Pure organic room temperature phosphorescent materials with a phenanthridinone structure, preparation methods and applications

Abstract

The present invention obtains a pure organic room temperature phosphorescent material with a long luminescence lifetime and high luminescence efficiency by simply constructing a π-conjugated structure of a phenanthridinone structure; this design principle has the advantages of simplicity and universality; the pure organic room temperature phosphorescent material of the present invention has a long luminescence lifetime and high luminescence efficiency, enriches existing building blocks, and can achieve regulation of luminescence properties by introducing substituents with different push-pull structures; the preparation method of the present invention is simple, has inexpensive and readily available raw materials, requires few reaction steps, has mild reaction conditions, has a high yield, and is easy to industrialize; the preparation method of the present invention is conducive to introducing push-pull electronic functional groups into the main core structure, promoting the application of pure organic room temperature phosphorescent materials in organic electroluminescent devices, chemical sensing, biological imaging, data encryption, anti-counterfeiting marking, and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and in particular to a pure organic room temperature phosphorescent material with a phenanthridinone structure, a preparation method and an application thereof. Background Art

[0002] Phosphorescence is a radiative transition, which, unlike fluorescence, occurs between different electron spin multiplets. Generally speaking, phosphorescence refers to the transition from a triplet state to a singlet state in a stable molecule (i.e., the transition between the first excited triplet state (T1) and the ground singlet state (S0)). Phosphorescent molecules are sensitive to environmental factors, such as molecular aggregation, temperature, and oxygen. In the early days, due to limitations in theoretical knowledge and development, people generally conducted research on molecular phosphorescence at low temperatures or in an inert gas atmosphere. This means that phosphorescent molecules are difficult to process and apply to practical scenarios, and it also prevents the application of phosphorescence phenomena in different fields, such as technical applications in bio-optics and optoelectronics (fluorescent molecules have made good progress in these fields).

[0003] Traditional room-temperature phosphorescent materials are mostly based on inorganic compounds and organometallic complexes. These metals, such as platinum, iridium, and osmium, leverage the d-orbitals of these metals to effectively achieve spin-orbit coupling, resulting in high-performance room-temperature phosphorescent materials. However, these materials also have significant drawbacks. Inorganic compounds are limited in variety and have poor processability. In contrast, organometallic complexes offer a wide variety and better processability, but they rely on precious metals. Furthermore, the introduction of toxic and heavy metals harms the environment and biological health, hindering bioavailability. Therefore, the development of metal-free, purely organic phosphorescent materials offers unique advantages: first, organic materials are widely available, easily modified, and low in cost. Second, organic materials offer excellent flexibility, film-forming properties, solution processing, and large-area fabrication, making them promising for applications in flexible displays, wearable electronic devices, and other fields. Third, purely organic materials exhibit excellent biocompatibility, facilitating the development of safe biomaterials. However, designing pure organic room-temperature phosphorescent materials is extremely challenging. Typically, the internal magnetic perturbations of organic molecules are too weak to promote the spin-forbidden triplet-singlet phosphorescent transition, making it difficult to achieve high quantum yields. This slow transition rate generally cannot compete with non-radiative electronic energy transfer to vibrational and translational states. Therefore, phosphorescence quenching by vibrational relaxation caused by molecular collisions is the primary reason for the low quantum yield of organic phosphorescent materials under natural conditions.

[0004] Although the luminescence performance of pure organic room-temperature phosphorescent materials has been greatly improved in the past five years, the building blocks of phosphorescent materials are still limited to structures such as carbazole and triphenylamine. Therefore, it is very necessary to develop new structural blocks to construct new organic room-temperature phosphorescent molecules. Summary of the Invention

[0005] The purpose of the present invention is to provide a pure organic room temperature phosphorescent material based on a phenanthridinone structure and a preparation method thereof, so as to solve the problems of an extreme shortage of pure organic room temperature phosphorescent materials in the prior art, a single molecular structure, and poor luminescence performance.

[0006] According to one aspect of the present invention, a pure organic room temperature phosphorescent material having a phenanthridinone structure is provided, wherein the structural formula of the pure organic room temperature phosphorescent material is any one of the following I and II:

[0007]

[0008] Wherein, X is any one of Cl, Br or CN.

