Metal halide based on 2-(p-tolyl) pyridine and preparation method and application thereof

Abstract

The invention discloses a metal halide based on 2-(p-tolyl) pyridine and a preparation method and application thereof.The chemical formula of the metal halide based on 2-(p-tolyl) pyridine is C24H24N2ZnCl4, Zn < 2 + > in the crystal structure of the metal halide is coordinated with four Cl <-> to form an isolated [ZnCl4] < 2-> tetrahedron, Zn < 2 + > in the center of the tetrahedron spread in different directions along the axis a, and Zn < 2 + > in the center of the tetrahedron differs along the axis b; the space group has specific unit cell parameters; the preparation method comprises the following steps: dissolving 2-(p-tolyl) pyridine serving as an organic ligand raw material, zinc acetate, zinc chloride and the like serving as metal salt raw materials and hydrochloric acid aqueous solution-deionized water-absolute ethyl alcohol serving as a composite solvent, and slowly volatilizing the solvent or cooling and crystallizing to obtain a target product. The metal halide prepared by the invention has efficient luminescence property and excellent stability, the preparation process is simple, the reaction condition is mild, large-scale industrial production can be realized, and the metal halide can be widely applied to photoluminescent devices as a luminescent material.

Description

Technical Field

[0001] This invention belongs to the field of new materials technology, specifically relating to a metal halide based on 2-(p-tolyl)pyridine, its preparation method, and its application. Background Technology

[0002] Organic-inorganic hybrid metal halides (OIMHs) have become a class of functional materials with great development potential due to their outstanding advantages such as easy synthesis, easy processing and designable crystal structure. They are widely used in electrical, optical and magnetic research as well as in fields such as fluorescent anti-counterfeiting and information encryption. They can also be used as sandwich materials for spintronic devices to construct optoelectronic devices such as light-emitting diodes.

[0003] The optical properties of organic-inorganic hybrid metal halides depend mainly on the types of metal ions and halide ions. By flexibly selecting functional organic cations and metal halide units, their electronic and optical properties can be precisely controlled. Therefore, these compounds are considered key materials for manufacturing micro-devices and even molecular devices with specific properties, and have great application potential in cutting-edge fields such as microelectronics.

[0004] 2-(p-Tolyl)pyridine, as a classic "cyclic metal ligand," possesses the characteristics of simple structure and well-defined coordination. It has been successfully applied in phosphorescent materials, especially in high-efficiency green organic light-emitting diodes (OLEDs), attracting significant industry attention. The introduction of the methyl group significantly improves the solubility of its derivatives in organic solvents, providing a key technological advantage for developing solution-processable hybrid materials.

[0005] Although numerous studies have reported the preparation of various lead-free organic-inorganic hybrid metal halides, the systematic introduction of 2-(p-tolyl)pyridine as a key organic component into lead-free metal halides (such as Sn-based compounds) remains a significant challenge. 2+ Sb 3+ Bi 3+ Research on constructing novel hybrid luminescent materials using environmentally friendly metal frameworks is still in its infancy. The highly efficient luminescence properties of this ligand, already verified in phosphorescent OLEDs, combined with the stability of lead-free halide frameworks, provide a novel approach to resolving the core contradiction in current lead-free materials where luminescence efficiency and chemical / photothermal stability are difficult to balance.

[0006] Therefore, designing and synthesizing lead-free organic-inorganic hybrid metal halide luminescent materials based on 2-(p-tolyl)pyridine, which possess high luminescence efficiency, excellent stability, and good processability, is a promising yet challenging research direction in the field of optical crystals and optoelectronic materials. This exploration not only aims to fill specific material gaps but also strives to verify the feasibility of synergistically improving the overall performance of lead-free hybrid materials through rational ligand design at the molecular assembly level. This has significant theoretical and practical application value for promoting the development of next-generation green, high-performance optoelectronic devices. Summary of the Invention

[0007] To address the aforementioned problems, this invention proposes a metal halide based on 2-(p-tolyl)pyridine, its preparation method, and its applications.

