Novel room-temperature phosphorescent luminescent body with mechanochromic properties and preparation method thereof

Abstract

The present invention relates to a novel room-temperature phosphorescent luminescent material with mechanochromic properties and a preparation method thereof. The reaction structure is shown in FIG1 ; carbazole and 1,4-dibromobutane are used as raw materials, acetone is used as a solvent, potassium hydroxide is added, and the reaction is stirred; an intermediate is obtained after extraction, drying, rotary evaporation, and separation and purification; the obtained intermediate, cyanobiphenol or cyanonaphthol, acetone, potassium iodide, and potassium carbonate are mixed for reaction; and 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile or 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthonitrile having mechanochromic properties and room-temperature phosphorescent emission is obtained after extraction, drying, rotary evaporation, and separation and purification; the molecular structure does not contain metal elements, heavy atoms such as bromine and iodine, and has no distorted D-A conformation, and has high potential application value in the fields of anti-counterfeiting, information encryption, organic electroluminescent diodes, and biosensor imaging.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent materials, and in particular relates to a novel room-temperature phosphorescent luminescent body with mechanochromic properties and a preparation method thereof. Background Art

[0002] Current phosphorescent materials are mainly divided into two types: traditional metal complexes and pure organic room temperature phosphorescent materials. Traditional metal complex phosphorescent materials can achieve an internal quantum efficiency of 100%, which has very important application value in the field of electroluminescent devices. However, such metal complex phosphorescent materials usually use heavy metals such as iridium (Ir) and platinum (Pt), which are expensive and not conducive to their large-scale application and promotion. Pure organic room temperature phosphorescent (RTP) materials, an organic compound that does not contain metal elements in its molecular structure, are relatively low in cost, relatively environmentally friendly, have low biotoxicity, and have considerable stability and good processability. These advantages make pure organic room temperature phosphorescent materials have broad application prospects in optoelectronic devices and bioimaging. One of the key conditions for obtaining pure organic room temperature phosphors is to promote the intersystem crossing (ISC) process between singlet and triplet states (Nat. Commun., 2019, 10, 2111). The ISC process can effectively fill triplet excitons, thereby facilitating phosphorescent emission.

[0003] Due to their wide applications in anti-counterfeiting, sensing and imaging, stimuli-responsive luminescent materials have also been increasingly developed in recent years. So far, there have been many reports on the study of stimuli-responsive materials or phosphorescent materials alone. Paris et al. reported a temperature-responsive polymer containing the dye 4,4-difluoro-4-boron-3a,4a-diaza-s-indenene, which showed a reversible change in fluorescence intensity with temperature and could act as a fluorescent thermometer in water (Macromolecules, 2011, 44(1):80-86). As a type of stimuli-responsive material, force-responsive luminescent materials have high research value. They can change the intensity or wavelength of fluorescence under mechanical stimulation and have potential application value in sensing, display and storage. The luminescence properties of a given molecular system usually change significantly depending on the molecular stacking pattern because the interaction between molecules always changes the photophysical process. When subjected to mechanical forces such as shearing, crushing, grinding, stretching and hydrostatic pressure, their luminescence wavelength may change significantly, thereby showing a change in emission color. Zhang et al. studied a mechanochromic fluorescent material. They synthesized a difluoroborane compound using a traditional strong ultraviolet absorbing molecule avobenzone as a raw material. After crushing or scratching the compound crystal, the fluorescence color changed significantly from blue-green to yellow, and returned to blue-green emission after high-temperature heating (J.Am.Chem.Soc, 2010, 132(7)2160-2162). Although room temperature phosphorescent materials have made great progress in recent years, there are still few studies on room temperature phosphorescent materials with mechanochromic properties. Moreover, room temperature phosphorescent luminescent bodies with mechanochromic properties often need to introduce heavy metal elements such as iridium and platinum, or introduce heavy atoms such as bromine and iodine, or construct a distorted electron donor-electron acceptor (DA) conformation to achieve better mechanochromic properties and room temperature phosphorescent emission. This greatly limits the diversity of the chemical structure of mechanochromic room temperature phosphorescent molecules. Summary of the Invention

[0004] In response to the problems that the above-mentioned mechanochromic room temperature phosphorescent luminescent materials are relatively few in variety and have limited diversity in chemical structures, the present invention provides a novel room temperature phosphorescent luminescent material with mechanochromic properties and a preparation method thereof. The novel room temperature phosphorescent luminescent material with mechanochromic properties of the present invention is a pure organic compound that does not contain metal elements in its molecular structure, does not contain heavy atoms such as bromine and iodine, and has no distorted DA conformation. Carbazole is selected as the fluorophore, a long chain of four carbons is used as a connecting bridge, naphthalene nitrile and diphenyl nitrile are respectively used as ISC promoting factors, the molecular bonds are easy to rotate, the space is large, and the molecular conformation is relatively planar. The present invention synthesizes new organic light-emitting molecules through simple chemical reactions, expanding the structure of mechanochromic room temperature phosphors. The luminescent material of the present invention has a simple structure, a simple synthesis method, few reaction steps, cheap and readily available raw materials, and is easy to industrialize.

