A near-infrared organic free radical afterglow material, its preparation method and application

Abstract

This invention belongs to the field of organic light-emitting materials technology, specifically disclosing a near-infrared organic free radical afterglow material, its preparation method, and its applications. Based on the compound molecule TPP-o-3OMe-NH2-Br, electron-pulling groups 6-(dimethylamino)naphthaleneimide (NNI) and 6-bromonaphthaleneimide (NBI) were introduced to design and synthesize the molecules TPP-o-3OMe-NNI-Br and TPP-o-3OMe-NBI-Br. Doping TPP-o-3OMe-NNI-Br and TPP-o-3OMe-NBI-Br with the polymer PMMA resulted in long afterglow emission characteristics with different photoactivation times. The photoactivation time of the afterglow of the TPP-o-3OMe-NBI-Br@PMMA film was significantly shortened, while the TPP-o-3OMe-NNI-Br@PMMA film successfully achieved red afterglow emission. Finally, combining the luminescent properties of the two films, applications for multi-color display and storage of optical information were created. This type of material is expected to provide new ideas for the development of organic free radical light-emitting materials and multi-level information encryption applications.

Description

Technical Field

[0001] This invention belongs to the field of organic light-emitting materials technology, specifically relating to a near-infrared organic free radical afterglow material, its preparation method, and its application. Background Technology

[0002] Compared to inorganic light-emitting materials, organic light-emitting materials can have their luminescence properties (lifetime, color modulation, and luminescence intensity) modified through molecular structure design. They offer more convenient synthesis strategies, broader application prospects, and better environmental friendliness, effectively addressing the resource scarcity and environmental pollution issues associated with inorganic light-emitting materials (most inorganic materials require the introduction of rare metal elements). Currently, organic light-emitting materials show broad application prospects in electroluminescence, organic lasers, sensors, and bioimaging.

[0003] Among organic light-emitting materials, those emitting red light possess excellent tissue penetration and anti-interference capabilities, making them particularly important for fields such as bioimaging in extreme environments, information encryption technology, and information storage, and thus holding significant research value. Currently, the main luminescence mechanisms of red-emitting materials are fluorescence induced by excitation of a singlet state and phosphorescence induced by excitation of a triplet state. Developing a class of radical luminescent materials capable of achieving red afterglow emission in different states remains a challenging problem. Studies have shown that organic quaternary phosphine salts have good water solubility. In recent years, researchers have also constructed many long-afterglow organic quaternary phosphine salt materials by introducing π-conjugated groups such as benzene rings and carbazole to regulate the luminescence range. These studies provide new insights into the design and regulation of red fluorescence and red afterglow of quaternary phosphine salts. Summary of the Invention

[0004] To address the aforementioned technical problems, this invention proposes a near-infrared organic free radical afterglow material, its preparation method, and its application.

[0005] In a first aspect, the present invention provides a near-infrared organic free radical afterglow material, with the general structural formula being:

[0006]

[0007] Wherein, R includes

[0008]

[0009] They respectively constitute aryl quaternary phosphine salt derivatives TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br.

[0010] Secondly, the present invention provides a method for preparing the above-mentioned near-infrared organic free radical afterglow material, comprising the following steps:

[0011] S1. Synthesis of compound TPP-o-3OMe-NH2-Br: Tris(2-methoxyphenyl)phosphine and 2-bromoethylamine hydrobromide were added to a reaction flask, dissolved in CH3CH2CN, and stirred under reflux overnight. After the reaction was completed, the solvent was evaporated under vacuum. Ultrapure water was added to the obtained solid powder and NaOH was added to adjust the pH. The crude product was then obtained by EA extraction. The crude product was purified by silica gel column chromatography to obtain the white solid compound TPP-o-3OMe-NH2-Br.

[0012] S2. The compounds TPP-o-3OMe-NH2-Br, 4-bromo-1,8-naphthalenedicarboxylic anhydride, and 4-dimethylaminopyridine (DMAP) from S1 were mixed and added to a reaction flask. After vacuum drying, ethanol solution was added under a nitrogen atmosphere, and the mixture was stirred and refluxed. After the reaction was completed, the solvent was removed by vacuum drying. The crude product was purified by silica gel column chromatography to obtain the yellow solid compound TPP-o-3OMe-NBI-Br.