[0008] To achieve the above objectives, the present invention adopts the following technical solution:

[0009] A metal halide based on 2-(p-tolyl)pyridine, wherein the chemical formula of the 2-(p-tolyl)pyridine-based metal halide is C 24 H 24 N2ZnCl4; the C 24 H 24 In the N₂ZnCl₄ crystal structure, Zn 2+ It coordinates with four Cl- groups to form isolated [ZnCl4]. 2- A tetrahedron, with Zn at its center. 2+ It spreads in opposite directions along the a-axis.

[0010] Preferably, the C 24 H 24 The space group of N₂ZnCl₄ crystal is: Unit cell parameters α=94.902°, β=90.806°, γ=95.376°, Z=2.

[0011] A method for preparing a metal halide based on 2-(p-tolyl)pyridine includes the following steps:

[0012] S1. Preparation of raw materials: The organic ligand raw material is 2-(p-tolyl)pyridine, and the metal salt raw material is one or more of zinc acetate and zinc chloride;

[0013] S2. Preparation of composite solvent: The composite solvent is composed of hydrochloric acid aqueous solution, deionized water and anhydrous ethanol;

[0014] S3. Dissolving raw materials: Add the raw materials from step S1 to the composite solvent prepared in step S2, stir and heat to the dissolution temperature until the raw materials are completely dissolved.

[0015] S4. Crystallization Process 1: Maintain the dissolution temperature of step S3, allowing the solvent to evaporate slowly, resulting in slow crystallization and the precipitation of 2-(p-tolyl)pyridine zinc chloride crystals; or

[0016] S5. Crystallization process two: The solution obtained in step S3 is slowly cooled from high temperature to room temperature, and 2-(p-tolyl)pyridine zinc chloride crystals are precipitated during the cooling process.

[0017] Preferably, in step S1, the molar ratio of 2-(p-tolyl)pyridine to the metal salt raw material is (0.5-2):1.

[0018] Preferably, in step S2, the volume ratio of hydrochloric acid aqueous solution, deionized water, and anhydrous ethanol in the composite solvent is (3-8):1:(0.5-2).

[0019] Preferably, in step S3, the dissolution temperature is 30-60℃.

[0020] Preferably, in step S5, the cooling rate is 0.004-50℃ / h.

[0021] An application of a 2-(p-tolyl)pyridine-based metal halide, wherein the 2-(p-tolyl)pyridine-based metal halide is used as a luminescent material in a photoluminescent device.

[0022] Preferably, the photoluminescent device is a light-emitting diode.

[0023] By adopting the above technical solution, the present invention has the following beneficial effects:

[0024] 1. The 2-(p-tolyl)pyridine-based metal halide prepared in this invention is a novel organic-inorganic hybrid metal halide with a unique crystal structure. (Zn) 2+ It forms isolated [ZnCl4] with Cl-. 2- The tetrahedral structure and anisotropic propagation along the a-axis endow the material with efficient luminescence properties. The excitation peak center is 364 nm, the emission peak center is 394 nm, and the fluorescence lifetime fitting value reaches 8.5 ns, which can meet the high-performance requirements of optoelectronic devices for luminescent materials.

[0025] 2. The metal halide based on 2-(p-tolyl)pyridine of the present invention has excellent stability, exhibits no thermal weight loss at 200°C, and does not undergo phase change after 30 days of storage at room temperature. It solves the core problem of the difficulty in balancing luminescence efficiency and stability in existing lead-free hybrid materials, and has strong practicality.

[0026] 3. The preparation method of the present invention has simple steps, low reaction temperature and short time, no need for complicated equipment, and adopts solvent evaporation or slow cooling crystallization process, which is easy to control, facilitates large-scale preparation and industrial production, and reduces production costs.

