Novel room-temperature phosphorescent illuminant with mechanochromism characteristic and preparation method of novel room-temperature phosphorescent illuminant

Abstract

The invention relates to a novel room-temperature phosphorescent illuminant with mechanochromism characteristics and a preparation method of the room-temperature phosphorescent illuminant. The reaction structural formula is as shown in Figure 1. Carbazole and 1, 4-dibromobutane are used as raw materials, acetone is used as a solvent, potassium hydroxide is added, and stirring reaction is performed; performing extraction, drying, rotary evaporation, separation and purification to obtain an intermediate; mixing and reacting the obtained intermediate, cyano diphenol or cyano naphthol, acetone, potassium iodide and potassium carbonate; 4 '-(4-(9H-carbazole-9-yl) butoxy)-[1, 1'-biphenyl]-4-carbonitrile or 6-(4-(9H-carbazole-9-yl) butoxy)-2-naphthyl nitrile with mechanochromic characteristic and room temperature phosphorescence emission is obtained through extraction, drying, rotary evaporation, separation and purification. The molecular structure of the material does not contain metal elements, does not contain heavy atoms such as bromine and iodine, has no distorted D-A conformation, and has high potential application value in the fields of anti-counterfeiting, information encryption, organic light-emitting diodes, biosensing imaging and the like.

Description

Technical Field

[0001] The 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] At present, phosphorescent materials are mainly divided into two types: traditional metal complexes and pure organic room temperature phosphorescent materials. The internal quantum efficiency of traditional metal complex phosphorescent materials can reach 100%, which has very important application value in the field of electroluminescent devices. However, this metal complex phosphorescent material usually uses heavy metals such as iridium (Ir) and platinum (Pt), which is expensive and not conducive to its 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, have relatively low cost, are relatively environmentally friendly, have weak biological toxicity, 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, which is conducive to the emission of phosphorescence.

[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 are 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 luminescent 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 luminescent wavelength may change significantly, thereby showing a change in emission color. Zhang et al. studied a mechanochromic fluorescent material. They synthesized a difluoroboric compound using a traditional strong ultraviolet absorption molecule avobenzone as a raw material. After crushing or scratching the compound crystal, the fluorescence color changed significantly from blue-green to yellow, and recovered 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. 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, which greatly limits the diversity of the chemical structure of mechanochromic room temperature phosphorescent molecules. Summary of the invention

[0004] In view of the problem that there are few types of the above-mentioned mechanochromic room temperature phosphorescent luminescent bodies and the diversity of chemical structures is limited, the present invention provides a novel room temperature phosphorescent luminescent body with mechanochromic properties and a preparation method thereof. The novel room temperature phosphorescent luminescent body 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 a fluorophore, a long chain of four carbons is used as a connecting bridge, naphthalene nitrile and biphenyl 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 body of the present invention has a simple structure, a simple synthesis method, few reaction steps, cheap and easy-to-obtain raw materials, and is easy to industrialize.

[0005] The technical solution of the present invention is as follows:

[0006] A novel room temperature phosphorescent luminescent body with mechanochromic properties, the structural formula of which is as follows:

[0007]

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

[0009]

[0010] The invention discloses 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 are used as raw materials, acetone is used as solvent, potassium hydroxide is added, and the reaction is stirred. After the reaction is completed, the reaction mixture is poured into distilled water to quench the reaction, and dichloromethane is used for extraction. The organic phase is dried and rotary evaporated, and then ethyl acetate and petroleum ether are used as eluents, and column chromatography is used to separate the intermediate 9-(4-bromobutyl)-9H-carbazole;

[0012] 2): Use cyanobiphenol or cyanonaphthol, 9-(4-bromobutyl)-9H-carbazole obtained in step 1) as raw materials, acetone as solvent, potassium iodide as catalyst, add potassium carbonate, and stir to react. After the reaction is completed, pour into distilled water to quench, extract with dichloromethane, dry the organic phase, and evaporate it by rotary evaporation, and then use ethyl acetate and petroleum ether as eluents to separate by column chromatography to obtain 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile or 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthonitrile.

[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); the weight volume ratio of carbazole to solvent acetone is (2-5) g / 100 mL.

