Room temperature phosphorescent material based on carbonyl modified column [5] arene and preparation method thereof
By using carbonyl-modified columns[5] and doping with aromatic derivatives and polymers, room temperature phosphorescent materials with high stability and low cost were prepared, which solved the problems of biotoxicity and environmental pollution of traditional precious metal phosphorescent materials and achieved long-life room temperature phosphorescent emission, which is suitable for anti-counterfeiting, information encryption and bioimaging fields.
Patent Information
- Application Number
- CN202511255743.8
- Authority / Receiving Office
- CN · China
- Patent Type
- Applications(China)
- Current Assignee / Owner
- Filing Date
- 2025-09-04
- Publication Date
- 2025-12-12
AI Technical Summary
Traditional precious metal phosphorescent materials are expensive, highly toxic to organisms, cause serious environmental pollution, are complex to synthesize, have short lifespans, and lack stability. They are difficult to achieve room temperature phosphorescence and dynamic response, and have poor compatibility with flexible matrices, narrow emission wavelengths, and are difficult to control.
By employing a polymer doping strategy, carbonyl-modified column[5] aromatic derivatives are used to provide a closed environment with the polymer matrix, restricting molecular movement and isolating oxidation. Combined with ultrasonic mixing and drop-coating film formation processes, room temperature phosphorescent materials with excellent stability and long lifespan are prepared.
It achieves effective control of phosphorescence from low temperature to room temperature, improves the chemical stability and mechanical properties of materials, reduces costs, is suitable for mass production, and is applicable to fields such as anti-counterfeiting, information encryption, and bioimaging.
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Abstract
Description
Technical Field
[0001] This invention belongs to the field of organic phosphorescent materials technology, specifically relating to a room temperature phosphorescent material based on carbonyl-modified columnar [5] aromatic hydrocarbons and its preparation method. Background Technology
[0002] Room-temperature phosphorescent materials have attracted widespread attention from scientists due to their potential applications in anti-counterfeiting, information storage, sensing, and bioimaging. However, traditional phosphorescent materials are mostly based on noble metal complexes (such as Ir and Pt complexes). While these materials possess high phosphorescence quantum yields and long lifetimes, the abundance of noble metals (Ir, Pt, etc.) in the Earth's crust is extremely low, making mining and purification costs prohibitively high. Noble metal ions (such as Pt) 2+ Ir 3+ Precious metals exhibit strong cytotoxicity, and their complexes readily dissociate in vivo, interfering with enzyme activity and DNA replication, thus limiting their application in medical fields such as bioimaging and biosensing. Furthermore, the wastewater containing precious metals generated during production is difficult to treat and easily causes environmental pollution, contradicting the trend of green chemistry. The preparation of precious metal complexes requires precise control of the coordination environment between the ligand structure (e.g., pyridine, phenylpyridine ligands) and the metal center. Reactions often require harsh conditions such as high temperatures and inert atmospheres, and are prone to numerous side reactions and low yields (typically less than 50%). The steric hindrance and electronic effects of the ligands must be precisely matched; even slight deviations can lead to a sharp drop in phosphorescence performance, increasing the difficulty of process scale-up. Although precious metal complexes are stable in inert environments, they are prone to photo-oxidation or ligand shedding under actual conditions such as light, oxygen, and humidity, resulting in a rapid decline in phosphorescence quantum yield (e.g., efficiency may decrease by more than 30% after one week of exposure to air). In addition, their rigid molecular structure has poor compatibility with flexible matrices (e.g., polymers), easily agglomerating during thin film preparation and triggering luminescence quenching. The electronic configuration of noble metal centers determines their narrow emission wavelength range (mostly concentrated in the red to near-infrared region). Achieving blue or white light emission through ligand modification often results in a significant decrease in quantum yield. Furthermore, their luminescence lifetime is limited by the metal spin-orbit coupling effect, making it difficult to achieve orders-of-magnitude control through simple means, thus failing to meet the dynamic response requirements of fields such as encryption and anti-counterfeiting. While non-noble metal organic phosphorescent materials avoid dependence on noble metals, they face significant non-radiative transitions and low phosphorescence efficiency. The intense intramolecular motion in traditional organic materials leads to the easy deactivation of triplet excitons through vibration and rotation, making phosphorescence difficult to observe at room temperature. In addition, the lack of systematic methods for structural control makes it difficult to achieve an effective conversion from low-temperature phosphorescence to room-temperature phosphorescence.
