Stable light-emitting free radical material based on space-induced energy level inversion effect

Abstract

The invention relates to the technical field of organic light-emitting materials, and discloses a stable light-emitting free radical material based on a space-induced energy level inversion effect, the light-emitting free radical material is a light-emitting free radical compound based on a donor-bridging group-free radical structure, and a donor group and a free radical are not directly linked but are close to each other in space. The key properties of the light-emitting free radical material are that a donor group is connected with a free radical through a bridging group, the obtained free radical molecule realizes high-efficiency photoluminescence through space charge transfer, and the special property of energy level inversion is realized through a space induction effect; not only is the molecular stability enhanced, but also the transition path of electrons is optimized, so that the luminescence process is more efficient and stable.

Description

Technical Field

[0001] The invention relates to the technical field of organic luminescent materials, and in particular to a stable luminescent free radical material based on a spatially induced energy level inversion effect. Background Art

[0002] Energy level inversion is a unique phenomenon of free radical materials. The energy of the single occupied molecular orbital of a free radical molecule with energy level inversion is lower than the highest doubly occupied molecular orbital energy level. The energy level inversion property is considered to be a reliable technical route to improve the stability of free radical materials, thereby enabling free radical materials to demonstrate their unique properties in many different fields.

[0003] In luminescent free radical materials, energy level inversion is a very rare property. Although the characteristics of free radicals with energy level inversion have been studied and summarized, it is difficult to accurately construct luminescent free radical materials with energy level inversion using corresponding strategies. There are few free radical luminescent materials that achieve energy level inversion, and there is a lack of effective molecular design strategies to achieve energy level inversion properties. Summary of the invention

[0004] In view of the above-mentioned deficiencies in the prior art, the present invention provides a stable luminescent free radical material based on the spatially induced energy level inversion effect, which is connected to the electron donating group and the free radical unit by using a bridging group, thereby obtaining a luminescent free radical material with energy level inversion properties, which has excellent stability and luminescence properties.

[0005] In order to achieve the above-mentioned purpose of the invention, the technical solution adopted by the present invention is: a stable luminescent free radical material based on the spatially induced energy level inversion effect, the luminescent free radical material is a luminescent free radical compound based on a donor-bridging group-free radical structure, the donor group and the free radical are not directly linked, but are close to each other in space; the structural formula of the luminescent free radical compound is any one of M1, M2 or M3:

[0006]

[0007] In the general structural formula M1, B is one of the following groups:

[0008]

[0009] Furthermore, in the above-mentioned stable luminescent free radical material based on the space-induced energy level inversion effect, D1 in the general structural formula M1 is one of the following groups:

[0010]

[0011]

[0012] Furthermore, in the above-mentioned stable luminescent free radical material based on the space-induced energy level inversion effect, R1, R2 and R3 in the general structural formulas M1, M2 and M3 are each independently one of the following groups:

[0013]

[0014] Furthermore, in the above-mentioned stable luminescent free radical material based on the space-induced energy level inversion effect, D2 and D3 in the general structural formulas M2 and M3 are each independently one of the following groups:

[0015]

[0016]

[0017] Furthermore, in the above-mentioned stable luminescent free radical material based on the space-induced energy level inversion effect, the luminescent free radical compound is any one of compounds 1 to 18:

[0018]

[0019]

[0020]

[0021] The beneficial effects of the present invention are as follows: the present invention uses a bridging group (such as fluorene, benzene ring, naphthalene ring, etc.) as a medium to bring the donor group (such as carbazole, diphenylamine, phenothiazine, etc.) and the free radical unit (such as PTM, TTM, CzBTM, PyBTM, etc.) close to each other in space but not directly connected, effectively avoiding the problem of electronic structure instability caused by direct connection in traditional luminescent free radical materials, and at the same time utilizing the spatial induction effect to promote efficient charge transfer from the donor to the free radical, thereby achieving the special property of energy level inversion. Energy level inversion not only enhances the stability of the molecule, but also optimizes the transition path of the electron, making the luminescence process more efficient and stable. By adjusting the types and combinations of the donor group, the bridging group and the free radical unit, the wavelength, bandwidth, color and other characteristics of the luminescence spectrum can be accurately regulated to meet the needs of different application scenarios, especially the presence of the spatial induction effect, which makes the excited state energy level more stable and the luminescence efficiency significantly improved. BRIEF DESCRIPTION OF THE DRAWINGS

