Variable-temperature fluorescent sensing material of pyrene dimer with V-shaped structure

Abstract

The invention discloses a pyrene dimer variable-temperature fluorescence sensing material with a V-shaped structure. The material has excellent temperature sensitivity and fluorescence response characteristics. The pyrene dimer is of a V-shaped structure formed by two pyrene molecules in a specific chemical bonding mode, and the fluorescence property of the pyrene dimer is remarkably changed when the temperature changes. Specifically, at 80K, the material shows relatively strong fluorescence emission at 500nm, and at the moment, the material shows yellow; along with the rise of the temperature, the fluorescence intensity of the material at 500nm is gradually attenuated, and the fluorescence intensity at 600nm is increased, and at the moment, the color of the solution is red. This phenomenon originates from intermolecular interactions and temperature dependent changes in intramolecular electron transfer. By adjusting the molecular structure and the synthesis condition of the pyrene dimer, the temperature response range and the fluorescence characteristic of the pyrene dimer can be accurately controlled. The material has a wide application prospect, especially in the fields of temperature sensing, temperature monitoring, intelligent temperature control equipment and the like. Compared with a traditional temperature sensor, the temperature sensor is high in response speed, stability and sensitivity. According to the invention, efficient and reliable temperature detection can be realized, and a new thought and a technical solution are provided for the development of a temperature sensing technology.

Description

Technical Field

[0001] The present invention belongs to the technical field of organic optoelectronic functional materials, and specifically relates to a pyrene dimer organic compound with a "V"-shaped structure that is synthesized for the first time, and is applied in the field of temperature fluorescence sensing. This type of compound uses dibenzofuran as a bridging unit and replaces pyrene with a phenylethynyl group as a chromophore to form a "V"-shaped pyrene dimer. Selecting a dibenzofuran bridge group can avoid the formation of an excited complex caused by the strong interaction between the two pyrene units, and can provide better interaction between the two pyrene monomers. The introduction of a diacetylene group can effectively regulate the singlet and triplet energy levels of the pyrene monomer and optimize the electronic structure. The present invention successfully realizes the synthesis of the compound for the first time, and by optimizing the molecular design and structural modification, it exhibits excellent performance in temperature fluorescence sensing, achieves a balance between the optical properties and thermal stability of the material, and provides an important reference for the development of high-efficiency optoelectronic materials. Background Art

[0002] Temperature-variable fluorescent materials are optical materials that are sensitive to temperature changes. Their fluorescence intensity, color or wavelength can change significantly with temperature changes. Such materials have important application value in the fields of temperature sensing, fluorescent probes, bioimaging and intelligent display. However, current temperature-variable fluorescent materials have problems such as insufficient response sensitivity, poor repeatability and complex preparation.

[0003] 1,3,6,8-tetraphenylethynylpyrene is a compound with a rigid planar π-conjugated structure. Its molecular structure can significantly enhance the electron coupling effect within the molecule by introducing multiple phenylethynyl groups, and the formation of an exciplex caused by the strong interaction between the two pyrene units can be avoided by using dibenzofuran as a bridge group, while providing a better interaction between the two pyrene units, thereby showing a sensitive fluorescence response to changes in the external environment (such as temperature). The present invention aims at the deficiencies in the prior art and provides a temperature-variable fluorescent material that is easy to prepare, sensitive to response, and excellent in thermal stability. Summary of the invention

[0004] In view of the problems existing in the above-mentioned prior art and the application needs in this research field, the present invention provides a method for preparing a temperature-variable fluorescent sensing material with a "V"-shaped pyrene dimer with low cost and simple preparation process and its application. The fluorescence change characteristics and response mechanism of the material in different temperature ranges are studied.

[0005] The molecular structures of 4,6-diethynyldibenzofuran (Formula 1), 1-bromo-3.6.8-triphenylethynylpyrene (Formula 2) and "V" type pyrene dimer (Formula 3) are as follows:

[0006] Synthesis of 4,6-disilylethynyldibenzofuran: Weigh 4,6-dibromodibenzofuran (1.0444 g, 3.20 mmol), bis(triphenylphosphine)palladium dichloride (25.2 mg, 0.32 mmol), and cuprous iodide (60.8 mg, 0.32 mmol) in a dry three-necked flask, remove oxygen from the flask by three pumps, then add 30.0 mL of degassed tetrahydrofuran and 30.0 mL of triethylamine, respectively, heat to 80 ° C, then add trimethylsilyl acetylene (4.4 mL, 32.0 mmol), stir the reaction for 24 hours, stop the reaction, then cool the reaction mixture to room temperature, evaporate to dryness under reduced pressure to obtain a crude product, and finally purify 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).

[0007] Synthesis of 4,6-diethynyldibenzofuran: 4,6-Disilylethynyldibenzofuran (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 the protection of nitrogen, 10.0 mL (1.0 mol / L) of 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 distilled under reduced pressure to remove the solvent. The crude product was purified by silica gel column chromatography (dichloromethane / n-hexane=2 / 7) to obtain 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).

[0008] Preparation of 1-bromo-3.6.8-triphenylethynylpyrene: 1.3.6.8-Tetrabromopyrene (517.1 mg, 1.0 mmol) was 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, and three pumps were used to remove the oxygen in the three-necked flask. Then, 30.0 mL of bubbling degassed tetrahydrofuran and 30.0 mL of triethylamine were added respectively, and the mixture was heated to 80°C. 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 a crude product. Finally, the product was purified by silica gel column chromatography (dichloromethane / n-hexane = 1 / 20) to obtain a yellow powder solid (150.1 mg, 18%).