[0005] The technical solutions of the present invention are as follows:

[0006] A novel room-temperature phosphorescent luminescent material with mechanochromic properties has the following structural formula:

[0007]

[0008] Wherein R is one of the following groups:

[0009]

[0010] The present invention provides a novel method for preparing a room temperature phosphorescent luminescent body having mechanochromic properties, comprising the following steps:

[0011] 1) Carbazole and 1,4-dibromobutane were used as raw materials, acetone was used as solvent, potassium hydroxide was added, and the mixture was stirred. After the reaction was completed, the reaction mixture was poured into distilled water to quench the reaction, extracted with dichloromethane, and the organic phase was dried and rotary evaporated. Then, column chromatography was performed using ethyl acetate and petroleum ether as eluents to obtain the intermediate 9-(4-bromobutyl)-9H-carbazole.

[0012] 2) Using cyanobiphenol or cyanonaphthol, 9-(4-bromobutyl)-9H-carbazole obtained in step 1) as raw materials, acetone as solvent, potassium iodide as catalyst, potassium carbonate is added, and the mixture is stirred for reaction. After the reaction is completed, the mixture is poured into distilled water for quenching, extracted with dichloromethane, and the organic phase is dried and rotary evaporated. Then, column chromatography is performed using ethyl acetate and petroleum ether as eluents to separate 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile or 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthocarbonitrile.

[0013] In the step 1), the preferred reaction temperature is 20° C. to 50° C., and the reaction time is 12 to 30 hours.

[0014] In the step 2), the preferred reaction temperature is 45° C. to 65° C., and the reaction time is 20 to 30 hours.

[0015] In the step 1), the molar ratio of carbazole: 1,4-dibromobutane: potassium hydroxide is preferably 1: (3-6): (2-4); and the weight-to-volume ratio of carbazole to solvent acetone is (2-5) g / 100 mL.

[0016] In the step 2), the molar ratio of 9-(4-bromobutyl)-9H-carbazole: cyanobiphenol or cyanonaphthol: potassium iodide: potassium carbonate is preferably 1:(1-2):(0.01-0.02):(2-4); and the weight-to-volume ratio of 9-(4-bromobutyl)-9H-carbazole to the solvent acetone is (2-4) g / 100 mL.

[0017] The novel room temperature phosphorescent luminescent body with mechanochromic properties of the present invention is applied to the fields of anti-counterfeiting, information encryption, organic electroluminescent diodes, biosensor imaging, etc.

[0018] The specific instructions are as follows:

[0019] A novel room-temperature phosphorescent luminescent material with mechanochromic properties has the following general structural formula:

[0020]

[0021] Wherein R is one of the following groups:

[0022]

[0023] When R is a biphenyl group, the luminophore is 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile, and its structural formula is:

[0024]

[0025] When R is a naphthalene group, the luminophore is 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile, and its structure is:

[0026]

[0027] The present invention provides a method for preparing the luminous bodies 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile and 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthonitrile. The synthetic routes are as follows: Figure 1 shown.

[0028] Prepare according to the following steps:

[0029] Step 1) Synthesis of intermediate 9-(4-bromobutyl)-9H-carbazole:

[0030] Carbazole and 1,4-dibromobutane are used as raw materials, acetone is used as solvent, potassium hydroxide is added, and the reaction is stirred for 12 to 30 hours at a temperature of 20°C to 50°C. After the reaction is completed, the reaction mixture is poured into distilled water to quench the reaction, extracted with dichloromethane, and the organic phase is dried and the solvent is removed by rotary evaporation. Then, the intermediate 9-(4-bromobutyl)-9H-carbazole is separated by column chromatography using ethyl acetate and petroleum ether as eluents to obtain the intermediate 9-(4-bromobutyl)-9H-carbazole as a light yellow powder.