[0016] In the step 2), the preferred molar ratio of 9-(4-bromobutyl)-9H-carbazole: cyanobiphenol or cyanonaphthol: 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.

[0017] The novel room temperature phosphorescent luminescent body with mechanochromic characteristics 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 body with mechanochromic properties, the general structural formula of which is as follows:

[0020]

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

[0022]

[0023] When R is a biphenyl group, the luminophore is 4'-(4-(9H-carbazole-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-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile, and its structure is:

[0026]

[0027] The present invention provides a method for preparing 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 reaction 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, the organic phase is dried, the solvent is removed by rotary evaporation, and then ethyl acetate and petroleum ether are used as eluents. Column chromatography separation obtains the intermediate 9-(4-bromobutyl)-9H-carbazole, which is a light yellow powder.

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

[0032] 9-(4-bromobutyl)-9H-carbazole, cyanobiphenol or cyanonaphthol are used as raw materials, acetone is used as solvent, potassium iodide is used as catalyst, potassium carbonate is added, the reaction temperature is raised to 45°C to 65°C, and the reaction is stirred for 20 to 30 hours. After the reaction is completed, it is poured into distilled water for quenching, extracted with dichloromethane, the organic phase is dried and rotary evaporated, and then ethyl acetate and petroleum ether are used as eluents, and column chromatography is used to separate the white target product 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile or 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthonitrile.

[0033] Furthermore, in the method for preparing 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] The weight-volume ratio of carbazole to solvent acetone in step 1) is (2-5) g / 100 mL; the weight-volume ratio of carbazole to distilled water is (1-4) g / 100 mL; and the weight-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] The molar ratio of 9-(4-bromobutyl)-9H-carbazole to cyanobiphenol or cyanonaphthol in step 2) 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] The weight volume ratio of 9-(4-bromobutyl)-9H-carbazole to the solvent acetone in the step 2) is (2-4) g / 100 mL; the weight volume ratio of 9-(4-bromobutyl)-9H-carbazole to distilled water is (2-8) g / 100 mL; and the weight 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 is characterized by a steady-state / transient fluorescence spectrometer. The steady-state fluorescence spectrum and delayed spectrum of the original powder of the luminophore 4'-(4-(9H-carbazole-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, which are at 373nm, 416nm, 443nm and 470nm, respectively, all of which are immediate fluorescence emission, attributed to the radiative transition of the exciton from the first excited state of the singlet state to the ground state. In the delayed spectrum, it shows a double peak emission with wavelengths of 553nm and 605nm, respectively. This emission peak is the room temperature phosphorescence peak, attributed to the light emitted by the exciton 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 state transition is longer than the wavelength of the fluorescence emitted from the singlet state transition. It can be seen from the steady-state fluorescence spectrum and the delayed spectrum that the luminophore 4'-(4-(9H-carbazole-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-carbazole-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 proportion of the fluorescence peaks of the luminophore 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile at 416nm, 443nm and 470nm in the spectrum decreased. This may be because the microcrystalline structure in the original powder was partially destroyed under the action of external force, and the interaction force between molecules also partially disappeared. Figure 3 The illustration shows the fluorescence emission color coordinates of the luminophore 4'-(4-(9H-carbazole-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-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile has mechanochromic properties.

[0041] The luminophore prepared by the present invention is characterized by a steady-state / transient fluorescence spectrometer. The steady-state fluorescence spectrum and delayed spectrum of the original powder of the luminophore 6-(4-(9H-carbazole-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, which is immediate fluorescence emission. In the delayed spectrum, its phosphorescence emission peak is located at 630nm, showing a wide single peak emission property. It can be seen from the steady-state fluorescence spectrum and the delayed spectrum that the luminophore 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile has good dual emission of immediate fluorescence and room temperature phosphorescence.

[0042] The original powder of the luminophore 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile was ground in a mortar. The steady-state fluorescence spectra before and after grinding were 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. This may be because under the action of external force, the interaction between molecules has changed, its conformation has become planar, the π-π stacking interaction between molecules has been enhanced, and the emission spectrum has red-shifted. After grinding, the half-peak width of its fluorescence peak has also become wider, which means that the arrangement of molecules tends to be disordered. Figure 5 The illustration shows the fluorescence emission color coordinates of the luminophore 6-(4-(9H-carbazole-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-carbazole-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, and 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, inhibiting non-radiative decay, and allowing more energy to be emitted in the form of light, which is conducive 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 present a force stimulus response characteristic.

