Preparation method of multifunctional room-temperature phosphorescent material based on benzophenone derivative polyvinyl chloride system

Abstract

The invention belongs to the technical field of optical materials, and particularly relates to a preparation method of a multifunctional room-temperature phosphorescent material based on a benzophenone derivative polyvinyl chloride system. The method comprises the following steps: adding o-4 '-benzoyl-[1, 1'-biphenyl]-4-formaldehyde / 4 '-(4-bromobenzoyl)-[1, 1'-biphenyl]-4-formaldehyde and malononitrile into a reaction flask, taking sodium hydroxide as a catalyst, taking absolute methanol as a solvent, stirring and reacting at room temperature, and separating and purifying a crude reaction product to obtain two benzophenone derivatives. Dichloromethane / petroleum ether is selected as an eluent, and a white solid is obtained through column chromatography purification. And doping the white solid with polyvinyl chloride, dissolving with tetrahydrofuran, uniformly mixing, pouring into a watch glass, volatilizing the solvent at room temperature, putting into a drying oven, drying to obtain the host-guest doped phosphorescent material, and repeatedly folding, axially stretching and testing room temperature phosphorescent performance to confirm that the doped film can realize flexible long-life room temperature phosphorescence.

Description

TECHNICAL FIELD

[0001] The application belongs to the technical field of optical materials, and particularly relates to a preparation method of a multifunctional room temperature phosphorescent material based on a benzophenone derivative polyvinyl chloride system. BACKGROUND

[0002] Room temperature phosphorescent materials show great application potential in the fields of biomedical, complex encryption, and efficient lighting. However, existing room temperature phosphorescent (RTP) materials generally lack flexibility. Flexible RTP materials can withstand bending and stretching while maintaining excellent luminescent performance. Flexible RTP materials, with their superior mechanical flexibility and durability, have gradually become the ideal choice for wearable electronic devices and flexible display technologies, and provide endless possibilities for material damage prediction, limb movement monitoring, future smart clothing, and portable devices.

[0003] At present, many research teams at home and abroad have carried out a large number of explorations in the development of flexible RTP materials. Some studies have constructed block copolymers with both rigidity and flexibility to endow the materials with good flexibility. There are also studies that have doped organic RTP molecules into a polymer matrix to utilize the flexibility of the polymer to endow the material with good mechanical properties, and to improve the luminescent efficiency and stability of the RTP molecules through molecular design and matrix optimization. Some researchers have successfully prepared polymer thin films with long afterglow, high RTP quantum efficiency, and excellent mechanical properties by using the addition polymerization reaction of amine and isocyanate. In addition, ionic gels, hydrogels, and flexible crystals also play an important role in realizing flexible RTP.

[0004] Significant progress has been made in the research and development of flexible RTP materials. However, the relationship between molecular structure, flexibility, and RTP performance is not yet clear, which hinders accurate guidance for material design and makes the balance between flexibility and RTP performance a challenge. In addition, many methods currently used to prepare flexible RTP materials involve the design and synthesis of complex elastomers, resulting in high cost and limited versatility.

[0005] Based on this, a preparation method of a multifunctional room temperature phosphorescent material based on a benzophenone derivative polyvinyl chloride system is proposed, hoping to solve the deficiencies in the prior art. SUMMARY

[0006] The purpose of the present application is to provide a preparation method of a multifunctional room temperature phosphorescent material based on a benzophenone derivative polyvinyl chloride system to solve the existing problems.

[0007] The present application is realized by the following technical solutions: A preparation method of a multifunctional room temperature phosphorescent material based on a benzophenone derivative polyvinyl chloride system, comprising the following steps: (1) 4'-benzoyl-[1,1'-biphenyl]-4-carboxaldehyde / 4'- (4-bromobenzoyl)-[1,1'-biphenyl]-4-carboxaldehyde is added to a reaction bottle, malononitrile is added, sodium hydroxide is used as a catalyst, anhydrous methanol is used as a solvent, stirring is carried out at room temperature until the reaction is complete, and column chromatography is used for separation and purification to obtain a benzophenone derivative; (2) The benzophenone derivative is doped with PVC at a mass ratio of 1:100, is uniformly dispersed by tetrahydrofuran, and is dried into a film to obtain a doped film with long-life room-temperature phosphorescent emission performance, so that strain detection and three-dimensional modeling applications are realized.