[0031] Step 2) Synthesis of 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile or 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthocarbonitrile:

[0032] Using 9-(4-bromobutyl)-9H-carbazole, cyanobiphenol, or cyanonaphthol as raw materials, acetone as solvent, and potassium iodide as catalyst, potassium carbonate is added. The reaction temperature is raised to 45°C to 65°C and stirred for 20 to 30 hours. After the reaction, the mixture is quenched in distilled water and extracted with dichloromethane. The organic phase is dried and rotary evaporated. Column chromatography using ethyl acetate and petroleum ether as eluents yields the desired white product, 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile or 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthocarbonitrile.

[0033] Furthermore, in the preparation method of a novel room-temperature phosphorescent luminescent body with mechanochromic properties described in the present invention, the molar ratio of carbazole to 1,4-dibromobutane in step 1) is 1:(3-6); the molar ratio of carbazole to potassium hydroxide is 1:(2-4).

[0034] In the step 1), the weight-to-volume ratio of carbazole to the solvent acetone is (2-5) g / 100 mL; the weight-to-volume ratio of carbazole to distilled water is (1-4) g / 100 mL; and the weight-to-volume ratio of carbazole to dichloromethane is (0.5-1) g / 100 mL.

[0035] In the step 1), a silica gel column is used for separation and purification, and the eluent is petroleum ether: ethyl acetate = (70-100): 1

[0036] In the step 2), the molar ratio of 9-(4-bromobutyl)-9H-carbazole to cyanobiphenol or cyanonaphthol is 1:(0.5-2); the molar ratio of 9-(4-bromobutyl)-9H-carbazole to potassium iodide is 1:(0.01-0.02); and the molar ratio of 9-(4-bromobutyl)-9H-carbazole to potassium carbonate is 1:(2-4).

[0037] In the step 2), the weight-to-volume ratio of 9-(4-bromobutyl)-9H-carbazole to the solvent acetone is (2-4) g / 100 mL; the weight-to-volume ratio of 9-(4-bromobutyl)-9H-carbazole to distilled water is (2-8) g / 100 mL; and the weight-to-volume ratio of 9-(4-bromobutyl)-9H-carbazole to dichloromethane is (1-4) g / 100 mL.

[0038] In the step 2), a silica gel column is used for separation and purification, and the eluent is petroleum ether:ethyl acetate = (20-40):1.

[0039] The luminophore prepared by the present invention was characterized by using a steady-state / transient fluorescence spectrometer. The steady-state fluorescence spectrum and delayed spectrum of the original powder of the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile at room temperature are shown in FIG. Figure 2As shown. Its fluorescence spectrum shows four emission peaks at 373nm, 416nm, 443nm and 470nm, all of which are immediate fluorescence emissions, attributed to the radiative transition of excitons from the first excited state of the singlet state to the ground state. In the delayed spectrum, a double-peak emission is shown, with wavelengths of 553nm and 605nm, respectively. This emission peak is the room temperature phosphorescence peak, attributed to the light emitted by the excitons from the first excited state of the triplet state to the ground state. Since the energy of the triplet state is lower than that of the singlet state, the wavelength of the phosphorescence emitted by the triplet transition is longer than the wavelength of the fluorescence emitted from the singlet transition. From the steady-state fluorescence spectrum and the delayed spectrum, it can be seen that the luminescent material 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile has good dual emission of immediate fluorescence and room temperature phosphorescence.

[0040] The original powder of the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile was ground in a mortar. The steady-state fluorescence spectra before and after grinding were as follows: Figure 3 After grinding, the fluorescence peaks of the luminescent material 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile at 416nm, 443nm, and 470nm account for a smaller proportion of the spectrum. This may be because the microcrystalline structure of the original powder is partially destroyed under the action of external force, and the intermolecular interaction force is also partially eliminated. Figure 3 The illustration shows the fluorescence emission color coordinates of the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile before and after grinding. It can be seen that the color coordinates of the light emitted by the luminophore change after grinding, and the emission color of the luminophore changes from dark blue to light blue, proving that the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile has mechanochromic properties.

[0041] The luminophore prepared by the present invention was characterized by using a steady-state / transient fluorescence spectrometer. The steady-state fluorescence spectrum and delayed spectrum of the original powder of the luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile at room temperature are shown in FIG. Figure 4 As shown. Its fluorescence spectrum shows a narrow single-peak emission at 376nm, indicating immediate fluorescence emission. In the delayed spectrum, its phosphorescence emission peak is located at 630nm, showing broad single-peak emission properties. From the steady-state fluorescence spectrum and delayed spectrum, it can be seen that the luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthocarbonitrile has good dual emission of immediate fluorescence and room temperature phosphorescence.