[0027] 4. The metal halide material based on 2-(p-tolyl)pyridine of this invention has broad application prospects. As a luminescent material, it can be effectively applied to photoluminescent devices such as light-emitting diodes, providing key material support for the research and development of next-generation green and high-performance optoelectronic devices and promoting technological progress in the optoelectronic industry. Attached Figure Description

[0028] Figure 1 C obtained in Embodiment 1 of the present invention 24 H 24 Structural framework diagram of N2ZnCl4 crystal;

[0029] Figure 2 The XRD powder diffraction patterns of the products obtained in Examples 1-5 of this invention are shown below.

[0030] Figure 3 The fluorescence spectrum of the crystal obtained in Example 1 of this invention;

[0031] Figure 4 The fluorescence lifetime diagram is shown for the crystal obtained in Example 1 of this invention.

[0032] Figure 5 The graph shows the thermal stability test results of the crystal obtained in Example 1 of this invention;

[0033] Figure 6 C grown in Example 6 of the present invention 24 H 24 Physical image of a large-size N2ZnCl4 crystal;

[0034] Figure 7 This is the transmission spectrum of the crystal obtained in Example 1 of the present invention. Detailed Implementation

[0035] To make the objectives, technical solutions, and advantages of this invention clearer, the invention will be further described in detail below with reference to examples. It should be understood that the specific examples described herein are merely illustrative and not intended to limit the invention.

[0036] See Figures 1 to 7 .

[0037] Example 1

[0038] The preparation of a metal halide based on 2-(p-tolyl)pyridine includes the following steps:

[0039] S101. At room temperature, 2-(p-tolyl)pyridine and zinc acetate are weighed as raw materials in a molar ratio of 1:2; a composite solvent is prepared in a volume ratio of 3:1:0.5, wherein the composite solvent is composed of hydrochloric acid aqueous solution, deionized water and anhydrous ethanol.

[0040] S102. At 25°C, the above raw materials are added to the composite solvent, stirred and heated to 60°C, and stirred continuously until the raw materials are completely dissolved to form a precursor solution.

[0041] S103. The precursor solution was reacted at 60°C for 1 hour, and then cooled to room temperature at a rate of 0.7°C / min. Crystals were precipitated during this process.

[0042] S104. Filter and collect the precipitated crystals, wash three times with ethanol, and then dry at 60°C to obtain C. 24 H 24 N2ZnCl4 crystals.

[0043] Regarding the obtained C 24 H 24 Characterization of N₂ZnCl₄ crystals:

[0044] X-ray single-crystal diffraction was used to test the space group, which was found to be [space group number missing]. Unit cell parameters α = 94.902°, β = 90.806°, γ = 95.376°, Z = 2, crystal structure as follows Figure 1 As shown;

[0045] XRD powder diffraction pattern as follows Figure 2 As shown, the diffraction peak positions are consistent with those of the theoretically simulated XRD diffraction pattern, indicating that the product is a pure phase.

[0046] Fluorescence spectroscopy test such as Figure 3 As shown, the excitation peak center is 364 nm and the emission peak center is 394 nm, exhibiting excellent photoluminescence characteristics;

[0047] Fluorescence lifetime test, such as Figure 4 As shown, the fitted value for fluorescence lifetime is 8.5 ns;

[0048] Thermal stability test, such as Figure 5 As shown, the crystal exhibits no thermal weight loss at 200℃; after being stored at room temperature for 30 days, no phase transition occurs, demonstrating excellent stability.

[0049] Example 2

[0050] The preparation of a metal halide based on 2-(p-tolyl)pyridine includes the following steps:

[0051] S201. At room temperature, 2-(p-tolyl)pyridine and zinc acetate are weighed as raw materials in a molar ratio of 1:1; a composite solvent is prepared in a volume ratio of 5:1:1, wherein the composite solvent is composed of hydrochloric acid aqueous solution, deionized water and anhydrous ethanol.

[0052] S202. At 25°C, the above raw materials are added to the composite solvent, stirred and heated to 60°C, and stirred continuously until the raw materials are completely dissolved to form a precursor solution.