[0044] In summary, the novel luminescent materials 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile and 6-(4-(9H-carbazole-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 characteristics of the present invention can be applied to the fields of anti-counterfeiting, information encryption, organic electroluminescent diodes, biosensor imaging, etc.

[0046] The luminophore 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile was dissolved in dichloromethane, and then the solution was coated on a non-fluorescent paper. After the dichloromethane evaporated, 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-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile is dissolved in dichloromethane, and then the solution is coated on a non-fluorescent paper. After the dichloromethane is evaporated, Figure 7As shown, blue fluorescence can be clearly observed under ultraviolet light, and no obvious luminescence occurs after the ultraviolet light is removed. This indicates that the luminophores 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile and 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthalenenitrile of 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 invention discloses a novel room temperature phosphorescent luminescent body with mechanochromic characteristics. Carbazole is selected as a fluorophore, a long chain of four carbon atoms is used as a connecting bridge, and naphthalene nitrile and biphenyl nitrile are used as ISC promoting factors, respectively. Two mechanochromic room temperature phosphorescent luminescent bodies are obtained by simple chemical synthesis. The molecular structure does not contain metal elements, heavy atoms such as bromine and iodine, and there is no distorted DA conformation. The molecular bond is easy to rotate in a large space, and the molecular conformation is relatively planar. The problem that the current mechanochromic room temperature phosphorescent luminescent body is small in variety and the diversity of chemical structures is limited is solved, and a new idea is provided for the design of mechanochromic room temperature phosphorescent luminescent body. According to the El-Sayed rule, cyano is a pseudohalogen, and there is a pair of lone pairs of electrons on its N atom, which can induce the transformation of n→π*, thereby promoting ISC. The introduction of naphthalene nitrile and biphenyl nitrile can not only further promote the occurrence of the ISC process in the molecular system, but also the introduction of heteroatoms and conjugated systems can help increase the abundant intermolecular interaction forces, thereby constructing a rigid environment, limiting the thermal motion of molecules, inhibiting non-radiative decay, and helping to achieve RTP emission. The invention discloses a novel method for preparing a room temperature phosphorescent luminescent body with mechanochromic properties. The luminescent body is obtained by using carbazole as a raw material through two steps of CN coupling reaction and CO coupling reaction. The synthesis method is simple, the reaction steps are few, the conditions are mild, and the luminescent body is easy to industrialize. The luminescent body has high potential application value in the fields of anti-counterfeiting, information encryption, organic electroluminescent diodes, biosensor imaging, etc. BRIEF DESCRIPTION OF THE DRAWINGS

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

[0050] Figure 2 It is a superposition diagram 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 figure. The inset is the color coordinates before and after grinding.

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

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

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

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

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

[0057] Fig. 9 The luminescent substance 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile 1 H NMR spectrum;

[0058] Fig.10 The luminophore 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile 1 H NMR spectrum. DETAILED DESCRIPTION

[0059] The technical solution of the present invention is further described below in conjunction with specific embodiments, but the present invention is not limited thereto.

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

[0061] Add carbazole (0.50 g, 3 mmol) and acetone (20 mL) to a clean three-necked flask with a magnetic stirrer. After stirring and dissolving, continue to add potassium hydroxide (0.50 g, 9 mmol) to the three-necked flask, and finally add 1,4-dibromobutane (3.24 g, 15 mmol). Stir and react for 24 hours at 25°C. After the reaction is completed, pour the reaction mixture in the three-necked flask into 20 mL of distilled water to quench the reaction. Extract with 60 mL of dichloromethane. Dry the organic phase, remove the solvent by rotary evaporation, and separate and purify by silica gel column chromatography with 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 with a yield of 83%. 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] Add carbazole (0.50 g, 3 mmol) and acetone (10 mL) to a clean three-necked flask with a magnetic stirrer. After stirring and dissolving, continue to add potassium hydroxide (0.34 g, 6 mmol) to the three-necked flask, and finally add 1,4-dibromobutane (1.94 g, 9 mmol). Stir and react for 12 hours at 20°C. After the reaction is completed, pour the reaction mixture in the three-necked flask into 12.5 mL of distilled water to quench the reaction. Extract with 50 mL of dichloromethane. Dry the organic phase, remove the solvent by rotary evaporation, and separate and purify by silica gel column chromatography with 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 with a yield of 73%.

