Temperature-sensitive fluorescent sensing material with "v" type structure pyrene dimer

Abstract

The application discloses a pyrene dimer variable-temperature fluorescent sensing material with a "V" type structure, which has excellent temperature sensitivity and fluorescent response characteristics. The pyrene dimer forms a "V" type structure through specific chemical bonding of two pyrene molecules, and its fluorescent performance changes significantly when the temperature changes. Specifically, at 80K, the material exhibits strong fluorescence emission at 500nm, and at this time, it presents yellow color; as the temperature rises, the fluorescence intensity of the material at 500nm gradually decreases, and the fluorescence intensity at 600nm increases, and at this time, the solution color presents red. This phenomenon is due to the temperature-dependent change of intermolecular interaction and intramolecular electron transfer. By adjusting the molecular structure and synthesis conditions of the pyrene dimer, the temperature response range and fluorescent characteristics can be accurately controlled. The material has wide application prospects, especially in the fields of temperature sensing, temperature monitoring, intelligent temperature control equipment, etc. Compared with traditional temperature sensors, it has higher response speed, stability and sensitivity. Through the application, efficient and reliable temperature detection can be realized, and new ideas and technical solutions are provided for the development of temperature sensing technology.

Description

Technical Field

[0001] This invention belongs to the field of organic optoelectronic functional materials technology, specifically relating to the first synthesis of a V-shaped pyrene dimer organic compound and its application in the field of temperature fluorescence sensing. This type of compound is a V-shaped pyrene dimer with dibenzofuran as the bridging unit and phenylethynyl groups replacing pyrene as the chromophore. Choosing the dibenzofuran bridging group avoids the formation of excitocomplexes caused by strong interactions between the two pyrene units, while providing better interactions between the two pyrene monomers. The introduction of the diethynyl group effectively modulates the singlet and triplet energy levels of the pyrene monomers, optimizing the electronic structure. This invention successfully synthesizes this compound for the first time, and through optimized molecular design and structural modification, it exhibits excellent performance in temperature fluorescence sensing, achieving a balance between optical performance and thermal stability, providing an important reference for the development of high-efficiency optoelectronic materials. Background Technology

[0002] Temperature-dependent fluorescent materials are optical materials that are sensitive to temperature changes, with their fluorescence intensity, color, or wavelength changing significantly with temperature. These materials have important applications in temperature sensing, fluorescent probes, bioimaging, and smart displays. However, current temperature-dependent fluorescent materials suffer from problems such as insufficient response sensitivity, poor repeatability, and complex fabrication processes.

[0003] 1,3,6,8-Tetraphenylethynylpyrene is a compound with a rigid planar π-conjugated structure. Its molecular structure, through the introduction of multiple phenylethynyl groups, significantly enhances intramolecular electronic coupling. Furthermore, using dibenzofuran as a bridging group avoids the formation of exosome complexes caused by strong interactions between the two pyrene units, while simultaneously providing better interaction between the two pyrene units, thus exhibiting a sensitive fluorescence response to changes in the external environment (such as temperature). This invention addresses the shortcomings of existing technologies by providing a temperature-variable fluorescent material that is easy to prepare, highly responsive, and exhibits excellent thermal stability. Summary of the Invention

[0004] To address the problems existing in the prior art and the application needs of this research field, this invention provides a method for preparing a low-cost, simple-process, V-shaped pyrene dimer temperature-varying fluorescent sensing material and its application. The fluorescence change characteristics and response mechanism of this material in different temperature ranges are investigated.

[0005] The molecular structures of 4,6-diethynyldibenzofuran (Formula 1), 1-bromo-3,6,8-triphenylethynylpyrene (Formula 2), and the "V"-shaped pyrene dimer (Formula 3) are shown below:

[0006]

[0007] Synthesis of 4,6-disiloxyethynyldibenzofuran:

[0008]