[0053] S203. The precursor solution was reacted at 60℃ for 0.5 h, then cooled to room temperature at a rate of 0.2℃ / min. After filtration, washing with ethanol, and drying at 60℃, C was obtained. 24 H 24 N2ZnCl4 crystals.

[0054] The obtained crystal was subjected to XRD powder diffraction analysis, and the resulting pattern is shown below. Figure 2 As shown, the spectrum is consistent with the theoretical simulation, indicating that the product is a pure phase; performance tests show that its luminescence properties and stability are similar to those of Example 1.

[0055] Example 3

[0056] The preparation of a metal halide based on 2-(p-tolyl)pyridine includes the following steps:

[0057] S301. At room temperature, 2-(p-tolyl)pyridine and zinc chloride are weighed as raw materials in a molar ratio of 0.5:1; a composite solvent is prepared in a volume ratio of 8:1:2, wherein the composite solvent is composed of hydrochloric acid aqueous solution, deionized water and anhydrous ethanol.

[0058] S302. At 25°C, the above raw materials are added to the composite solvent, stirred and heated to 60°C, and stirred continuously until the raw materials are completely dissolved to form a precursor solution.

[0059] S303. The precursor solution was reacted at 60℃ for 1 h, then cooled to room temperature at a rate of 0.7℃ / min. After filtration, washing with ethanol, and drying at 60℃, C was obtained. 24 H 24 N2ZnCl4 crystals.

[0060] XRD powder diffraction analysis showed that the product was a pure phase. Figure 2 Its luminescence performance and stability meet the application requirements.

[0061] Example 4

[0062] The preparation of a metal halide based on 2-(p-tolyl)pyridine includes the following steps:

[0063] S401. At room temperature, 2-(p-tolyl)pyridine and zinc chloride are weighed as raw materials in a molar ratio of 1:1; a composite solvent is prepared in a volume ratio of 3:1:0.5, wherein the composite solvent is composed of hydrochloric acid aqueous solution, deionized water and anhydrous ethanol.

[0064] S402. At 25°C, the above raw materials are added to the composite solvent, stirred and heated to 60°C, and stirred continuously until the raw materials are completely dissolved to form a precursor solution.

[0065] S403. The precursor solution was reacted at 60°C for 1 hour, then cooled to room temperature at a rate of 0.77°C / min. After filtration, washing with ethanol, and drying at 60°C, C was obtained. 24 H 24 N2ZnCl4 crystals.

[0066] XRD powder diffraction analysis showed that the product was a pure phase. Figure 2 It has good luminescent properties and stability.

[0067] Example 5

[0068] The preparation of a metal halide based on 2-(p-tolyl)pyridine includes the following steps:

[0069] S501. At room temperature, 2-(p-tolyl)pyridine, zinc acetate and zinc chloride are weighed as raw materials in a molar ratio of 1:1:1; a composite solvent is prepared in a volume ratio of 4:1:1, wherein the composite solvent is composed of hydrochloric acid aqueous solution, deionized water and anhydrous ethanol.

[0070] S502. At 30°C, the above raw materials are added to the composite solvent and stirred until all the raw materials are dissolved to form a precursor solution.

[0071] S503. Keep the precursor solution at a constant temperature of 30°C and let it stand for 20 days. During this period, the solvent will continue to evaporate and crystals will precipitate.

[0072] S504. Filter and collect the crystals, wash with ethanol, and dry at 60°C to obtain C. 24 H 24 N2ZnCl4 crystals.

[0073] XRD powder diffraction analysis showed that the product was a pure phase. Figure 2 It exhibits excellent luminescence properties and stability.

[0074] Example 6

[0075] The preparation of large-sized 2-(p-tolyl)pyridine-based metal halide crystals includes the following steps:

[0076] S601. Prepare a composite solvent according to a volume ratio of 5:1:1, wherein the composite solvent is composed of hydrochloric acid aqueous solution, deionized water and anhydrous ethanol;

[0077] S602. At 25°C, the C prepared in Example 1 is... 24 H 24N2ZnCl4 crystals were added to a composite solvent, stirred and heated to 60°C until all the crystals dissolved, thus preparing a saturated solution.