[0009] According to another aspect of the present invention, a method for preparing a pure organic room temperature phosphorescent material having a phenanthridinone structure is provided, wherein a compound represented by structural formula III is mixed with a reaction reagent and an alkaline reagent, and a nucleophilic substitution reaction is carried out in a polar organic solvent to obtain a pure organic room temperature phosphorescent material based on a phenanthridinone structure.

[0010]

[0011] Wherein, X is any one of H, Cl, Br or CN; when preparing the pure organic room temperature phosphorescent material shown in formula I, the reaction reagent is the compound shown in structural formula IV; when preparing the pure organic room temperature phosphorescent material shown in formula II, the reaction reagent is the compound shown in structural formula IV and chlorine\bromine substituted succinimide, and the compound shown in structural formula III first undergoes an electrophilic reaction with chlorine\bromine substituted succinimide, and the obtained reactant then undergoes a nucleophilic reaction with the compound shown in structural formula IV and an alkaline reagent.

[0012] In the preparation method provided by the present invention, when preparing the pure organic room temperature phosphorescent material represented by formula I, the molar ratio of the alkaline reagent, the reaction reagent represented by structural formula IV and the compound represented by structural formula III is 1.5:1.5:1.

[0013] In the preparation method provided by the present invention, the alkaline reagent is potassium carbonate.

[0014] In the preparation method provided by the present invention, the polar organic solvent is N,N-dimethylformamide.

[0015] In the preparation method provided by the present invention, the reaction temperature of the nucleophilic reaction is 100° C., and the reaction time is 8 h to 12 h.

[0016] In the preparation method provided by the present invention, the molar ratio of the compound represented by structural formula III to chloro\bromo substituted succinimide is 1:1.1.

[0017] In the preparation method provided by the present invention, the reaction temperature of the electrophilic reaction is 100°C.

[0018] According to another aspect of the present invention, there is also provided the application of the pure organic room temperature phosphorescent material with a phenanthridinone structure as described above and / or the preparation method of the pure organic room temperature phosphorescent material with a phenanthridinone structure as described above in organic electroluminescent devices, chemical sensing, biological imaging, data encryption and anti-counterfeiting marking.

[0019] The pure organic room temperature phosphorescent material with a phenanthridinone structure of the present invention, as well as its preparation method and application, have the following beneficial effects: in the present invention, a pure organic room temperature phosphorescent material with a long luminescence lifetime and high luminescence efficiency is obtained by simply constructing a π-conjugated structure of the phenanthridinone structure; this design principle has the advantages of simplicity and universality; the pure organic room temperature phosphorescent material of the present invention has a long luminescence lifetime and high luminescence efficiency, enriches the existing building blocks, and can achieve regulation of luminescence properties by introducing substituents with different push-pull structures; the preparation method of the present invention is simple, the raw materials are cheap and easily available, the reaction steps are few, the reaction conditions are mild, the yield is high, and it is easy to industrialize; the preparation method of the present invention is conducive to introducing push-pull electronic functional groups into the main core structure, and promotes the application of pure organic room temperature phosphorescent materials in organic electroluminescent devices, chemical sensing, biological imaging, data encryption and anti-counterfeiting marking, etc. BRIEF DESCRIPTION OF THE DRAWINGS

[0020] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the following briefly introduces the drawings required for use in the embodiments or the description of the prior art. Obviously, the drawings described below are only embodiments of the present invention. Those skilled in the art can also derive other drawings based on the provided drawings without inventive work.

[0021] Figure 1 These are luminescence photos of the crystals of compounds A1-A3 and B1-B3 under ultraviolet light and after the ultraviolet light is turned off;

[0022] Figure 2 is a superposition of the steady-state emission spectrum of compound A1 in the crystalline state and the steady-state emission spectrum after a delay of 1 millisecond;

[0023] Figure 3 is the time-resolved phosphorescence emission decay curve of compound A1 in the crystalline state;

[0024] Figure 4 is a superposition of the steady-state emission spectrum of compound A2 in the crystalline state and the steady-state emission spectrum after a delay of 1 millisecond;

[0025] Figure 5is the time-resolved phosphorescence emission decay curve of compound A2 in the crystalline state;

[0026] Figure 6 is a superposition of the steady-state emission spectrum of compound A3 in the crystalline state and the steady-state emission spectrum after a delay of 1 millisecond;

[0027] Figure 7 is the time-resolved phosphorescence emission decay curve of compound A3 in the crystalline state;

[0028] Figure 8 It is the superposition of the steady-state emission spectrum of compound B1 in the crystalline state and the steady-state emission spectrum after a delay of 1 millisecond;

