A phenoxazine derivative with both solvatochromic effect and self-recovery force-induced color change performance, and a preparation method and application thereof

Abstract

The present application provides a kind of phenoxazine derivative with solvation effect and self-recovery force-induced color change performance, and preparation method and application thereof, belong to organic photoelectric functional material technical field.The structural formula of the phenoxazine derivative of the present application is: the phenoxazine derivative of the present application realizes aggregation-induced emission, solvation effect and self-recovery force-induced color change three functions simultaneously, and application scene is widely;Phenoxazine derivative sample after grinding can be placed at room temperature and spontaneously restored initial luminescence color and micro-pile-up state;Fluorescence quantum yield is high under aggregation state and solid state, suitable for solid-state device application;Raw material is easy to obtain, simple purification, stable yield, suitable for scale-up synthesis and industrialization promotion.

Description

Technical Field

[0001] This invention relates to the field of organic optoelectronic functional materials technology, and in particular to a phenoxazine derivative that combines solvation effect and self-restoring force-induced color change properties, its preparation method and application. Background Technology

[0002] Traditional organic fluorescent dyes typically exhibit excellent fluorescence emission performance in dilute solutions. However, in aggregated or solid states, strong π-π stacking interactions easily form between molecules, triggering aggregation-induced fluorescence quenching (ACQ), leading to a significant decrease or even complete quenching of fluorescence intensity. This inherent defect greatly limits the practical application of these dyes in solid-state optoelectronic devices, functional fluorescent thin films, and other fields. In contrast, fluorescent molecules with aggregation-induced emission (AIE) properties exhibit completely opposite luminescence behavior: their fluorescence emission is weak in dilute solutions, but after aggregation, the fluorescence emission efficiency is significantly improved due to mechanisms such as restricted intramolecular rotation. This provides a novel strategy for the design and development of high-performance solid-state luminescent functional materials.

[0003] In the field of intelligent fluorescent responsive materials, mechanochromic materials can reversibly control the color of emission or the intensity of fluorescence under external stimuli such as grinding and extrusion, showing significant application potential in stress visualization sensing, high-level anti-counterfeiting labels, and dynamic information storage. Among them, room-temperature self-restoring mechanochromic materials can spontaneously recover to their initial luminescent state at room temperature without external assistance such as heating or solvent fumigation after the removal of external force. Compared with traditional reversible mechanochromic materials, these materials are easier to operate and have a longer cycle life, making them a current research hotspot and a technical challenge in the field of intelligent responsive luminescent materials.

[0004] Benzo[c][1,2,5]thiadiazole (BT) is a classic strongly electron-deficient conjugated acceptor unit, possessing both excellent molecular planarity and electron-trapping capabilities. It is often used to construct donor-acceptor (DA) type organic fluorescent molecules. Molecules based on this unit can produce significant intramolecular charge transfer (ICT) effects, thereby endowing materials with sensitive solvation effects. 5,6-Difluoro-substituted benzo[c][1,2,5]thiadiazole can further reduce the molecular LUMO energy level and enhance intramolecular charge transfer. At the same time, fluorine atoms can introduce CF···H weak hydrogen bonding interactions, achieving precise control over intermolecular stacking modes. However, pure benzo[c][1,2,5]thiadiazole conjugated molecules generally suffer from excessive molecular planarity, low solid-state quantum yield, and are prone to ACQ effects in the aggregated state, leading to fluorescence quenching. Furthermore, the conformational reversibility after mechanochromic changes is poor, making it difficult to simultaneously meet the design requirements of efficient solid-state luminescence and multi-stimulus response. Phenoxazine is a typical electron-rich donor unit. Its inherent butterfly-shaped non-planar twisted conformation effectively weakens intermolecular π-π stacking interactions, making it an ideal structural unit for constructing aggregation-induced emission (ICT) luminescent molecules. Simultaneously, the nitrogen and oxygen atoms in the phenoxazine structure possess strong electron-donating capabilities, allowing them to couple with acceptor units to form a strong ICT effect. Furthermore, phenoxazine exhibits conformational flexibility, undergoing a conformational planarization transition under external forces. After the external force is removed, the molecular skeleton can spontaneously rebound based on its inherent structural foundation, providing a structural prerequisite for constructing self-healing mechanochromic materials.