[0042] The original powder of the luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthocarbonitrile was ground in a mortar. The steady-state fluorescence spectra before and after grinding were as follows: Figure 5 As shown in Figure 2, the fluorescence spectrum undergoes a red shift after grinding, from 376 nm to 391 nm, a 15 nm shift. This is likely due to changes in intermolecular interactions under the action of external forces, which alter the conformation of the material and strengthen the π-π stacking interactions, leading to a red shift in the emission spectrum. The half-width of the fluorescence peak also widens after grinding, indicating a more disordered molecular arrangement. Figure 5 The illustration shows the fluorescence emission color coordinates of the luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile before and after grinding. It can be seen that the color coordinates of the light emitted by the luminophore also change after grinding, and the emission color becomes lighter, proving that the luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile has mechanochromic properties.

[0043] In the luminophore molecules of the present invention, the introduction of naphthalene nitrile and biphenyl nitrile can promote the occurrence of the ISC process in the molecular system. The lone pair of electrons on the cyano nitrogen atom can participate in the n→π* transition, which can promote ISC, reduce the energy level difference between the singlet state and the triplet state, and then increase the yield of triplet excitons, and promote the emission of room temperature phosphorescence. In addition, the introduction of heteroatoms and conjugated systems also helps to increase the abundant intermolecular interaction forces, thereby constructing a rigid environment, limiting the thermal motion of molecules, suppressing non-radiative decay, and allowing more energy to be emitted in the form of light, which contributes to the emission of room temperature phosphorescence. The present invention applies external force to the original powder of the luminophore by grinding, changes the intermolecular interaction, and makes it show a force stimulus response characteristic.

[0044] In summary, the new luminophores 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile and 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthocarbonitrile proposed in the present invention have good mechanochromic properties and room temperature phosphorescence properties.

[0045] The novel room-temperature phosphorescent luminescent body with mechanochromic properties of the present invention can be applied to fields such as anti-counterfeiting, information encryption, organic electroluminescent diodes, and biosensor imaging.

[0046] Dissolve the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile in dichloromethane, then apply the solution on a non-fluorescent paper. Wait until the dichloromethane evaporates. Figure 6 As shown, blue fluorescence can be clearly observed under ultraviolet light. After removing the ultraviolet light, the paper shows yellow emission visible to the naked eye. The luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile is dissolved in dichloromethane, and the solution is then coated on a non-fluorescent paper. After the dichloromethane evaporates, Figure 7As shown, blue fluorescence can be clearly observed under ultraviolet light. After the ultraviolet light is removed, no obvious luminescence is observed. This indicates that the luminophores 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile and 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthocarbonitrile described in the present invention have application potential in the field of anti-counterfeiting.

[0047] Compared with the prior art, the present invention has the following beneficial effects:

[0048] The present invention describes a novel room-temperature phosphorescent (RTP) luminescent material with mechanochromic properties. Carbazole is used as the fluorophore, a long carbon chain serves as a bridge, and naphthalene nitrile and diphenyl nitrile serve as ISC-promoting factors, respectively. Two mechanochromic room-temperature phosphorescent luminescent materials were obtained through simple chemical synthesis. Their molecular structures contain no metal elements, heavy atoms such as bromine and iodine, and exhibit no distorted DA conformation. The molecular bonds offer ample room for easy rotation and a relatively planar molecular conformation. This approach addresses the current limitations of the limited variety and chemical diversity of mechanochromic room-temperature phosphorescent luminescent materials, providing a new approach for the design of mechanochromic room-temperature phosphorescent luminescent materials. According to the El-Sayed rule, the cyano group is a pseudohalogen with a lone pair of electrons on its nitrogen atom, which can trigger an n→π* transition, thereby promoting ISC. The introduction of naphthalene nitrile and diphenyl nitrile not only further promotes the ISC process within the molecular system, but also contributes to the enrichment of intermolecular interactions by heteroatoms and conjugated systems, thereby creating a rigid environment that restricts thermal motion, inhibits non-radiative decay, and facilitates RTP emission. The invention discloses a method for preparing a novel room-temperature phosphorescent luminescent body with mechanochromic properties. The luminescent body is obtained by using carbazole as a raw material through a two-step CN coupling reaction and a CO coupling reaction. The synthesis method is simple, has few reaction steps, and employs mild conditions. The luminescent body is easy to industrialize and has high potential application value in the fields of anti-counterfeiting, information encryption, organic electroluminescent diodes, and biosensor imaging. BRIEF DESCRIPTION OF THE DRAWINGS

[0049] Figure 1 The synthetic route for the luminophores 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile and 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthocarbonitrile;

[0050] Figure 2 The figure shows the overlay of the steady-state fluorescence spectrum and delayed spectrum of the original powder of the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile;

[0051] Figure 3The steady-state fluorescence spectra of the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile before and after grinding are shown in the inset. The color coordinates before and after grinding are shown in the inset.