[0003] This invention's polymer doping strategy provides a closed environment for phosphorescent molecules through a rigid polymer matrix, effectively restricting intramolecular motion and reducing energy loss caused by vibrational dissipation. Simultaneously, the polymer matrix isolates singlet oxygen from the air (preventing oxidative quenching of triplet excitons), thus successfully modulating low-temperature phosphorescence (such as long afterglow at -77 K) to room-temperature phosphorescence. The interactions between the polymer matrix and phosphorescent molecules (such as hydrogen bonds and van der Waals forces) enhance the material's chemical stability and mechanical properties. Experiments show that this type of doped material maintains excellent phosphorescence performance even after being exposed to air for three months, solving the problem of traditional organic phosphorescent materials being susceptible to environmental factors (light, humidity) and thus prone to failure. The preparation of this type of material does not require harsh conditions such as high temperature, high pressure, or inert gas protection; it can be achieved through a simple "dissolution-doping-film formation" process (such as dissolving phosphorescent molecules and polymers in an organic solvent, ultrasonically mixing, and then drop-coating to form a film). The process is highly controllable and suitable for large-scale production. Compared to traditional precious metal-based phosphorescent materials, this material uses organic macrocyclic derivatives and general-purpose polymers as raw materials, significantly reducing costs and avoiding the use of heavy metals. With organic macrocyclic derivatives and polymers as the main components, this type of material avoids the biotoxicity problems of traditional heavy metal complexes and has significant practical application value. Summary of the Invention
[0004] In view of the shortcomings of existing organic room temperature phosphorescent materials, such as complex synthesis, short lifespan and insufficient stability, this invention aims to provide a room temperature phosphorescent material based on carbonyl modified column[5] aromatic hydrocarbons that is easy to synthesize, has high stability and long lifespan and its preparation method, so as to expand its practical application in related fields.
[0005] 1. Design and synthesis of column[5] aromatic derivatives: Seven column[5] aromatic derivatives were designed and synthesized, including derivatives modified with methoxy, ethoxy, bromo, amino, benzamide, terephthalamide, and trimesamide. The singlet-tritium band gap (ΔE) was reduced by introducing carbonyl groups. ST ), and selected pyromellitic tricarboxylate-modified columnar aromatic derivatives (TP) with excellent low-temperature phosphorescence properties [5].
[0006] 2. Preparation of warm phosphorescent materials: This invention relates to a method for preparing room-temperature phosphorescent materials based on carbonyl-modified columnar [5] aromatics. Through a "dissolution-doping-film formation" process, suitable columnar [5] aromatic derivatives and polymers are selected and dissolved in the correct ratio to ensure maximum intermolecular interaction. Subsequently, the mixture is ultrasonically mixed uniformly, then drop-coated to form a film, and the film thickness is controlled to optimize phosphorescence performance. The specific steps are as follows: A polymer doping strategy is employed, where phosphoric acid (TP) is dissolved in an organic solvent (tetrahydrofuran or N,N-dimethylformamide) with polymethyl methacrylate (PMMA) or polyacrylonitrile (PAN). The mixture is ultrasonically mixed for 20-50 minutes, then drop-coated onto a substrate surface. After natural air drying, it is cured at 100-150℃ for 1-6 hours to form a uniform film. Reactive oxygen molecules are removed by ultraviolet light irradiation to obtain a room-temperature phosphorescent material. The mass ratio of TP to polymer is 1:2 to 1:4, and the film thickness is 10-100 μm.
[0007] The structural formula of the columnar aromatic hydrocarbon TP modified with pyromellitic tricarboxylate [5] is: ; The method for synthesizing the pyromellitic tricarboxylate-functionalized column[5] aromatic derivative TP includes the following steps: (1) Synthesis of amino-functionalized column[5] aromatic P5-NH2: P5-Br and potassium phthalimide were dissolved in DMF and refluxed at 80-100℃ for 45-50 hours under nitrogen atmosphere. The solvent was removed by vacuum distillation, and hydrazine hydrate was added to it. Then ethanol was added as solvent and refluxed at 130-150℃ for 6-10 hours to produce a white precipitate. The precipitate was filtered while hot and the crude product was washed with hot ethanol and dried under vacuum to obtain P5-NH2. The molar ratio of P5-Br to potassium phthalimide was 1:4-1:5. The structural formula of P5-Br is: For the synthesis method, please refer to the literature New Journal of Chemistry, 2020, 44: 12531-7. (2) P5-NH2 and trimesoyl chloride were dissolved in dichloromethane and reacted at room temperature for 20-25 hours. The reaction solution was separated by column chromatography to obtain trimesoyl chloride-functionalized column[5] aromatic derivative TP. The molar ratio of P5-NH2 and trimesoyl chloride was 1:3-1:4.