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

[0065] Add carbazole (0.50 g, 3 mmol) and acetone (25 mL) to a clean three-necked flask with a magnetic stirrer, stir and dissolve, then continue to add potassium hydroxide (0.67 g, 12 mmol) to the three-necked flask, and finally add 1,4-dibromobutane (3.89 g, 18 mmol), and stir and react at 50°C for 30 hours. After the reaction is completed, pour the reaction mixture in the three-necked flask into 50 mL of distilled water to quench the reaction. Extract with 100 mL of dichloromethane. Dry the organic phase, remove the solvent by rotary evaporation, and separate and purify by silica gel column chromatography with 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 with a yield of 79%.

[0066] Example 4: Synthesis of 4'-(4-(9H-carbazole-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 with a magnetic stirrer and dissolved with 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 the reaction was completed, the reaction mixture in the three-necked flask was poured into 20 mL of distilled water to quench the reaction. Extracted with 60 mL of dichloromethane, the organic phase was dried and the solvent was evaporated, and ethyl acetate and petroleum ether (v / v, 1:20) were used as eluents. The mixture was separated and purified by silica gel column chromatography to obtain 0.71 g of 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile as a white powder with a yield of 85%. 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 Fig. 9 shown.

[0068] Example 5: Synthesis of 4'-(4-(9H-carbazole-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 with a magnetic stirrer and dissolved with 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 the reaction was completed, the reaction mixture in the three-necked flask was poured into 15 mL of distilled water to quench the reaction. Extracted with 30 mL of dichloromethane, the organic phase was dried and the solvent was evaporated, and ethyl acetate and petroleum ether (v / v, 1:30) were used as eluents. The mixture was separated and purified by silica gel column chromatography to obtain 1.15 g of 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile as a white powder with a yield of 69%.

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

[0071] Add 9-(4-bromobutyl)-9H-carbazole (1.19 g, 4.0 mmol) and cyanobiphenol (1.56 g, 8.0 mmol) to a three-necked flask with a magnetic stirrer and dissolve them 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 the reaction is completed, pour the reaction mixture in the three-necked flask into 60 mL of distilled water to quench the reaction. The mixture was extracted with 120 mL of dichloromethane, and the organic phase was dried and the solvent was removed by rotary evaporation. The mixture 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-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile as a white powder with a yield of 72%.

[0072] Example 7: Synthesis of 6-(4-(9H-carbazole-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 with a magnetic stirrer and dissolved with 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. Stir and reflux for 24 h at 56 ° C. After the reaction was completed, the reaction mixture in the three-necked flask was poured into 20 mL of distilled water to quench the reaction. Extracted with 60 mL of dichloromethane, the organic phase was dried and the solvent was evaporated, and ethyl acetate and petroleum ether (v / v, 1:20) were used as eluents. Separated and purified by silica gel column chromatography, 6-(4-(9H-carbazole-9-yl) butoxy)-2-naphthalenecarbonitrile 0.63 g was finally obtained as a white powder with a yield of 81%. 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 Fig.10 shown.

[0074] Example 8: Synthesis of 6-(4-(9H-carbazole-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 with a magnetic stirrer and dissolved with 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. Stir and reflux for 20 h at 45 ° C. After the reaction was completed, the reaction mixture in the three-necked flask was poured into 7.5 mL of distilled water to quench the reaction. Extract with 15 mL of dichloromethane. After drying the organic phase, the solvent was evaporated and separated and purified by silica gel column chromatography with 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-naphthalenecarbonitrile as a white powder with a yield of 69%.