[0009] Weigh 1.0444 g (3.20 mmol) of 4,6-dibromodibenzofuran, 25.2 mg (0.32 mmol) of bis(triphenylphosphine)palladium dichloride, and 60.8 mg (0.32 mmol) of cuprous iodide into a dry three-necked flask. Remove oxygen from the flask by three suction cycles and three purging cycles. Then add 30.0 mL of tetrahydrofuran and 30.0 mL of triethylamine, which have been degassed by bubbling. Heat to 80 °C, then add 4.4 mL (32.0 mmol) of trimethylsilylacetylene. Stir and react for 24 hours, then stop the reaction. Cool the reaction mixture to room temperature and evaporate to dryness under reduced pressure to obtain the crude product. Finally, purify the crude product by silica gel column chromatography (dichloromethane / n-hexane = 1 / 8) to obtain a white powder solid (944.6 mg, 82%). 1H NMR (400MHz, Chloroform-d) δ7.88 (dd, J=7.7, 1.3Hz, 2H), 7.58 (dd, J=7.6, 1.3Hz, 2H), 7.29 (td, J=7.6, 1.1Hz, 2H), 0.34 (d, J=1.2Hz, 18H).

[0010] Synthesis of 4,6-diethynyldibenzofuran:

[0011]

[0012] 4,6-disilynylethynyldibenzofuran (360.0 mg, 1.0 mmol) was placed in a 50 mL three-necked flask, and then 20.0 mL of dehydrated tetrahydrofuran was added. Under nitrogen protection, 10.0 mL (1.0 mol / L) tetrabutylammonium fluoride solution was slowly added dropwise to the three-necked flask, and the reaction was continued at room temperature for 30 minutes. The reaction solution was then poured into 50 mL of water and extracted with dichloromethane (3 × 50 mL). The organic layer solutions were combined and dried over anhydrous MgSO4. The extracted organic solution was removed by vacuum distillation. The crude product was purified by silica gel column chromatography (dichloromethane / n-hexane = 2 / 7) to give a white solid (164.2 mg, yield 76%). 1 H NMR (400MHz, Chloroform-d) δ7.93 (dd, J = 7.7, 1.3 Hz, 2H), 7.62 (dd, J = 7.6, 1.3 Hz, 2H), 7.32 (td, J = 7.7, 1.1 Hz, 2H), 3.47 (d, J = 1.1 Hz, 2H).

[0013] Preparation of 1-bromo-3,6,8-triphenylethynylpyrene:

[0014]

[0015] 1,3,6,8-Tetrabromopyrene (517.1 mg, 1.0 mmol) was placed in a 50 mL three-necked flask, and bis(triphenylphosphine)palladium dichloride (12.5 mg, 0.16 mmol) and cuprous iodide (30.4 mg, 0.16 mmol) were placed in a dry three-necked flask. The oxygen in the three-necked flask was removed by three suction cycles and three purging cycles. Then, 30.0 mL of tetrahydrofuran and 30.0 mL of triethylamine were added separately after bubbling and degassing. The mixture was heated to 80 °C, and then 1-ethynyl-4-hexylbenzene (186 mg, 1 mmol) was added. After stirring for 12 hours, the reaction was stopped, and the reaction mixture was cooled to room temperature and evaporated to dryness under reduced pressure to obtain the crude product. Finally, the crude product was purified by silica gel column chromatography (dichloromethane / n-hexane = 1 / 20) to obtain a yellow powder solid (150.1 mg, 18%).

[0016] Synthesis of “V”-shaped pyrene dimers:

[0017]

[0018] 1-Bromo-3,6,8-triphenylethynylpyrene (834.1 mg, 1.0 mmol) and 4,6-diethynyldibenzofuran (108 mg, 0.5 mmol) were placed in a 50 mL three-necked flask. Bis(triphenylphosphine)palladium dichloride (12.5 mg, 0.16 mmol) and cuprous iodide (30.4 mg, 0.16 mmol) were placed in a dry three-necked flask. Oxygen was removed from the flask by a three-way evacuation. Then, 30.0 mL of bubbly degassed tetrahydrofuran and 30.0 mL of triethylamine were added, respectively. The mixture was heated to 80 °C and stirred for 12 hours. The reaction was then stopped, and the reaction mixture was cooled to room temperature and evaporated to dryness under reduced pressure to obtain the crude product. Finally, the crude product was purified by silica gel column chromatography (dichloromethane / n-hexane = 1 / 5) to obtain a brown powder solid (216 mg, 12%).