[0005] Currently, organic fluorescent molecular systems capable of simultaneously integrating aggregation-induced emission, solvation effect, and room-temperature self-restoring mechanochromatic effect are still very limited, and D-π-A-π-D type symmetrical luminescent molecules constructed based on difluorosubstituted benzothiadiazoles and phenoxazines have not been reported in the literature. Therefore, developing multi-stimulus-responsive AIE fluorescent molecules with simple structure, easy synthesis, and excellent performance has significant theoretical and practical value for promoting the mechanistic research and industrial application of intelligent luminescent materials. Summary of the Invention

[0006] The purpose of this invention is to provide a phenoxazine derivative that combines solvation effect and self-restoring chromogenic properties, as well as its preparation method and application. The phenoxazine derivative has aggregation-induced emission, solvation effect and self-restoring chromogenic properties.

[0007] To achieve the above-mentioned objectives, the present invention provides the following technical solution: This invention provides a phenoxazine derivative that combines solvation effect and self-restoring methochromic properties, the structural formula of which is: .

[0008] This invention also provides a method for preparing the phenoxazine derivatives that combine solvation effect and self-restoring color-changing properties, wherein the synthetic route of the phenoxazine derivatives is as follows: ; The preparation method of the phenoxazine derivative includes the following steps: 1) Phenyrazine, 4-bromoiodobenzene, cuprous iodide, sodium tert-butoxide and cyclohexanediamine are reacted by heating in 1,4-dioxane to give intermediate I; 2) Intermediate I, pinacol diborate, potassium acetate, and dppf palladium dichloride undergo a borylation substitution reaction in a 1,4-dioxane ring to give intermediate II; 3) Intermediate II, 4,7-dibromo-5,6-difluorobenzo[c][1,2,5]thiadiazole, potassium carbonate and dppf palladium dichloride were coupled in a mixed solvent to obtain phenoxazine derivatives.

[0009] Preferably, the molar ratio of phenoxazine, 4-bromoiodobenzene, cuprous iodide, sodium tert-butoxide and cyclohexanediamine in step 1) is 1:1.1~1.2:0.03~0.05:2.1~2.2:0.1~0.12.

[0010] Preferably, the heating reaction temperature in step 1) is 100~120℃, and the heating reaction time is 8~12h.

[0011] Preferably, the molar ratio of intermediate I, pinacol diborate, potassium acetate, and dppf palladium dichloride in step 2) is 1:1.2~1.4:4~6:0.03~0.05.

[0012] Preferably, the temperature of the borylation substitution reaction in step 2) is 110~120℃, and the time of the borylation substitution reaction is 18~24h.

[0013] Preferably, in step 3), the molar ratio of 4,7-dibromo-5,6-difluorobenzo[c][1,2,5]thiadiazole, intermediate II, potassium carbonate, and dppf palladium dichloride is 1:2.1~2.2:1.4~1.6:0.03~0.05; the mixed solvent is composed of toluene, anhydrous ethanol, and water in a volume ratio of 15~17:5~7:1.5~2.5.

[0014] Preferably, the temperature of the coupling reaction in step 3) is 110~120℃ and the time of the coupling reaction is 36~40h.

[0015] This invention also provides the application of the phenoxazine derivatives, which combine solvation effect and self-restoring force-induced color change properties, in solid-state luminescent films, anti-counterfeiting inks, solvent polarity detection sensors, flexible stress detection materials, or information storage devices.

[0016] The beneficial effects of this invention are: 1) Triple performance integration: The phenoxazine derivative of the present invention simultaneously realizes three functions—aggregation-induced emission, solvation effect, and self-restoring methochromia—in a single molecule, which has a wide range of applications.

[0017] 2) Room temperature self-recovery characteristics: The phenoxazine derivatives of the present invention do not require external treatment such as heating or solvent fumigation. The ground samples can spontaneously recover their initial luminescence color and micro-aggregate state when placed at room temperature, which is simple to operate.