[0013] S3. Compounds TPP-o-3OMe-NH2-Br, 4-dimethylamino-1,8-naphthalenedicarboxylic anhydride, and 4-dimethylaminopyridine from S1 were mixed and added to a reaction flask. After vacuum drying, 20 mL of dry ethanol solution was added under a nitrogen atmosphere, and the mixture was stirred and refluxed. After the reaction was completed, the solvent was removed by vacuum drying. The crude product was purified by silica gel column chromatography to obtain an orange-yellow solid compound TPP-o-3OMe-NH2-Br.

[0014] Preferably, the molar ratio of compound TPP-o-3OMe-NH2-Br, compound 4-bromo-1,8-naphthalenedicarboxylic anhydride, and 4-dimethylaminopyridine in S2 is 3.12:3.4:3.4.

[0015] Preferably, the molar ratio of compound TPP-o-3OMe-NH2-Br, compound 4-dimethylamino-1,8-naphthalenedicarboxylic anhydride, and 4-dimethylaminopyridine in S3 is 1:1.1:1.1.

[0016] Preferably, the synthesis method of compound 4-dimethylamino-1,8-naphthalenedicarboxylic anhydride in S3 is as follows: 4-bromo-1,8-naphthalenedicarboxylic anhydride is dissolved in isoamyl alcohol, heated to reflux in an oil bath, and then 3-dimethylaminopropionitrile is added to the mixture and refluxed overnight. The precipitate is filtered at room temperature, washed with water and hexane, and dried under reduced pressure to obtain a yellow solid powder of 4-dimethylamino-1,8-naphthalenedicarboxylic anhydride (NNI).

[0017] Preferably, the molar ratio of 4-bromo-1,8-naphthalenedicarboxylic anhydride to 3-dimethylaminopropionitrile is 1:4.

[0018] Thirdly, the present invention provides applications of the above-mentioned near-infrared organic free radical afterglow material for the preparation of at least one of semiconductor electronic devices, bioimaging, and spin materials.

[0019] The beneficial effects of this invention are:

[0020] This invention, based on the compound molecule TPP-o-3OMe-NH2-Br, introduces electron-pulling groups 6-(dimethylamino)naphthaleneimide (NNI) and 6-bromonaphthaleneimide (NBI) to design and synthesize the molecules TPP-o-3OMe-NNI-Br and TPP-o-3OMe-NBI-Br. Doping TPP-o-3OMe-NNI-Br and TPP-o-3OMe-NBI-Br with the polymer PMMA resulted in long afterglow emission characteristics with different photoactivation times. The photoactivation time of the afterglow of the TPP-o-3OMe-NBI-Br@PMMA film was significantly shortened, while the TPP-o-3OMe-NNI-Br@PMMA film successfully achieved red afterglow emission. Finally, combining the luminescent properties of the two films, applications for multicolor display and storage of optical information were developed. These materials are expected to provide new ideas for the development of organic free radical luminescent materials and multi-layered information encryption applications. Attached Figure Description

[0021] To more clearly illustrate the technical solutions of the embodiments of the present invention, the accompanying drawings used in the description of the embodiments will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For those skilled in the art, other drawings can be obtained based on these drawings without creative effort.

[0022] Figure 1 These are the UV absorption spectra and HPLC spectra of TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br.

[0023] Figure 2 This is a diagram showing the monomer, dimer, and π···π stacking interactions of OC and YC crystals.

[0024] Figure 3 These are Hirschfeld surface analysis diagrams of PC and YC crystals.

[0025] Figure 4 Thermogravimetric analysis (a), solid UV (b), and XRD spectra (c) of TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br are shown.

[0026] Figure 5The solid-state fluorescence spectra (a), fluorescence lifetime (b), and phosphorescence spectra (c) of TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br are shown.

[0027] Figure 6 It is TPP-o-3OMe-NBI-Br@PMMA and

[0028] Thermogravimetric analysis (a), solid UV (b), and XRD patterns (c) of TPP-o-3OMe-NNI-Br@PMMA.

