Piezochromic organic light-emitting material as well as preparation method and application thereof

Abstract

The invention relates to the field of organic light-emitting materials, and mainly relates to a piezochromic organic light-emitting material and a preparation method and application thereof. A preparation method of the piezo-chromic organic light-emitting material comprises the following steps: synthesizing an intermediate; mixing the intermediate, 4-(diphenylamino) phenylboronic acid, tetrakis (triphenylphosphine) palladium, tetrabutylammonium bromide, alkali and a reaction solvent, and performing heating reaction to obtain a second mixture; and extracting, drying, concentrating and purifying the second mixture to obtain the piezochromic organic luminescent material. The piezochromic luminescent material disclosed by the invention has the characteristics of single force stimulation induction of multicolor change, piezoluminescence enhancement and crystalline phase-to-crystalline phase conversion function; the luminescent material also has the advantages of low raw material cost, simplicity and convenience in synthesis, wide application environment, multicolor reversible switching and high contrast ratio, is an excellent force stimulation response type luminescent material, and can be used for pressure detection, sensors, information storage devices, anti-counterfeiting materials, memory materials or biological probes.

Description

Technical Field

[0001] This application relates to the field of organic light-emitting materials, and mainly to a pressure-sensitive color-changing organic light-emitting material, its preparation method, and its application. Background Technology

[0002] Pyrochromic luminescence refers to the phenomenon where the color of light emitted by a luminescent material changes significantly under external stimuli such as force (e.g., grinding, pressure, scratching), heating, and solvent evaporation. Pyrochromic materials have broad application prospects in fields such as light-emitting devices, sensors, detection, data storage, and security.

[0003] In previous reports, a single stimulus to a sample typically induces only one type of luminescence change, while polychromatic changes generally require multiple different types of stimulus treatments. Most piezochromic luminescent compounds experience a decrease in fluorescence quantum yield (ΦPL) or luminescence quenching under external force, resulting in luminescence shutdown rather than luminescence conversion. Furthermore, most piezochromic reactions are attributed to the amorphization of molecular crystalline phases, i.e., the transformation from a crystalline phase to an amorphous state. However, piezochromic materials based on crystalline-to-crystalline phase transitions are still relatively limited. Compared to common crystalline-to-amorphous phase transitions, crystalline-to-crystalline phase transitions will provide a more intuitive understanding of the relationship between the luminescence properties of luminescent materials and their molecular packing arrangement, conformation, and intermolecular interactions.

[0004] Therefore, existing technologies still need to be improved and developed. Summary of the Invention

[0005] In view of the shortcomings of the prior art, the purpose of this application is to provide a pressure-sensitive organic light-emitting material, its preparation method and application, with the aim of obtaining a multicolor light-emitting material that responds to mechanical stimuli of different intensities.

[0006] The piezochromic organic light-emitting material of this application is a small-molecule organic light-emitting material that also possesses piezoluminescence enhancement properties and a crystal phase-to-crystal phase transition function. This type of piezochromic light-emitting compound, which achieves gradual color switching based on a mechanical stimulus, will be suitable for more precise mechanical pressure detection applications.

[0007] The technical solution of this application is as follows: A pressure-sensitive organic light-emitting material, with the structural formula shown in Formula I: .

[0008] Furthermore, pressure-sensitive organic light-emitting materials exhibit two or more light-emitting changes under external force stimulation.

[0009] This application also provides a method for preparing a piezochromic organic light-emitting material, comprising the following steps: Synthetic intermediate 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine; The 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine, 4-(diphenylamino)phenylboronic acid, tetra(triphenylphosphine)palladium, tetrabutylammonium bromide, base, and reaction solvent are mixed and heated to react, yielding a second mixture. The second mixture was extracted, dried, concentrated, and purified to obtain the pressure-sensitive organic light-emitting material.

[0010] Furthermore, the reaction solvent is toluene, and the base is potassium carbonate.

[0011] Furthermore, the molar ratio of the 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine, the 4-(diphenylamino)phenylboronic acid, the tetra(triphenylphosphine)palladium, and the tetrabutylammonium bromide is 1:2-6:0.005-0.1:0.005-0.1; The mixture of 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine, 4-(diphenylamino)phenylboronic acid, the base, the tetra(triphenylphosphine)palladium, tetrabutylammonium bromide, and the reaction solvent is heated under reflux for 8-18 hours.