[0029] Figure 9 is the time-resolved phosphorescence emission decay curve of compound B1 in the crystalline state;

[0030] Figure 10 It is the superposition of the steady-state emission spectrum of compound B2 in the crystalline state and the steady-state emission spectrum after a delay of 1 millisecond;

[0031] Figure 11 is the time-resolved phosphorescence emission decay curve of compound B2 in the crystalline state;

[0032] Figure 12 It is the superposition of the steady-state emission spectrum of compound B3 in the crystalline state and the steady-state emission spectrum after a delay of 1 millisecond;

[0033] Figure 13 is the time-resolved phosphorescence emission decay curve of compound B3 in the crystalline state;

[0034] Figure 14 is compound A1 1 H NMR spectrum;

[0035] Figure 15 is compound A2 1 H NMR spectrum;

[0036] Figure 16 is compound A3 1 H NMR spectrum;

[0037] Figure 17 is compound B1 1 H NMR spectrum;

[0038] Figure 18 is compound B2 1 H NMR spectrum;

[0039] Figure 19 Compound B3 1 H NMR spectrum;

[0040] Figure 20 Schematic diagram of data encryption application prepared for five luminescent materials. DETAILED DESCRIPTION

[0041] To facilitate understanding of the present invention, the present invention will be described more fully below with reference to the accompanying drawings. The drawings illustrate exemplary embodiments of the present invention. However, the present invention may be implemented in many different forms and is not limited to the embodiments described herein. Rather, these embodiments are provided to provide a more thorough and comprehensive understanding of the present invention.

[0042] Unless otherwise defined, all technical and scientific terms used herein have the same meaning as those commonly understood by those skilled in the art of the present invention. The terms used in this specification of the present invention are only for the purpose of describing specific embodiments and are not intended to limit the present invention.

[0043] The following is a further description of the pure organic room temperature phosphorescent material based on the phenanthridinone structure and its preparation method and application in conjunction with the accompanying drawings and examples:

[0044] By constructing a π-conjugated structure based on a phenanthridinone structure, this invention achieves a pure organic room-temperature phosphorescent material with a long luminescence lifetime and high luminescence efficiency. This design principle also has good universal applicability. This invention provides a simple and universal design principle that promotes the application of pure organic room-temperature phosphorescent materials in organic electroluminescent devices, chemical sensing, bioimaging, data encryption, and anti-counterfeiting marking.

[0045] By simply constructing a π-conjugated structure with a phenanthridinone structure, the present invention reduces the energy difference between the singlet and triplet excited states, thereby increasing the intersystem crossing rate between the singlet and triplet excited states and improving the phosphorescence efficiency. Furthermore, the larger π-conjugated structure helps reduce the radiation rate of the triplet excited state, increasing the phosphorescence lifetime, enriching existing building blocks. By introducing substituents with different push-pull structures, the luminescence properties can be controlled.

[0046] The present invention relates to a pure organic room temperature phosphorescent material based on a phenanthridinone structure, wherein the structural formula of the pure organic room temperature phosphorescent material is any one of the following I and II:

[0047]

[0048] Wherein, X is any one of Cl, Br or CN.

[0049] The present invention also provides a method for preparing a pure organic room temperature phosphorescent material having a phenanthridinone structure, comprising mixing a compound represented by structural formula III with a reaction reagent and an alkaline reagent, and performing a nucleophilic substitution reaction in a polar organic solvent to obtain a pure organic room temperature phosphorescent material based on a phenanthridinone structure.

[0050]

[0051] Wherein, X is any one of H, Cl, Br or CN; when preparing the pure organic room temperature phosphorescent material shown in formula I, the reaction reagent is the compound shown in structural formula IV; when preparing the pure organic room temperature phosphorescent material shown in formula II, the reaction reagent is the compound shown in structural formula IV and chlorine\bromine substituted succinimide, and the compound shown in structural formula III first undergoes an electrophilic reaction with chlorine\bromine substituted succinimide, and the obtained reactant then undergoes a nucleophilic reaction with the compound shown in structural formula IV and an alkaline reagent.

[0052] Specifically, when preparing a pure organic room temperature phosphorescent material represented by formula I, the reaction raw material is III (X=H), and the corresponding reaction reagents are substituted benzyl bromide compounds IV (including Cl, Br, CN); when preparing a pure organic room temperature phosphorescent material represented by formula II, the compound represented by the unsubstituted III is first introduced into Cl or Br through an electrophilic reaction, wherein the cyano-substituted compound III is further obtained by a nucleophilic reaction of the Br substitution product, and the reaction at the nitrogen substitution position utilizes the nucleophilic reaction of p-bromobenzylamine under alkaline reagent conditions.

