methods and applications have the following advantages: The series of compounds are sensitive to water. They can not only detect the water content of organic solvents based on the intensity of emission, but also detect the water content of organic solvents based on changes in emission displacement. The raw materials are cheap and easy to obtain, the synthesis is simple, and the detection is convenient, solving the existing problems. The technology solves the technical problems of high detection cost and complex synthesis route, and effectively improves the detection accuracy.

Description of the drawings

Figure 1 is the fluorescence emission spectrum of the compound 4-fluoro-4'-indoline phenyl sulfone with a concentration of 5 μmol/L in Example 3 of the present invention in a mixed solution of tetrahydrofuran and water with different water volume contents;

Figure 2 shows the relationship between the water volume fraction, emission wavelength and fluorescence intensity ratio of compound 4-fluoro-4'-indoline phenyl sulfone in a mixed solution of tetrahydrofuran and water with a concentration of 5 μmol/L in Example 3 of the present invention;

Figure 3 is the fluorescence emission spectrum of the compound bis(4-indolinebenzene)sulfone with a concentration of 5 μmol/L in Example 4 of the present invention in a mixed solution of tetrahydrofuran and water with different water volume contents;

Figure 4 shows the relationship between the water volume fraction, emission wavelength and fluorescence intensity ratio of compound bis(4-indolinebenzene)sulfone in a mixed solution of tetrahydrofuran and water with a concentration of 5 μmol/L in Example 4 of the present invention.

Detailed ways

Example 1

Add indole (0.23g, 2mmol), 4,4'-difluorodiphenyl sulfone (1.02g, 4mmol) and potassium carbonate (0.28g, 2mmol) into a 20mL round-bottomed flask. Under nitrogen protection, inject N- 5 mL of methylpyrrolidone was reacted at 100°C for 0.5 hours, then cooled to room temperature. The reaction solution was poured into 20 mL of ice water, extracted three times with ethyl acetate, washed with saturated brine, and the organic phase was rotary evaporated to obtain a light yellow solid. Separate and purify by column chromatography, using petroleum ether: ethyl acetate = 10:1 (v/v) as the eluent, to obtain white solid 2-1, which is 4-fluoro-4'-indole phenyl sulfone, yield 68%. 1H NMR (400MHz, DMSO-d6) δ (ppm): 8.19-8.09 (m, 4H), 7.91-7.84 (m, 2H), 7.76 (d, J＝3.4Hz, 1H), 7.68 (dd, J＝ 11.0,4.1Hz,2H),7.55-7.44(m,2H),7.21(dtd,J＝14.8,7.1,1.2Hz,2H),6.78(dd,J＝3.4,0.6Hz,1H).

Example 2

Add indole (0.52g, 4.4mmol), 4,4'-difluorodiphenyl sulfone (0.508g, 2mmol) and potassium carbonate (2.76g, 20mmol) into a 20mL round-bottomed flask. Under nitrogen protection, inject N - 10 mL of methylpyrrolidone, react at 160°C for 4 hours, then naturally cool to room temperature. Pour the reaction solution into 50 mL of ice water while stirring, extract three times with ethyl acetate, wash with saturated brine, and evaporate the organic phase to remove the solvent. Obtain a light yellow solid, which is separated and purified by column chromatography. Petroleum ether: ethyl acetate = 10:1 (v/v) is used as the eluent to obtain a white solid 2-2, which is bis(4-indolebenzene). Sulfone, yield 81%. 1H NMR (400MHz, DMSO-d6) δ (ppm): 8.22-8.14 (m, 4H), 7.90-7.86 (m, 4H), 7.75 (d, J＝3.4Hz, 2H), 7.67 (dd, J＝ 12.8,7.8Hz,4H),7.26-7.12(m,4H),6.76(d,J＝3.4Hz,2H).

Example 3

Add indoline (0.24g, 2mmol), 4,4'-difluorodiphenyl sulfone (1.12g, 4.4mmol) and potassium carbonate (2.76g, 20mmol) into a 20mL round-bottomed flask. Under nitrogen protection, inject 10 mL of N-methylpyrrolidone was reacted at 160°C for 2 hours, then naturally cooled to room temperature. The reaction solution was poured into 50 mL of ice water, extracted three times with ethyl acetate, washed with saturated brine, and the organic phase was rotary evaporated to remove the solvent to obtain The light yellow solid was separated and purified by column chromatography, using petroleum ether: ethyl acetate = 10:1 (v/v) as the eluent to obtain off-white solid 2-3, which is 4-fluoro-4'-indole. Phylinophenyl sulfone, yield 69%. 1H NMR(400MHz, DMSO-d6)δ(ppm):8.04-7.7(m,2H),7.90-7.83(m,2H),7.50-7.40(m,2H),7.40-7.34(m,2H), 7.32(d,J＝8.0Hz,1H),7.28-7.20(m,1H),7.12(t,J＝7.7Hz,1H),6.86(td,J＝7.5,0.7Hz,1H),4.00(t ,J＝8.4Hz,2H),3.21-3.02(m,2H).