[0012] Furthermore, the molar ratio of the 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine to the potassium carbonate is 1:8-20; The potassium carbonate is mixed with water to obtain a potassium carbonate solution; The concentration of the potassium carbonate solution is 1M-2M.

[0013] The volume ratio of the potassium carbonate solution to the toluene is 1:2 to 1:4.

[0014] Furthermore, the synthesis of the 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine includes the following steps: An alcohol solvent, acenaphthene[1,2-b]dione, and 2,5-dibromopyridine-3,4-diamine are mixed to obtain a first mixture; The first mixture is mixed with acetic acid or aminosulfonic acid, heated to react, and filtered to obtain the 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine.

[0015] Furthermore, the molar ratio of the acenaphthene[1,2-b]dione and the 2,5-dibromopyridine-3,4-diamine is 1:1 to 1:1.5.

[0016] Furthermore, the yield of the piezochromic organic light-emitting material is 75-90%; The yield of the 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine was 75-95%.

[0017] Furthermore, the alcohol solvent includes one or a mixture of two or more of methanol and ethanol; When the first mixture is mixed with the acetic acid or aminosulfonic acid, it is heated under reflux for 6-12 hours.

[0018] This application also provides an application of a pressure-sensitive organic light-emitting material in the fields of pressure detection, sensors, information storage devices, anti-counterfeiting materials, memory materials, and biological probes.

[0019] The piezochromic organic light-emitting material provided in this application is driven by a single force stimulus and can achieve continuous multicolor transitions from yellow to orange and then to red, etc. Its essential mechanism originates from the reversible phase-to-phase transition. This piezochromic organic light-emitting material exhibits significant piezoluminescence enhancement characteristics, with luminous efficiency increasing dramatically from 40% to over 60%, significantly enhancing signal intensity and contrast. Simultaneously, its multicolor changes are highly reversible; it can be restored to orange by heating or solvent fumigation, and samples in each state can completely revert to their original color after simple treatment (such as ultrasonic treatment with methanol), supporting multicolor cyclic switching.

[0020] From a comprehensive perspective, pressure-sensitive organic light-emitting materials have the advantages of low raw material cost, simple synthesis, strong environmental adaptability, and high multicolor contrast, breaking through the technical limitations of traditional multi-stimulus synergy to achieve multicolor changes.

[0021] At the application level, as a force-stimulated fluorescent switch material, it can be widely used in pressure detection (visualization of mechanical stress), sensors (force-light signal conversion), information storage (multi-color encoding storage), anti-counterfeiting materials (reversible color-changing verification), memory materials (state programmable) and other fields, showing significant application potential and technological innovation value in smart materials, sensing, anti-counterfeiting and other directions.

[0022] Compared with the prior art, this application has the following beneficial effects: 1. The pressure-sensitive organic light-emitting material of this application has pressure-sensitive light-emitting enhancement characteristics and crystal phase to crystal phase conversion function. It can achieve gradual switching of light emission color type based on a mechanical stimulus, and is suitable for more precise mechanical pressure detection and other applications.

[0023] 2. The pressure-sensitive color-changing luminescent material of this application has the advantages of low raw material cost, simple synthesis, wide application environment, multi-color reversible switching, and high contrast. Attached Figure Description

[0024] Figure 1 The diagram shows the results of each stage of the pressure-sensitive organic light-emitting material test in Example 1 of this application.

[0025] Figure 2 The images show the spectra of the pressure-sensitive organic light-emitting material in Example 1 of this application at various stages of the pressure-sensitive test.

[0026] Figure 3 This is an X-ray diffraction pattern of the piezochromic organic light-emitting material of Example 1 of this application at each stage of the piezochromic test. Detailed Implementation

[0027] This application provides a piezochromic organic light-emitting material, its preparation method, and its application. To make the objectives, technical solutions, and effects of this application clearer and more explicit, the following provides a more detailed description. It should be understood that the specific embodiments described herein are merely illustrative and not intended to limit the scope of this application.

