A dual-state emission pyrrolopyridine dinitrile dye and its preparation method

Abstract

This invention discloses a dual-state emission pyrrolopyridinedionitrile dye and its preparation method. As a novel fluorescent dye parent structure, the dual-state emission pyrrolopyridinedionitrile dye has excellent dual-state fluorescence emission characteristics, enabling it to absorb ultraviolet light and emit visible light. By modifying its structure, it can easily achieve high quantum yield emission in solution or solid. Moreover, the preparation method has the advantages of inexpensive and readily available raw materials, simple synthetic route, universal reaction conditions, simple post-processing method, reaction yield of 20% to 80%, large-scale preparation, and easy large-scale production.

Description

Technical Field

[0001] This invention relates to the fields of organic chemical engineering and functional fluorescent dyes, and more specifically, to a dual-state emitting pyrrolopyridine dinitrile dye and its preparation method. Background Technology

[0002] In recent years, organic light-emitting materials have attracted widespread attention due to their unique photophysical properties. Currently, there is a strong push to realize these emitting organic compounds in many applications, both in solution (i.e., sensors, bioimaging) and in their solid form (i.e., optoelectronic devices or data encryption). Despite significant progress in the development of emitting compounds, the past decade has seen an increasing demand for materials that maintain emission in both solution and solid states—a phenomenon known as dual-state emission (DSE). While some dual-state emission fluorescent materials have been reported, most are synthesized based on traditional backbones such as rhodamine dyes, coumarin dyes, and BODIPY dyes.

[0003] Therefore, the search for novel dual-state organic fluorescent chromophores is attracting increasing attention. Summary of the Invention

[0004] The purpose of this invention is to overcome the above-mentioned defects in the prior art and provide a novel dual-state emission pyrrolopyridine dinitrile dye and its preparation method. The fluorescence emission spectrum of this type of fluorescent dye is located in the visible light region, and it has high fluorescence quantum yield in both solution and solid states. Moreover, its preparation method has the advantages of inexpensive and readily available raw materials, simple operation, easy purification, and high reaction yield.

[0005] To achieve the above objectives, the technical solution of the present invention is as follows:

[0006] A dual-state emitting pyrrolopyridinedionitrile dye, the general structural formula of which is shown below:

[0007]

[0008] Among them, R1, R2, and R3 are each independently selected from H, halogens, and C1-C. 20 Straight-chain or branched alkyl groups, C1-C 20 One of straight-chain or branched alkoxy groups; Ar is selected from N-heteroaromatic groups.

[0009] The present invention also provides a method for preparing the dual-state emitting pyrrolopyridine dinitrile dye as described above, characterized by comprising the following steps:

[0010]

[0011] (1) Compound Ia was mixed with POCl3 at a mass-to-volume ratio of 1:(2~20)(g:ml) and reacted at 80℃~120℃ for 1h~12h. POCl3 was removed by vacuum distillation to obtain compound Ib.

[0012] (2) Compound Ib and compound Ic are added to a solvent at a molar ratio of 1:(0.5-8) and reacted at 50℃-150℃ for 1h-72h. After the reaction is completed, deionized water is added to quench the reaction, the solvent is removed by rotary evaporation, and methanol is added to precipitate the product. The crude product is then filtered to obtain the crude product. The crude product is recrystallized, filtered, and dried to obtain compound I.

[0013] Implementing the embodiments of the present invention will have the following beneficial effects:

[0014] (1) This invention provides a novel dual-state emission pyrrolopyridine dinitrile dye. As a novel fluorescent dye parent structure, it has good dual-state fluorescence emission characteristics and can achieve ultraviolet light absorption and visible light emission. By changing the structure, it can easily achieve high quantum yield emission in solution or solid.

[0015] (2) This invention provides a simple preparation method for a novel dual-state emission pyrrolopyridine dinitrile dye. The reaction raw materials are inexpensive and readily available, the synthesis route is simple, the reaction conditions are universal, the post-processing method is simple, the reaction yield is 20% to 80%, and it can be prepared in large quantities and is easy to scale up. Attached Figure Description

[0016] Figure 1 The reaction route diagram for the dual-state emission pyrrolopyridine dinitrile dye of the present invention is shown.

[0017] Figure 2 The image shows the 1H NMR spectrum of the dual-state fluorescent dye PD from Example 1.

[0018] Figure 3 The image shows the carbon NMR spectrum of the dual-state fluorescent dye PD from Example 1.

[0019] Figure 4 This is a high-resolution mass spectrum of the dual-state fluorescent dye PD from Example 1.

[0020] Figure 5 This is a single-crystal X-ray diffraction structure analysis diagram of the dual-state fluorescent dye PD in Example 1.

[0021] Figure 6 The images show the UV-Vis absorption spectra of the dual-state fluorescent dye PD in different solvents in Example 1.

[0022] Figure 7 The images show the fluorescence spectra of the dual-state fluorescent dye PD in different solvents in Example 1.

[0023] Figure 8 The image shows the fluorescence spectrum of the solid powder of the dual-state fluorescent dye PD in Example 1.

[0024] Figure 9 The image shows the 1H NMR spectrum of the dual-state fluorescent dye PQ from Example 2.

[0025] Figure 10 The image shows the carbon NMR spectrum of the dual-state fluorescent dye PQ from Example 2.

[0026] Figure 11 This is a high-resolution mass spectrum of the dual-state fluorescent dye PQ from Example 2.

[0027] Figure 12 This is a single-crystal X-ray diffraction structure analysis diagram of the dual-state fluorescent dye PQ in Example 2.

[0028] Figure 13 The images show the UV-Vis absorption spectra of the dual-state fluorescent dye PQ in different solvents in Example 2.

[0029] Figure 14 The images show the fluorescence spectra of the dual-state fluorescent dye PQ in different solvents in Example 2.

[0030] Figure 15 The image shows the fluorescence spectrum of the solid powder of the dual-state fluorescent dye PQ in Example 2.

[0031] Figure 16 The image shows the 1H NMR spectrum of the dual-state fluorescent dye PO from Example 3.

[0032] Figure 17 The image shows the carbon NMR spectrum of the dual-state fluorescent dye PO from Example 3.

[0033] Figure 18 This is a high-resolution mass spectrum of the dual-state fluorescent dye PO from Example 3.

[0034] Figure 19 The images show the UV-Vis absorption spectra of the dual-state fluorescent dye PO in different solvents in Example 3.

[0035] Figure 20 The images show the fluorescence spectra of the dual-state fluorescent dye PO in different solvents in Example 3.