[0029] Figure 7 The images show the spectrum (a) and phenomena (b, c) of TPP-o-33OMe-NBI-Br doped in PMMA thin films.

[0030] Figure 8 The images show the spectrum (a) and phenomena (b, c) of TPP-o-33OMe-NNI-Br doped in PMMA thin films.

[0031] Figure 9 These are the low-temperature spectra (77K) of TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br in 2-Me-THF solution, where ad is the low-temperature spectrum of TPP-o-3OMe-NBI-Br (a is the steady-state spectrum, c is the transient spectrum; b is the lifetime at 428 nm, d is the lifetime at 450 nm); eh is the low-temperature spectrum of TPP-o-3OMe-NNI-Br (e is the steady-state spectrum, g is the transient spectrum; f is the lifetime at 500 nm, h is the lifetime at 450 nm).

[0032] Figure 10 This is a luminescence mechanism diagram of TPP-o-3OMe-NNI-Br, where a is the EPR diagram of singlet oxygen before and after illumination, b is the EPR diagram of free radical before and after illumination, c is the doublet electrostatic potential, and d is the theoretical calculation of the luminescence mechanism.

[0033] Figure 11 It is TPP-o-3OMe-NBI-Br@PMMA and

[0034] An image showing the application of optical information anti-counterfeiting fabricated using TPP-o-3OMe-NNI-Br@PMMA. Detailed Implementation

[0035] The technical solutions of the present invention will be clearly and completely described below with reference to the accompanying drawings of the embodiments of the present invention. Obviously, the described embodiments are only some embodiments of the present invention, and not all embodiments.

[0036] Main experimental drugs and reagents

[0037] Sodium hydroxide (CAS: 1310-73-2), tris(2-methoxyphenyl)phosphine (CAS: 4731-65-1), 2-bromoethylamine hydrobromide (CAS: 2576-47-8), 4-dimethylaminopyridine acetonitrile (CAS: 1122-58-3), 4-bromo-1,8-naphthalenedicarboxylic anhydride (CAS: 81-86-7), isoamyl alcohol (CAS: 123-51-3), N,N-dimethylaminoacetonitrile (CAS: 926-64-7), methanol, n-hexane. Commonly used analytical grade solvents include methanol, dichloromethane, ethyl acetate, and petroleum ether. Ultrapure water is prepared using a Mili-Q ultrapure water system, along with silica gel powder (200-300 mesh) and silica gel plates.

[0038] Main experimental instruments

[0039] 1 H NMR, 13 C NMR and 31 P NMR spectra were obtained using a Bruker AVANCE-600 NMR spectrometer. High-resolution mass spectrometry (HMS) was performed using an Agilent 6540Q-TOF mass spectrometer, and high-performance liquid chromatography (HPLC) was performed using an Agilent 1260 Infinity HPLC system with a 4.6 mm × 250 mm C18 reversed-phase column. UV-Vis absorption spectra were obtained using a UV-2600 UV-Vis spectrophotometer. Thermogravimetric analysis (TGA) data were obtained using a Mettler TGA / DSC / 1600LF instrument with a heating rate of 10 K / min. Steady-state and transient spectra, lifetimes, and quantum yields were obtained using a Horiba Jobin Yvon Fluorolog-3 instrument. Electron spin resonance (EPR) spectra were obtained using a Bruker Emxplus-6 / 1 instrument. The theoretical calculations were performed using Gaussian 09 software for time-dependent density functional theory (TD-DFT) calculations, Orca software for spin-orbit coupling constant calculations, and Crystal Explorer software for Hirschfeld surface analysis.

[0040] Example 1

[0041] A method for preparing near-infrared organic free radical afterglow materials includes the following steps:

[0042] S1. Synthesis of compound TPP-o-3OMe-NH2-Br: Tris(2-methoxyphenyl)phosphine (1 g, 2.8 mmol) and 2-bromoethylamine hydrobromide (0.63 g, 4.4 mmol) were added to a 50 mL Schlenk reaction flask, dissolved in 20 mL CH3CH2CN, and stirred under reflux overnight (12 h). The reaction was monitored for completeness using a TCL. After the reaction, the solvent was evaporated to dryness under vacuum. 30 mL of ultrapure water was added to the resulting solid powder, and NaOH was added to adjust the pH. The crude product was then extracted with EA. The crude product was purified by silica gel column chromatography (eluent: MeOH:DCM = 1:5) to obtain a white solid compound TPP-o-OMe-NH2-Br (1.02 g, 2.12 mmol) with a yield of 74%. The synthetic route is as follows:

[0043]

[0044] Atlas information: 1 H NMR (500MHz, MeOD) δ7.95–7.89 (m, 3H), 7.49–7.44 (m, 3H), 7.29–7.23 (m, 3H), 7.15 (dd, J=15.5, 9.5Hz, 3H), 3.93 (s, 9H), 3.69–3.59 (m, 4H), 3.33 (s, 1H), 3.29–3.22 (m, 2H).ppm 13 C NMR (126MHz, MeOD) δ161.77, 137.69, 134.65, 122.30, 112.95, 104.81, 104.06, 56.94, 55.91, 47.82, 34.98, 24.40, 23.91.ppm 31 P NMR (202MHz, MeOD) δ21.83ppm.[M+H] + Calcd.for C 23 H 27 NO3PBr, 476.0898, found, 476.0892;

[0045] S2. Synthesis of TPP-o-3OMe-NBI-Br: The compounds TPP-o-3OMe-NH2-Br (1.5 g, 3.12 mmol), 4-bromo-1,8-naphthalenedicarboxylic anhydride (0.95 g, 3.43 mmol), and 4-dimethylaminopyridine (DMAP) (0.42 g, 3.43 mmol) from S1 were mixed and added to a dry Schlenk reaction flask (50 ml). The mixture was dried under vacuum for 30 min. Then, 20 ml of dry ethanol solution was added under a nitrogen atmosphere, and the mixture was stirred and refluxed for 7 h. After the reaction was complete, the solvent was removed by vacuum drying. The crude product was purified by silica gel column chromatography (eluent: MeOH:DCM = 1:5) to obtain a yellow solid compound TPP-o-3OMe-NBI-Br (1.24 g, 1.70 mmol) in 61% yield. The synthetic route is as follows:

[0046]

[0047] Atlas information: 1 H NMR (600MHz, MeOD) δ8.49 (dd, J=17.7, 7.9Hz, 2H), 8.24 (d, J=7.9Hz, 1H), 8.06 (d, J=7.9Hz, 1H), 7.92–7.83 (m, 4H), 7.5 2–7.45 (m, 3H), 7.41–7.36 (m, 3H), 7.33–7.28 (m, 3H), 4.24 (d, J = 11.2Hz, 2H), 3.85 (s, 9H), 3.60 (d, J = 18.2Hz, 2H).ppm. 13 C NMR (151MHz, MeOD) δ163.00, 161.86, 137.15, 134.74, 133.10, 131.64, 131.09, 130.28, 13 0.01, 128.51, 128.06, 122.48, 121.94, 112.53, 105.65, 105.03, 55.57, 35.16, 22.06.ppm. 31 P NMR(243MHz, MeOD)δ20.08.ppm.HRMS m / z:[M+H] + Calcd.for C 35 H 30 NBr2O5P, 736.0329, found736.0322;

[0048] S3. Synthesis of compound TPP-o-3OMe-NNI-Br: 4-Bromo-1,8-naphthalenedicarboxylic anhydride (1 g, 2 mmol) was dissolved in isoamyl alcohol and heated to reflux in an oil bath. Then, 3-dimethylaminopropionitrile (1.4 g, 8 mmol) was added to the mixture and refluxed overnight. The precipitate was filtered at room temperature, washed with water and hexane, and dried under reduced pressure to obtain a yellow NNI solid powder with a yield of 90%. The synthetic route is as follows:

[0049]

[0050] Atlas information: 1 H NMR (400MHz, CDCl3) δ8.50 (d, 1H) 8.46 (d, 1H) 8

[0051] .37(d,1H)7.65(t,1H)7.06(d,1H)3.18(s,6H). 13 C NMR (400MHz, CDCl3) δ161.76, 160.78, 157.98, 135.03, 133.20, 133.00, 125.02, 124.83, 119.19, 113.18, 109.30, 44.69;

[0052] Then, compounds TPP-o-3OMe-NH2-Br (1.2 g, 2.50 mmol), 4-dimethylamino-1,8-naphthalenedicarboxylic anhydride (0.67 g, 2.75 mmol), and DMAP (0.34 g, 2.75 mmol) were added.