[0022] Figure 1 is the FT-IR pattern of compound 1;

[0023] Figure 2 is the luminescence spectrum of compound 1 in cyclohexane solution;

[0024] Figure 3 The DFT theoretical calculation results for the ground state optimization of compound 1;

[0025] Figure 4 This is the cyclic voltammetry test diagram of compound 1 and its free radical precursor;

[0026] Figure 5 is the FT-IR pattern of compound 2;

[0027] Figure 6 is the luminescence spectrum of compound 2 in cyclohexane solution;

[0028] Figure 7 The DFT theoretical calculation results for the ground state optimization of compound 2;

[0029] Figure 8 This is the cyclic voltammetry test diagram of compound 2 and its free radical precursor;

[0030] Fig. 9 is the luminescence spectrum of compound 3 in cyclohexane solution;

[0031] Fig.10 The DFT theoretical calculation results for the ground state optimization of compound 3;

[0032] Fig.11 is the luminescence spectrum of compound 4 in cyclohexane solution;

[0033] Fig.12 The DFT theoretical calculation results for the ground state optimization of compound 4;

[0034] Fig.13 is the luminescence spectrum of compound 6 in cyclohexane solution;

[0035] Fig.14 The DFT theoretical calculation results for the ground state optimization of compound 6;

[0036] Fig.15 is the luminescence spectrum of compound 7 in cyclohexane solution;

[0037] Fig.16 The DFT theoretical calculation results for the ground state optimization of compound 7;

[0038] Fig.17 is the luminescence spectrum of compound 10 in cyclohexane solution;

[0039] Fig.18 The DFT theoretical calculation results for the ground state optimization of compound 10;

[0040] Fig.19 is the luminescence spectrum of compound 11 in cyclohexane solution;

[0041] Fig. 20 The DFT theoretical calculation results for the ground state optimization of compound 11;

[0042] Fig.21 is the luminescence spectrum of compound 12 in cyclohexane solution;

[0043] Fig. 22 The DFT theoretical calculation results for the ground state optimization of compound 12;

[0044] Fig.23 is the luminescence spectrum of compound 13 in cyclohexane solution;

[0045] Fig.24 The DFT theoretical calculation results for the ground state optimization of compound 13;

[0046] Fig.25 is the luminescence spectrum of compound 14 in cyclohexane solution;

[0047] Fig.26 The DFT theoretical calculation results for the ground state optimization of compound 14;

[0048] Fig. 27 is the luminescence spectrum of compound 15 in cyclohexane solution;

[0049] Fig.28 The DFT theoretical calculation results for the ground state optimization of compound 15;

[0050] Fig.29 is the luminescence spectrum of compound 16 in cyclohexane solution;

[0051] Fig.30 The DFT theoretical calculation results for the ground state optimization of compound 16;

[0052] Fig.31 is the luminescence spectrum of compound 17 in cyclohexane solution;

[0053] Fig.32 This is the DFT theoretical calculation result of the ground state optimization of compound 17. DETAILED DESCRIPTION

[0054] The specific implementation modes of the present invention are described below so that those skilled in the art can understand the present invention. However, it should be clear that the present invention is not limited to the scope of the specific implementation modes. For those of ordinary skill in the art, as long as various changes are within the spirit and scope of the present invention as defined and determined by the attached claims, these changes are obvious, and all inventions and creations utilizing the concept of the present invention are protected.

[0055] Example 1

[0056] This embodiment is a method for synthesizing compound 1, comprising the following steps:

[0057] Step 1: Under argon protection, add 24 mL of toluene, 8 mL of anhydrous ethanol, 16 mL of H2O, 1.41 g (10.18 mmol) of potassium carbonate, 0.44 g (1.96 mmol) of 9-fluorenone-1-boric acid, 1.71 g (3.08 mmol) of tris(2,4,6-trichlorobenzene)methane and 293.95 mg (0.12 mmol) of tetrakis(triphenylphosphine)palladium to a 250 ml single-necked flask, and stir at 95 degrees Celsius for 48 hours. The reaction system was cooled to room temperature and extracted three times with dichloromethane, 50 mL each time. After combining the organic layers, an appropriate amount of anhydrous magnesium sulfate was added for drying. The solvent was evaporated to dryness to obtain a crude product. The crude product was purified by column chromatography (silica gel, dichloromethane, petroleum ether) to finally obtain product A1 (0.55 g) with a yield of 40%. The chemical reaction equation for generating A1 is:

[0058]

[0059] Step 2: Under argon protection and minus -78 degrees Celsius, add 10 mL of tetrahydrofuran and 0.45 g (1.39 mmol) of 2-bromotriphenylamine to a 50 ml Schlenk bottle, and add 0.49 mL (1.17 mmol) of 2.4 M n-butyl lithium dropwise. After stirring for 1 hour at -78 degrees Celsius, add 0.70 g (1.00 mmol) of compound A1. After continuing to stir for one hour, slowly warm the reaction system to room temperature and stir for 24 hours. After the reaction is completed, evaporate the solvent to obtain a crude product. Purify the crude product by column chromatography (silica gel, dichloromethane, petroleum ether) to finally obtain product A2 (0.35 g) with a yield of 37%. The chemical reaction equation for generating A2 is:

[0060]

[0061] Step 3: Under argon protection, add formic acid 18mL, hydrochloric acid 6mL and compound A20.35g (0.37mmol) to a 100ml single-necked flask and stir at 120 degrees Celsius for 48 hours. The reaction system is cooled to room temperature and extracted three times with dichloromethane, 50mL each time. After combining the organic layers, add an appropriate amount of anhydrous magnesium sulfate and dry. The solvent is evaporated to dryness to obtain a crude product. The crude product is purified by column chromatography (silica gel, dichloromethane, petroleum ether) to finally obtain product A3 (0.24g) with a yield of 68%. The chemical reaction equation for generating A3 is:

[0062]

[0063] The fourth step: under argon protection and luminescence conditions, tetrahydrofuran 40mL, compound A30.24g (0.25mmol) were added to a 100ml single-necked flask, and potassium tert-butoxide 0.51g (4.56mmol) was added after the compound was completely dissolved, and the system turned red. After stirring at room temperature for 24 hours, tetrachlorobenzoquinone 0.19g (0.76mmol) was added. After the reaction was completed, the solvent was evaporated to obtain a crude product. The crude product was purified by column chromatography (silica gel, dichloromethane, petroleum ether), and finally compound 1 (0.14g) was obtained, with a yield of 60%. The chemical reaction equation for generating compound 1 is:

[0064]

[0065] Figure 1 is the FT-IR spectrum of compound 1, Figure 2 is the luminescence spectrum of compound 1 in cyclohexane solution, Figure 3 This is the DFT theoretical calculation result of the ground state optimization of compound 1. Figure 4 This is the cyclic voltammetry test diagram of compound 1 and its free radical precursor. Figure 3 and Figure 4 Its energy level inversion properties were confirmed.

[0066] Example 2

[0067] This example is a method for synthesizing compound 2.

[0068] The synthesis steps are the same as those of compound 1, except that the raw material 2-bromotriphenylamine in the second step reaction is replaced with 9-(2-bromophenyl)-9H-carbazole, and compound 2 is finally obtained.

[0069] Figure 5 is the FT-IR spectrum of compound 2. Figure 6 is the luminescence spectrum of compound 2 in cyclohexane solution, Figure 7 This is the DFT theoretical calculation result of the ground state optimization of compound 2. Figure 8 This is the cyclic voltammetry test diagram of compound 2 and its free radical precursor. Figure 7 and Figure 8 Its energy level inversion properties were confirmed.

[0070] Example 3

[0071] This example is a method for synthesizing compound 3.

[0072] The synthesis steps are the same as those of compound 1, except that the raw material 2-bromotriphenylamine in the second step reaction is replaced with 10-(2-bromophenyl)-9,9-dimethyl-9,10-dihydroacridine, and compound 3 is finally obtained.

[0073] Fig. 9is the luminescence spectrum of compound 3 in cyclohexane solution, Fig.10 This is the DFT theoretical calculation result of the ground state optimization of compound 3. Fig.10 Its energy level inversion properties were confirmed.

[0074] Example 4

[0075] This example is a method for synthesizing compound 4.

[0076] The synthesis steps are the same as those of compound 1, except that the raw material 2-bromotriphenylamine in the second step reaction is replaced with 10-(2-bromophenyl)-10H-dibenzo[2,1-b:1',2'-e][1,4]oxazepine, and finally compound 4 is obtained.