[0052] Figure 4 This is a superposition of the steady-state fluorescence spectrum and delayed spectrum of the original powder of the luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile;

[0053] Figure 5 The steady-state fluorescence spectra of the luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile before and after grinding are shown in the inset. The color coordinates before and after grinding are shown in the inset.

[0054] Figure 6 This is a photo of the application of the luminescent material 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile in the field of anti-counterfeiting;

[0055] Figure 7 This is a real photo of the application of the luminescent material 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile in the field of anti-counterfeiting;

[0056] Figure 8 9-(4-bromobutyl)-9H-carbazole 1 H NMR spectrum;

[0057] Figure 9 The luminescent material 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile 1 H NMR spectrum;

[0058] Figure 10 The luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthocarbonitrile 1 H NMR spectrum. DETAILED DESCRIPTION

[0059] The technical solution of the present invention will be further described below with reference to specific embodiments, but the present invention is not limited thereto.

[0060] Example 1: Synthesis of 9-(4-bromobutyl)-9H-carbazole:

[0061] To a clean three-necked flask equipped with a magnetic stirrer, carbazole (0.50 g, 3 mmol) was added sequentially. Acetone (20 mL) was stirred and dissolved. Potassium hydroxide (0.50 g, 9 mmol) was then added, followed by 1,4-dibromobutane (3.24 g, 15 mmol). The mixture was stirred at 25°C for 24 h. After completion of the reaction, the reaction mixture was poured into 20 mL of distilled water to quench the reaction. The mixture was then extracted with 60 mL of dichloromethane. The organic phase was dried, the solvent removed by rotary evaporation, and the product was purified by silica gel column chromatography using ethyl acetate and petroleum ether (v / v, 1:80) as eluents to obtain 0.75 g of the intermediate 9-(4-bromobutyl)-9H-carbazole as a light yellow powder in an 83% yield. 1 H NMR (400MHz, DMSO-d6) δ8.12(d,J=7.8Hz,2H),7.53(d,J=8.2Hz,2H),7.40(t,J=7.6H z, 2H), 7.17 (t, J = 7.4Hz, 2H), 4.37 (d, J = 6.2Hz, 2H), 3.32 (s, 4H), 1.95–1.77 (m, 2H). That 1 H NMR spectrum Figure 8 shown.

[0062] Example 2: Synthesis of 9-(4-bromobutyl)-9H-carbazole:

[0063] To a clean three-necked flask equipped with a magnetic stirrer, carbazole (0.50 g, 3 mmol) and acetone (10 mL) were added sequentially and stirred to dissolve. Potassium hydroxide (0.34 g, 6 mmol) was then added, followed by 1,4-dibromobutane (1.94 g, 9 mmol). The mixture was stirred at 20°C for 12 h. After completion of the reaction, the reaction mixture was poured into 12.5 mL of distilled water to quench the reaction. Extraction was then performed with 50 mL of dichloromethane. The organic phase was dried, the solvent removed by rotary evaporation, and the product was purified by silica gel column chromatography using ethyl acetate and petroleum ether (v / v, 1:70) as eluents to obtain 0.66 g of the intermediate 9-(4-bromobutyl)-9H-carbazole as a light yellow powder in a 73% yield.

[0064] Example 3: Synthesis of 9-(4-bromobutyl)-9H-carbazole:

[0065] To a clean three-necked flask equipped with a magnetic stirrer, carbazole (0.50 g, 3 mmol) was added sequentially. Acetone (25 mL) was stirred to dissolve the mixture. Potassium hydroxide (0.67 g, 12 mmol) was then added, followed by 1,4-dibromobutane (3.89 g, 18 mmol). The mixture was stirred at 50°C for 30 h. After completion of the reaction, the reaction mixture was poured into 50 mL of distilled water to quench the reaction. The mixture was then extracted with 100 mL of dichloromethane. The organic phase was dried, the solvent removed by rotary evaporation, and the product was separated and purified by silica gel column chromatography using ethyl acetate and petroleum ether (v / v, 1:100) as eluents to obtain 0.71 g of the intermediate 9-(4-bromobutyl)-9H-carbazole as a light yellow powder in a 79% yield.