[0076] Example 9: Synthesis of 6-(4-(9H-carbazole-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 with a magnetic stirrer and dissolved with 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. Stir and reflux for 30 h at 65 ° C. After the reaction was completed, the reaction mixture in the three-necked flask was poured into 30 mL of distilled water to quench the reaction. Extract 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 with 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-naphthalenecarbonitrile as a white powder with a yield of 65%.

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

[0079] The luminophore prepared by the present invention is characterized by a steady-state / transient fluorescence spectrometer. The steady-state fluorescence spectrum and delayed spectrum of the original powder of the luminophore 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile at room temperature are shown in FIG. Figure 2 As shown. There are four immediate fluorescence emission peaks in the steady-state fluorescence spectrum, which are at 373nm, 416nm, 443nm and 470nm respectively. In the delayed spectrum, there are two room temperature phosphorescence peaks at 553nm and 605nm. From the steady-state fluorescence spectrum and the delayed spectrum, it can be concluded that the luminophore 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile has good dual emission of immediate fluorescence and room temperature phosphorescence.

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

[0081] The luminophore prepared by the present invention is characterized by a steady-state / transient fluorescence spectrometer. The steady-state fluorescence spectrum and delayed spectrum of the original powder of the luminophore 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile at room temperature are shown in FIG. Figure 4 As shown. In the steady-state fluorescence spectrum, there is a narrow emission peak at 376nm, which is immediate fluorescence emission. In the delayed spectrum, there is a phosphorescence emission peak at 630nm, showing a broad single-peak emission property. It can be seen from the steady-state fluorescence spectrum and the delayed spectrum that the luminophore 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile has good dual emission of immediate fluorescence and room temperature phosphorescence.

[0082] Example 12: Mechanochromic properties of luminophore 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile

[0083] Take 20-30 mg of the original powder of the luminophore 4'-(4-(9H-carbazole-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-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile at 416nm, 443nm and 470nm in the spectrum decreased. Figure 3 As can be seen from the color coordinate illustration, the color coordinates of the light emitted by the luminescent body change after grinding, and the emission color changes from dark blue to light blue, proving that the luminescent body 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile has mechanochromic properties.

[0084] Example 13: Mechanochromic properties of luminophore 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile

[0085] Take 20-30 mg of the original powder of the luminophore 6-(4-(9H-carbazole-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 in the figure. 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-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile has mechanochromic properties.

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

[0087] Dissolve 10-20 mg of the luminophore 4'-(4-(9H-carbazole-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-carbazole-9-yl)butoxy)-2-naphthalenecarbonitrile in the field of anti-counterfeiting encryption

[0089] Dissolve 10-20 mg of the luminophore 6-(4-(9H-carbazole-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 UV light, and no obvious luminescence is observed after removing the UV light.

[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 modifications without departing from the purpose of the present invention, which are all within the protection of the present invention.

Claims

1. A novel room temperature phosphorescent luminescent body with mechanochromic properties, characterized in that the structural formula as follows: Wherein R is one of the following groups:

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 reaction is stirred; after the reaction is completed, the reaction mixture is poured into distilled water to quench the reaction, and dichloromethane is used for extraction, the organic phase is dried and rotary evaporated, and then ethyl acetate and petroleum ether are used as eluents, and column chromatography is used for separation to obtain the intermediate 9-(4-bromobutyl)-9H-carbazole; 2): using cyanobiphenol or cyanonaphthol, 9-(4-bromobutyl)-9H-carbazole obtained in step 1) as raw materials, acetone as solvent, potassium iodide as catalyst, adding potassium carbonate, stirring for reaction; after the reaction, pouring into distilled water for quenching, extracting with dichloromethane, drying the organic phase, rotary evaporation, and then using ethyl acetate and petroleum ether as eluents, column chromatography separation to obtain 4'-(4-(9H-carbazole-9-yl)butoxy)-[1,1'-biphenyl]-4-carbonitrile or 6-(4-(9H-carbazole-9-yl)butoxy)-2-naphthocarbonitrile.

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

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

1.

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

7. The preparation method according to claim 2, characterized in that: In step 2), the molar ratio of 9-(4-bromobutyl)-9H-carbazole: cyanobiphenol or cyanonaphthol: 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, characterized in that: Step 2) The eluent is petroleum ether:ethyl acetate=(20-40):

1.

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

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