[0053] The mixture was added to a dry Schlenk reaction flask (50 ml), dried under vacuum for 30 min, and then 20 ml of dry ethanol solution was added under a nitrogen atmosphere. The mixture was stirred and refluxed for 7 h. After the reaction was completed, the solvent was removed by vacuum drying. The crude product was purified by silica gel column chromatography (eluent: MeOH:DCM = 1:5) to obtain the orange-yellow solid compound TPP-o-3OMe-NNI-Br(700) (1.10 g 2.50 mmol) with a yield of 63%.

[0054] The synthesis route is as follows:

[0055]

[0056] Atlas information: 1H NMR (600MHz, MeOD) δ8.47 (d, J=9.7Hz, 1H), 8.36 (d, J=8.4Hz, 1H), 8.24 (d, J=8.3Hz, 1H), 7.89–7.84 (m, 3H), 7.64–7.60 (m, 1H), 7.53 (dd, J=15.3 , 7.8Hz, 3H), 7.38–7.32 (m, 3H), 7.32–7.26 (m, 3H), 7.10 (d, J=8.3Hz, 1H ), 4.20–4.14(m, 2H), 3.82(s, 9H), 3.60–3.53(m, 2H), 3.15(s, 6H).ppm. 13 C NMR (151MHz, MeOD) δ164.06, 163.43, 161.86, 157.56, 137.03, 134.70, 132.56, 131

[0057] .93, 130.72, 130.11, 124.67, 124.37, 122.02, 121.88, 121.80, 113.01, 1 12.65, 112.45, 105.77, 105.15, 55.50, 43.66, 34.76, 21.83, 21.47.ppm. 31 P NMR(243MHz, MeOD)δ19.65.ppm.HRMS m / z:[M+H] + Calcd.for C 37 H 36 N2O5PBr, 699.1544; found, 699.1541.

[0058] The purity of the compound was verified by high-performance liquid chromatography (HPLC) (with pure methanol as the mobile phase). Figure 1 As shown, the high performance liquid chromatography of TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br showed only one peak signal in each ultraviolet absorption band, indicating that the compounds TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br have high purity and the influence of impurities on their long afterglow emission is almost negligible.

[0059] Single crystal structure analysis:

[0060] Compound TPP-o-3OMe-NNI-Br was slowly evaporated from a mixed solution of ethyl acetate / dichloromethane to yield orange-yellow fluorescent crystals (OC), and from a mixed solvent of n-hexane / methanol / dichloromethane to yield yellow fluorescent crystals (YC). Crystallographic data indicate that OC has a monoclinic crystal system with space group C1 2 / c 1, while YC has an orthorhombic crystal system with space group P bc a. The unit cell of OC contains 7 molecules, and the unit cell of YC contains 5 molecules, where YC(ρ

[0061] = 1.442 g.cm -3 ) compared to OC (ρ=1.427g.cm -3 The arrangement is more compact, and the volume is smaller. Compare The volume is larger (Table 1). The molecular crystal of compound TPP-o-3OMe-NBI-Br was obtained by slow solvent evaporation (ethyl acetate / dichloromethane) and showed no fluorescence emission at room temperature. Crystallographic data indicated that the crystal system was triclinic with space group P-1 and only two molecules in the unit cell.

[0062] Table 1 Crystal data for TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br

[0063]

[0064] like Figure 2 As shown, we analyzed the fluorescence color crystal data of two types of TPP-o-3OMe-NNI-Br molecules. For the monomer, using the NNI group as the reference plane, we found that almost all the dimethylamino atoms in the OC crystal are coplanar with the NNI group, while the plane formed by the NN-2-methyl group in the YC crystal is almost perpendicular to the NNI plane. This results in a higher charge transport efficiency for the OC crystal when the molecule is excited, which can effectively enhance the fluorescence enhancement caused by the π···π interaction formed by crystal stacking. Therefore, we analyzed the interaction between the two crystal dimers. Compared to YC crystals It has a stronger CH...O effect, and compared to YC ) crystal, OC crystal The greater π···π overlap, and the coplanarity of dimethylamino and NNI in the OC crystal greatly enhances the transfer of π conjugated electrons, resulting in a redshift in crystal luminescence.