[0018] 3) High solid-state luminescence efficiency: The non-planar structure of the phenoxazine derivatives of this invention effectively suppresses aggregation quenching, resulting in high fluorescence quantum yield in both aggregated and solid states, making it suitable for solid-state device applications.

[0019] 4) Simple synthesis: The present invention can prepare the target product phenoxazine derivatives through a simple coupling reaction. The raw materials are readily available, the purification is simple, the yield is stable, and it is suitable for scale-up synthesis and industrialization. Attached Figure Description

[0020] Figure 1 The ultraviolet absorption spectra of compound POZ-BTF prepared in Example 1 under different water volume fractions in a mixed solvent of tetrahydrofuran and water; Figure 2 The fluorescence emission spectra of compound POZ-BTF prepared in Example 1 under different water volume fractions in a mixed solvent of tetrahydrofuran and water. Figure 3 The ultraviolet absorption spectra of compound POZ-BTF prepared in Example 1 in toluene, tetrahydrofuran, dichloromethane, N,N-dimethylformamide, and dimethyl sulfoxide solvents are shown. Figure 4 The fluorescence emission spectra of compound POZ-BTF prepared in Example 1 in toluene, tetrahydrofuran, dichloromethane, N,N-dimethylformamide, and dimethyl sulfoxide solvents are shown. Figure 5 The images show the original solid powder, the ground solid powder, and the fluorescence images of the ground solid powder after self-recovery after being left at room temperature for 20 min for the compound POZ-BTF prepared in Example 1. Figure 6 The images show the original solid powder, the ground solid powder, and the fluorescence emission spectra of the compound POZ-BTF prepared in Example 1 after self-recovery at room temperature for 20 min, respectively. Detailed Implementation

[0021] This invention provides a phenoxazine derivative that combines solvation effect and self-restoring methochromic properties. The structural formula of the phenoxazine derivative (POZ-BTF) is as follows: .

[0022] This invention also provides a method for preparing the phenoxazine derivatives that combine solvation effect and self-restoring color-changing properties, wherein the synthetic route of the phenoxazine derivatives is as follows: ; The preparation method of the phenoxazine derivative includes the following steps: 1) Phenyrazine, 4-bromoiodobenzene, cuprous iodide, sodium tert-butoxide and cyclohexanediamine are reacted by heating in 1,4-dioxane to give intermediate I; 2) Intermediate I, pinacol diborate, potassium acetate, and dppf palladium dichloride undergo a borylation substitution reaction in a 1,4-dioxane ring to give intermediate II; 3) Intermediate II, 4,7-dibromo-5,6-difluorobenzo[c][1,2,5]thiadiazole, potassium carbonate and dppf palladium dichloride were coupled in a mixed solvent to obtain phenoxazine derivatives.

[0023] In this invention, the molar ratio of phenoxazine, 4-bromoiodobenzene, cuprous iodide, sodium tert-butoxide, and cyclohexanediamine in step 1) is preferably 1:1.1~1.2:0.03~0.05:2.1~2.2:0.1~0.12, more preferably 1:1.12~1.18:0.035~0.045:2.12~2.18:0.105~0.115, and even more preferably 1:1.14~1.15:0.04:2.14~2.15:0.11.

[0024] In this invention, the temperature of the heating reaction in step 1) is preferably 100~120℃, more preferably 105~115℃, and even more preferably 110℃, and the heating reaction time is preferably 8~12h, more preferably 9~11h, and even more preferably 10h.

[0025] In this invention, the molar ratio of intermediate I, pinacol diborate, potassium acetate, and dppf palladium dichloride in step 2) is preferably 1:1.2~1.4:4~6:0.03~0.05, more preferably 1:1.25~1.35:4.5~5.5:0.035~0.045, and even more preferably 1:1.3:5:0.04.

[0026] In this invention, the temperature of the borylation substitution reaction in step 2) is preferably 110~120℃, more preferably 112~118℃, and even more preferably 114~115℃, and the time of the borylation substitution reaction is preferably 18~24h, more preferably 19~23h, and even more preferably 20~22h.