Example 4

Add indoline (1.04g, 8.8mmol), 4,4'-difluorodiphenyl sulfone (0.508g, 2mmol) and sodium hydride (0.22g, 8.8mmol) into a 20mL round-bottomed flask under nitrogen protection. Inject 10 mL of anhydrous N,N-dimethylformamide, react at 100°C for 10 hours, then cool to room temperature under natural conditions, pour the reaction solution into 50 mL of ice water, extract three times with ethyl acetate, and wash with saturated brine. The organic phase was rotary evaporated to remove the solvent to obtain a light yellow solid, which was separated and purified by column chromatography using petroleum ether: ethyl acetate = 10:1 (v/v) as the eluent to obtain a white solid 2-4, which is Bis(4-indolinebenzene)sulfone, yield 47%. 1HNMR (400MHz, DMSO-d6) δ (ppm): 7.91-7.66 (m, 4H), 7.39-7.32 (m, 4H), 7.30 (d, J = 8.0Hz, 2H), 7.24 (dd, J = 7.3 ,0.8Hz,2H),7.11(t,J＝7.8Hz,2H),6.85(td,J＝7.4,0.8Hz,2H),4.00(dd,J＝15.2,6.9Hz,4H),3.11(t ,J=8.4Hz,4H).

Test example 1

The compound obtained in Example 3 was prepared into a mixed solution of tetrahydrofuran and water. The proportions of water were 0%, 1%, 3%, 5%, and 7%, and the concentrations were all 5 μmol/L. Add 2 mL of the solution into a 1 cm × 1 cm × 4 cm cuvette with a stopper, and test its fluorescence emission spectrum, λex = 345 nm, and the results are shown in Figure 1.

It can be seen from Figure 1 that within a certain range, as the water content in the solution increases, the fluorescence intensity gradually weakens and the emission wavelength gradually increases.

Test example 2

The compound obtained in Example 3 was prepared into a mixed solution of tetrahydrofuran and water. The proportions of water were 0%, 1%, 3%, 5%, and 7%, and the concentrations were all 5 μmol/L. Add 2 mL of the solution into a 1 cm × 1 cm × 4 cm cuvette with a stopper, test its fluorescence emission spectrum, λ _ex = 345 nm, and observe the change of its emission wavelength with the water content. The results are shown in the dotted line A in Figure 2 .

It can be seen from Figure 2 that within a certain range, the emission wavelength has a good linear relationship with the water content in the solution, R ² =0.9982.

Test example 3

The compound obtained in Example 3 was prepared into a mixed solution of tetrahydrofuran and water. The proportions of water were 0%, 1%, 3%, 5%, and 7%, and the concentrations were all 5 μmol/L. Add 2 mL of the solution into a 1 cm × 1 cm × 4 cm cuvette with a stopper, test its fluorescence emission spectrum, λ _ex = 345 nm, and observe the relationship between the emission intensity ratio and the water content. The results are shown in the dotted line B in Figure 2 .

It can be seen from Figure 2 that within a certain range, the emission intensity ratio has a good linear relationship with the water content in the solution, R ² =0.9826.

Test example 4

The compound obtained in Example 4 was prepared into a mixed solution of tetrahydrofuran and water. The proportions of water were 0%, 1%, 3%, 5%, and 7% in sequence, and the concentrations were all 5 μmol/L. Add 2 mL of the solution into a 1 cm × 1 cm × 4 cm cuvette with a stopper, and test the fluorescence emission spectrum, λ _ex = 350 nm, and the results are shown in Figure 3.

It can be seen from Figure 3 that within a certain range, as the water content in the solution increases, the fluorescence intensity gradually weakens and the emission wavelength gradually increases.