[0066] Example 4: Synthesis of 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile:

[0067] 9-(4-Bromobutyl)-9H-carbazole (1.19 g, 4.0 mmol) and cyanobiphenol (0.39 g, 2.0 mmol) were added to a three-necked flask equipped with a magnetic stirrer and dissolved in acetone (40 mL). Potassium carbonate (1.11 g, 8.0 mmol) and potassium iodide (9.96 mg, 0.06 mmol) were added to the reaction vessel. The reaction system was stirred and refluxed at 56°C for 24 h. After completion of the reaction, the reaction mixture in the three-necked flask was poured into 20 mL of distilled water to quench the reaction. Extraction was performed with 60 mL of dichloromethane. The organic phase was dried and the solvent was evaporated. The product was separated and purified by silica gel column chromatography using ethyl acetate and petroleum ether (v / v, 1:20) as eluents to obtain 0.71 g of 4'-(4-(9H-carbazol-9-yl)butyloxy)-[1,1'-biphenyl]-4-carbonitrile as a white powder in an 85% yield. 1 H NMR(400MHz, DMSO-d6)δ8.16(dt,J=7.8,0.9Hz,2H),7.94–7.75(m,4H),7.73–7.55(m,4H),7.46(ddd,J=8.3,7.1, 1.2Hz,2H),7.29–7.13(m,2H),7.10–6.95(m,2H),4.50(t,J=7.0Hz,2H),4.03(t,J=6.4Hz,2H),2.06–1.68(m,4H). 13C NMR(101MHz,DMSO-d6)δ162.50,140.43,134.58,126.13,122.53,120.72,119.5 9,119.15,115.97,109.72,103.15,68.22,42.30,26.50,25.53.HRMS(ESI):m / z calcd.for C 29 H 24 N2O[M+H] + 417.1961, found 417.1978. 1 H NMR spectrum Figure 9 shown.

[0068] Example 5: Synthesis of 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile:

[0069] 9-(4-Bromobutyl)-9H-carbazole (1.19 g, 4.0 mmol) and cyanobiphenol (0.78 g, 4.0 mmol) were added to a three-necked flask equipped with a magnetic stirrer and dissolved in acetone (30 mL). Potassium carbonate (1.38 g, 10.0 mmol) and potassium iodide (6.64 mg, 0.04 mmol) were added to the reaction vessel. The reaction system was stirred and refluxed at 45°C for 20 h. After completion of the reaction, the reaction mixture in the three-necked flask was poured into 15 mL of distilled water to quench the reaction. Extraction with 30 mL of dichloromethane was performed, and the organic phase was dried and the solvent was evaporated. The product was separated and purified by silica gel column chromatography using ethyl acetate and petroleum ether (v / v, 1:30) as eluents to obtain 1.15 g of 4'-(4-(9H-carbazol-9-yl)butyloxy)-[1,1'-biphenyl]-4-carbonitrile as a white powder in a yield of 69%.

[0070] Example 6: Synthesis of 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile:

[0071] To a three-necked flask equipped with a magnetic stirrer, add 9-(4-bromobutyl)-9H-carbazole (1.19 g, 4.0 mmol) and cyanodiphenol (1.56 g, 8.0 mmol) and dissolve in acetone (60 mL). Add potassium carbonate (2.21 g, 16.0 mmol) and potassium iodide (13.28 mg, 0.08 mmol) to the reaction vessel. Stir and reflux the reaction system at 65°C for 30 h. After completion, pour the reaction mixture in the three-necked flask into 60 mL of distilled water to quench the reaction. The product was extracted with 120 mL of dichloromethane, and the organic phase was dried and the solvent was removed by rotary evaporation. The product was separated and purified by silica gel column chromatography using ethyl acetate and petroleum ether (v / v, 1:40) as eluents to obtain 1.12 g of 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile as a white powder in a yield of 72%.

[0072] Example 7: Synthesis of 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile:

[0073] 9-(4-Bromobutyl)-9H-carbazole (0.60 g, 2.0 mmol) and cyanonaphthol (0.67 g, 4.0 mmol) were added to a three-necked flask equipped with a magnetic stirrer and dissolved in acetone (25 mL). Potassium carbonate (0.58 g, 4.0 mmol) and potassium iodide (6.64 mg, 0.04 mmol) were added to the reaction vessel. The mixture was stirred and refluxed at 56°C for 24 h. After completion of the reaction, the reaction mixture in the three-necked flask was poured into 20 mL of distilled water to quench the reaction. The reaction mixture was extracted with 60 mL of dichloromethane, and the organic phase was dried and the solvent was evaporated. The product was separated and purified by silica gel column chromatography using ethyl acetate and petroleum ether (v / v, 1:20) as eluents to obtain 0.63 g of 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile as a white powder in an 81% yield. 1 H NMR (400MHz, DMSO-d6) δ8.46(d,J=1.7Hz,1H),8.16(d,J=7.7Hz,2H),7.94(dd,J=8.8,5.3Hz,2H),7.75–7.59(m,3H),7.45(ddd ,J=16.0,7.4,1.9Hz,3H),7.33–7.16(m,3H),4.52(t,J=7.0Hz,2H),4.16(t,J=6.4Hz,2H),1.91(ddd,J=61.5,10.0,6.8Hz,4H). 13C NMR (101MHz, DMSO) δ159.42,140.45,136.66,134.38,130.61,128.43,127.75,127.31,126.14,122.54 ,120.95,120.73,119.93,119.15,109.73,107.48,106.05,68.06,42.38,26.63,25.67.HRMS(ESI):m / z calcd.for C 27 H 22 N2O[M+H] + 391.1804, found 391.2839. 1 H NMR spectrum Figure 10 shown.