[0027] In this invention, the molar ratio of 4,7-dibromo-5,6-difluorobenzo[c][1,2,5]thiadiazole, intermediate II, potassium carbonate, and dppf palladium dichloride in step 3) is preferably 1:2.1~2.2:1.4~1.6:0.03~0.05, more preferably 1:2.12~2.18:1.45~1.55:0.035~0.045, and even more preferably 1:2.15~2.16:1.5:0.04; the mixed solvent is preferably composed of toluene, anhydrous ethanol, and water in a volume ratio of 15~17:5~7:1.5~2.5, and more preferably composed of toluene, anhydrous ethanol, and water in a volume ratio of 16:6:2.

[0028] In this invention, the temperature of the coupling reaction in step 3) is preferably 110~120℃, more preferably 112~118℃, and even more preferably 115~116℃, and the time of the coupling reaction is preferably 36~40h, more preferably 37~39h, and even more preferably 38h.

[0029] This invention also provides the application of the phenoxazine derivatives, which combine solvation effect and self-restoring force-induced color change properties, in solid-state luminescent films, anti-counterfeiting inks, solvent polarity detection sensors, flexible stress detection materials, or information storage devices.

[0030] The phenoxazine derivatives of this invention use 5,6-difluorobenzo[c][1,2,5]thiadiazole as the electron-withdrawing acceptor unit, symmetrically linked with electron-rich phenoxazine donor units on both sides, and can be prepared via a Suzuki-Miyaura coupling reaction. The synthesis is simple, the yield is stable, and the purification is easy. The compound POZ-BTF of this invention is a D-π-A-π-D type organic conjugated compound based on a difluorobenzothiadiazole acceptor and a phenoxazine donor, exhibiting triple stimulus-response properties: weak fluorescence in good solvents, significantly enhanced fluorescence in the aggregated state, exhibiting typical aggregation-induced emission properties; a significant shift in emission wavelength with solvent polarity, demonstrating a significant solvation effect; and a change in luminescence color after grinding of the solid, which spontaneously recovers to its initial state at room temperature without additional treatment, exhibiting excellent self-healing mechanochromic properties. This compound can be widely used in fields such as smart luminescent materials, anti-counterfeiting inks, optical sensing, stress detection, and information storage.

[0031] The technical solutions provided by the present invention will be described in detail below with reference to the embodiments, but they should not be construed as limiting the scope of protection of the present invention.

[0032] In the examples, the synthetic route for phenoxazine derivatives is as follows: .

[0033] Example 1

[0034] Synthesis of Intermediate I: 10.0 mmol phenoxazine, 12.0 mmol 1-bromo-4-iodobenzene, 0.30 mmol cuprous iodide, and 22.0 mmol sodium tert-butoxide were added sequentially to a 100 mL two-necked reaction flask. After sealing the reaction apparatus, the system was purged with high-purity nitrogen three times to remove air. Under nitrogen protection, 1.10 mmol cyclohexanediamine and 25 mL anhydrous 1,4-dioxane were injected into the reaction flask via a syringe, and the mixture was stirred to ensure thorough dispersion of the solid starting materials. The reaction system was heated to 110 °C and stirred under reflux for 12 h under a nitrogen atmosphere. After the reaction was complete, the reaction solution was allowed to cool naturally to room temperature. Extraction was then performed using a mixture of dichloromethane and saturated brine (volume ratio 1:1.2) to obtain the organic phase. Anhydrous sodium sulfate was added to the organic phase to remove water, and the mixture was allowed to stand and filtered. The obtained organic filtrate was subjected to rotary evaporation under reduced pressure to remove the solvent, yielding the crude product. The sample was separated and purified by silica gel column chromatography. A mixed solvent of dichloromethane and petroleum ether at a volume ratio of 1:1 was used as the eluent to elute and collect the target component. Finally, intermediate I was purified to obtain the final product.