[0053] Furthermore, the molar ratio of the reaction reagent to the compound represented by structural formula III is 1.5:1.5:1; the alkaline reagent is potassium carbonate; the polar organic solvent is N,N-dimethylformamide; the reaction temperature of the nucleophilic reaction is 100°C, and the reaction time is 8h-12h; the molar ratio of the compound represented by structural formula III to the chloro\bromo substituted succinimide is 1:1.1; and the reaction temperature of the electrophilic reaction is 100°C.

[0054] The following further describes the embodiments of the present invention in multiple embodiments. The embodiments of the present invention are not limited to the following specific embodiments. Within the scope of the unchanged main rights, appropriate changes can be made to the implementation.

[0055] Synthesis routes of compounds A1-A3

[0056]

[0057] Example 1: Synthesis of Compound A1

[0058]

[0059] 6(5H)-phenanthridinone (0.781 g, 4.0 mmol) and potassium carbonate (1.658 g, 12.0 mmol) were weighed and dissolved in DMF (20 mL). The mixture was stirred at 100°C under nitrogen for 1 hour. Then, the reaction reagent p-bromobenzyl bromide (1.50 g, 6.0 mmol) was added, and the reaction was continued at 80°C for 8 hours. After the reaction, water was added to the reaction solution, and the mixture was extracted three times with dichloromethane. The organic phases were combined, dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and separated by silica gel column chromatography (eluent: petroleum ether:dichloromethane = 2:1). The mixture was recrystallized from a methanol / dichloromethane mixture to obtain white crystalline Compound A1 (1.035 g, yield: 71.0%). Figure 14 Shown 1 H-NMR (CDCl3, 400MHz): 5.52 (s, 2H), 7.06 (d, J = 8.4Hz, 2H), 7.24–7.11 (m, 2H), 7. 32(m,3H),7.54(t,J=7.6Hz,1H),7.72(t,J=7.7Hz,1H),8.22(m,2H),8.53(m,1H).

[0060] Figure 2 This is an overlay of the steady-state emission spectrum of compound A1 in its crystalline state and after a 1-millisecond delay. The figure shows that the position of the emission peak in the 1-millisecond delay steady-state emission spectrum is consistent with the position of the emission peak in the long-wavelength range of the steady-state emission spectrum, indicating that the emission peak in the short-wavelength range of the steady-state emission spectrum is short-lived fluorescence emission, while the emission peak in the long-wavelength range is long-lived phosphorescence emission.

[0061] Figure 3 This is the time-resolved phosphorescence emission decay curve of compound A1 in the crystalline state. Using a first-order exponential fitting, the phosphorescence lifetime can be calculated to be 25.71 milliseconds.

[0062] Example 2: Synthesis of Compound A2

[0063]

[0064] The synthesis method of compound A2 is the same as that of A1. The reaction substrates are 6(5H)-phenanthridinone (0.586 g, 3.0 mmol) and p-chlorobenzyl bromide (0.925 g, 4.5 mmol). Purification gives white crystalline compound A2 (0.537 g, yield: 56%). Figure 15 Shown 1H-NMR (CDCl3, 400MHz): 5.63 (s, 2H), 7.21 (d, J = 8.6Hz, 2H), 7.27 (m, 4H), 7.41 (m, 1H), 7.63 (t, J = 7.6Hz, 1H), 7.81 (m, 1H), 8.31 (m, 2H), 8.62 (m, 1H).

[0065] Figure 4 This is an overlay of the steady-state emission spectrum of compound A2 in its crystalline state and the steady-state emission spectrum after a 1-millisecond delay. The figure shows that the position of the emission peak in the steady-state emission spectrum after a 1-millisecond delay is consistent with the position of the emission peak in the long-wavelength range of the steady-state emission spectrum, indicating that the emission peak in the short-wavelength range of the steady-state emission spectrum is short-lived fluorescence emission, while the emission peak in the long-wavelength range is long-lived phosphorescence emission.

[0066] Figure 5 This is the time-resolved phosphorescence emission decay curve of compound A2 in the crystalline state. Using a first-order exponential fitting, the phosphorescence lifetime can be calculated to be 114.9 milliseconds.