[0008] The prepared polymer-doped film was dried to room temperature and then activated under ultraviolet light to remove reactive oxygen molecules, resulting in a significant increase in phosphorescence intensity and enhanced stability. The solvent ratio and film thickness were adjusted. Experimental results show that only doping with TP compounds and polymers can achieve the control of phosphorescence from low temperature to room temperature.
[0009] The beneficial effects of this invention are: This invention provides a new strategy for constructing room temperature phosphorescent materials. The strategy of polymer doping is used to restrict intramolecular motion, and the introduction of carbonyl groups promotes the n-π to n-π* transition between lone pair electrons and carbon-oxygen double bonds, thereby increasing the probability of the transition from singlet to triplet state. The isolation of singlet oxygen and the donor-acceptor interaction between the columnar aromatic hydrocarbon and the polymer successfully achieve the regulation of the molecule from low temperature phosphorescence to room temperature phosphorescence. By restricting intramolecular motion by polymer chain segments, isolating reactive oxygen species and constructing a donor-acceptor microenvironment, the long-lifetime phosphorescence emission of columnar aromatic hydrocarbon derivatives at room temperature was achieved for the first time, with a lifetime of 65-125 ms.
[0010] This series of materials features a simple synthesis process, requires no complex equipment, and exhibits excellent chemical and thermal stability. The materials are solution-processable, enabling large-area coating on various substrates, making them suitable for mass production. They hold significant application value in fields such as anti-counterfeiting inks, information encryption, bio-imaging, and room-temperature afterglow lighting. Attached Figure Description
[0011] Figure 1 p-NH2 compounds 1 1H NMR spectrum (400 MHz, CDCl3, 293 K).
[0012] Figure 2 p-NH2 compounds 13 1H NMR spectrum (150 MHz, CDCl3, 293 K).
[0013] Figure 3 ESI-MS mass spectra of P-NH2 compounds.
[0014] Figure 4 SP compounds 1 1H NMR spectrum (400 MHz, CDCl3, 293 K).
[0015] Figure 5 SP compounds 13 1H NMR spectrum (150 MHz, CDCl3, 293 K).
[0016] Figure 6 DP compounds 1 1H NMR spectrum (400 MHz, CDCl3, 293 K).
[0017] Figure 7 ESI-MS mass spectra of DP compounds.
[0018] Figure 8 TP compounds 1 1H NMR spectrum (400 MHz, CDCl3, 293 K).
[0019] Figure 9 ESI-MS mass spectra of TP compounds.
[0020] Figure 10 Long afterglow photographs of methoxy-modified column P5, ethoxy-modified column EtP5, bromo-modified column [5] aromatic P5-Br, amino-modified column [5] aromatic P5-NH2, benzamide-modified column [5] aromatic SP, terephthalamide-modified column [5] aromatic DP, and pyromellitic terephthalamide-modified column [5] aromatic TP.
[0021] Figure 11 Normalized spectrum of P5 molecules (a) and low-temperature phosphorescence lifetime test (b).
[0022] Figure 12 Normalized spectrum of EtP5 molecules (a) and low-temperature phosphorescence lifetime test (b).
[0023] Figure 13 Normalized spectrum of P5-Br molecule (a) and low-temperature phosphorescence lifetime test (b).
[0024] Figure 14 Normalized spectrum of P5-NH2 molecule (a) and low-temperature phosphorescence lifetime test (b).
[0025] Figure 15 Normalized spectrum of DP molecules (a) and low-temperature phosphorescence lifetime test (b).
[0026] Figure 16 Normalized spectrum of TP molecules (a) and phosphorescence lifetime test (b).
[0027] Figure 17 Normalized spectra of TP molecules after doping with polymer PMMA (a) and room temperature phosphorescence lifetime test (b).
[0028] Figure 18 Normalized spectra of TP molecules and polymer PAN doping (a) and room temperature phosphorescence lifetime test (b).
[0029] Figure 19 A schematic diagram of phosphorescence of TP-doped PMMA and PAN polymers modified with pyromellitic trimethylamide [5]. Detailed Implementation
[0030] The present invention will be further described below with reference to the accompanying drawings and specific embodiments, but the embodiments do not limit the present invention in any way; unless otherwise specified, the reagents, methods and equipment used in the present invention are conventional reagents, methods and equipment in this technical field; unless otherwise specified, the reagents and materials used in the following embodiments are all commercially available.