[0036] Figure 21 The image shows the fluorescence spectrum of the solid powder of the dual-state fluorescent dye PO in Example 3.

[0037] Figure 22 The image shows the 1H NMR spectrum of the dual-state fluorescent dye PS from Example 4.

[0038] Figure 23 The image shows the carbon NMR spectrum of the dual-state fluorescent dye PS in Example 4.

[0039] Figure 24 This is a high-resolution mass spectrum of the dual-state fluorescent dye PS from Example 4.

[0040] Figure 25 The images show the UV-Vis absorption spectra of the dual-state fluorescent dye PS in different solvents in Example 4.

[0041] Figure 26 The images show the fluorescence spectra of the dual-state fluorescent dye PS in different solvents in Example 4.

[0042] Figure 27 The image shows the fluorescence spectrum of the solid powder of the dual-state fluorescent dye PS in Example 4.

[0043] Figure 28 The image shows the 1H NMR spectrum of the dual-state fluorescent dye PD4Br from Example 5.

[0044] Figure 29 The image shows the carbon NMR spectrum of the dual-state fluorescent dye PD4Br from Example 5.

[0045] Figure 30 This is a high-resolution mass spectrum of the dual-state fluorescent dye PD4Br from Example 5.

[0046] Figure 31 The images show the UV-Vis absorption spectra of the dual-state fluorescent dye PD4Br in different solvents in Example 5.

[0047] Figure 32 The images show the fluorescence spectra of the two-state fluorescent dye PD4Br in different solvents in Example 5.

[0048] Figure 33 The image shows the fluorescence spectrum of the solid powder of the dual-state fluorescent dye PD4Br from Example 5.

[0049] Figure 34 The image shows the 1H NMR spectrum of the dual-state fluorescent dye PD5Cl from Example 6.

[0050] Figure 35 The image shows the carbon NMR spectrum of the dual-state fluorescent dye PD5Cl from Example 6.

[0051] Figure 36 This is a high-resolution mass spectrum of the dual-state fluorescent dye PD5Cl from Example 6.

[0052] Figure 37 The images show the UV-Vis absorption spectra of the dual-state fluorescent dye PD5Cl in different solvents in Example 6.

[0053] Figure 38 The images show the fluorescence spectra of the two-state fluorescent dye PD5Cl in different solvents in Example 6.

[0054] Figure 39 The image shows the fluorescence spectrum of the solid powder of the dual-state fluorescent dye PD5Cl from Example 6.

[0055] Figure 40 The image shows the 1H NMR spectrum of the dual-state fluorescent dye PD4A from Example 7.

[0056] Figure 41 The image shows the carbon NMR spectrum of the dual-state fluorescent dye PD4A from Example 7.

[0057] Figure 42 This is a high-resolution mass spectrum of the dual-state fluorescent dye PD4A from Example 7.

[0058] Figure 43 The images show the UV-Vis absorption spectra of the dual-state fluorescent dye PD4A in different solvents in Example 7.

[0059] Figure 44 The images show the fluorescence spectra of the dual-state fluorescent dye PD4A in different solvents in Example 7.

[0060] Figure 45 The image shows the fluorescence spectrum of the solid powder of the dual-state fluorescent dye PD4A in Example 7.

[0061] Figure 46 The image shows the 1H NMR spectrum of the dual-state fluorescent dye TPS from Example 8.

[0062] Figure 47 The image shows the carbon NMR spectrum of the dual-state fluorescent dye TPS from Example 8.

[0063] Figure 48 This is a high-resolution mass spectrum of the dual-state fluorescent dye TPS from Example 8.

[0064] Figure 49 The UV-Vis absorption spectra of the dual-state fluorescent dye TPS in different solvents in Example 8 are shown.

[0065] Figure 50 The images show the fluorescence spectra of the dual-state fluorescent dye TPS in different solvents in Example 8.

[0066] Figure 51 The image shows the fluorescence spectrum of the solid powder of the dual-state fluorescent dye TPS in Example 8. Detailed Implementation

[0067] The present invention will be further described below with reference to specific embodiments, but this does not limit the present invention in any way.

[0068] This invention discloses a novel two-state emitting pyrrolopyridinedionitrile dye, the general structural formula of which is shown below:

[0069]

[0070] Among them, R1, R2, and R3 are each independently selected from H, halogens, and C1-C. 20 Straight-chain or branched alkyl groups, C1-C 20 One of straight-chain or branched alkoxy groups; Ar is selected from N-heteroaromatic groups.

[0071] In one specific embodiment, the halogen is selected from one of F, Cl, Br, and I.

[0072] In one specific embodiment, Ar is selected from one of imidazole, pyrazolyl, oxazolyl, thiazolyl, pyridinyl, pyrimidinyl, pyridazinyl, quinolinyl, quinoxalinyl, isoquinolinyl, indolyl, purine, benzothiazolyl, benzoxazolyl, and benzopyrazolyl.

[0073] In one specific embodiment, Ar is preferably one of the following structures:

[0074]

[0075] Among them, R4-R7 are each independently selected from H, halogens, homoaromatic groups, heteroaromatic groups, C1-C 20 Straight-chain or branched alkyl groups, C1-C 20 One of straight-chain or branched alkoxy groups.

[0076] In one specific embodiment, the dual-state emitting pyrrolopyridine dinitrile dye has one of the following structures:

[0077]

[0078] R2 is selected from H, halogens, C1-C 20 Straight-chain or branched alkyl groups, C1-C 20 One of straight-chain or branched alkoxy groups; R4-R7 are each independently selected from H, halogens, homoaromatic groups, heteroaromatic groups, C1-C 20 Straight-chain or branched alkyl groups, C1-C 20 One of straight-chain or branched alkoxy groups.

[0079] In one specific embodiment, the novel dual-state emitting pyrrolopyridine dinitrile dye is preferably one of the following structures:

[0080]

[0081] In one specific embodiment, the UV-Vis absorption peak of the dual-state pyrrolopyridine dinitrile dye is 380 nm to 500 nm; the fluorescence emission peak of the dual-state pyrrolopyridine dinitrile dye is 450 nm to 600 nm.

[0082] The present invention also provides a method for preparing a two-state emitting pyrrolopyridine dinitrile dye as described in any embodiment of the present invention, specifically comprising the following steps:

[0083]

[0084] (1) Compound Ia was mixed with POCl3 at a mass-to-volume ratio of 1:(2~20)(g:ml) and reacted at 80℃~120℃ for 1h~12h. POCl3 was removed by vacuum distillation to obtain compound Ib.