[0067] Example 3: One-pot synthesis of compound A3

[0068]

[0069] The synthesis method of compound A3 is the same as that of A1. The reaction substrates are 6(5H)-phenanthridinone (0.734 g, 3.76 mmol) and p-cyanobenzyl bromide (1.106 g, 5.64 mmol). Purification afforded compound A3 as white crystals (0.794 g, yield: 68%). Figure 16 Compound A3 is shown: 1 H-NMR (CDCl3, 500MHz): δ5.71(s,2H),7.16(d,J=8.4Hz,1H),7.34–7.30(m,1H),7.36(d,J=8.4Hz,2H),7.40–7.43m, 1H),7.60(d,J=8.4Hz,2H),7.67–7.62(m,1H),7.85–7.80(m,1H),8.33(d,J=8.1Hz,2H),8.60(dd,J=8.0,1.1Hz,1H).

[0070] Figure 6 This is an overlay of the steady-state emission spectrum of compound A3 in its crystalline state and after a 1-millisecond delay. The figure shows that the position of the emission peak in the 1-millisecond delay steady-state emission spectrum is consistent with the position of the emission peak in the long-wavelength range of the steady-state emission spectrum, indicating that the emission peak in the short-wavelength range of the steady-state emission spectrum is short-lived fluorescence emission, while the emission peak in the long-wavelength range is long-lived phosphorescence emission.

[0071] Figure 7 This is the time-resolved phosphorescence emission decay curve of compound A3 in the crystalline state. Using a first-order exponential fitting, the phosphorescence lifetime can be calculated to be 66.45 milliseconds.

[0072] Example 4: Synthesis of Compound B1

[0073] Synthesis route of compound B1:

[0074]

[0075] Synthesis of Compound B1: 6(5H)-phenanthridinone (1.562 g, 8.0 mmol) was weighed and dissolved in dry DMF (30 mL). The mixture was heated to 80°C to dissolve the solid. NBS (1.566 g, 8.8 mmol) was added in three portions and the mixture was heated at 80°C for 8 hours. After cooling to room temperature, the mixture was directly filtered and the filter cake was recrystallized from glacial acetic acid to obtain 2-bromo-6(5H)-phenanthridinone (1.707 g, yield: 77.84%). 2-Bromo-6(5H)-phenanthridinone (0.685 g, 2.5 mmol) and potassium carbonate (0.691 g, 5.0 mmol) were weighed and dissolved in DMF (20 mL). The mixture was stirred at 100°C under nitrogen for 1 hour. Then, the reaction reagent p-bromobenzyl bromide (0.937 g, 3.75 mmol) was added and the reaction was continued at 80°C for 8 hours. After the reaction, water was added to the reaction solution, and the mixture was extracted three times with dichloromethane. The organic phases were combined and dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and separated by silica gel column chromatography (eluent: petroleum ether: dichloromethane = 2:1). The residue was recrystallized from a methanol / dichloromethane mixed solvent to obtain white crystalline compound B1 (0.804 g, yield: 72.6%). Figure 17 Shown 1 H-NMR(CDCl3,400MHz):5.57(s,2H),7.11(dd,J=8.6,5.5Hz,3H),7.42(d,J=8.4Hz,2H),7.48(dd,J=9.0,2.1Hz,1H ), 7.66 (t, J = 7.6Hz, 1H), 7.82 (t, J = 7.7Hz, 1H), 8.23 (d, J = 8.2Hz, 1H), 8.38 (d, J = 2.1Hz, 1H), 8.60 (d, J = 8.0Hz, 1H).

[0076] Figure 8This is an overlay of the steady-state emission spectrum of compound B1 in its crystalline state and the steady-state emission spectrum after a 1-millisecond delay. The figure shows that the position of the emission peak in the 1-millisecond delay steady-state emission spectrum is consistent with the position of the emission peak in the long-wavelength range of the steady-state emission spectrum, indicating that the emission peak in the short-wavelength range of the steady-state emission spectrum is short-lived fluorescence emission, while the emission peak in the long-wavelength range is long-lived phosphorescence emission.

[0077] Figure 9 This is the time-resolved phosphorescence emission decay curve of compound B1 in the crystalline state. Using a first-order exponential fitting, the phosphorescence lifetime can be calculated to be 15.13 milliseconds.