[0031] The emission spectra and lifetime decay curves of the samples were obtained using a HORIBA FluoroMax+ transient fluorescence spectrometer.
[0032] Example 1: Design and synthesis of column[5] aromatic derivatives Seven columnar aromatic derivatives[5] were designed and synthesized, including derivatives modified with methoxy, ethoxy, bromo, amino, benzamide, terephthalamide, and trimesoamide. By introducing carbonyl groups to reduce the singlet-triplet band gap (ΔEST), columnar aromatic derivatives[5] with excellent low-temperature phosphorescence properties (TP) were screened out. The seven columnar aromatic derivatives are methoxy-modified columnar aromatics[5] (P5), ethoxy-modified columnar aromatics[5] (Etp5), columnar aromatic derivatives[5] modified with bromoalkyl chains containing heavy atoms (P5-Br), amino-modified columnar aromatic derivatives[5] (P5-NH2), benzamide-modified columnar aromatic derivatives[5] (SP), terephthalamide-modified columnar aromatic derivatives[5] (DP), and trimesoamide-modified columnar aromatic derivatives[5] (TP).
[0033] 1. Synthesis of TP, a column-derived aromatic derivative functionalized with trimesoamide[5]. (1) Synthesis of amino-functionalized column[5] aromatic P5-NH2: First, 1 g (1.15 mmol) of P5-Br and 1 g (5.4 mmol) of potassium phthalimide were weighed into a round-bottom flask, and 50 mL of DMF was added as a solvent. Under a nitrogen atmosphere, the reaction solution was refluxed at 90 °C for 48 hours. The solvent was removed by vacuum distillation, and then 3 mL of hydrazine hydrate and 50 mL of ethanol were added as a solvent. The reaction solution was refluxed at 140 °C for 8 hours, and a white precipitate formed. The mixture was filtered while hot, and the crude product was washed 3-5 times with hot ethanol. It was dried under vacuum to obtain a white solid (2.1091 g, yield: 87%, melting point mp = 167-168 °C). The structure of P5-NH2 was characterized by 1H NMR. 1 H NMR (400 MHz, CDCl3), δ / ppm: 6.76 (s, 10H), 3.78 (s, 16H), 3.64 (s, 27H), 1.48 (d, J = 90.4 Hz, 4H). 13 C NMR (150 MHz, CDCl3) δ 150.81,128.23,114.11, 55.77, 29.67. ESI-MS m / z:[P5-NH2+H + Theoretical value C 48 H57 NO 10 : 808.4055, actual value: 808.4023.
[0034] (2) Synthesis of TP, a column-functionalized aromatic derivative of pyromellitic trimethylamide [5]: 2.421 g (3 mmol) of P5-NH2 was weighed into a round-bottom flask and dissolved in 20 mL of dichloromethane. Then, 0.2112 g (0.8 mmol) of pyromellitic trimethylamide chloride was weighed into a beaker and dissolved in dichloromethane. The solution was added dropwise to the round-bottom flask using a constant pressure dropping funnel. The reaction solution was reacted at room temperature for 24 hours. Then, an appropriate amount of silica gel was added to the reaction solution for mixing. The crude product (petroleum ether: ethyl acetate = 1:1, v / v) was separated by column chromatography. The white solid obtained was the compound TP (2.1091 g, yield: 46%, melting range: 167-168℃). 1 The structure of TP was characterized by H NMR. 1 H NMR (400 MHz, CDCl3) δ / ppm: 8.34 (s, 2H), 6.75-6.71 (m, 15H), 6.67 (s, 2H), 3.83 (d, J = 5.6 Hz, 3H), 3.75 (d, J = 9.1 Hz, 15H), 3.63-3.58 (m, 41H), 3.50 (d, J = 6.0 Hz, 3H), 1.69 (s, 3H), 0.93-0.79 (m, 3H). ESI-MS m / z:[P5-NH2+Na + Theoretical value C 153 H 172 O 33 N3+Na + : 2602.1801, Actual value: 2602.1802. Synthesis route: .