[0019] The preparation method of temperature-varying fluorescent materials with "V"-shaped pyrene dimers includes the following steps:

[0020] Step 1: Weigh 17.2 mg of the "V"-shaped pyrene dimer, add 10 mL of dichloromethane to completely dissolve it, and prepare a solution of 1×10⁻⁶. -3 mol / L of mother liquor;

[0021] Step 2: Pipette 0.1 mL of the mother liquor into a colorimetric tube and let it stand until the dichloromethane has completely evaporated;

[0022] Step 3: Add 10 mL of methyltetrahydrofuran to the colorimetric tube from Step 2 to prepare a 1×10⁻⁶ solution. -5 mol / L methyltetrahydrofuran solution;

[0023] Step 4: Take 2 mL of 1×10 -5 Pour a mol / L methyltetrahydrofuran solution into a round cuvette and place the cuvette in a fluorescent low-temperature accessory.

[0024] Step 5: Test its fluorescence spectrum at different temperatures (e.g., 80K to 300K).

[0025] The beneficial effects of this invention are as follows: a new material has been discovered that can be used as a temperature-variable fluorescent material. The preparation process and equipment for this temperature-variable fluorescent material are simple and easy to industrialize. Choosing a dibenzofuran bridging group avoids the formation of excitocomplexes caused by strong interactions between the two pyrene units, while providing better interactions between the two pyrene monomers. Its molecular structure, by introducing multiple phenylacetylene groups, significantly enhances the intramolecular electronic coupling effect, effectively improving photoelectric properties, increasing temperature sensitivity, and enabling the visualization of temperature changes. Attached Figure Description

[0026] The present invention will be further described below with reference to the accompanying drawings and embodiments.

[0027] Figure 1 It is the NMR spectrum of 4,6-disilethynyldibenzofuran;

[0028] Figure 2 It is the NMR spectrum of 4,6-dieethynyldibenzofuran;

[0029] Figure 3 This is the NMR spectrum of 1-bromo-3,6,8-triphenylethynylpyrene;

[0030] Figure 4 This is the mass spectrum of 1-bromo-3,6,8-triphenylethynylpyrene;

[0031] Figure 5 This is the NMR spectrum of a "V"-shaped pyrene dimer;

[0032] Figure 6 This is the mass spectrum of a "V"-shaped pyrene dimer;

[0033] Figure 7 This is the UV spectrum of the "V"-shaped pyrene dimer in methyltetrahydrofuran solution;

[0034] Figure 8 This is a thermochromic fluorescence image of the V”-shaped pyrene dimer in methyltetrahydrofuran;

[0035] Figure 9This is the CIE chromatogram of the V-shaped pyrene dimer in methyltetrahydrofuran. As can be seen from the figure, the color of the pyrene dimer in the methyltetrahydrofuran solution changes from yellow to red when the temperature increases from 80K to 300K, thus realizing the visualization of temperature changes and monitoring a wide temperature range.

[0036] The above description is merely a preferred embodiment of the present invention and is not intended to limit the present invention in any way. Those skilled in the art can readily implement the present invention based on the accompanying drawings and the above description. However, any modifications, alterations, and variations made by those skilled in the art without departing from the scope of the present invention, utilizing the disclosed technical content, are equivalent embodiments of the present invention. Furthermore, any equivalent changes, alterations, and variations made to the above embodiments based on the implementation techniques of the present invention are within the protection scope of the present invention.

Claims

1. A pyrene dimer temperature-varying fluorescent sensing material with a "V"-shaped structure, characterized as shown in formula (3). Equation (3) The pyrene dimer is formed by two pyrene molecules linked by dibenzofuran as a connecting group, forming a "V"-shaped pyrene dimer as shown in formula (3).

2. A method for preparing the pyrene dimer temperature-varying fluorescent sensing material according to claim 1, characterized in that, Includes the following steps: Two pyrene molecules are linked by a benzene ring linking group to form a pyrene dimer with a "V" structure through chemical synthesis. During the synthesis process, the reaction conditions are adjusted to control the molecular structure, morphology and fluorescence properties of the pyrene dimer.

3. An application of the pyrene dimer temperature-varying fluorescence sensing material according to claim 1, characterized in that, The material can be used in temperature sensing, temperature monitoring, intelligent temperature control equipment, or temperature detection sensors.

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