[0077] Fig.11 is the luminescence spectrum of compound 4 in cyclohexane solution, Fig.12 This is the DFT theoretical calculation result of the ground state optimization of compound 4. Fig.12 Its energy level inversion properties were confirmed.

[0078] Example 5

[0079] This example is a method for synthesizing compound 5.

[0080] The synthesis steps are the same as those of compound 1, except that the raw material 2-bromotriphenylamine in the second step reaction is replaced with 10-(2-bromophenyl)-10H-dibenzo[2,1-b:1',2'-e][1,4]oxazacyclohexane, and compound 5 is finally obtained.

[0081] Example 6

[0082] This example is a method for synthesizing compound 6.

[0083] The synthesis steps are the same as those of compound 1, except that the raw material 2-bromotriphenylamine in the second step reaction is replaced with 3-[4-bromo-3-(carbazole-9-yl)phenyl]-9-phenylcarbazole, and compound 6 is finally obtained.

[0084] Fig.13 is the luminescence spectrum of compound 6 in cyclohexane solution, Fig.14 This is the DFT theoretical calculation result of the ground state optimization of compound 6. Fig.14 Its energy level inversion properties were confirmed.

[0085] Example 7

[0086] This example is a method for synthesizing compound 7.

[0087] The synthesis steps are the same as those of compound 1, except that the raw material 2-bromotriphenylamine in the second step reaction is replaced with 3-[3-bromo-4-(carbazole-9-yl)phenyl]-9-phenylcarbazole, and compound 7 is finally obtained.

[0088] Fig.15 is the luminescence spectrum of compound 7 in cyclohexane solution, Fig.16 This is the DFT theoretical calculation result of the ground state optimization of compound 7. Fig.16 Its energy level inversion properties were confirmed.

[0089] Example 8

[0090] This example is a method for synthesizing compound 8.

[0091] The synthesis steps are the same as those of compound 1, except that the raw material 2-bromotriphenylamine in the second step reaction is replaced with 6-bromo-5,12-diphenylindolo[3,2-c]carbazole, and compound 8 is finally obtained.

[0092] Example 9

[0093] This example is a method for synthesizing compound 9.

[0094] The synthesis steps are the same as those of compound 1, except that the raw material 2-bromotriphenylamine in the second step reaction is replaced with 5-(2-bromophenyl)azulene[1,2-b]indole, and compound 9 is finally obtained.

[0095] Example 10

[0096] This example is a method for synthesizing compound 10.

[0097] The synthesis steps are the same as those of compound 1, except that the raw material 2-bromotriphenylamine in the second step reaction is replaced with 9-(2-bromophenyl)pyrido[3,4-b]indole, and compound 10 is finally obtained.

[0098] Fig.17 is the luminescence spectrum of compound 10 in cyclohexane solution, Fig.18 This is the DFT theoretical calculation result of the ground state optimization of compound 10. Fig.18 Its energy level inversion properties were confirmed.

[0099] Embodiment 11

[0100] This embodiment is a method for synthesizing compound 11. It comprises the following steps:

[0101] The first step: under argon protection, add tetrahydrofuran 100mL, H2O40mL, potassium carbonate 11.04g (79.88mmol), 2-boric acid-triphenylamine 2.31g (7.99mmol), tris (2,4,6-trichlorobenzene) methane 5.41g (9.80mmol) and tetrakis (triphenylphosphine) palladium 293.95mg (0.12mmol) to a 250ml single-necked flask, and stir at 80 degrees Celsius for 48 hours. The reaction system is cooled to room temperature and extracted with dichloromethane three times, 50mL each time. After the organic layer is combined, an appropriate amount of anhydrous magnesium sulfate is added and dried. The solvent is evaporated to dryness to obtain a crude product. The crude product is purified by column chromatography (silica gel, dichloromethane, petroleum ether) to finally obtain product K1 (2.56g) with a yield of 42%. The chemical reaction equation for generating K1 is:

[0102]

[0103] The second step: under argon protection and luminescence, tetrahydrofuran 100mL, compound K11.77g (2.32mmol) were added to a 250ml single-necked flask, and potassium tert-butoxide 1.04g (9.30mmol) was added after the compound was completely dissolved, and the system turned red. After stirring at room temperature for 24 hours, tetrachlorobenzoquinone 1.71g (6.96mmol) was added. After the reaction was completed, the solvent was evaporated to obtain a crude product. The crude product was purified by column chromatography (silica gel, dichloromethane, petroleum ether), and compound 11 (0.8g) was finally obtained with a yield of 45%. The chemical reaction equation for generating compound 11 is:

[0104]

[0105] Fig.19 is the luminescence spectrum of compound 11 in cyclohexane solution, Fig. 20 This is the DFT theoretical calculation result of the ground state optimization of compound 11. Fig. 20 Its energy level inversion properties were confirmed.