[0078] Example 5: Synthesis of Compound B2

[0079] Synthesis route of compound B2:

[0080]

[0081] Synthesis of Compound B2: 6(5H)-phenanthridinone (0.976 g, 5.0 mmol) was weighed and dissolved in dry DMF (30 mL). The mixture was heated to 80°C to dissolve the solid. NCS (0.734 g, 5.5 mmol) was added in three batches and heated at 80°C for 8 hours. After cooling to room temperature, the mixture was directly filtered and the filter cake was recrystallized from glacial acetic acid to obtain 2-chloro-6(5H)-phenanthridinone (0.846 g, yield: 73.7%). 2-Bromochloro-6(5H)-phenanthridinone (0.565 g, 2.46 mmol) and potassium carbonate (1.02 g, 7.38 mmol) were weighed and dissolved in DMF (20 mL). The mixture was stirred at 100°C under nitrogen for 1 hour. Then, the reaction reagent p-bromobenzyl bromide (1.844 g, 7.38 mmol) was added and the reaction was continued at 80°C for 8 hours. After the reaction, water was added to the reaction solution, and the mixture was extracted three times with dichloromethane. The organic phases were combined and dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and separated by silica gel column chromatography (eluent: petroleum ether: dichloromethane = 2:1). The residue was recrystallized from a methanol / dichloromethane mixed solvent to obtain white crystalline compound B2 (0.775 g, yield: 79%). Figure 18 Shown 1 H-NMR (CDCl3, 500MHz): 5.58 (s, 2H), 7.12 (d, J = 8.4Hz, 2H), 7.16 (d, J = 9.0Hz, 1H), 7.35 (dd, J = 9.0, 2.3Hz, 1H) ,7.42(d,J=8.4Hz,2H),7.70–7.63(m,1H),7.85–7.80(m,1H),8.26–8.21(m,2H),8.60(dd,J=8.0,1.3Hz,1H).

[0082] Figure 10 This is an overlay of the steady-state emission spectrum of compound B2 in its crystalline state and the steady-state emission spectrum after a 1-millisecond delay. The figure shows that the position of the emission peak in the 1-millisecond delay steady-state emission spectrum is consistent with the position of the emission peak in the long-wavelength range of the steady-state emission spectrum, indicating that the emission peak in the short-wavelength range of the steady-state emission spectrum is short-lived fluorescence emission, while the emission peak in the long-wavelength range is long-lived phosphorescence emission.

[0083] Figure 11 This is the time-resolved phosphorescence emission decay curve of compound B2 in the crystalline state. Using a first-order exponential fitting, the phosphorescence lifetime can be calculated to be 16.09 milliseconds.

[0084] Example 6: Synthesis of Compound B3

[0085] Synthesis route of compound B3:

[0086]

[0087] Synthesis of Compound B3: Weigh 2-bromo-6(5H)-phenanthridinone (0.548 g, 2.0 mmol) and cuprous cyanide (0.215 g, 2.4 mmol) and purge the nitrogen atmosphere three times. Add the mixture to dry DMF (15 mL) and heat to 150°C for 24 hours. Cool to room temperature and filter directly to obtain 2-cyano-6(5H)-phenanthridinone (0.339 g, 77% yield). Weigh 2-cyano-6(5H)-phenanthridinone (0.482 g, 2.19 mmol) and potassium carbonate (0.907 g, 6.57 mmol) in DMF (15 mL) and stir at 100°C under nitrogen for 1 hour. Then, add the reaction reagent p-bromobenzyl bromide (1.642 g, 6.57 mmol) and continue the reaction at 80°C for 8 hours. After the reaction, water was added to the reaction solution, and the mixture was extracted three times with dichloromethane. The organic phases were combined and dried over anhydrous magnesium sulfate, concentrated under reduced pressure, and separated by silica gel column chromatography (eluent: petroleum ether: dichloromethane = 2:1). The residue was recrystallized from a methanol / dichloromethane mixed solvent to obtain white crystalline compound B3 (0.655 g, yield: 76.9%). Figure 19 Shown 1 H-NMR (CDCl3, 500MHz): δ5.59 (s, 2H), 7.11 (d, J = 8.4Hz, 2H), 7.30 (d, J = 8.8Hz, 1H), 7.43 (d, J = 8.4Hz, 2H), 7.63 (dd, J = 8.8, 1. 8Hz,1H),7.71(t,J=7.5Hz,1H),7.90–7.84(m,1H),8.26(d,J=8.2Hz,1H),8.56(d,J=1.6Hz,1H),8.60(dd,J=8.0,1.0Hz,1H).