[0028] Regarding raw materials, this application does not impose any particular restrictions on the source of the raw materials used in the following embodiments. They can be commercially available products or prepared using methods well known to those skilled in the art.

[0029] This application provides a piezochromic organic light-emitting material with the structural formula shown in Formula I: .

[0030] This application also provides a method for preparing a piezochromic organic light-emitting material, comprising the following steps: Step 1: Synthesis of the intermediate (8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine): An alcohol solvent was added to a mixture of acenaphthene[1,2-b]dione and 2,5-dibromopyridine-3,4-diamine. A first mixture was obtained.

[0031] The molar ratio of acenaphthene[1,2-b]dione to 2,5-dibromopyridine-3,4-diamine is 1:1 to 1:1.5.

[0032] Acetic acid was added dropwise to the first mixture. After heating under reflux for 6-12 hours, the system was cooled to room temperature. The resulting solid was filtered off and then purified by column chromatography using a mixture of dichloromethane and petroleum ether (volume ratio 1:3) as eluent to give a pale yellow solid (yield: 75-95%), namely the intermediate 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine.

[0033] The alcohol solvent includes one or more of methanol and ethanol; preferably ethanol.

[0034] Ethanol can be used in excess, and there is no strict limit to the amount used. The volume of acetic acid should be 2% to 5% of that of ethanol.

[0035] Acetic acid can also be replaced by aminosulfonic acid; when using aminosulfonic acid, the molar ratio of aminosulfonic acid to acenaphthenic[1,2-b]dione is in the range of 5:1 to 10:1.

[0036] The CAS number for acenaphthene[1,2-b]dione is 82-86-0.

[0037] Step 2: Dissolve the intermediates 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine, 4-(diphenylamino)phenylboronic acid, tetra(triphenylphosphine)palladium (Pd(PPh3)4) and tetrabutylammonium bromide (TBAB) in toluene.

[0038] Then, potassium carbonate solution was added dropwise to toluene.

[0039] The above system was heated under reflux for 8-18 hours and then cooled to room temperature to obtain a second mixture.

[0040] Potassium carbonate solution is prepared by mixing potassium carbonate with water; the potassium carbonate solution is 1M-2M.

[0041] The intermediate 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine, 4-(diphenylamino)phenylboronic acid, tetra(triphenylphosphine)palladium (Pd(PPh3)4) and tetrabutylammonium bromide (TBAB) are in a molar ratio of 1:2-6:0.005-0.1:0.005-0.1.

[0042] The molar ratio of 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine to potassium carbonate is 1:8-20.

[0043] The volume ratio of potassium carbonate solution to toluene is 1:2 to 1:4.

[0044] The second mixture was extracted three times with dichloromethane. The organic layer was dried over anhydrous sodium sulfate, concentrated, and then purified by column chromatography using dichloromethane as the eluent to finally obtain the target product as an orange solid (yield: 75-90%).

[0045] The reaction formula for the preparation method of the above-mentioned pressure-sensitive organic light-emitting material is shown in Formula II: Formula II; This application also provides an application of a pressure-sensitive organic light-emitting material in pressure detection, sensors, information storage devices, anti-counterfeiting materials, memory materials, and biological probes.

[0046] Preferred application of pressure-sensitive organic light-emitting materials in force-stimulated fluorescent switch materials.

[0047] The present application will be further described below through specific embodiments.

[0048] Example 1 A pressure-sensitive organic light-emitting material, with the structural formula shown in Formula I: .

[0049] A method for preparing a piezochromic organic light-emitting material includes the following steps: Step 1: Synthesis of the intermediate (8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine): 200 mL of ethanol was added to a mixture of acenaphthene[1,2-b]dione (2.73 g, 15 mmol) and 2,5-dibromopyridine-3,4-diamine (4.81 g, 18 mmol). The first mixture was obtained.

[0050] Add 5 mL of acetic acid dropwise to the first mixture. After heating under reflux for 8 hours, cool the system to room temperature. Filter off the resulting solid and then purify it by column chromatography using a dichloromethane / petroleum ether (1:3) eluent to give a pale yellow solid (5.14 g, yield: 83%), namely the intermediate 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine.