[0085] Preferably, step (1) specifically includes the following steps: adding compound Ia and POCl3 in a mass (g) to volume (ml) ratio of 1:(4~8) into a three-necked flask, reacting at 100℃~110℃ for 2h~6h, cooling to room temperature after the reaction is completed, and removing POCl3 by vacuum distillation to obtain compound Ib.

[0086] (2) Compound Ib and compound Ic were added to a solvent at a molar ratio of 1:(0.5-8) and reacted at 50℃-150℃ for 1h-72h. After the reaction was completed, deionized water was added to quench the reaction, the solvent was removed by rotary evaporation, and methanol was added to precipitate the product. The crude product was then filtered to obtain the crude product. The crude product was recrystallized, filtered, and dried to obtain compound I.

[0087] In one specific embodiment, the solvent includes one or more of toluene, dioxane, chlorobenzene, tetrahydrofuran, and cyclohexane. Preferably, the solvent is toluene or tetrahydrofuran.

[0088] In one specific embodiment, the mass-to-volume ratio of compound Ib to solvent is 1:(50-500) (g:ml). Preferably, the mass-to-volume ratio of compound Ib to solvent is 1:(70-200).

[0089] Preferably, step (2) specifically includes the following steps: adding compound Ib and compound Ic in a molar ratio of 1:(2-4) into a three-necked flask, reacting in tetrahydrofuran or toluene solvent at 70℃-110℃ for 6h-24h, quenching the reaction with deionized water after the reaction is completed, cooling to room temperature, removing the solvent by rotary evaporation, adding methanol for precipitation, and filtering to obtain the crude product; recrystallizing the obtained crude product through a mixed solution of dichloromethane and n-hexane, filtering to remove the by-product residue, and drying the mother liquor to obtain compound I.

[0090] In one specific embodiment, if further purification is required, a second recrystallization can be performed using tetrahydrofuran as a solvent to obtain high-purity compound I.

[0091] Specifically, the method for preparing fluorescent dyes provided by this invention uses inexpensive and readily available raw materials, has a simple synthetic route, universal reaction conditions, simple post-processing methods, high reaction yield, can be prepared in large quantities, and is easy to scale up for production.

[0092] The following are specific embodiments.

[0093] Example 1

[0094] A dual-state fluorescent dye PD has the following molecular structure: Preparation methods include:

[0095]

[0096] (1) 0.4 g of compound 1a (Wuhan Fengyao Tonghui Chemical Co., Ltd.) and 2 ml of POCl3 were added to a three-necked flask. The mixture was heated to 105 °C under nitrogen atmosphere and refluxed for 3 hours. After cooling to room temperature, the POCl3 in the reaction flask was removed by vacuum distillation to obtain the wine-red intermediate compound 1b.

[0097] (2) Add 60 ml of anhydrous tetrahydrofuran to a three-necked flask containing intermediate compound 1b, then add 0.4 g of compound 1c. Under a nitrogen atmosphere, heat to 75 °C, reflux for 12 hours, quench the reaction with 1 ml of deionized water, and cool to room temperature. Remove the tetrahydrofuran solvent using a rotary evaporator and add 100 ml of methanol to precipitate the product. Filter to obtain a solid crude product. Further dissolve the crude product in 50 ml of dichloromethane, slowly add 50 ml of n-hexane until a large amount of purple byproduct crystals precipitate. Filter to obtain a further purified crude PD product. Dissolve the crude PD product in 20 ml of hot tetrahydrofuran solution and slowly cool to room temperature. A large amount of light green PD crystals precipitate, totaling 0.202 g, with a yield of 42%.

[0098] The fluorescent dye PD provided in this embodiment was tested using the following method:

[0099] I. Structural Characterization of the Target Product PD

[0100] Structural characterization, including 1H NMR, 1C NMR, high-resolution mass spectrometry, and single-crystal X-ray diffraction analysis, confirmed the feasibility of the synthetic route and the correct target compound. The results are as follows:

[0101] The 1H NMR spectrum of PD is as follows Figure 2 As shown, the 1H NMR data are: 1H NMR (400MHz, CDCl3) δ (ppm) = 10.32 (d, 1H), 8.53 (d, 1H), 8.30 (d, 2H), 7.99 (t, 1H), 7.75 (t, 1H), 7.67 (s, 4H), 7.54 (d, 2H), 1.43 (s, 9H), 1.37 (s, 9H).

[0102] The carbon NMR spectrum of PD is as follows Figure 3 As shown, the carbon NMR data are: 13 C NMR (400MHz, CDCl3) δ (ppm) = 154.17, 153.02, 148.83, 137.67, 132.24, 129.68, 129.50, 129.24, 127 .86,125.79,125.54,124.40,122.69,120.10,116.97,116.01,84.47,35.06,34.89,31.30,31.24.

[0103] High-resolution mass spectrometry of PD, such as Figure 4 As shown, the high-resolution mass spectrometry data are: theoretical molecular precursor ion mass [M] + m / z = 482.2470; Detection data: [M] + m / z = 482.2483.

[0104] The single-crystal X-ray diffraction analysis results of PD are as follows: Figure 5 As shown in the figure, we can see that we have accurately obtained the fluorescent dye PD.

[0105] II. Ultraviolet-Vis absorption spectroscopy, fluorescence spectroscopy, and fluorescence quantum yield measurement

[0106] The photophysical properties of the fluorescent dye PD provided in this embodiment were tested using a UV-Vis spectrophotometer (UV-3700, Shimadzu), a fluorescence spectrometer (FLS-1000, Edinburgh), and a UV-NIR absolute fluorescence quantum yield meter (C13534-31, Hamamatsu). The UV-Vis absorption spectra in different solvents were obtained as follows: Figure 6 As shown, from Figure 6 It can be seen that the fluorescent dye PD has an ultraviolet absorption peak at around 424 nm; the fluorescence spectra obtained in different solvents are as follows: Figure 7 As shown, from Figure 7 It can be seen that the fluorescent dye PD has a fluorescence emission peak at around 473 nm; the fluorescence spectrum of the obtained solid powder is as follows. Figure 8 As shown, from Figure 8It can be seen that the fluorescent dye PD solid powder has a fluorescence emission peak at around 483 nm; the fluorescence quantum yield of the fluorescent dye in toluene solution is 0.435; and the fluorescence quantum yield of the fluorescent dye solid powder is 0.341.