[0008] Further, the equation of step (1) is as follows: Further, the benzophenone derivative is 2-amino-4- (4'-benzoyl-[1,1'-biphenyl]-4-yl) -6-methoxypyridine-3,5-dicyanide (BP-DCP) or 2-amino-4- (4'- (4-bromobenzoyl) -[1,1'-biphenyl]-4-yl) -6-methoxypyridine-3,5-dicyanide (Br-BP-DCP).

[0009] Further, the structural formula of the BP-DCP and the Br-BP-DCP is as follows: Further, the molar ratio of 4'-benzoyl-[1,1'-biphenyl]-4-carboxaldehyde / 4'- (4-bromobenzoyl)-[1,1'-biphenyl]-4-carboxaldehyde, malononitrile and sodium hydroxide in step (1) is 1:2.5:1.5.

[0010] Further, the molar ratio of methanol and 4'-benzoyl-[1,1'-biphenyl]-4-carboxaldehyde / 4'- (4-bromobenzoyl)-[1,1'-biphenyl]-4-carboxaldehyde in step (1) is 50:1.

[0011] Further, the separation and purification method in step (1) is column chromatography, and dichloromethane / petroleum ether at a volume ratio of 2:1 is used as an eluent.

[0012] Compared with the prior art, the present application has the following advantages: 1. The application selects 2-amino-6-methoxypyridine-3,5-dicyanide and benzophenone / 4-bromobenzophenone units as electron donor (D) and electron acceptor (A) respectively to form intramolecular charge transfer (ICT) state, and the benzophenone / 4-bromobenzophenone unit has high intersystem crossing (ISC) ability due to the very close energy level between the S1 state (n-π* characteristic) and T2 state (π-π* characteristic) of benzophenone. The T1 state energy level and n-π* transition characteristics of the benzophenone / 4-bromobenzophenone unit are adjusted through D-π-A type molecular design to significantly prolong the RTP lifetime. In addition, the heteroatoms and cyano groups in the two benzophenone derivatives can form intermolecular interaction with the chlorine atoms in PVC to inhibit non-radiative energy loss. The application balances the optical performance and flexibility of the RTP material, avoids complex elastomer synthesis, reduces the cost of flexible RTP material, and realizes the application of flexible long afterglow, long afterglow three-dimensional modeling and strain detection.

[0013] 2. The application selects industrialized PVC as a flexible doped matrix to construct a flexible room temperature phosphorescent material through host-guest doping of small molecule phosphor powder, avoids complex elastomer synthesis, reduces the cost of flexible RTP material, enhances the versatility of flexible RTP material, and presents excellent transparency and film forming property, can withstand stretching, folding, curling and other preparation methods, and can be dissolved into film by organic solvent to complete the large-area preparation and application of flexible long afterglow film.

[0014] 3. The two benzophenone derivatives synthesized by the application can promote intersystem crossing through the benzophenone structural unit, and can form strong intermolecular interaction with the PVC matrix through the pyridine ring and multiple heteroatoms to reduce non-radiative loss, thereby maintaining the good optical performance of the flexible RTP material, and enabling the doped material to maintain an RTP lifetime of more than 200 ms during the entire stretching process. BRIEF DESCRIPTION OF DRAWINGS

[0015] Figure 1 The hydrogen spectrum of the target product BP-DCP obtained in Example 1; Figure 2 The carbon spectrum of the target product BP-DCP obtained in Example 1; Figure 3 The mass spectrum of the target product BP-DCP obtained in Example 1; Figure 4 The hydrogen spectrum of the target product Br-BP-DCP obtained in Example 1; Figure 5 The carbon spectrum of the target product Br-BP-DCP obtained in Example 1; Figure 6 The mass spectrum of the target product Br-BP-DCP obtained in Example 1; Figure 7a are the stress-strain curves of blank PVC film and 1% BP-DCP@PVC film at different stretching rates (10, 20 and 50 mm / min) (the thickness of the film is 0.129 mm); Figure 7 b are the photos of 1% BP-DCP@PVC film stretched from the original length of 0% (3 cm) to 80% (5.4 cm) under 365 nm light irradiation; Figure 7 c are the phosphorescence intensity spectra of 1% BP-DCP@PVC film stretched from the original length of 0% (3 cm) to 80% (5.4 cm); Figure 7 d are the time-resolved RTP decay curves of 1% BP-DCP@PVC film stretched from the original length of 0% (3 cm) to 80% (5.4 cm); Figure 7 e are the trends of RTP intensity and lifetime of 1% BP-DCP@PVC film at different elongations; Figure 8 is the three-dimensional model of the doped system and long afterglow. DETAILED DESCRIPTION

[0016] In order to further explain the present application, the following specific examples are combined to illustrate the present application.