[0035] Synthesis of Intermediate II: 5.0 mmol of Intermediate I, 6.0 mmol of pinacol diborate, 25.0 mmol of potassium acetate, and 0.25 mmol of dppf palladium dichloride were added sequentially to a 100 mL two-necked reaction flask. After sealing the reaction apparatus, the system was purged with high-purity nitrogen three times to remove air. Under nitrogen protection, 30 mL of anhydrous 1,4-dioxane was injected into the reaction flask using a syringe, and the mixture was stirred to ensure thorough dispersion of the solid raw materials. The reaction system was heated to 110 °C and refluxed under a nitrogen atmosphere with stirring for 20 h. After the reaction was complete, the reaction solution was allowed to cool naturally to room temperature. The solution was then extracted with a mixture of dichloromethane and saturated brine at a volume ratio of 1:1.2 to obtain the organic phase. Anhydrous sodium sulfate was added to the organic phase to remove water, and the mixture was allowed to stand and filtered. The obtained organic filtrate was subjected to rotary evaporation under reduced pressure to remove the solvent, yielding the crude product. The sample was separated and purified by silica gel column chromatography. A mixed solvent of dichloromethane and petroleum ether at a volume ratio of 1:1 was used as the eluent to elute and collect the target component. Finally, intermediate II was obtained by purification.

[0036] Synthesis of the target product POZ-BTF: 1.0 mmol of 4,7-dibromo-5,6-difluorobenzo[c][1,2,5]thiadiazole, 2.2 mmol of intermediate II, 1.5 mmol of potassium carbonate, and 0.04 mmol of dppf palladium dichloride were added sequentially to a 100 mL two-necked reaction flask. After sealing the reaction apparatus, the system was purged with high-purity nitrogen three times to remove air. Under nitrogen protection, 24 mL of a mixed solvent of toluene, anhydrous ethanol, and water (volume ratio of toluene, anhydrous ethanol, and water 16:6:2) was injected into the reaction flask using a syringe, and the mixture was stirred to ensure thorough dispersion of the solid starting materials. The reaction system was heated to 110 °C and refluxed under a nitrogen atmosphere with stirring for 36 h. After the reaction was completed, the reaction solution was allowed to cool naturally to room temperature. The sample was then extracted with a mixture of dichloromethane and saturated brine at a volume ratio of 1:1.2 to obtain the organic phase. After washing the organic phase with saturated brine, anhydrous sodium sulfate was added to the organic phase for drying and removal of water. The mixture was then allowed to stand and filtered. The resulting organic filtrate was subjected to rotary evaporation under reduced pressure to remove the solvent, yielding the crude product. The sample was then purified by silica gel column chromatography using dichloromethane as the eluent to collect the target component. Finally, the compound POZ-BTF was obtained after purification.

[0037] Example 2

[0038] Synthesis of Intermediate I: 10.0 mmol phenoxazine, 11.0 mmol 1-bromo-4-iodobenzene, 0.35 mmol cuprous iodide, and 21.0 mmol sodium tert-butoxide were added sequentially to a 100 mL two-necked reaction flask. After sealing the reaction apparatus, the system was purged with high-purity nitrogen three times to remove air. Under nitrogen protection, 1.05 mmol cyclohexanediamine and 23 mL anhydrous 1,4-dioxane were injected into the reaction flask via a syringe, and the mixture was stirred to ensure thorough dispersion of the solid starting materials. The reaction system was heated to 105 °C and stirred under reflux for 11 h under a nitrogen atmosphere. After the reaction was complete, the reaction solution was allowed to cool naturally to room temperature. Extraction was then performed using a mixture of dichloromethane and saturated brine (volume ratio 1:1.3) to obtain the organic phase. Anhydrous sodium sulfate was added to the organic phase for drying to remove water, and the mixture was allowed to stand and filtered. The obtained organic filtrate was subjected to rotary evaporation under reduced pressure to remove the solvent, yielding the crude product. The sample was separated and purified by silica gel column chromatography. A mixed solvent of dichloromethane and petroleum ether at a volume ratio of 1:1 was used as the eluent to elute and collect the target component. Finally, intermediate I was purified to obtain the final product.