[0107] Example 2

[0108] A two-state fluorescent dye, PQ, has the following molecular structure: The preparation method is as follows:

[0109]

[0110] (1) 0.4 g of compound 1a and 2 ml of POCl3 were added to a three-necked flask, heated to 105 °C under nitrogen atmosphere, refluxed for 3 hours, cooled to room temperature, and POCl3 was removed from the reaction flask by vacuum distillation to obtain wine-red intermediate compound 1b.

[0111] (2) 60 ml of anhydrous tetrahydrofuran was added to a three-necked flask containing intermediate compound 1b, followed by 0.555 g of compound 2c. The mixture was heated to 75 °C under a nitrogen atmosphere and refluxed for 12 hours. The reaction was quenched with 1 ml of deionized water and cooled to room temperature. The tetrahydrofuran solvent was removed using a rotary evaporator, and 100 ml of methanol was added to precipitate the product. The mixture was filtered to obtain a solid crude product. The crude product was further dissolved in 70 ml of dichloromethane, and 70 ml of n-hexane was slowly added until a large amount of purple byproduct crystals precipitated. The mixture was filtered to obtain a further purified crude PQ product. The crude PQ product was dissolved in 30 ml of a hot tetrahydrofuran solution and slowly cooled to room temperature. A large amount of bright yellow PQ crystals precipitated, totaling 0.282 g, with a yield of 51%.

[0112] The fluorescent dye PQ provided in this embodiment was tested using the following method:

[0113] I. Structural Characterization of Target Product PQ

[0114] Structural characterization, including 1H NMR, 1C NMR, high-resolution mass spectrometry, and single-crystal X-ray diffraction analysis, confirmed the feasibility of the synthetic route and the correct target compound. The results are as follows:

[0115] The 1H NMR spectrum of PQ is as follows: Figure 9 As shown, the 1H NMR data are: 1 H NMR (400MHz, CDCl3) δ (ppm) = 11.42 (d, 1H), 9.83 (s, 1H), 8.42 (d, 2H), 8.33 (d, 1H), 8.07 (t,1H),7.97(t,1H),7.68(d,2H),7.67(d,2H),7.60(d,2H),1.45(s,9H),1.40(s,9H).

[0116] The carbon NMR spectrum of PQ is as follows: Figure 10 As shown, the carbon NMR data are: 13 C NMR (400MHz, CDCl3) δ (ppm) = 163.74, 154.47, 154.34, 147.13, 147.04, 146.07, 139.31, 131.76, 130.89, 130.82, 130.63, 130.35, 12 9.58,128.88,128.73,128.46,127.56,126.04,125.63,124.11,116.17,114.73,98.70,84.27,35.11,35.05,31.30,31.20,29.72.

[0117] PQ's high-resolution mass spectrometry, such as Figure 11 As shown, the high-resolution mass spectrometry data are: theoretical molecular precursor ion mass [M] + m / z = 533.2579; Detection data: [M] + m / z = 533.2613.

[0118] The single-crystal X-ray diffraction analysis results of PQ are as follows: Figure 12 As shown, we can see that we have accurately obtained the fluorescent dye PQ.

[0119] II. Ultraviolet-Vis absorption spectroscopy, fluorescence spectroscopy, and fluorescence quantum yield measurement

[0120] The photophysical properties of the fluorescent dye PQ provided in this embodiment were tested using a UV-Vis spectrophotometer (UV-3700, Shimadzu), a fluorescence spectrometer (FLS-1000, Edinburgh), and a UV-NIR absolute fluorescence quantum yield meter (C13534-31, Hamamatsu). The UV-Vis absorption spectra in different solvents were obtained as follows: Figure 13 As shown, from Figure 13 It can be seen that the fluorescent dye PQ has an ultraviolet absorption peak at around 435 nm; the fluorescence spectra obtained in different solvents are as follows: Figure 14 As shown, from Figure 14 It can be seen that the fluorescent dye PQ has a fluorescence emission peak at around 530 nm; the fluorescence spectrum of the obtained solid powder is as follows. Figure 15 As shown, from Figure 15 It can be seen that the fluorescent dye PQ solid powder has a fluorescence emission peak at around 546 nm; the fluorescence quantum yield of the fluorescent dye in toluene solution is 0.356; and the fluorescence quantum yield of the fluorescent dye solid powder is 0.221.

[0121] Example 3

[0122] A two-state fluorescent dye PO, with the following molecular structure: The preparation method is as follows:

[0123]

[0124] (1) 0.4 g of compound 1a and 2 ml of POCl3 were added to a three-necked flask, heated to 105 °C under nitrogen atmosphere, refluxed for 3 hours, cooled to room temperature, and POCl3 was removed from the reaction flask by vacuum distillation to obtain wine-red intermediate compound 1b.

[0125] (2) Add 60 ml of anhydrous tetrahydrofuran to a three-necked flask containing intermediate compound 1b, then add 0.528 g of compound 3c. Under a nitrogen atmosphere, heat to 75 °C, reflux for 24 hours, quench the reaction with 1 ml of deionized water, and cool to room temperature. Remove the tetrahydrofuran solvent using a rotary evaporator and add 100 ml of methanol to precipitate the product. Filter to obtain a solid crude product. Further dissolve the crude product in 60 ml of dichloromethane, slowly add 60 ml of n-hexane until a large amount of purple byproduct crystals precipitate. Filter to obtain a further purified crude PO product. Dissolve the crude PO product in 25 ml of hot tetrahydrofuran solution and slowly cool to room temperature. A large amount of yellow-green PO crystals precipitate, totaling 0.188 g, with a yield of 36%.

[0126] The fluorescent dye PO provided in this embodiment was tested using the following method:

[0127] I. Structural characterization of the target product PO

[0128] Structural characterization included 1H NMR, 1C NMR, and high-resolution mass spectrometry, confirming the feasibility of the synthetic route and the correct target compound. The results are as follows:

[0129] The 1H NMR spectrum of PO is as follows Figure 16 As shown, the 1H NMR data are: 1 H NMR (400MHz, CDCl3) δ (ppm) = 9.06 (d, 1H), 8.34 (d, 2H), 7.86 (d, 1H), 7.80 (m, 2H), 7.68 (d, 2H), 7.67 (d, 2H), 7.55 (d, 2H), 1.43 (s, 9H), 1.38 (s, 9H).