[0035] 2. Synthesis of benzoyl chloride-modified column[5] aromatic SP: 0.8074 g (1 mmol) of P5-NH2 was weighed into a round-bottom flask and dissolved in 20 mL of dichloromethane. Then, 0.21 g (1.5 mmol) of benzoyl chloride was weighed into a beaker and dissolved in dichloromethane. The solution was then added dropwise to the round-bottom flask using a constant-pressure dropping funnel. The reaction mixture was allowed to react at room temperature for 24 hours. Then, an appropriate amount of silica gel was added to the reaction mixture for stirring. The crude product (petroleum ether:ethyl acetate = 5:1, v / v) was separated by column chromatography, yielding a white solid, which was compound SP (2.1091 g, yield: 61%, melting point: 167-168 °C). 1 The structure of SP was characterized by H NMR. 1 H NMR (400 MHz, CDCl3) δ / ppm: 7.80-7.76 (m, 2H), 7.65 (t, J = 5.1 Hz, 1H), 7.55-7.50 (m, 1H), 7.46-7.41(m, 2H), 6.75-6.62 (m, 10H), 3.97(t, J = 5.7 Hz, 2H), 3.81 (d, J = 7.0 Hz, 37H), 3.31 (q, J = 5.2 Hz, 2H), 1.84-1.76 (m, 2H), 1.71-1.64 (m, 2H). ESI-MS m / z:[P5-NH2+H + Theoretical value C 55 H 61 NO 11 : 911.4310, actual value: 911.4317.
[0036] 3. Synthesis of column-modified terephthaloyl chloride [5] aromatic DP: Weigh 1.8901 g (2 mmol) of P5-NH2 into a round-bottom flask and dissolve it in 20 mL of dichloromethane. Then weigh 0.112 g (0.8 mmol) of terephthaloyl chloride into a beaker and dissolve it in dichloromethane. Add the solution dropwise to the round-bottom flask using a constant-pressure dropping funnel. React the solution at room temperature for 24 hours, then add an appropriate amount of silica gel and stir. Separate the crude product (petroleum ether:ethyl acetate = 1:1, v / v) by column chromatography to obtain a white solid, which is compound DP (2.1091 g, melting point: 167-168 ℃). 1 The structure of DP was characterized by H NMR. 1H NMR (400 MHz, CDCl3) δ / ppm: 7.79 (s, 4H), 6.87-6.80 (m, 20H), 3.70 (td, J = 17.6, 17.0, 7.6 Hz, 82H), 1.91-1.85 (m, 8H). ESI-MS m / z:[DP+H + Theoretical value C 104 H 117 O 22 N2: 1746.8131, actual value: 1746.8112.
[0037] Methoxy-based columnar [5]arene (P5), ethoxy-based columnar [5]arene (Etp5), and columnar [5]arene derivatives modified with heavy-atom brominated alkyl chains (P5-Br) were all synthesized according to literature; compound P5 was synthesized according to the literature Acs Applied Materials & Interfaces, 2021, 13: 16507-15.; compound EtP5 was synthesized according to the literature Angewandte Chemie-International Edition, 2021, 60: 8115-20.; compound P5-Br was synthesized according to the literature New Journal of Chemistry, 2020, 44: 12531-7.
[0038] Example 2 Low-temperature phosphorescence properties of column[5] aromatic hydrocarbon derivatives 1. Study on long afterglow of low-temperature phosphorescence The low-temperature phosphorescence of methoxy-based columnar [5]arene P5, ethoxy-based columnar [5]arene EtP5, columnar [5]arene derivative P5-Br modified with a heavy atom-containing brominated alkyl chain, columnar [5]arene derivative P5-NH2 functionalized with an amino-substituted alkyl chain, columnar [5]arene derivative SP functionalized with benzamide, columnar [5]arene derivative DP functionalized with terephthalamide, and columnar [5]arene derivative TP functionalized with trimesonide were studied. 50 mL of liquid nitrogen was taken in a thermos, and 5 mg of samples of more than seven compounds were added to a 1 mL sample bottle. The bottle was then immersed in the liquid nitrogen and allowed to stand for 5 min before being removed. Subsequently, the samples were irradiated with a 365 nm ultraviolet lamp, and after 5 s, the ultraviolet lamp was turned off to observe the long afterglow emission of phosphorescence for each compound.