[0017] Example 1; 4'-benzoyl-[1,1'-biphenyl]-4-carbaldehyde / 4'- (4-bromobenzoyl) - [1,1'-biphenyl] -4-carbaldehyde (1 g, 3.5 mmol), malononitrile (0.58 g, 8.75 mmol), sodium hydroxide (0.21 g, 5.2 mmol), anhydrous methanol (7 mL) were added to a reaction bottle and stirred at room temperature for 2 h. The crude product was directly filtered and washed with water three times, using dichloromethane / petroleum ether (v / v = 2:1) as eluent, and the product was purified by column chromatography to obtain white solid BP-DCP and Br-BP-DCP. The yield was 51% and 56%, respectively.

[0018] 0.1 g of BP-DCP was added to 10 g of PVC, 20 mL of tetrahydrofuran was added, and it was completely dissolved by stirring, poured into a 20 cm diameter surface dish, and 1% BP-DCP@PVC film was obtained after volatilizing dry at room temperature.

[0019] Three-dimensional butterfly and ingot models were constructed by folding and curling 1% BP-DCP@PVC films, which presented a 6 s afterglow after the 365 nm UV light was turned off. 1% BP-DCP@PVC films (thickness 0.129 mm) were used for uniaxial stretching experiments (films for testing were prepared as standard dumbbell shapes, the thickness was measured at different positions using a thousandth thickness gauge three times, and the average value was taken).

[0020] The structural characterization data of the resulting target product BP-DCP are as follows: 1 H NMR (500 MHz, DMSO-d6) δ / ppm = 7.98 (d, J = 5.0 Hz, 5H), 7.88 (d, J = 7.9 Hz, 2H), 7.79 (d, J = 7.8 Hz, 2H), 7.69 (q, J = 8.9 Hz, 4H), 7.60 (t, J = 7.5 Hz, 2H), 3.99 (s, 3H); 13C NMR (126 MHz, DMSO-d6) δ / ppm = 195.83, 166.30, 161.71, 160.67, 143.43, 141.07, 137.57, 136.76, 134.48, 133.20, 131.00, 130.07, 129.79, 129.12, 127.70, 127.55, 116.01, 115.59, 83.81, 83.63, 55.27; HRMS (MALDI-TOF): m / z 453.1332 [[M +Na] +, calculated 453.1327]. The structural characterization data of the resulting target product Br-BP-DCP are as follows: 1H NMR (500 MHz, DMSO-d6) δ / ppm = 7.98 (d, J = 4.8 Hz, 5H), 7.88 (d, J = 7.6 Hz, 3H), 7.81 (d, J = 6.5 Hz, 2H), 7.73 (d, J = 7.8 Hz, 2H), 7.68 (d, J = 7.8 Hz, 2H), 3.99 (s, 3H); 13C NMR (126 MHz, DMSO-d6) δ / ppm = 194.90, 166.30, 161.71, 160.65, 143.62, 141.00, 136.59, 134.53, 132.20, 132.08, 131.01, 129.80, 127.72, 127.60, 127.21, 116.00, 115.59, 83.80, 83.63, 55.28; HRMS (MALDI-TOF): m / z 531.0425 [[M + Na] +, calcd 531.0433]. The structure of the target compound was deduced from the above characterization data as follows: Subsequently, the stress-strain curves of the blank PVC film and the 1% BP-DCP@PVC film at different stretching speeds were studied (see Figure 7 a). With the increase of the stretching speed, the tensile stress of the 1% BP-DCP@PVC film increased from 14.87 MPa to 16.35 MPa and 22.16 MPa, but its elongation decreased from 137.38% to 130.68% and 103.73%. Compared with the blank PVC film with a tensile stress of 5.19 MPa and an elongation of 115.25%, the tensile stress (16.35 MPa) and elongation (130.68%) of the 1% BP-DCP@PVC film at the same stretching speed were significantly improved, which indicated that the mechanical properties and flexibility of the film were significantly improved after doping, and this improvement was attributed to the enhanced intermolecular interaction between the host and guest materials.