[0065] To further analyze the differences in chemical bonding between the two crystals, we performed Hirschfeld surface analysis calculations on the monomer molecules of both crystals, such as... Figure 3 As shown, in OC crystal, the interactions are mainly dominated by six types: H···H (54.5%), C···H (19.2%), H···Br (10.5%), H···O (8.0%), C···C (1.2%), and C···O (1.0%). In YC crystal, H···H (54.5%) is similar to that in OC, C···H (12.4%) is weakened by 6.4%, H···Br (12.4%) is strengthened by 1.9%, and H···O (5.6%) is weakened by 2.4%. This indicates that in the crystal stacking structure, OC crystal possesses stronger weak interactions.

[0066] Characterization of photophysical properties:

[0067] The photophysical properties of TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br in solid and solution states were systematically studied. For example... Figure 4 As shown, both TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br molecules exhibit good thermal stability, and the TPP-o-3OMe-NNI-Br molecule shows an ultraviolet absorption of 500 nm in the solid state, indicating that the introduction of electron-donating groups may enable the TPP-o-3OMe-NNI-Br molecule to possess better intramolecular charge transfer. Single-crystal powder diffraction reveals that both solid powders maintain good crystal structure.

[0068] like Figure 5 As shown, the TPP-o-3OMe-NBI-Br solid powder exhibits red fluorescence emission (650nm) under a 365nm UV lamp, while the TPP-o-3OMe-NNI-Br molecule exhibits bright yellow fluorescence emission (580nm). Unfortunately, the TPP-o-3OMe-NBI-Br molecule does not exhibit long-persistent emission at room temperature, nor can it be detected by instruments. Although the two crystals of the TPP-o-3OMe-NNI-Br molecule do not exhibit persistent emission to the naked eye, they do show a persistent emission signal at 680nm when detected by instruments.

[0069] Photoactivated long afterglow properties:

[0070] To obtain a long, red afterglow emission visible to the naked eye at room temperature, TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br molecules were doped into PMMA at a mass ratio of 0.5%, resulting in two photoactivated long afterglow materials, TPP-o-3OMe-NBI-Br@PMMA and TPP-o-3OMe-NNI-Br@PMMA films. Thermogravimetric analysis was performed on the obtained films, such as... Figure 6 As shown, both doped polymers exhibit good thermal stability. UV absorption was performed on the TPP-o-3OMe-NBI-Br@PMMA and TPP-o-3OMe-NNI-Br@PMMA films. Both films showed broad absorption bands, providing a basis for the selection of excitation light sources. Furthermore, both doped systems maintained a well-defined amorphous structure.

[0071] like Figure 7 As shown, the TPP-o-3OMe-NBI-Br@PMMA film exhibits three emission peaks before activation, at 420 nm, 570 nm, and 610 nm. After activation, the emission peak intensities at 570 nm and 610 nm increase, while the intensity of the emission peak at 420 nm decreases. This causes the fluorescence color of the TPP-o-3OMe-NBI-Br@PMMA film to change from purple to pink under visual observation before and after photoactivation. In the steady-state spectrum after a delay of 0.1 ms, no fluorescence peak at 420 nm was detected before or after activation. Moreover, unlike the TPP-o-3OMe-NMI-Br@PMMA film in Chapter 3, although no afterglow emission was observed visually before photoactivation, the afterglow emission signal could be detected by instruments. This is because the introduction of the heavy atom bromine enhances spin-orbit coupling and improves the intersystem crossing efficiency (ISC) from the singlet to the triplet state.

[0072] The luminescence phenomenon of the TPP-o-3OMe-NNI-Br@PMMA film differs from that of the previous doped systems, such as... Figure 8 The introduction of dimethylamino groups enabled the TPP-o-3OMe-NNI-Br@PMMA film to successfully achieve red afterglow emission. By analyzing the transient and steady-state spectra before and after activation, we found that the fluorescence of the TPP-o-3OMe-NNI-Br@PMMA film also weakened after activation, indicating that a similar luminescence mechanism may exist during the activation process of the TPP-o-3OMe-NNI-Br@PMMA film.