[0039] The results showed that ( Figure 10Trimethylbenzene-functionalized columnar [5]arenes have the longest afterglow time, up to 9 s. As the number of carbonyl groups decreases, the afterglow time of the corresponding trimethylbenzene-functionalized columnar [5]arene derivatives decreases significantly, to only 3 s. However, no obvious long afterglow phenomenon was observed in benzamide-functionalized columnar [5]arenes SP at low temperatures. This may be because the introduction of benzamide with alkyl chains means that the alkyl chain ends of its own structure cannot effectively penetrate into the cavity of the columnar [5]arene, resulting in excessive internal molecular motion that suppresses triplet emission, thus causing the molecule to lack visible low-temperature phosphorescence. Methoxymethylene columnar [5]arenes P5 and ethoxymethylene columnar [5]arenes EtP5 both have moderate levels of long afterglow emission, and there is no significant difference in their long afterglow durations. However, compared to P5-Br and P5-NH2 with single alkyl chains, their low-temperature long afterglow emission time is longer. This may be due to the stronger rigidity of P5 and EtP5 molecules, which restricts the internal molecular motion. For column[5]arene derivatives P5-Br modified with brominated alkyl chains containing heavy atoms and column[5]arene derivatives P5-NH2 functionalized with alkyl chains substituted with amino groups, the heavy atom effect is a localized effect and is only relatively effective when the heavy atom is near the transition electron. Therefore, introducing alkyl bromides into the column[5]arene skeleton results in a longer afterglow luminescence compared to column[5]arenes with amino groups, with an afterglow duration of about 5 seconds. This experiment preliminarily demonstrates that the reasonable introduction of heteroatoms—carbonyl groups and heavy atoms into the column[5]arene skeleton is an effective strategy for increasing phosphorescence.
[0040] 2. Low-temperature phosphorescence testing The low-temperature phosphorescence emission spectrum and low-temperature phosphorescence lifetime of the P5 molecule were measured using a phosphorescence spectroscopy instrument. The normalized spectrum and low-temperature phosphorescence lifetime of the P5 molecule are shown below. Figure 11 As shown, the results indicate that at -77 K, the peak at 330 nm in the normalized spectrum of the methoxy-based homogeneous column P5 is a fluorescence emission peak. However, after the light source is turned off, the multiple peaks at 450 nm are the low-temperature phosphorescence emission peaks of the methoxy-based homogeneous column, and its low-temperature phosphorescence lifetime is measured to be 1050 ms.
[0041] Figure 12 Normalized spectra and low-temperature phosphorescence lifetime measurements of EtP5 molecules showed that the multiplet at 325 nm in the normalized spectrum of ethoxylated EtP5 belongs to fluorescence emission peaks. Figure 12 As shown in (a), the peak at 450 nm belongs to the low-temperature phosphorescence emission peak of ethoxylated EtP5. The lifetime of its low-temperature phosphorescence was measured to be 10¹⁰ ms. Figure 12 (b)).
[0042] Figure 13 The normalized spectrum and low-temperature phosphorescence lifetime of P5-Br molecules showed that the fluorescence emission peak of the heavy atom bromine-functionalized columnar aromatic P5-Br was at 330 nm, and the low-temperature phosphorescence emission peak was at 475 nm. Figure 13 (a) Furthermore, its low-temperature phosphorescence lifetime is significantly shortened to only 650 ms compared to P5 and EtP5 molecules.
[0043] Figure 14 The normalized spectrum and low-temperature phosphorescence lifetime of the P5-NH2 molecule showed that the fluorescence emission peak of the amino-functionalized [5] columnar aromatic hydrocarbon P5-NH2 was at 330 nm, and the low-temperature phosphorescence emission peak was at 475 nm. Figure 14 (a)), and its low-temperature phosphorescence lifetime is significantly shortened to 700 ms compared to methoxy and ethoxy homogeneous columns. Figure 14 (b)). It can be seen that the lifetime of the columnar aromatic hydrocarbons modified with heavy atoms[5] is not significantly increased. This is because the heavy atom effect has a certain localization effect. That is to say, the heavy atom can only play its role when the transitioning electron is near the heavy atom. In addition, the introduction of alkyl chains will lead to excessive internal molecular motion, thereby suppressing triplet emission.
[0044] However, for benzamide-functionalized columnar aromatics (SPs)[5], no low-temperature phosphorescence is visible to the naked eye. Theoretical calculations also show that there is no effective orbital for the transition from T1 to T3 in the molecule, thus failing to achieve the triplet state through intersystem crossing (ISC). Therefore, the molecule does not exhibit low-temperature phosphorescence.
[0045] Figure 15 The normalized spectrum and low-temperature phosphorescence lifetime of DP molecules were measured. For terephthalamide-functionalized columnar aromatic DP[5], a significant fluorescence emission peak appeared at 480 nm. When the light source was turned off, a new emission peak appeared at 475 nm, which is the emission peak of low-temperature phosphorescence. Figure 15 (a)), and its phosphorescence emission lifetime is 700 ms ( Figure 15 (b)).