[0009] Synthesis of "V" type pyrene dimer: 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, and three pumps were used to remove oxygen from the flask. Then, 30.0 mL of bubbling degassed tetrahydrofuran and 30.0 mL of triethylamine were added respectively, and the mixture was heated to 80°C. 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 a crude product, which was finally purified by silica gel column chromatography (dichloromethane / n-hexane = 1 / 5) to obtain a brown powder solid (216 mg, 12%).

[0010] The preparation method of the variable temperature fluorescent material having a "V"-shaped pyrene dimer comprises the following steps: Step 1: Weigh 17.2 mg of "V" type pyrene dimer, add 10 mL of dichloromethane to completely dissolve it, and prepare 1×10 -3 mol / L mother solution; Step 2: Pipette 0.1 mL of the mother solution into a colorimetric tube and let it stand until the dichloromethane evaporates completely; Step 3: Add 10 mL of methyltetrahydrofuran to the colorimetric tube in step 2 to make 1×10 -5 mol / L methyltetrahydrofuran solution; Step 4: Pipette 2 mL of 1×10 -5 mol / L methyltetrahydrofuran solution in a round cuvette, and place the round cuvette in a fluorescence low-temperature accessory. Step 5: Test its fluorescence spectrum at different temperatures (such as 80K to 300K).

[0011] The beneficial effects of the present invention are: a new material is found that can be used as a variable temperature fluorescent material. The preparation process and equipment of the variable temperature fluorescent material are simple and easy to realize industrial production. The selection of a dibenzofuran bridge group can avoid the formation of an exciplex caused by the strong interaction between the two pyrene units, and can provide a better interaction between the two pyrene monomers. Its molecular structure can significantly enhance the electron coupling effect within the molecule by introducing multiple phenylethynyl groups, can effectively improve the photoelectric performance, increase the temperature sensitivity, and realize the visualized temperature change. BRIEF DESCRIPTION OF THE DRAWINGS

[0012] The present invention is further described below in conjunction with the accompanying drawings and embodiments.

[0013] Figure 1 This is the NMR of 4,6-disilylethynyldibenzofuran;

[0014] Figure 2 This is the NMR of 4,6-diethynyldibenzofuran;

[0015] Figure 3 This is the NMR of 1-bromo-3.6.8-triphenylethynylpyrene;

[0016] Figure 4 is the mass spectrum of 1-bromo-3.6.8-triphenylethynylpyrene;

[0017] Figure 5 This is the NMR image of the "V"-shaped pyrene dimer;

[0018] Figure 6 This is the mass spectrum of the "V"-shaped pyrene dimer;

[0019] Figure 7 This is the UV image of the "V" type pyrene dimer in methyltetrahydrofuran solution;

[0020] Figure 8 This is the temperature-dependent fluorescence diagram of V”-type pyrene dimer in methyltetrahydrofuran;

[0021] Fig. 9 This is the CIE chromaticity diagram of the V”-shaped pyrene dimer in methyltetrahydrofuran. It can be seen from the figure that when the temperature of the pyrene dimer in the methyltetrahydrofuran solution increases from 80K to 300K, the color changes from yellow to red, which realizes the visualization of temperature changes and monitors a wide temperature range.

[0022] The above description is only a preferred embodiment of the present invention and does not limit the present invention in any form. Any ordinary technician familiar with the profession can smoothly implement the present invention according to the drawings and the above description. However, any technician familiar with the profession can make some changes, modifications and equivalent changes made by using the technical content disclosed above without departing from the scope of the technical solution of the present invention, which are all equivalent embodiments of the present invention. At the same time, any equivalent changes, modifications and evolutions made to the above embodiments based on the implementation technology of the present invention are within the protection scope of the technical solution of the present invention.

Claims

1. A pyrene dimer variable temperature fluorescent sensing material with a "V"-shaped structure, characterized in that: The pyrene dimer is a "V"-shaped structure formed by two pyrene molecules chemically bonded together, and the pyrene dimer has adjustable fluorescence response characteristics under different temperature conditions. At 80K, the material exhibits strong fluorescence emission at 500nm, and appears yellow at this time; as the temperature increases, the fluorescence intensity of the material at 500nm gradually decays, and the fluorescence intensity at 600nm increases, and the color of the solution appears red at this time.

2. The pyrene dimer variable temperature fluorescent sensing material according to claim 1, characterized in that: In the structure of the pyrene dimer, two pyrene molecules form a "V"-shaped structure through a benzene ring connecting group, and the connecting group is dibenzofuran, and the pyrene dimer with a "V"-shaped structure in which phenylethynyl replaces pyrene as a chromophore.

3. The pyrene dimer variable temperature fluorescent sensing material according to claim 1, characterized in that: The pyrene dimer exhibits temperature-dependent fluorescence intensity changes in the temperature range of 80K to 300K, and there is a linear or nearly linear relationship between the fluorescence intensity and the temperature.

4. A method for preparing the pyrene dimer variable temperature fluorescent sensing material according to claim 1, characterized in that: The following steps are involved: Two pyrene molecules are connected through a benzene ring connecting group through a chemical synthesis method to form a pyrene dimer with a "V"-shaped structure; during the synthesis process, the reaction conditions are adjusted to control the molecular structure, morphology and fluorescence properties of the pyrene dimer.

5. An application of the pyrene dimer variable temperature fluorescent 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.

6. The use according to claim 5, characterized in that: The pyrene dimer variable temperature fluorescent sensing material can achieve high-sensitivity and reversible fluorescence changes within a temperature range, and is used for high-precision temperature detection and abnormal temperature warning.

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