[0021] Finally, at a stretching speed of 10 mm / min, the 1% BP-DCP@PVC film was stretched from 3 cm to 5.4 cm, and the length and elongation after stretching were shown in Figure 7 b. It is worth noting that the afterglow lifetime and room temperature phosphorescence (RTP) emission peak position of the 1% BP-DCP@PVC film remained stable before and after stretching, which meant that the film was expected to be used for dynamic three-dimensional modeling. However, with the increase of the elongation from 0 to 80%, its RTP intensity and lifetime gradually decreased (seeFigure 7 c-d). Theoretically, the intermolecular attraction and repulsion of the material decrease after stretching, leading to the intensification of molecular motion, thus reducing the RTP intensity and lifetime. In addition, the decrease of BP-DCP content in the same area should also be one of the reasons for the weakening of RTP intensity.

[0022] Notably, the tensile strength and elongation at break of 1% BP-DCP@PVC film reached 14.87 MPa and 137.38% respectively at a stretching speed of 10 min⁻¹, and exhibited excellent RTP (246.78-489.03 ms) and afterglow lifetime (6-7 s) before and after stretching. This structural stability is beneficial to the performance of the material in practical applications, especially in the fields of flexible display, mechanical force detection and three-dimensional modeling.

[0023] The above specific embodiments further illustrate the purpose, technical solutions and beneficial effects of the present application. It should be understood that the above description is only a specific embodiment of the present application and is not intended to limit the protection scope of the present application. Any modification, equivalent replacement, improvement, etc. within the spirit and principles of the present application shall be included in the protection scope of the present application.

Claims

1. A method for preparing multifunctional room temperature phosphorescent materials based on benzophenone derivative polyvinyl chloride systems, characterized by, The method comprises the following steps: (1) adding 4'-benzoyl-[1,1'-biphenyl]-4-carboxaldehyde / 4'- (4-bromobenzoyl)-[1,1'-biphenyl]-4-carboxaldehyde into a reaction bottle, adding malononitrile, taking sodium hydroxide as a catalyst, taking anhydrous methanol as a solvent, stirring at room temperature until the reaction is complete, and separating and purifying by column chromatography to obtain a benzophenone derivative; (2) doping the benzophenone derivative as a guest with PVC at a mass ratio of 1:100, uniformly dispersing by dissolving in tetrahydrofuran, and drying into a film to obtain a doped film with long-life room-temperature phosphorescent emission performance, and realizing strain detection and three-dimensional modeling applications.

2. A process for the preparation of multifunctional room temperature phosphor based on benzophenone derivative polyvinyl chloride system as claimed in claim 1, wherein, The equation of step (1) is as follows: 。 3. The method of claim 1, wherein the method of preparing a multifunctional room temperature phosphorescent material based on a benzophenone derivative polyvinyl chloride system is characterized by, The benzophenone derivative is 2-amino-4- (4'-benzoyl-[1,1'-biphenyl]-4-yl) -6-methoxypyridine-3,5-dicyanide (BP-DCP) or 2-amino-4- (4'- (4-bromobenzoyl) -[1,1'-biphenyl]-4-yl) -6-methoxypyridine-3,5-dicyanide (Br-BP-DCP).

4. The method of claim 3, wherein the method of preparing a multifunctional room temperature phosphorescent material based on a benzophenone derivative polyvinyl chloride system is characterized by, The structural formula of the BP-DCP and Br-BP-DCP is as follows: 。 5. The method of claim 1, wherein the method of preparing a multifunctional room temperature phosphorescent material based on a benzophenone derivative polyvinyl chloride system is characterized by, The molar ratio of 4'-benzoyl-[1,1'-biphenyl]-4-carboxaldehyde / 4'- (4-bromobenzoyl) -[1,1'-biphenyl]-4-carboxaldehyde, malononitrile and sodium hydroxide in step (1) is 1:2.5:1.

5.

6. The method of claim 1, wherein the method of preparing a multifunctional room temperature phosphorescent material based on a benzophenone derivative polyvinyl chloride system is characterized by, The molar ratio of methanol and 4'-benzoyl-[1,1'-biphenyl]-4-carboxaldehyde / 4'- (4-bromobenzoyl) -[1,1'-biphenyl]-4-carboxaldehyde in step (1) is 50:

1.

7. The method of claim 1, wherein the method of preparing a multifunctional room temperature phosphorescent material based on a benzophenone derivative polyvinyl chloride system is characterized by, The separation and purification method in step (1) is column chromatography, and dichloromethane / petroleum ether at a volume ratio of 2:1 is used as an eluent.

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