[0051] Step 2: The intermediates 8,11-dibromoacenaphthene[1,2-b]pyrido[3,4-e]pyrazine (2.06 g, 5 mmol), 4-(diphenylamino)phenylboronic acid (4.34 g, 15 mmol), tetra(triphenylphosphine)palladium (Pd(PPh3)4) (0.29 g, 0.25 mmol), and tetrabutylammonium bromide (TBAB) (0.08 g, 0.25 mmol) were dissolved in 150 mL of toluene. 50 mL of 1.6 M potassium carbonate solution was added dropwise to the toluene. The system was heated under reflux for 12 hours and then cooled to room temperature. A second mixture was obtained.

[0052] The second mixture was extracted three times with dichloromethane. The organic layer was dried over anhydrous sodium sulfate, concentrated, and then purified by column chromatography using dichloromethane as the eluent to finally obtain the target product as an orange solid (2.96 g, yield: 83%).

[0053] Characterize the target product: Characterization of the target product includes proton NMR, carbon NMR, mass spectrometry, and elemental analysis, specifically: Proton NMR: 1 H NMR (500 MHz, CD2Cl2) δ 8.95 (s, 1H), 8.47 (t, J = 7.2 Hz, 2H), 8.36 (d, J= 8.2 Hz, 2H), 8.25 (dd, J = 11.2, 8.4 Hz, 2H), 7.96 – 7.86 (m,4H), 7.40 (td, J = 7.7, 4.2 Hz, 8H), 7.29 (dd, J = 13.1, 5.5 Hz, 12H), 7.16 (dd, J = 16.0, 8.6 Hz, 4H).

[0054] Carbon NMR: 13 C NMR (126 MHz, CDCl3) δ 158.05, 156.20, 153.76, 148.82,147.85, 147.68, 147.59, 146.09, 142.76, 137.42, 134.30, 132.55, 132.06,131.86, 131.53, 131.38, 130.36, 130.06, 129.81, 129.40, 129.36, 129.03,128.76, 128.69, 125.12, 125.00, 123.36, 123.28, 123.22, 122.72, 122.65, 122.30.

[0055] Theoretical value of mass spectrometry data: 741.71, measured value: 741.29.

[0056] Theoretical value of elemental analysis data: C 53 H 35 N5: C, 85.80; H, 4.76; N, 9.44; Measured values: C, 85.95; H, 4.86; N, 9.39.

[0057] The aforementioned pressure-sensitive organic light-emitting materials exhibit the property of changing colors in multiple colors under a single force stimulus, thus they can be used as force-stimulated fluorescent switch materials and applied in pressure detection, sensors, information storage devices, anti-counterfeiting materials, memory materials, biological probes, and other fields.

[0058] The solid of compound M1 (pressure-sensitive organic light-emitting material) prepared by synthesis was subjected to a grinding-stimulus-response luminescence test. The emission wavelength of the original solid of compound M1 before grinding and the emission wavelength after step-by-step grinding were tested.

[0059] Figure 1 The emission spectrum test results of each sample are shown in Table 1, which shows the results of the original sample being gradually ground from slightly ground to fully ground.

[0060] Figure 2 This is the spectrum corresponding to the pressure-induced color change test sample of the compound in the embodiments of this application.

[0061] Table 1

[0062] Reference Figure 1 It can be seen that before grinding, the solid compound M1 appears yellow under ultraviolet light (i.e., the figure corresponding to the original solid P). After grinding, the color changes from yellow to orange and finally to red. Furthermore, combined with the data in Table 1, it can be seen that the luminescence efficiency of the compound increases from 40% to over 60% after grinding, exhibiting grinding-enhanced luminescence properties.

[0063] The above experimental results show that compound M1 has a typical mechanochromic luminescence effect and can induce polychromatic changes under a single force stimulus.

[0064] After thoroughly grinding sample G4 was heated (to 200°C for 20 minutes) or fumigated in a dichloromethane solvent atmosphere, the sample color changed from red back to orange. However, when the samples from each grinding stage were added to methanol and subjected to ultrasonic treatment, the samples returned to their original yellow color. This indicates that the samples can interconvert after simple stimulation treatment.