[0073] like Figure 9As shown, TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br were dissolved in dimethyltetrahydrofuran at extremely low concentrations (0.001 mM), and their transient / steady-state spectra at 77 K were detected. The spectroscopic data showed that both TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br exhibited persistent emission at 450 nm, with lifetimes of 0.95 ms and 0.86 ms, respectively. These results indicate that the long persistent emission at room temperature of TPP-o-3OMe-NBI-Br@PMMA and TPP-o-3OMe-NNI-Br@PMMA does not originate from the monomer molecules of TPP-o-3OMe-NBI-Br and TPP-o-3OMe-NNI-Br, which is consistent with the conclusions of our previous two chapters.

[0074] To further verify whether the luminescence mechanism is consistent with the previous study, we used the TPP-o-3OMe-NNI-Br molecule as an example (because its afterglow emission is red) to detect the electron paramagnetic resonance (EPR) spectrum of oxygen vacancies and the singlet oxygen EPR spectrum of the TPP-o-3OMe-NNI-Br@PMMA film. Before activation, no signal was detected. After 30 s of activation, the EPR signal of singlet oxygen was significantly enhanced, indicating that TPP-o-3OMe-NNI-Br@PMMA can also convert triplet oxygen into singlet oxygen during photoactivation. During the 30 s of UV lamp activation, the oxygen diffused into the PMMA film was consumed, and the quenching effect of triplet oxygen on triplet excitons was weakened, thereby releasing triplet excitons.

[0075] At the same time, oxygen vacancy radicals (such as...) were successfully detected 30 seconds after activation. Figure 10 Furthermore, the TPP-o-3OMe-NNI-Br@PMMA molecule exhibits strong absorption at 420 nm, which largely overlaps with the phosphorescence peak of its monomer molecule at low temperature (450 nm), indicating that phosphorescent energy transfer (PRET) can be formed between the monomer triplet state and the radical doublet state.

[0076] like Figure 10 As shown, TD-DF calculations of the TPP-o-3OMe-NNI-Br monomer and dimer revealed that the emission peak around 650 nm in the long-afterglow emission spectrum is close to the emission band generated during the radical doublet state D8→D0 (f=0.036) transition, while the emission peak at 570 nm is similar to the emission band generated during the dimer's D1 triplet state T2→S0 (f=0.036).<T2|HSO|S0> =0.8717cm -1The close proximity indicates that the organic long afterglow originates from the synergistic effect of the radical doublet and the dimer triplet states. Therefore, combining experiments and theoretical calculations, we have successfully obtained a red organic long afterglow material with the synergistic effect of triplet and doublet states.

[0077] Optical information anti-counterfeiting applications:

[0078] like Figure 11 As shown in Figure 4-14, a photoluminescent anti-counterfeiting material with photoactivation time-dependent fluorescence change and long afterglow characteristics of TPP-o-3OMe-NBI-Br@PMMA and TPP-o-3OMe-NNI-Br@PMMA films was successfully prepared. Figure 4-14 illustrates a multi-color emitting flower pattern. A 0.5% doping ratio TPP-o-3OMe-NNI-Br@PMMA film was used as petals, a 0.5% doping ratio TPP-o-3OMe-NBI-Br@PMMA film as leaves, and a 1.0% doping ratio TPP-o-3OMe-NBI-Br@PMMA film as branches. Before photoactivation, the petals were green, the leaves were blue, and the branches were purple. After photoactivation, the leaves remained purple, while the branches turned pink, and the petal fluorescence remained unchanged. After the UV lamp was turned off, a long-afterglow flower with yellow branches and leaves and red petals was revealed. The multi-colored luminescence exhibits excellent optical anti-counterfeiting capabilities.

[0079] In summary, the introduction of NBI molecules enables the detection of afterglow signals in the TPP-o-3OMe-NBI-Br@PMMA film before photoactivation, due to the enhanced intramolecular charge transfer (ISC) resulting from the introduction of heavy atoms. The introduction of NNI molecules enhances intramolecular charge transfer capabilities, enabling the TPP-o-3OMe-NNI-Br@PMMA film to successfully achieve red afterglow emission. Thus, through molecular structure design, two radical luminescent materials achieving red afterglow emission under different environmental conditions have been successfully obtained. These molecules have broad application prospects in fields such as optical anti-counterfeiting and information encryption under extreme conditions.