[0039] Synthesis of Intermediate II: 5.0 mmol of Intermediate I, 6.5 mmol of pinacol diborate, 22.5 mmol of potassium acetate, and 0.15 mmol of dppf palladium dichloride were added sequentially to a 100 mL two-necked reaction flask. After sealing the reaction apparatus, the system was purged with high-purity nitrogen three times to remove air. Under nitrogen protection, 28 mL of anhydrous 1,4-dioxane was injected into the reaction flask using a syringe, and the mixture was stirred to ensure thorough dispersion of the solid raw materials. The reaction system was heated to 115 °C and stirred under reflux in a nitrogen atmosphere for 22 h. After the reaction was complete, the reaction solution was allowed to cool naturally to room temperature. Extraction was then performed using a mixture of dichloromethane and saturated brine (volume ratio 1:1.3) to separate the organic phase. Anhydrous sodium sulfate was added to the organic phase to remove water, and the mixture was allowed to stand and filtered. The resulting organic filtrate was subjected to rotary evaporation under reduced pressure to remove the solvent, yielding the crude product. The sample was separated and purified by silica gel column chromatography. A mixed solvent of dichloromethane and petroleum ether at a volume ratio of 1:1 was used as the eluent to elute and collect the target component. Finally, intermediate II was obtained by purification.

[0040] Synthesis of the target product POZ-BTF: 1.0 mmol of 4,7-dibromo-5,6-difluorobenzo[c][1,2,5]thiadiazole, 2.1 mmol of intermediate II, 1.45 mmol of potassium carbonate, and 0.035 mmol of dppf palladium dichloride were added sequentially to a 100 mL two-necked reaction flask. After sealing the reaction apparatus, the system was purged with high-purity nitrogen three times to remove air. Under nitrogen protection, 24 mL of a mixed solvent of toluene, anhydrous ethanol, and water (volume ratio of toluene, anhydrous ethanol, and water 15:5:2) was injected into the reaction flask using a syringe, and the mixture was stirred to ensure thorough dispersion of the solid starting materials. The reaction system was heated to 120 °C and refluxed under a nitrogen atmosphere with stirring for 36 h. After the reaction was completed, the reaction solution was allowed to cool naturally to room temperature. The organic phase was then extracted with a mixture of dichloromethane and saturated brine at a volume ratio of 1:1.3. After washing with saturated brine, anhydrous sodium sulfate was added to the organic phase to remove water, and the mixture was allowed to stand and filtered. The resulting organic filtrate was subjected to rotary evaporation under reduced pressure to remove the solvent, yielding the crude product. The sample was then purified by silica gel column chromatography using dichloromethane as the eluent to collect the target component. Finally, the compound POZ-BTF was obtained after purification.

[0041] Example 3

[0042] Synthesis of Intermediate I: 10.0 mmol phenoxazine, 11.5 mmol 1-bromo-4-iodobenzene, 0.45 mmol cuprous iodide, and 21.5 mmol sodium tert-butoxide were added sequentially to a 100 mL two-necked reaction flask. After sealing the reaction apparatus, the system was purged with high-purity nitrogen three times to remove air. Under nitrogen protection, 1.15 mmol cyclohexanediamine and 27 mL anhydrous 1,4-dioxane were injected into the reaction flask using a syringe, and the mixture was stirred to ensure thorough dispersion of the solid starting materials. The reaction system was heated to 115 °C and stirred under reflux for 10 h under a nitrogen atmosphere. After the reaction was complete, the reaction solution was allowed to cool naturally to room temperature. Extraction was then performed using a mixture of dichloromethane and saturated brine (volume ratio 1:1.4) to obtain the organic phase. Anhydrous sodium sulfate was added to the organic phase to remove water, and the mixture was allowed to stand and filtered. The resulting organic filtrate was subjected to rotary evaporation under reduced pressure to remove the solvent, yielding the crude product. The sample was separated and purified by silica gel column chromatography. A mixed solvent of dichloromethane and petroleum ether at a volume ratio of 1:1 was used as the eluent to elute and collect the target component. Finally, intermediate I was purified to obtain the final product.