[0046] Figure 16 Normalized spectra and low-temperature phosphorescence lifetime tests of TP molecules showed that when three carbonyl groups were introduced into the columnar aromatic backbone, the TP molecule exhibited a significant fluorescence emission peak at 480 nm. However, when the light source was removed, a new emission peak appeared at 520 nm, which is attributed to low-temperature phosphorescence. Figure 16 (a) Compared to terephthalamide-functionalized columnar aromatic TP[5], the phosphorescence lifetime has been significantly improved, reaching up to 2000 ms. Figure 16 (b) This shows that rationally introducing carbonyl groups into the skeleton of columnar aromatic hydrocarbons[5] is an effective and feasible strategy to increase the phosphorescence emission lifetime. The lone pair electrons on the oxygen atom and the carbon-oxygen double bond are more likely to achieve n-π to n-π* transitions. The energy required for two parallel electrons in the same orbital to undergo spin flipping is relatively high. However, when carbonyl groups are introduced into the system, the lone pair electrons on the oxygen atom and the π orbital form a 90-degree angle. Under such conditions, the energy required for electron spin flipping is lower, thereby increasing the transition probability of the molecule itself. This is beneficial to its phosphorescence emission.
[0047] Example 3: Preparation and testing of room temperature phosphorescent materials 1. Preparation of PMMA-doped room temperature phosphorescent materials 1 mg of a trimesin-modified columnar aromatic derivative [5] and 4 mg of polymethyl methacrylate (PMMA) were dissolved in 6 mL of tetrahydrofuran (THF) and sonicated for 30 minutes to mix them evenly. The mixture was then drop-coated onto a glass plate, allowed to air dry naturally, and dried in a vacuum drying oven at 150 degrees Celsius for 1 hour to form a uniform film. After cooling to room temperature, the film was activated with a 365 nm UV lamp to obtain a PMMA-doped room-temperature phosphorescent material. Figure 19 As shown in (a), the molecule was found to have excellent room-temperature long afterglow luminescence after being doped with a polymer.
[0048] 2. Preparation of PAN-doped room-temperature phosphorescent materials 1 mg of a pyromellitic trimethylamide-modified columnar aromatic derivative [5] and 4 mg of polyacrylonitrile (PAN) were dissolved in 6 mL of N,N-dimethylformamide (DMF) and sonicated for 30 minutes to mix them evenly. The mixture was then drop-coated onto a glass plate, allowed to air dry naturally, and dried in a vacuum drying oven at 150 degrees Celsius for 1 hour to form a uniform film. After cooling to room temperature, the film was activated with a 365 nm ultraviolet lamp to obtain PAN-doped room temperature phosphorescent material. Figure 19 As shown in (b), the molecule was found to have excellent long afterglow luminescence after being doped with a polymer.
[0049] 3. Room temperature phosphorescence testing of room temperature phosphorescent materials Its phosphorescence emission was tested using a phosphorometer. Figure 17 Normalized spectra and room-temperature phosphorescence lifetimes of TP molecules doped with the polymer PMMA were measured. We found that the molecule, after doping with the polymer, exhibits excellent room-temperature long afterglow luminescence. Subsequently, we used a phosphorometer to measure its phosphorescence emission. Experiments revealed two emission peaks at 365 nm and 540 nm, corresponding to the fluorescence and room-temperature phosphorescence emission peaks of the doped material, respectively. Figure 17 (a) and the corresponding phosphorescence lifetime is 125 ms. Figure 17 (b)).
[0050] Its phosphorescence emission was tested using a phosphorometer. Figure 18 Normalized spectra and room-temperature phosphorescence lifetime measurements were performed on TP molecules doped with polymer PAN. The normalized spectra revealed two emission peaks at 365 nm and 540 nm, corresponding to the fluorescence emission peak and room-temperature phosphorescence emission peak of the doped material, respectively. Figure 18 (a)), and the corresponding phosphorescence lifetime is 65 ms ( Figure 18 (b) The above experiments demonstrate that, after effective polymer doping, both produced room-temperature phosphorescent materials visible to the naked eye.
[0051] The above experiments show that after effective polymer doping, room temperature phosphorescent materials visible to the naked eye were produced. Doping a certain amount of organic molecules into a rigid polymer substrate can provide a closed environment to restrict the movement of molecules to minimize the deactivation of triplet excitons mediated by molecular motion, and can also isolate the quenching effect of reactive oxygen species on phosphorescence and obtain conventional room temperature phosphorescent materials. In addition, the cavity of the columnar aromatic molecule is an electron-rich cavity. Constructing a simple donor-acceptor environment near the columnar aromatic skeleton promotes the emission of room temperature phosphorescence of the molecule. Therefore, polymer doping is an effective method for constructing room temperature phosphorescent materials. This study not only provides theoretical support for the phosphorescence research of columnar aromatic derivatives[5], but also plays a good guiding role in the regulation of molecules from low temperature phosphorescence to room temperature phosphorescence. Therefore, this part of the work has certain application value in confidential materials and imaging.