[0106] Example 12

[0107] This example is a method for synthesizing compound 12.

[0108] The synthesis steps are the same as those of compound 11, except that the raw material 2-bromotriphenylamine in the first step is replaced with 9-(2-boronic acid pinacol ester phenyl)-9H-carbazole, and compound 12 is finally obtained.

[0109] Fig.21 is the luminescence spectrum of compound 12 in cyclohexane solution, Fig. 22 This is the DFT theoretical calculation result of the ground state optimization of compound 12. Fig. 22 Its energy level inversion properties were confirmed.

[0110] Embodiment 13

[0111] This example is a method for synthesizing compound 13.

[0112] The synthesis steps are the same as those of compound 11, except that the raw material 2-bromotriphenylamine in the first step is replaced by 4-(2-bromophenyl)triphenylamine, and tri(2,4,6-trichlorophenyl)methane is replaced by 4-[bis(2,4,6-trichlorophenyl)methyl]-3,5-dichlorophenylboronic acid pinacol ester, to finally obtain compound 13.

[0113] Fig.23 is the luminescence spectrum of compound 13 in cyclohexane solution, Fig.24 This is the DFT theoretical calculation result of the ground state optimization of compound 13. Fig.24 Its energy level inversion properties were confirmed.

[0114] Embodiment 14

[0115] This example is a method for synthesizing compound 14.

[0116] The synthesis steps are the same as those of compound 11, except that the raw material 2-bromotriphenylamine in the first step is replaced by 9-[4-(2-bromophenyl)phenyl]carbazole, and tri(2,4,6-trichlorophenyl)methane is replaced by 4-[bis(2,4,6-trichlorophenyl)methyl]-3,5-dichlorophenylboronic acid pinacol ester, to finally obtain compound 14.

[0117] Fig.25 is the luminescence spectrum of compound 14 in cyclohexane solution, Fig.26 This is the DFT theoretical calculation result of the ground state optimization of compound 14.

[0118] Embodiment 15

[0119] This example is a method for synthesizing compound 15.

[0120] Under argon protection, 50mL of dimethylformamide, 0.80g (1.95mmol) of 4-carbazole triphenylamine, 1.40g (2.53mmol) of tri(2,4,6-trichlorobenzene)methane free radical and 0.95g (2.93mmol) of cesium carbonate were added to a 250ml single-necked flask and stirred at 160 degrees Celsius for 10 hours. The reaction system was cooled to room temperature, diluted hydrochloric acid was added to adjust the pH to neutral, and then extracted with dichloromethane three times, 50mL each time. After the organic layers were combined, an appropriate amount of anhydrous magnesium sulfate was added and dried. The solvent was evaporated to dryness to obtain a crude product. The crude product was purified by column chromatography (silica gel, dichloromethane, petroleum ether), and compound 15 (0.05g) was finally obtained with a yield of 3%. The chemical reaction equation for generating compound 15 is:

[0121]

[0122] Fig. 27 is the luminescence spectrum of compound 15 in cyclohexane solution, Fig.28 This is the DFT theoretical calculation result of the ground state optimization of compound 15. Fig.28 Its energy level inversion properties were confirmed.

[0123] Example 16

[0124] This example is a method for synthesizing compound 16.

[0125] The synthesis steps are the same as those of compound 15, except that the raw material 4-carbazole triphenylamine in the first step is replaced by 9-[4-(9H-carbazole-1-yl)phenyl]carbazole, and tri(2,4,6-trichlorophenyl)methane is replaced by 4-[bis(2,4,6-trichlorophenyl)methyl]-3,5-dichlorophenylboronic acid pinacol ester, to finally obtain compound 16.

[0126] Fig.29 is the luminescence spectrum of compound 16 in cyclohexane solution, Fig.30 This is the DFT theoretical calculation result of the ground state optimization of compound 16. Fig.30 Its energy level inversion properties were confirmed.