[0043] Synthesis of Intermediate II: 5.0 mmol of Intermediate I, 7.0 mmol of pinacol diborate, 27.5 mmol of potassium acetate, and 0.20 mmol of dppf palladium dichloride were added sequentially to a 100 mL two-necked reaction flask. After sealing the reaction apparatus, the system was purged with high-purity nitrogen three times to remove air. Under nitrogen protection, 32 mL of anhydrous 1,4-dioxane was injected into the reaction flask using a syringe, and the mixture was stirred to ensure thorough dispersion of the solid raw materials. The reaction system was heated to 120 °C and stirred under reflux in a nitrogen atmosphere for 20 h. After the reaction was complete, the reaction solution was allowed to cool naturally to room temperature. The solution was then extracted with a mixture of dichloromethane and saturated brine (volume ratio 1:1.4) to separate the organic phase. Anhydrous sodium sulfate was added to the organic phase to remove water, and the mixture was allowed to stand and filtered. The resulting organic filtrate was subjected to rotary evaporation under reduced pressure to remove the solvent, yielding the crude product. The sample was separated and purified by silica gel column chromatography. A mixed solvent of dichloromethane and petroleum ether at a volume ratio of 1:1 was used as the eluent to elute and collect the target component. Finally, intermediate II was obtained by purification.

[0044] Synthesis of the target product POZ-BTF: 1.0 mmol of 4,7-dibromo-5,6-difluorobenzo[c][1,2,5]thiadiazole, 2.15 mmol of intermediate II, 1.55 mmol of potassium carbonate, and 0.045 mmol of dppf palladium dichloride were added sequentially to a 100 mL two-necked reaction flask. After sealing the reaction apparatus, the system was purged with high-purity nitrogen three times to remove air. Under nitrogen protection, 24 mL of a mixed solvent of toluene, anhydrous ethanol, and water (volume ratio of toluene, anhydrous ethanol, and water 17:7:2) was injected into the reaction flask using a syringe, and the mixture was stirred to ensure thorough dispersion of the solid starting materials. The reaction system was heated to 115 °C and refluxed under a nitrogen atmosphere with stirring for 38 h. After the reaction was completed, the reaction solution was allowed to cool naturally to room temperature. The organic phase was then extracted with a mixture of dichloromethane and saturated brine at a volume ratio of 1:1.4. After washing the organic phase with saturated brine, anhydrous sodium sulfate was added to the organic phase to remove water, and the mixture was allowed to stand and filtered. The obtained organic filtrate was subjected to rotary evaporation under reduced pressure to remove the solvent, yielding the crude product. The sample was then purified by silica gel column chromatography using dichloromethane as the eluent to elute and collect the target component. Finally, the compound POZ-BTF was obtained after purification.

[0045] The performance of compound POZ-BTF prepared in Example 1 was tested.

[0046] (1) Aggregation-induced emission performance test: The compound POZ-BTF prepared in Example 1 was dissolved in the benign solvent tetrahydrofuran to prepare a concentration of 1×10- 5 A solution of mol / L was prepared by mixing this solution with deionized water to form mixed solutions with different water volume fractions (10%, 20%, 30%, 40%, 50%, 60%, 70%, 80%, 90%, and 99%). The fluorescence emission spectra of these solutions with different water volume fractions were then measured sequentially. The results are shown below. Figure 2 As shown. (Through) Figure 2 It can be seen that the fluorescence intensity of POZ-BTF is very weak in pure tetrahydrofuran solvent, but the fluorescence intensity increases significantly with the continuous increase of water volume fraction. The fluorescence intensity is strongest when the water volume fraction is 99%. Therefore, the compound POZ-BTF exhibits excellent aggregation-induced emission properties.

[0047] (2) Solvation test: The compound POZ-BTF prepared in Example 1 was dissolved in toluene, tetrahydrofuran (THF), dichloromethane (DCM), N,N-dimethylformamide (DMF), and dimethyl sulfoxide (DMSO) to prepare a solution with a concentration of 1×10⁻⁶. -5 A solution of mol / L was prepared, and then the fluorescence emission spectra of POZ-BTF in different solvents were measured. The results are as follows: Figure 4 As shown. (Through) Figure 4 It can be seen that the peak values ​​in the fluorescence emission spectra shifted significantly in different solvents, indicating that POZ-BTF has a solvation effect and a strong ICT effect.