[0130] The carbon NMR spectrum of PO is as follows Figure 17 As shown, the carbon NMR data are: 13C NMR (400MHz, CD2Cl4) δ (ppm) = 163.13, 154.76, 153.89, 151.58, 148.02, 147.54, 142.67, 131.41, 129.76, 129.13, 128.23, 12 7.25,126.08,125.96,125.71,123.28,120.73,118.28,117.62,113.28,112.27,82.97,80.89,35.15,34.98,31.40,31.36.

[0131] High-resolution mass spectrometry of PO, such as Figure 18 As shown, the high-resolution mass spectrometry data are: theoretical molecular precursor ion mass [M] + m / z = 522.2420; Detection data: [M] + m / z = 522.2437.

[0132] II. Ultraviolet-Vis absorption spectroscopy, fluorescence spectroscopy, and fluorescence quantum yield measurement

[0133] The photophysical properties of the fluorescent dye PO provided in this embodiment were tested using a UV-Vis spectrophotometer (UV-3700, Shimadzu), a fluorescence spectrometer (FLS-1000, Edinburgh), and a UV-NIR absolute fluorescence quantum yield meter (C13534-31, Hamamatsu). The UV-Vis absorption spectra in different solvents were obtained as follows: Figure 19 As shown, from Figure 19 It can be seen that the fluorescent dye PO has an ultraviolet absorption peak at around 396 nm; the fluorescence spectra obtained in different solvents are as follows: Figure 20 As shown, from Figure 20 It can be seen that the fluorescent dye PO has a fluorescence emission peak at around 514 nm; the fluorescence spectrum of the obtained solid powder is as follows. Figure 21 As shown, from Figure 21 It can be seen that the fluorescent dye PO solid powder has a fluorescence emission peak at around 519 nm; the fluorescence quantum yield of the fluorescent dye in toluene solution is 0.634; and the fluorescence quantum yield of the fluorescent dye solid powder is 0.682.

[0134] Example 4

[0135] A two-state fluorescent dye, PS, has the following molecular structure: The preparation method is as follows:

[0136]

[0137] (1) 0.4 g of compound 1a and 2 ml of POCl3 were added to a three-necked flask, heated to 105 °C under nitrogen atmosphere, refluxed for 3 hours, cooled to room temperature, and POCl3 was removed from the reaction flask by vacuum distillation to obtain wine-red intermediate compound 1b.

[0138] (2) 60 ml of anhydrous tetrahydrofuran was added to a three-necked flask containing intermediate compound 1b, followed by 0.576 g of compound 4c. The mixture was heated to 75 °C under a nitrogen atmosphere and refluxed for 24 hours. The reaction was quenched with 1 ml of deionized water and cooled to room temperature. The tetrahydrofuran solvent was removed using a rotary evaporator, and 100 ml of methanol was added to precipitate the product. The mixture was filtered to obtain a solid crude product. The crude product was further dissolved in 60 ml of dichloromethane, and 60 ml of n-hexane was slowly added until a large amount of purple byproduct crystals precipitated. The mixture was filtered to obtain a further purified crude PS product. The crude PS product was dissolved in 25 ml of a hot tetrahydrofuran solution and slowly cooled to room temperature. A large amount of yellow-green PS crystals precipitated, totaling 0.382 g, with a yield of 71%.

[0139] The fluorescent dye PS provided in this embodiment was tested using the following method:

[0140] I. Structural Characterization of the Target Product PS

[0141] Structural characterization included 1H NMR, 1C NMR, and high-resolution mass spectrometry, confirming the feasibility of the synthetic route and the correct target compound. The results are as follows:

[0142] PS's 1H NMR spectrum is as follows Figure 22 As shown, the 1H NMR data are: 1 H NMR (400MHz, CDCl3) δ (ppm) = 10.14 (d, 1H), 8.41 (d, 2H), 8.01 (d, 1H), 7.89 (t, 1H), 7.78 (t, 1H), 7.67 (t, 4H), 7.57 (d, 2H), 1.43 (s, 9H), 1.39 (s, 9H).

[0143] PS's carbon NMR spectrum is as follows Figure 23 As shown, the carbon NMR data are: 13 C NMR (400MHz, CDCl3) δ (ppm) = 161.49, 154.36, 153.30, 147.40, 146.89, 146.44, 137.83, 131.46, 12 9.64,129.09,128.82,128.40,128.13,126.68,125.81,125.60,125.30,122.52,121.98,117.11,

[0144] High-resolution mass spectrometry of PS, such as Figure 24 As shown, the high-resolution mass spectrometry data are: theoretical molecular precursor ion mass [M] + m / z = 538.2191; Detection data: [M] + m / z = 538.2191.

[0145] II. Ultraviolet-Vis absorption spectroscopy, fluorescence spectroscopy, and fluorescence quantum yield measurement

[0146] The photophysical properties of the fluorescent dye PS provided in this embodiment were tested using a UV-Vis spectrophotometer (UV-3700, Shimadzu), a fluorescence spectrometer (FLS-1000, Edinburgh), and a UV-NIR absolute fluorescence quantum yield meter (C13534-31, Hamamatsu). The UV-Vis absorption spectra in different solvents were obtained as follows: Figure 25 As shown, from Figure 25 It can be seen that the fluorescent dye PS has an ultraviolet absorption peak at around 416 nm; the fluorescence spectra obtained in different solvents are as follows: Figure 26 As shown, from Figure 26 It can be seen that the fluorescent dye PS has a fluorescence emission peak at around 512 nm; the fluorescence spectrum of the obtained solid powder is as follows. Figure 27 As shown, from Figure 27 It can be seen that the fluorescent dye PS solid powder has a fluorescence emission peak at around 522 nm; the fluorescence quantum yield of the fluorescent dye in toluene solution is 0.667; and the fluorescence quantum yield of the fluorescent dye solid powder is 0.476.

[0147] Example 5

[0148] A two-state fluorescent dye, PD4Br, has the following molecular structure: The preparation method is as follows:

[0149]

[0150] (1) 0.4 g of compound 1a and 2 ml of POCl3 were added to a three-necked flask, heated to 105 °C under nitrogen atmosphere, refluxed for 3 hours, cooled to room temperature, and POCl3 was removed from the reaction flask by vacuum distillation to obtain wine-red intermediate compound 1b.