[0127] Embodiment 17

[0128] This embodiment is a method for synthesizing compound 17. It comprises the following steps:

[0129] Step 1: Under argon protection, add 48 mL of toluene, 16 mL of anhydrous ethanol, 32 mL of H2O, 2.82 g (20.36 mmol) of potassium carbonate, 1.00 g (3.41 mmol) of 1-boric acid pinacol ester carbazole, 2.27 g (4.09 mmol) of tris (2,4,6-trichlorobenzene) methane and 587.90 mg (0.24 mmol) of tetrakis (triphenylphosphine) palladium to a 250 ml single-necked flask, and stir at 95 degrees Celsius for 48 hours. The reaction system was cooled to room temperature and extracted three times with dichloromethane, 50 mL each time. After combining the organic layers, an appropriate amount of anhydrous magnesium sulfate was added for drying. The solvent was evaporated to dryness to obtain a crude product. The crude product was purified by column chromatography (silica gel, dichloromethane, petroleum ether) to finally obtain product Q1 (0.90 g) with a yield of 40%. The chemical reaction equation for generating Q1 is:

[0130]

[0131] The second step: under argon protection, add toluene 24mL, anhydrous ethanol 8mL, H2O16mL, potassium tert-butoxide 0.03g (10.18mmol), product Q10.16g (0.23mmol), 4-bromotriphenylamine 0.11g (0.35mmol) and tetrakis (triphenylphosphine) palladium 5mg (0.004mmol) in a 250ml single-necked flask, and stir for 12 hours at 95 degrees Celsius. The reaction system is cooled to room temperature and extracted three times with dichloromethane, each time 50mL. After merging the organic layer, add an appropriate amount of anhydrous magnesium sulfate drying. The solvent is evaporated to dryness to obtain a crude product. Purify the crude product by column chromatography (silica gel, dichloromethane, petroleum ether), and finally obtain product Q2 (0.02g), with a yield of 8%. The chemical reaction equation for generating Q2 is:

[0132]

[0133] The third step: under argon protection and luminescence conditions, tetrahydrofuran 40mL, compound Q20.20g (0.22mmol) were added to a 100ml single-mouth flask, and potassium tert-butoxide 0.10g (0.88mmol) was added after the compound was completely dissolved, and the system turned red. After stirring for 24 hours at room temperature, tetrachlorobenzoquinone 0.16g (0.66mmol) was added. After the reaction was completed, the solvent was evaporated to obtain a crude product. The crude product was purified by column chromatography (silica gel, dichloromethane, petroleum ether), and compound 17 (0.10g) was finally obtained, with a yield of 48%. The chemical reaction equation for generating compound 17 is:

[0134]

[0135] Fig.31 is the luminescence spectrum of compound 17 in cyclohexane solution, Fig.32 This is the DFT theoretical calculation result of the ground state optimization of compound 17. Fig.32 Its energy level inversion properties were confirmed.

[0136] In the luminescent free radical materials M1, M2 and M3, other donor-bridging group-free radical organic luminescent materials can be obtained by the synthesis method in the above embodiments.

[0137] Although the present invention has been described in conjunction with the embodiments, the present invention is not limited to the above embodiments. It should be understood that under the guidance of the concept of the present invention, those skilled in the art can make various modifications and improvements. The attached claims summarize the scope of the present invention.

Claims

1. A stable luminescent free radical material based on spatially induced energy level inversion effect, characterized in that: The luminescent free radical material is a luminescent free radical compound based on a donor-bridging group-free radical structure, wherein the donor group and the free radical are not directly linked, but are close to each other in space; the structural formula of the luminescent free radical compound is any one of M1, M2 or M3: In the general structural formula M1, B is one of the following groups:

2. The stable luminescent free radical material based on the spatially induced energy level inversion effect according to claim 1, characterized in that: In the general structural formula M1, D1 is one of the following groups:

3. The stable luminescent free radical material based on the spatially induced energy level inversion effect according to claim 2, characterized in that: R1, R2 and R3 in the general structural formulas M1, M2 and M3 are each independently one of the following groups:

4. The stable luminescent free radical material based on the spatially induced energy level inversion effect according to claim 3, characterized in that: D2 and D3 in the general structural formulas M2 and M3 are each independently one of the following groups:

5. The stable luminescent free radical material based on the spatially induced energy level inversion effect according to claim 4, characterized in that: The luminescent free radical compound is any one of compounds 1 to 17:

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