Test example 5

The compound obtained in Example 4 was prepared into a mixed solution of tetrahydrofuran and water. The proportions of water were 0%, 1%, 3%, 5%, and 7% in sequence, and the concentrations were all 5 μmol/L. Add 2 mL of the solution into a 1 cm × 1 cm × 4 cm cuvette with a stopper, test its fluorescence emission spectrum, λ _ex = 350 nm, and observe the relationship between the emission wavelength and the water content. The results are shown in the dotted line C in Figure 4.

It can be seen from Figure 4 that within a certain range, the emission wavelength has a good linear relationship with the water content in the solution, R ² =0.9736.

Test example 6

The compound obtained in Example 4 was prepared into a mixed solution of tetrahydrofuran and water. The proportions of water were 0%, 1%, 3%, 5%, and 7% in sequence, and the concentrations were all 5 μmol/L. Add 2 mL of the solution to a 1 cm × 1 cm × 4 cm cuvette with a stopper, test its fluorescence emission spectrum, λ _ex = 350 nm, and observe the relationship between the emission intensity ratio and the water content. The results are shown in the dotted line D in Figure 4 .

It can be seen from Figure 4 that within a certain range, the emission intensity ratio has a good linear relationship with the water content in the solution, R ² =0.9889.

Similar results can also be obtained when the compounds prepared in Examples 1 and 2 are tested in Test Examples 3-6.

The above-mentioned specific embodiments are only specific cases of the present invention. The patent protection scope of the present invention includes but is not limited to the product forms and styles of the above-mentioned specific embodiments. Appropriate changes or modifications should fall within the scope of patent protection of the present invention.

Claims (5)

1. A series of preparation methods of acceptor-donating compounds based on diphenyl sulfone and indole derivatives are characterized in that: is a donor-acceptor compound formed by using indole derivatives as electron donors and diphenyl sulfone as electron acceptors, and the structural formula of the donor-acceptor compound is shown as a general formula II:

wherein the compound of the general formula II is 4-fluoro-4' -indoline phenylsulfone or di (4-indoline phenylsulfone).

2. The process for the preparation of a series of acceptor-donating compounds based on diphenyl sulfone and indole derivatives according to claim 1, characterized in that: the preparation method comprises the following steps: indoline, 4 '-difluoro diphenyl sulfone and potassium carbonate are added into a reaction vessel, wherein the molar mass ratio of the indoline, the 4,4' -difluoro diphenyl sulfone and the potassium carbonate is 0.9-1.1mmol:2-2.4mmol:9-11mmol, under the protection of nitrogen, 2-12ml of N-methyl pyrrolidone is injected, the reaction is carried out for 2 hours at 160 ℃, the reaction liquid is added into cold water, the ethyl acetate is used for extraction for three times, saturated saline water is used for washing, the organic phase is distilled off in a rotating way to remove the solvent, and the product 4-fluoro-4 '-indoline phenylsulfone is obtained through column chromatography separation and purification, wherein the 4-fluoro-4' -indoline phenylsulfone is a compound shown as a general formula II.

3. The process for the preparation of a series of acceptor-donating compounds based on diphenyl sulfone and indole derivatives according to claim 1, characterized in that: the preparation method comprises the following steps: indoline, 4 '-difluorodiphenyl sulfone and sodium hydride are added into a reaction vessel, wherein the molar mass ratio of the indoline to the 4,4' -difluorodiphenyl sulfone to the sodium hydride is 4-4.8mmol:0.9-1.1mmol:4-4.8mmol, under the protection of nitrogen, 2-12ml of N, N dimethylformamide is injected, the reaction is carried out for 10 hours at 100 ℃, the temperature is naturally reduced to room temperature, the reaction liquid is poured into ice water under stirring, the ice water is extracted three times by ethyl acetate, saturated saline water is used for washing, the organic phase is distilled off to remove the solvent, and the product of di (4-indoline phenyl) sulfone is obtained through column chromatography separation and purification, wherein the di (4-indoline phenyl) sulfone is a compound shown as a general formula II.

4. Use of a series of acceptor-donating compounds based on diphenyl sulfone and indole derivatives according to any of claims 1-3, characterized in that: as a fluorescence sensor for detecting the water content of organic solvents.

5. The use of a series of acceptor-donating compounds based on diphenyl sulfone and indole derivatives according to claim 4, characterized in that: the application method comprises the following steps:

(1) Dissolving a compound of the general formula II in a mixed solution of water and tetrahydrofuran;

(2) And measuring the system luminescence change caused by the water integral change, thereby detecting the water content in the organic solvent.