[0151] (2) 60 ml of anhydrous tetrahydrofuran was added to a three-necked flask containing intermediate compound 1b, followed by 0.633 g of compound 5c. The mixture was heated to 75 °C under a nitrogen atmosphere and refluxed for 36 hours. The reaction was quenched with 1 ml of deionized water and cooled to room temperature. The tetrahydrofuran solvent was removed using a rotary evaporator, and 100 ml of methanol was added to precipitate the product. The mixture was filtered to obtain a solid crude product. The crude product was further dissolved in 60 ml of dichloromethane, and 60 ml of n-hexane was slowly added until a large amount of purple byproduct crystals precipitated. The mixture was filtered to obtain a further purified crude PD4Br product. The crude PD4Br product was dissolved in 25 ml of hot tetrahydrofuran solution and slowly cooled to room temperature. A large amount of light green PD4Br crystals precipitated, totaling 0.157 g, with a yield of 28%.

[0152] The fluorescent dye PD4Br provided in this embodiment was tested using the following method:

[0153] I. Structural characterization of the target product PD4Br

[0154] Structural characterization included 1H NMR, 1C NMR, and high-resolution mass spectrometry, confirming the feasibility of the synthetic route and the correct target compound. The results are as follows:

[0155] The 1H NMR spectrum of PD4Br is shown below. Figure 28 As shown, the 1H NMR data are: 1 H NMR (400MHz, CDCl3) δ (ppm) = 10.64 (s, 1H), 8.53 (d, 1H), 8.29 (d, 2H), 7.77 (d, 1H), 7.68 (d, 2H), 7.66 (d, 2H), 7.55 (d, 2H), 1.43 (s, 9H), 1.36 (s, 9H).

[0156] The carbon NMR spectrum of PD4Br is as follows: Figure 29 As shown, the carbon NMR data are: 13 C NMR (400MHz, CD2Cl4) δ (ppm) = 160.71, 154.57, 153.44, 149.21, 142.86, 140.31, 137.91, 131.36, 130.06, 129.60, 12 9.55,128.03,125.96,125.65,123.04,122.73,121.72,117.46,116.00,93.95,84.37,35.13,34.94,31.41,31.35.

[0157] High-resolution mass spectrometry of PD4Br, such as Figure 30 As shown, the high-resolution mass spectrometry data are: theoretical molecular precursor ion mass [M] +m / z = 560.1576; Detection data: [M] + m / z = 560.1566.

[0158] II. Ultraviolet-Vis absorption spectroscopy, fluorescence spectroscopy, and fluorescence quantum yield measurement

[0159] The photophysical properties of the fluorescent dye PD4Br provided in this embodiment were tested using a UV-Vis spectrophotometer (UV-3700, Shimadzu), a fluorescence spectrometer (FLS-1000, Edinburgh), and a UV-NIR absolute fluorescence quantum yield meter (C13534-31, Hamamatsu). The UV-Vis absorption spectra in different solvents were obtained as follows: Figure 31 As shown, from Figure 31 It can be seen that the fluorescent dye PD4Br has an ultraviolet absorption peak at around 430 nm; the fluorescence spectra obtained in different solvents are as follows: Figure 32 As shown, from Figure 32 It can be seen that the fluorescent dye PD4Br has a fluorescence emission peak at around 486 nm; the fluorescence spectrum of the obtained solid powder is as follows. Figure 33 As shown, from Figure 33 It can be seen that the fluorescent dye PD4Br solid powder has a fluorescence emission peak at around 511 nm; the fluorescence quantum yield of the fluorescent dye in toluene solution is 0.201; and the fluorescence quantum yield of the fluorescent dye solid powder is 0.109.

[0160] Example 6

[0161] A two-state fluorescent dye, PD5Cl, has the following molecular structure: The preparation method is as follows:

[0162]

[0163] (1) 0.4 g of compound 1a and 2 ml of POCl3 were added to a three-necked flask, heated to 105 °C under nitrogen atmosphere, refluxed for 3 hours, cooled to room temperature, and POCl3 was removed from the reaction flask by vacuum distillation to obtain wine-red intermediate compound 1b.

[0164] (2) 60 ml of anhydrous tetrahydrofuran was added to a three-necked flask containing intermediate compound 1b, followed by 0.504 g of compound 6c. The mixture was heated to 75 °C under a nitrogen atmosphere and refluxed for 48 hours. The reaction was quenched with 1 ml of deionized water and cooled to room temperature. The tetrahydrofuran solvent was removed using a rotary evaporator, and 100 ml of methanol was added to precipitate the product. The mixture was filtered to obtain a solid crude product. The crude product was further dissolved in 60 ml of dichloromethane, and 60 ml of n-hexane was slowly added until a large amount of purple byproduct crystals precipitated. The mixture was filtered to obtain a further purified crude PD5Cl product. The crude PD5Cl product was dissolved in 25 ml of hot tetrahydrofuran solution and slowly cooled to room temperature. A large amount of light green PD5Cl crystals precipitated, totaling 0.108 g, with a yield of 21%.

[0165] The fluorescent dye PD5Cl provided in this embodiment was tested using the following method:

[0166] I. Structural characterization of the target product PD5Cl

[0167] Structural characterization included 1H NMR, 1C NMR, and high-resolution mass spectrometry, confirming the feasibility of the synthetic route and the correct target compound. The results are as follows:

[0168] The 1H NMR spectrum of PD5Cl is shown below. Figure 34 As shown, the 1H NMR data are: 1 H NMR (400MHz, CDCl3) δ (ppm) = 10.24 (s, 1H), 8.36 (d, 1H), 8.30 (d, 2H), 7.97 (d, 1H), 7.66 (s, 4H), 7.54 (d, 2H), 1.43 (s, 9H), 1.37 (s, 9H).

[0169] The carbon NMR spectrum of PD5Cl is as follows: Figure 35 As shown, the carbon NMR data are: 13 C NMR (400MHz, C2D2Cl4) δ (ppm) = 161.12, 154.52, 153.52, 148.40, 142.17, 135.91, 135.56, 131.39, 129.62, 129.53, 1 29.04,128.14,125.99,125.63,125.11,123.40,117.39,116.23,115.98,95.16,84.53,35.12,34.95,31.41,31.35.

[0170] High-resolution mass spectrometry of PD5Cl, such as Figure 36 As shown, the high-resolution mass spectrometry data are: theoretical molecular precursor ion mass [M] + m / z = 516.2081; Detection data: [M]+ m / z = 516.2.