[0088] Figure 12 This is an overlay of the steady-state emission spectrum of compound B3 in its crystalline state and the steady-state emission spectrum after a 1-millisecond delay. The figure shows that the position of the emission peak in the steady-state emission spectrum after a 1-millisecond delay is consistent with the position of the emission peak in the long-wavelength range of the steady-state emission spectrum, indicating that the emission peak in the short-wavelength range of the steady-state emission spectrum is short-lived fluorescence emission, while the emission peak in the long-wavelength range is long-lived phosphorescence emission.

[0089] Figure 13 This is the time-resolved phosphorescence emission decay curve of compound B3 in the crystalline state. Using a first-order exponential fitting, the phosphorescence lifetime can be calculated to be 81.2 milliseconds.

[0090] Figure 20 Schematic diagram of data encryption application prepared for five luminescent materials.

[0091] Table 1 Luminescent properties of compounds A1-A3 and B1-B3

[0092]

[0093] Note: ex,FL represents the fluorescence excitation wavelength, λ em,FL represents the fluorescence emission wavelength, τ F represents the fluorescence lifetime, Φ represents the quantum efficiency of fluorescence, and λ ex,PL represents the phosphorescence excitation wavelength, λ em,PL represents the phosphorescence emission wavelength, τ P Phosphorescence lifetime

[0094] As can be seen from Table 1, compounds Al-A3 and B1-B3 have room temperature phosphorescence properties in the crystalline state, and their luminescence lifetimes are all in the millisecond level, especially compound A2, which has a luminescence lifetime of up to 114.9 milliseconds.

[0095] The pure organic room temperature phosphorescent materials involved in the present invention have different luminescence lifetimes. According to the differences in luminescence lifetimes, time-separated luminescence technology can be used to achieve advanced data protection and anti-counterfeiting label applications. Figure 20 As shown, the numbers "1" and "0" made of the long-life room-temperature phosphorescent material A2 (luminescence lifetime is 114.9 milliseconds) in the above embodiment and the numbers "2" and "4" made of the short-life room-temperature phosphorescent material B1 (luminescence lifetime is 15.13 milliseconds) are combined into a digital password "1204". Under the irradiation of a 365nm ultraviolet lamp, "1204" is displayed, and the luminescence form at this time is short-life fluorescence; when the ultraviolet lamp is turned off, "10" is displayed, and the luminescence form at this time is phosphorescence with a longer life, so it can be used for data encryption.

[0096] The embodiments of the present invention are described above in conjunction with the accompanying drawings, but the present invention is not limited to the above-mentioned specific implementation methods. The above-mentioned specific implementation methods are merely illustrative and not restrictive. Under the guidance of the present invention, ordinary technicians in this field can also make many forms without departing from the scope of protection of the present invention and the claims, all of which are protected by the present invention.

Claims

1. A pure organic room temperature phosphorescent material having a phenanthridinone structure, characterized in that: The structural formula of the pure organic room temperature phosphorescent material is: Wherein, X in structural formula II is either Cl or Br.

2. A method for preparing a pure organic room temperature phosphorescent material having a phenanthridinone structure, characterized in that: Wherein, X in structural formula IV is Br; the compound represented by structural formula III is first subjected to an electrophilic reaction with a chloro\bromo substituted succinimide, and the obtained reactant is then subjected to a nucleophilic reaction with the compound represented by structural formula IV and an alkaline reagent to obtain the pure organic room temperature phosphorescent material as described in claim 1.

3. The preparation method according to claim 2, characterized in that The molar ratio of the alkaline reagent, the compound represented by structural formula IV and the compound represented by structural formula III is 1.5:1.5:

1.

4. The preparation method according to claim 2, characterized in that The alkaline reagent is potassium carbonate.

5. The preparation method according to claim 2, characterized in that The reaction temperature of the nucleophilic reaction is 100° C., and the reaction time is 8 h to 12 h.

6. The preparation method according to claim 2, characterized in that The molar ratio of the compound represented by structural formula III to the chloro\bromo substituted succinimide is 1:1.

1.

7. The preparation method according to claim 2, characterized in that The reaction temperature of the electrophilic reaction is 100°C.

8. Use of the pure organic room temperature phosphorescent material having a phenanthridinone structure according to claim 1 in data encryption and anti-counterfeiting marking.

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