[0065] Powder X-ray diffraction tests were performed on each sample, and the results are as follows: Figure 3 As shown. (Through) Figure 3 It can be seen that sample P, ground sample G2, and ground sample G4 belong to three different crystal phases, while ground samples G1 and G3 are intermediate between two crystal phases or a mixture of the two phases. Therefore, the grinding-induced color change of compound M1 is attributed to the phase-to-phase transformation.

[0066] It should be understood that the application of this application is not limited to the examples above. Those skilled in the art can make improvements or modifications based on the above description, and all such improvements and modifications should fall within the protection scope of this application.

Claims

1. A piezochromic organic light emitting material, characterized by, The structural formula is shown as Formula I: 。 2. The piezochromic organic light emitting material according to claim 1, characterized in that, Two or more luminescence changes are obtained under external force stimulation.

3. A method for producing the piezochromic organic light emitting material according to claim 1, characterized by, The method comprises the following steps: Synthesis of intermediate 8,11-dibromaceno[1,2-b]pyrido[3,4-e]pyrazine; The 8,11-dibromaceno[1,2-b]pyrido[3,4-e]pyrazine, 4-(diphenylamino)phenylboronic acid, tetrakis(triphenylphosphine)palladium, tetrabutylammonium bromide, a base, and a reaction solvent are mixed, and heated to react, to obtain a second mixture; The second mixture is subjected to extraction, drying, concentration, and purification to obtain the pressure-induced color change organic luminescent material.

4. The preparation method of the piezochromic organic light-emitting material according to claim 3, characterized in that, The reaction solvent is toluene, and the base is potassium carbonate.

5. The preparation method of the piezochromic organic light emitting material according to claim 3, characterized in that, The molar ratio of the 8,11-dibromaceno[1,2-b]pyrido[3,4-e]pyrazine, the 4-(diphenylamino)phenylboronic acid, the tetrakis(triphenylphosphine)palladium, and the tetrabutylammonium bromide is 1:2-6:0.005-0.1:0.005-0.

1. After the 8,11-dibromaceno[1,2-b]pyrido[3,4-e]pyrazine, the 4-(diphenylamino)phenylboronic acid, the base, the tetrakis(triphenylphosphine)palladium, the tetrabutylammonium bromide, and the reaction solvent are mixed, the mixture is heated to reflux for 8-18 hours.

6. The preparation method of the piezochromic organic light emitting material according to claim 4, characterized in that, The molar ratio of the 8,11-dibromaceno[1,2-b]pyrido[3,4-e]pyrazine to the potassium carbonate is 1:8-20. The potassium carbonate is mixed with water to obtain a potassium carbonate solution. The concentration of the potassium carbonate solution is 1M-2M. The volume ratio of the potassium carbonate solution to the toluene is 1:2-1:

4.

7. The preparation method of the piezochromic organic light emitting material according to claim 3, characterized in that, The synthesis of the 8,11-dibromaceno[1,2-b]pyrido[3,4-e]pyrazine comprises the following steps: An alcohol solvent, aceno[1,2-b]dione, and 2,5-dibromopyridine-3,4-diamine are mixed to obtain a first mixture; The first mixture is mixed with acetic acid or sulfamic acid, and heated to react, and the 8,11-dibromaceno[1,2-b]pyrido[3,4-e]pyrazine is obtained after filtration.

8. The preparation method of the piezochromic organic light emitting material according to claim 7, characterized in that, The molar ratio of the aceno[1,2-b]dione to the 2,5-dibromopyridine-3,4-diamine is 1:1-1:1.

5.

9. The preparation method of the piezochromic organic light emitting material according to claim 7, characterized in that, The alcohol solvent comprises one or more than two of methanol and ethanol. When the first mixture is mixed with the acetic acid or the sulfamic acid, the mixture is heated to reflux for 6-12 hours.

10. The pressure-induced color change organic luminescent material prepared by the preparation method of the pressure-induced color change organic luminescent material according to any one of claims 1-2 or any one of claims 3-9 is applied in the fields of pressure detection, sensors, information storage devices, anti-counterfeiting materials, memory materials, and biological probes.

Images