[0171] II. Ultraviolet-Vis absorption spectroscopy, fluorescence spectroscopy, and fluorescence quantum yield measurement

[0172] The photophysical properties of the fluorescent dye PD5Cl provided in this embodiment were tested using a UV-Vis spectrophotometer (UV-3700, Shimadzu), a fluorescence spectrometer (FLS-1000, Edinburgh), and a UV-NIR absolute fluorescence quantum yield meter (C13534-31, Hamamatsu). The UV-Vis absorption spectra in different solvents were obtained as follows: Figure 37 As shown, from Figure 37 It can be seen that the fluorescent dye PD5Cl has an ultraviolet absorption peak at around 432 nm; the fluorescence spectra obtained in different solvents are as follows: Figure 38 As shown, from Figure 38 It can be seen that the fluorescent dye PD5Cl has a fluorescence emission peak at around 490 nm; the fluorescence spectrum of the obtained solid powder is as follows. Figure 39 As shown, from Figure 39 It can be seen that the fluorescent dye PD5Cl solid powder has a fluorescence emission peak at around 490 nm; the fluorescence quantum yield of the fluorescent dye in toluene solution is 0.015; and the fluorescence quantum yield of the fluorescent dye solid powder is 0.013.

[0173] Example 7

[0174] The molecular structure of a two-state fluorescent dye PD4A is as follows: The preparation method is as follows:

[0175]

[0176] (1) 0.4 g of compound 1a and 2 ml of POCl3 were added to a three-necked flask, heated to 105 °C under nitrogen atmosphere, refluxed for 3 hours, cooled to room temperature, and POCl3 was removed from the reaction flask by vacuum distillation to obtain wine-red intermediate compound 1b.

[0177] (2) Add 60 ml of anhydrous toluene to a three-necked flask containing intermediate compound 1b, then add 1.508 g of compound 7c. Under a nitrogen atmosphere, heat to 110 °C, reflux for 48 hours, quench the reaction with 1 ml of deionized water, and cool to room temperature. Remove the toluene solvent using a rotary evaporator and add 100 ml of methanol to precipitate the product. Filter to obtain a solid crude product. Further dissolve the crude product in 100 ml of chloroform, slowly add 150 ml of n-hexane until a large amount of purple byproduct crystals precipitate. Filter to obtain a further purified crude PD4A product. Dissolve the crude PD4A product in 30 ml of hot chloroform solution and slowly cool to room temperature. A large amount of orange-red PD4A powder precipitates, totaling 0.160 g, with a yield of 22%.

[0178] The fluorescent dye PD4A provided in this embodiment was tested using the following method:

[0179] I. Structural characterization of the target product PD4A

[0180] Structural characterization included 1H NMR, 1C NMR, and high-resolution mass spectrometry, confirming the feasibility of the synthetic route and the correct target compound. The results are as follows:

[0181] The 1H NMR spectrum of PD4A is shown below. Figure 40 As shown, the 1H NMR data are: 1 H NMR (400MHz, CDCl3) δ (ppm) = 8.55 (s, 1H), 8.29 (d, 2H), 7.99 (s, 2H), 7.72 (d, 2H), 7.66 (s, 4H) ,7.52(d,2H),7.36(t,4H),7.21(d,2H),7.19(d,4H),7.17(t,2H),1.43(s,9H),1.36(s,9H).

[0182] The carbon NMR spectrum of PD4A is as follows: Figure 41 As shown, the carbon NMR data are: 13 C NMR (400MHz, C2D2Cl4) δ (ppm) = 159.92, 154.21, 152.95, 150.70, 149.13, 146.43, 144.84, 142.99, 140.11, 138.60, 131.95, 129.85, 129.57 ,128.36,127.96,125.91,125.55,124.79,121.59,118.76,109.58,9 7.04,94.75,83.75,35.09,34.90,31.44,31.38,29.86,23.98,14.41.

[0183] High-resolution mass spectrometry of PD4A, such as Figure 42 As shown, the high-resolution mass spectrometry data are: theoretical molecular precursor ion mass [M] + m / z = 725.3518; Detection data: [M] + m / z = 725.3483.

[0184] II. Ultraviolet-Vis absorption spectroscopy, fluorescence spectroscopy, and fluorescence quantum yield measurement

[0185] The photophysical properties of the fluorescent dye PD4A provided in this embodiment were tested using a UV-Vis spectrophotometer (UV-3700, Shimadzu), a fluorescence spectrometer (FLS-1000, Edinburgh), and a UV-NIR absolute fluorescence quantum yield meter (C13534-31, Hamamatsu). The UV-Vis absorption spectra in different solvents were obtained as follows: Figure 43 As shown, from Figure 43 It can be seen that the fluorescent dye PD4A has an ultraviolet absorption peak at around 465 nm; the fluorescence spectra obtained in different solvents are as follows: Figure 44 As shown, from Figure 44 It can be seen that the fluorescent dye PD4A has a fluorescence emission peak around 500-600 nm; the fluorescence spectrum of the obtained solid powder is as follows. Figure 45 As shown, from Figure 45 It can be seen that the fluorescent dye PD4A solid powder has a fluorescence emission peak at around 590 nm; the fluorescence quantum yield of the fluorescent dye in toluene solution is 0.820; and the fluorescence quantum yield of the fluorescent dye solid powder is 0.318.

[0186] Example 8

[0187] A dual-state fluorescent dye, TPS, has the following molecular structure: The preparation method is as follows:

[0188]

[0189] (1) 0.88 g of compound 2a (purchased from TCI (Shanghai) Chemical Industry Development Co., Ltd.) and 5 ml of POCl3 were added to a three-necked flask. The mixture was heated to 105 °C under nitrogen atmosphere and refluxed for 5 hours. After cooling to room temperature, POCl3 was removed from the reaction flask by vacuum distillation to obtain the wine-red intermediate compound 2b.

[0190] (2) 60 ml of anhydrous tetrahydrofuran was added to a three-necked flask containing intermediate compound 2b, followed by 0.768 g of compound 4c. The mixture was heated to 110 °C under a nitrogen atmosphere and refluxed for 48 hours. The reaction was quenched with 1 ml of deionized water and cooled to room temperature. The tetrahydrofuran solvent was removed using a rotary evaporator, and 100 ml of methanol was added to precipitate the product. The mixture was filtered to obtain a crude solid product. The crude product was further purified by column chromatography using hexane:ethyl acetate as the eluent (v / v), yielding 0.307 g of a pale yellow solid, TPS, with a yield of 31%.

[0191] The fluorescent dye TPS provided in this embodiment was tested using the following method:

[0192] I. Structural Characterization of the Target Product TPS

[0193] Structural characterization included 1H NMR, 1C NMR, and high-resolution mass spectrometry, confirming the feasibility of the synthetic route and the correct target compound. The results are as follows:

[0194] The TPS 1H NMR spectrum is as follows Figure 46 As shown, the 1H NMR data are: 1 H NMR (400MHz, CDCl3) δ (ppm) = 10.09 (d, 1H), 8.41 (d, 2H), 7.98 (d, 1H), 7.87 (t, 1H), 7.76 (t, 1H) ,7.68(d,2H),7.15(d,2H),7.06(d,2H),3.94(m,4H),1.83(m,2H),1.28(m,64H),0.88(m,12H).