[0048] (3) Take the original solid powder of the target compound POZ-BTF (Pristine) and test its fluorescence emission spectrum; then place the powder in an agate mortar and grind it thoroughly for 5 minutes (Grind) until it is visible to the naked eye, and immediately test the fluorescence spectrum; after the ground powder has been left to stand at room temperature for 20 minutes (Self-reversible), test the fluorescence spectrum and observe the recovery. The test results are as follows: Figure 5 , Figure 6 As shown. By Figure 5 , Figure 6 It can be seen that the fluorescence emission spectrum of the ground POZ-BTF showed a significant red shift compared to the original solid powder. The fluorescence emission spectrum measured after standing at room temperature for 20 minutes almost overlapped with the original fluorescence emission spectrum, indicating that the compound POZ-BTF has excellent room temperature self-restoring color-changing properties.

[0049] The phenoxazine derivatives of the present invention exhibit significantly higher fluorescence emission intensity in the aggregated state compared to the dilute solution state, demonstrating typical aggregation-induced emission properties. The fluorescence emission wavelengths of the phenoxazine derivatives shift in different polar solvents, exhibiting solvent-induced color-changing properties. Under the action of grinding force, the fluorescence emission wavelengths of the phenoxazine derivatives red-shift, and after being placed at room temperature, the fluorescence emission spectrum recovers to its original state, demonstrating room temperature self-restoring force-induced color-changing properties.

[0050] The above description is only a preferred embodiment of the present invention. It should be noted that for those skilled in the art, several improvements and modifications can be made without departing from the principle of the present invention, and these improvements and modifications should also be considered within the scope of protection of the present invention.

Claims

1. A phenoxazine derivative possessing both solvation and self-restoring mechanochromic properties, characterized in that, The structural formula of the phenoxazine derivative is: 。 2. The method for preparing the phenoxazine derivative with both solvation effect and self-restoring color-changing properties as described in claim 1, characterized in that, The synthetic route for the phenoxazine derivatives is as follows: ； The preparation method of the phenoxazine derivative includes the following steps: 1) Phenyrazine, 4-bromoiodobenzene, cuprous iodide, sodium tert-butoxide, and cyclohexanediamine are reacted by heating in 1,4-dioxane to give intermediate I; 2) Intermediate I, pinacol diborate, potassium acetate, and dppf palladium dichloride undergo a borylation substitution reaction in a 1,4-dioxane ring to give intermediate II; 3) Intermediate II, 4,7-dibromo-5,6-difluorobenzo[c][1,2,5]thiadiazole, potassium carbonate and dppf palladium dichloride were coupled in a mixed solvent to obtain phenoxazine derivatives.

3. The preparation method according to claim 2, characterized in that, In step 1), the molar ratio of phenoxazine, 4-bromoiodobenzene, cuprous iodide, sodium tert-butoxide, and cyclohexanediamine is 1:1.1~1.2:0.03~0.05:2.1~2.2:0.1~0.

12.

4. The preparation method according to claim 2 or 3, characterized in that, Step 1) The heating reaction temperature is 100~120℃, and the heating reaction time is 8~12h.

5. The preparation method according to claim 4, characterized in that, In step 2), the molar ratio of intermediate I, pinacol diboronate, potassium acetate, and dppf palladium dichloride is 1:1.2~1.4:4~6:0.03~0.

05.

6. The preparation method according to claim 5, characterized in that, Step 2) The borylation substitution reaction is carried out at a temperature of 110~120℃ for 18~24h.

7. The preparation method according to claim 5 or 6, characterized in that, In step 3), the molar ratio of 4,7-dibromo-5,6-difluorobenzo[c][1,2,5]thiadiazole, intermediate II, potassium carbonate, and dppf palladium dichloride is 1:2.1~2.2:1.4~1.6:0.03~0.05; the mixed solvent consists of toluene, anhydrous ethanol, and water in a volume ratio of 15~17:5~7:1.5~2.

5.

8. The preparation method according to claim 7, characterized in that, Step 3) The coupling reaction temperature is 110~120℃, and the coupling reaction time is 36~40h.

9. The application of the phenoxazine derivatives of claim 1, which possess both solvation effect and self-restoring force-induced color-changing properties, in solid-state luminescent films, anti-counterfeiting inks, solvent polarity detection sensors, flexible stress detection materials, or information storage devices.

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