[0052] This invention exhibits long-lifetime phosphorescence emission at room temperature. The phosphorescent material possesses unique emission wavelengths and afterglow characteristics, making it difficult to counterfeit and thus applicable to anti-counterfeiting fields. For example, phosphorescent materials are often embedded in anti-counterfeiting marks on RMB banknotes, passports, and securities. When excited by specialized instruments, they emit light of specific colors to verify authenticity. Bioimaging: In biomedical research, phosphorescent materials (especially long-afterglow phosphorescent nanomaterials) can serve as biological probes for in vivo imaging. Compared to traditional fluorescent probes, phosphorescent materials have a longer emission lifetime, effectively avoiding interference from the fluorescence of biological tissues, thus improving imaging clarity and accuracy. By labeling cancer cells with phosphorescent materials, the migration and distribution of cancer cells in vivo can be tracked in real time. Safety Marking: This phosphorescent material can be used for traffic signs (such as road markings and traffic light coatings) and ship lifesaving equipment (such as life jacket and life raft markings). These markings absorb sunlight during the day and automatically emit light at night or in low light conditions, improving safety.
Claims
1. A room-temperature phosphorescent material based on carbonyl-modified columnar aromatic hydrocarbons [5], characterized in that: The material is composed of a columnar aromatic hydrocarbon TP modified with pyromellitic tricarboxylate [5] and a polymer; The structural formula of the columnar aromatic hydrocarbon TP modified with pyromellitic tricarboxylate [5] is: ； The polymer is polymethyl methacrylate or polyacrylonitrile.
2. The room-temperature phosphorescent material according to claim 1, characterized in that: The material exhibits phosphorescence emission characteristics at room temperature, with a phosphorescence lifetime of 65 ms to 125 ms and an emission wavelength of 540 nm.
3. The room-temperature phosphorescent material according to claim 1, characterized in that: The mass ratio of the column-modified pyromellitic trimethylamide [5] aromatic hydrocarbon TP to the polymer is 1:2~1:
4.
4. A method for preparing the room-temperature phosphorescent material according to any one of claims 1-3, comprising the following steps: (1) Dissolve the pyromellitic tricarboxylate-modified column[5] aromatic TP and polymer in an organic solvent and ultrasonically mix for 20-50 minutes; (2) The mixed solution is dripped onto the surface of the substrate, and after air drying, it is dried and cured at 100-150℃ for 1-6 hours to form a uniform film with a thickness of 10-100 μm; (3) Remove reactive oxygen molecules by irradiating the film with ultraviolet light.
5. The preparation method according to claim 4, characterized in that: The organic solvent is tetrahydrofuran or N,N-dimethylformamide.
6. The preparation method according to claim 4, characterized in that, The method for synthesizing the pyromellitic tricarboxylate-functionalized column[5] aromatic derivative TP includes the following steps: (1) Synthesis of amino-functionalized column[5] aromatic P5-NH2: P5-Br and potassium phthalimide were dissolved in DMF and refluxed at 80-100℃ for 45-50 hours under nitrogen atmosphere. The solvent was removed by vacuum distillation, and hydrazine hydrate was added to it. Then ethanol was added as solvent and refluxed at 130-150℃ for 6-10 hours to produce a white precipitate. The precipitate was filtered while hot, and the crude product was washed with hot ethanol and dried under vacuum to obtain P5-NH2. The structural formula of P5-Br is: ； (2) P5-NH2 and trimesoyl chloride were dissolved in dichloromethane and reacted at room temperature for 20-25 hours. The reaction solution was separated by column chromatography to obtain trimesoyl chloride-functionalized column[5] aromatic derivative TP.
7. The preparation method according to claim 6, characterized in that, In step (1), the molar ratio of P5-Br to potassium phthalimide is 1:4-1:5; in step (2), the molar ratio of P5-NH2 to trimesoyl chloride is 1:3-1:
4.
8. The application of the room temperature phosphorescent material according to any one of claims 1-3 in anti-counterfeiting ink, information encryption, bio-imaging, or room temperature afterglow illumination.