[0074] Example 8: Synthesis of 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile:

[0075] 9-(4-Bromobutyl)-9H-carbazole (0.60 g, 2.0 mmol) and cyanonaphthol (0.17 g, 1.0 mmol) were added to a three-necked flask equipped with a magnetic stirrer and dissolved in acetone (15 mL). Potassium carbonate (0.83 g, 6.0 mmol) and potassium iodide (3.32 mg, 0.02 mmol) were added to the reaction vessel. The mixture was stirred and refluxed at 45°C for 20 h. After completion of the reaction, the reaction mixture in the three-necked flask was poured into 7.5 mL of distilled water to quench the reaction. The mixture was extracted with 15 mL of dichloromethane. After drying the organic phase, the solvent was evaporated and the product was separated and purified by silica gel column chromatography using ethyl acetate and petroleum ether (v / v, 1:30) as eluents to obtain 0.27 g of 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthocarbonitrile as a white powder in a 69% yield.

[0076] Example 9: Synthesis of 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile:

[0077] 9-(4-Bromobutyl)-9H-carbazole (0.60 g, 2.0 mmol) and cyanonaphthol (0.34 g, 2.0 mmol) were added to a three-necked flask equipped with a magnetic stirrer and dissolved in acetone (30 mL). Potassium carbonate (1.11 g, 8.0 mmol) and potassium iodide (4.98 mg, 0.03 mmol) were added to the reaction vessel. The mixture was stirred and refluxed at 65°C for 30 h. After completion of the reaction, the reaction mixture in the three-necked flask was poured into 30 mL of distilled water to quench the reaction. The mixture was extracted with 40 mL of dichloromethane. After drying the organic phase, the solvent was evaporated and the crude product was separated and purified by silica gel column chromatography using ethyl acetate and petroleum ether (v / v, 1:40) as eluents to obtain 0.51 g of 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthocarbonitrile as a white powder in a 65% yield.

[0078] Example 10: Emission properties of luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile

[0079] The luminophore prepared by the present invention was characterized by using a steady-state / transient fluorescence spectrometer. The steady-state fluorescence spectrum and delayed spectrum of the original powder of the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile at room temperature are shown in FIG. Figure 2 As shown in the figure, the steady-state fluorescence spectrum shows four immediate fluorescence emission peaks at 373nm, 416nm, 443nm, and 470nm. The delayed spectrum shows two room-temperature phosphorescence peaks at 553nm and 605nm. Both the steady-state fluorescence and delayed spectra indicate that the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile exhibits excellent dual emission of immediate fluorescence and room-temperature phosphorescence.

[0080] Example 11: Emission properties of luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile

[0081] The luminophore prepared by the present invention was characterized by using a steady-state / transient fluorescence spectrometer. The steady-state fluorescence spectrum and delayed spectrum of the original powder of the luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile at room temperature are shown in FIG. Figure 4 As shown in the figure, the steady-state fluorescence spectrum shows a narrow emission peak at 376 nm, indicating prompt fluorescence emission. In the delayed spectrum, a single phosphorescence emission peak is observed at 630 nm, indicating broad, single-peak emission. Both the steady-state fluorescence and delayed spectra indicate that the luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthocarbonitrile exhibits excellent dual emission characteristics, including prompt fluorescence and room-temperature phosphorescence.

[0082] Example 12: Mechanochromic Properties of Luminescent 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile

[0083] Take 20-30 mg of the original powder of the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile and grind it in a mortar. The steady-state fluorescence spectra before and after grinding are as follows: Figure 3 After grinding, the proportion of the fluorescence peaks of the luminescent body 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile at 416nm, 443nm and 470nm in the spectrum is reduced. Figure 3 As can be seen from the color coordinate illustration, the color coordinates of the light emitted by the luminescent body changed after grinding, and the emission color changed from dark blue to light blue, proving that the luminescent body 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile has mechanochromic properties.