[0195] TPS carbon NMR spectrum as shown Figure 47 As shown, the carbon NMR data are: 13 C NMR (400MHz, CDCl3) δ (ppm) = 161.70, 161.12, 160.98, 147.16, 146.91, 145.54, 137.72, 1 31.58,129.77,128.65,128.26,126.61,126.56,125.14,123.85,122.45,121.78,117.6 2,115.70,114.75,114.58,92.57,81.79,71.13,38.05,37.96,31.95,31.42,31.38,30.10,30.07,29.75,29.70,29.68,29.65,29.64,29.40,29.38,26.96,26.89,22.72,14.15.

[0196] High-resolution mass spectrometry of TPS, such as Figure 48 As shown, the high-resolution mass spectrometry data are: theoretical molecular precursor ion mass [M] + m / z = 1018.7097; Detection data: [M] + m / z = 1018.7.

[0197] II. Ultraviolet-Vis absorption spectroscopy, fluorescence spectroscopy, and fluorescence quantum yield measurement

[0198] The photophysical properties of the fluorescent dye TPS provided in this embodiment were tested using a UV-Vis spectrophotometer (UV-3700, Shimadzu), a fluorescence spectrometer (FLS-1000, Edinburgh), and a UV-NIR absolute fluorescence quantum yield meter (C13534-31, Hamamatsu). The UV-Vis absorption spectra in different solvents were obtained as follows: Figure 49 As shown, from Figure 49 It can be seen that the fluorescent dye TPS has an ultraviolet absorption peak at around 413 nm; the fluorescence spectra obtained in different solvents are as follows: Figure 50 As shown, from Figure 50 It can be seen that the fluorescent dye TPS has a fluorescence emission peak at around 504 nm; the fluorescence spectrum of the obtained solid powder is as follows. Figure 51 As shown, from Figure 51 It can be seen that the fluorescent dye TPS solid powder has a fluorescence emission peak at around 510 nm; the fluorescence quantum yield of the fluorescent dye in toluene solution is 0.875; and the fluorescence quantum yield of the fluorescent dye solid powder is 0.537.

[0199] The embodiments described above are merely illustrative of several implementations of the present invention, and while the descriptions are specific and detailed, they should not be construed as limiting the scope of the patent application. It should be noted that those skilled in the art can make various modifications and improvements without departing from the concept of the present invention, and these all fall within the scope of protection of the present invention. Therefore, the scope of protection of this patent should be determined by the appended claims.

Claims

1. A dual-state emitting pyrrolopyridine dinitrile dye, characterized in that, The general structural formula of the dual-state emitting pyrrolopyridinedionitrile dye is shown below: Formula I Among them, R1, R2, and R3 are each independently selected from H, halogens, and C1-C. 20 Straight-chain or branched alkyl groups, C1-C 20 One of straight-chain or branched alkoxy groups; Ar can be one of the following structures: 、 、 、 ； Among them, R4-R7 are each independently selected from H, halogens, C1-C 20 Straight-chain or branched alkyl groups, C1-C 20 One of straight-chain or branched alkoxy groups.

2. The dual-state emitting pyrrolopyridinedinitrile dye according to claim 1, characterized in that, The halogen is selected from one of F, Cl, Br, and I.

3. The dual-state emitting pyrrolopyridine dinitrile dye according to claim 1, characterized in that, The dual-state emitting pyrrolopyridinedionitrile dye has one of the following structures: Formula II Formula III Formula IV Formula V; R2 is selected from H, halogens, C1-C 20 Straight-chain or branched alkyl groups, C1-C 20 One of straight-chain or branched alkoxy groups; the halogen is selected from one of F, Cl, Br, and I; R4-R7 are each independently selected from H, halogens, C1-C. 20 Straight-chain or branched alkyl groups, C1-C 20 One of straight-chain or branched alkoxy groups.

4. The dual-state emitting pyrrolopyridinium dinitrile dye according to claim 3, characterized in that, The dual-state emitting pyrrolopyridinedionitrile dye has one of the following structures: 、 、 、 、 、 、 。 5. The dual-state emitting pyrrolopyridine dinitrile dye according to claim 1, characterized in that, The UV-Vis absorption peak of the dual-state emission pyrrolopyridine dinitrile dye is 380 nm to 500 nm; The fluorescence emission peak of the dual-state emission pyrrolopyridine dinitrile dye is 450 nm to 600 nm.

6. A method for preparing a dual-state emitting pyrrolopyridine dinitrile dye as described in any one of claims 1-5, characterized in that, Includes the following steps: ； (1) Compound Ia was mixed with POCl3 at a mass-to-volume ratio of 1:(2~20) (g:ml), and reacted at 80℃~120℃ for 1h~12h. POCl3 was removed by vacuum distillation to obtain compound Ib; (2) Compound Ib and compound Ic are added to a solvent at a molar ratio of 1:(0.5~8) and reacted at 50℃~150℃ for 1h~72h. After the reaction is completed, deionized water is added to quench the reaction, the solvent is removed by rotary evaporation, methanol is added to precipitate, and the crude product is obtained by filtration. The crude product is recrystallized, filtered, and dried to obtain compound I.

7. The preparation method according to claim 6, characterized in that, In step (1), the mass-to-volume ratio of compound Ia to POCl3 is 1:(4~8) (g:ml); the reaction temperature is 100℃~110℃; and the reaction time is 2h~6h.

8. The preparation method according to claim 6, characterized in that, In step (2), the solvent includes one or more of toluene, dioxane, chlorobenzene, tetrahydrofuran, and cyclohexane; The reaction temperature is 70℃~110℃; The reaction time is 6 hours to 24 hours. The molar ratio of compound Ib to compound Ic is 1:(2~4); The mass-to-volume ratio of compound Ib to solvent is 1:(50~500) (g:ml); The solvents used for recrystallization include one or both of dichloromethane and n-hexane.

9. The preparation method according to claim 8, characterized in that, In step (2), the mass-volume ratio of compound Ib to solvent is 1:(70~200).

10. A dual-state emitting pyrrolopyridine dinitrile dye, characterized in that, The structural formula is as follows: 。

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