[0080] The preferred embodiments of the present invention disclosed above are merely illustrative of the invention. These preferred embodiments do not describe all details exhaustively, nor do they limit the invention to the specific implementations described. Clearly, many modifications and variations can be made based on the content of this specification.

Claims

1. A near-infrared organic free radical afterglow material, characterized in that, A structure general formula is The R includes The compound TPP-o-3OMe-NBI-Br and the compound TPP-o-3OMe-NNI-Br are respectively constituted by an aryl quaternary phosphonium salt derivative.

2. The method of producing a near-infrared organic free radical persistent material according to claim 1, characterized by, The method comprises the following steps: S1, synthesizing the compound TPP-o-3OMe-NH2-Br: tri(2-methoxyphenyl) phosphine and 2-bromoethylamine hydrobromide are added into a reaction bottle, CH3CH2CN is added for dissolution, and reflux stirring is performed overnight; after the reaction is completed, the solvent is vacuum rotary dried; ultrapure water is added into the obtained solid powder, and NaOH is added to adjust the pH; then, the crude product is obtained by EA extraction; and the crude product is separated and purified by silica gel column chromatography to obtain the white solid compound TPP-o-OMe-NH2-Br; S2, the compound TPP-o-3OMe-NH2-Br in S1, the compound 4-bromo-1,8-naphthalic anhydride, and 4-dimethylaminopyridine (DMAP) are mixed and added into a reaction bottle; after vacuum drying, an ethanol solution is added under a nitrogen atmosphere; reflux stirring is performed; after the reaction is completed, the solvent is removed by vacuum drying; and the crude product is separated and purified by silica gel column chromatography to obtain the yellow solid compound TPP-o-3OMe-NBI-Br; S3, the compound TPP-o-3OMe-NH2-Br in S1, the compound 4-dimethylamino-1,8-naphthalic anhydride, and 4-dimethylaminopyridine are mixed and added into a reaction bottle; after vacuum drying, a dry 20m ethanol solution is added under a nitrogen atmosphere; reflux stirring is performed; after the reaction is completed, the solvent is removed by vacuum drying; and the crude product is separated and purified by silica gel column chromatography to obtain the orange-yellow solid compound TPP-o-3OMe-NNI-Br.

3. The method of producing a near-infrared organic radical persistent luminescence material according to claim 2, characterized by, The molar ratio of the compound TPP-o-3OMe-NH2-Br, the compound 4-bromo-1,8-naphthalic anhydride, and 4-dimethylaminopyridine in S2 is 3.12:3.4:3.

4.

4. The method for preparing near-infrared organic free radical afterglow material according to claim 2, characterized in that, The molar ratio of the compound TPP-o-3OMe-NH2-Br, the compound 4-dimethylamino-1,8-naphthalic anhydride, and 4-dimethylaminopyridine in S3 is 1:1.1:1.

1.

5. The method for preparing near-infrared organic free radical afterglow material according to claim 2, characterized in that, The synthesis method of the compound 4-dimethylamino-1,8-naphthalic anhydride in S3 is as follows: 4-bromo-1,8-naphthalic anhydride is dissolved in isoamyl alcohol, and the mixture is heated to reflux in an oil bath; then, 3-dimethylaminopropionitrile is added to the mixture and refluxed overnight; the precipitate is filtered at room temperature, washed with water and hexane, and dried under reduced pressure to obtain the yellow 4-dimethylamino-1,8-naphthalic anhydride (NNI) solid powder.

6. The method for preparing near-infrared organic free radical afterglow material according to claim 5, characterized in that, The molar ratio of the compound 4-bromo-1,8-naphthalic anhydride to 3-dimethylaminopropionitrile is 1:

4.

7. Use of a near-infrared organic free-radical persistent luminescence material according to claim 1, characterized in that, At least one of a semiconductor electronic device, biological imaging, and a spin material is prepared.

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