[0084] Example 13: Mechanochromic Properties of Luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile

[0085] Take 20-30 mg of the original powder of the luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile and grind it in a mortar. The steady-state fluorescence spectra before and after grinding are as follows: Figure 5 As shown. After grinding, its fluorescence spectrum has red-shifted from the original 376nm to 391nm, a red shift of 15nm. After grinding, the half-peak width of its fluorescence peak has also widened, which means that the arrangement of molecules tends to be disordered. Figure 5 As can be seen from the color coordinate illustration, the color coordinates of the light emitted by the luminescent body also change after grinding, proving that the luminescent body 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile has mechanochromic properties.

[0086] Example 14: Application of the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile in the field of anti-counterfeiting and encryption

[0087] Dissolve 10-20 mg of the luminophore 4'-(4-(9H-carbazol-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile in 5-10 mL of dichloromethane, then apply the solution on a non-fluorescent paper. Wait until the dichloromethane evaporates. Figure 6 As shown, blue fluorescence can be clearly observed under UV light, and after removing the UV light, the paper shows yellow emission visible to the naked eye.

[0088] Example 15: Application of luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile in the field of anti-counterfeiting and encryption

[0089] Dissolve 10-20 mg of luminophore 6-(4-(9H-carbazol-9-yl)butoxy)-2-naphthalenecarbonitrile in 5-10 mL of dichloromethane, then apply the solution on a non-fluorescent paper. After the dichloromethane evaporates, Figure 7 As shown, blue fluorescence can be clearly observed under ultraviolet light, and no obvious luminescence is observed after the ultraviolet light is removed.

[0090] Although the present invention has been described above, the present invention is not limited to the above-mentioned specific embodiments. The above-mentioned specific embodiments are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can make many variations without departing from the purpose of the present invention, and these are all protected by the present invention.

Claims

1. A novel room temperature phosphorescent luminescent body with mechanochromic properties, characterized by the structural formula as follows: Wherein R is the following group:

2. The method for preparing the novel room temperature phosphorescent luminescent body with mechanochromic properties according to claim 1, characterized in that: The following steps are involved: 1) Carbazole and 1,4-dibromobutane are used as raw materials, acetone is used as solvent, potassium hydroxide is added, and the mixture is stirred to react; after the reaction is completed, the reaction mixture is poured into distilled water to quench the reaction, extracted with dichloromethane, the organic phase is dried and rotary evaporated, and then separated by column chromatography using ethyl acetate and petroleum ether as eluents to obtain the intermediate 9-(4-bromobutyl)-9H-carbazole; 2) Using cyanobiphenol and 9-(4-bromobutyl)-9H-carbazole obtained in step 1) as raw materials, acetone as solvent, potassium iodide as catalyst, potassium carbonate is added, and the mixture is stirred for reaction; after the reaction is completed, the mixture is poured into distilled water for quenching, extracted with dichloromethane, the organic phase is dried and rotary evaporated, and then separated by column chromatography using ethyl acetate and petroleum ether as eluents to obtain 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile.

3. The preparation method according to claim 2, wherein: In step 1), the reaction temperature is 20° C. to 50° C., and the reaction time is 12 to 30 hours.

4. The preparation method according to claim 2, wherein: In step 1), the molar ratio of carbazole: 1,4-dibromobutane: potassium hydroxide is 1: (3-6): (2-4); and the weight-volume ratio of carbazole to solvent acetone is (2-5) g / 100 mL.

5. The preparation method according to claim 2, wherein: In step 1), the eluent is petroleum ether:ethyl acetate = (70-100):

1.

6. The preparation method according to claim 2, wherein: In step 2), the reaction temperature is 45° C. to 65° C., and the reaction time is 20 to 30 h.

7. The preparation method according to claim 2, wherein: In step 2), the molar ratio of 9-(4-bromobutyl)-9H-carbazole: cyanodiphenol: potassium iodide: potassium carbonate is 1:(1-2):(0.01-0.02):(2-4); the weight volume ratio of 9-(4-bromobutyl)-9H-carbazole to the solvent acetone is (2-4) g / 100 mL.

8. The preparation method according to claim 2, wherein: Step 2) The eluent is petroleum ether:ethyl acetate = (20-40):

1.

9. The novel room-temperature phosphorescent luminescent material with mechanochromic properties of claim 1 is used in the fields of anti-counterfeiting, information encryption, organic electroluminescent diodes, and biosensor imaging.

Images