[0078] S603. The saturated solution was slowly cooled to room temperature at a rate of 0.004℃ / min from 60℃ to obtain C. 24 H 24 Large-sized N₂ZnCl₄ crystals, as shown in the image. Figure 6 As shown;

[0079] S604. Perform transmission spectroscopy tests on large-size crystals, such as... Figure 7 As shown, the crystal has high transmittance and is a high-quality transparent crystal, which meets the crystal quality requirements of optoelectronic devices.

[0080] Application Examples

[0081] The C prepared in Example 1 24 H 24 N₂ZnCl₄ crystal was used as a luminescent material in the fabrication of light-emitting diode (LED) devices. The specific process involved uniformly mixing the crystal powder with an appropriate amount of organic binder, coating the mixture onto the luminescent layer substrate of the device, and then curing and encapsulating it to obtain a prototype LED device. Photoelectric performance testing of the device showed that it achieved efficient luminescence at 394 nm under 364 nm excitation light, with stable luminescence intensity. After 1000 hours of continuous operation, its performance showed no significant degradation, indicating that this metal halide is an excellent luminescent material for photoluminescent devices.

[0082] The above description is merely a preferred embodiment of the present invention, but the scope of protection of the present invention is not limited thereto. Any variations or substitutions that can be easily conceived by those skilled in the art within the technical scope disclosed in the present invention should be included within the scope of protection of the present invention. Therefore, the scope of protection of the present invention should be determined by the scope of the claims.

Claims

1. A metal halide based on 2-(p-tolyl)pyridine, characterized in that: The chemical formula of the metal halide based on 2-(p-tolyl)pyridine is C. 24 H 24 N2ZnCl4; the C 24 H 24 In the N₂ZnCl₄ crystal structure, Zn 2+ It coordinates with four Cl- groups to form isolated [ZnCl4]. 2- A tetrahedron, with Zn at its center. 2+ It spreads in opposite directions along the a-axis.

2. The metal halide based on 2-(p-tolyl)pyridine as described in claim 1, characterized in that: The C 24 H 24 The space group of N₂ZnCl₄ crystal is: Unit cell parameters α=94.902°, β=90.806°, γ=95.376°, Z=2.

3. A method for preparing a metal halide based on 2-(p-tolyl)pyridine as described in any one of claims 1 or 2, characterized in that, Includes the following steps: S1. Preparation of raw materials: The organic ligand raw material is 2-(p-tolyl)pyridine, and the metal salt raw material is one or more of zinc acetate and zinc chloride; S2. Preparation of composite solvent: The composite solvent is composed of hydrochloric acid aqueous solution, deionized water and anhydrous ethanol; S3. Dissolving raw materials: Add the raw materials from step S1 to the composite solvent prepared in step S2, stir and heat to the dissolution temperature until the raw materials are completely dissolved. S4. Crystallization Process 1: Maintain the dissolution temperature of step S3, allowing the solvent to evaporate slowly, resulting in slow crystallization and the precipitation of 2-(p-tolyl)pyridine zinc chloride crystals; or S5. Crystallization process two: The solution obtained in step S3 is slowly cooled from high temperature to room temperature, and 2-(p-tolyl)pyridine zinc chloride crystals are precipitated during the cooling process.

4. The method for preparing metal halides based on 2-(p-tolyl)pyridine as described in claim 3, characterized in that: In step S1, the molar ratio of 2-(p-tolyl)pyridine to the metal salt raw material is (0.5-2):

1.

5. The method for preparing metal halides based on 2-(p-tolyl)pyridine as described in claim 3, characterized in that: In step S2, the volume ratio of hydrochloric acid aqueous solution, deionized water and anhydrous ethanol in the composite solvent is (3-8):1:(0.5-2).

6. The method for preparing metal halides based on 2-(p-tolyl)pyridine as described in claim 3, characterized in that: In step S3, the dissolution temperature is 30-60℃.

7. The method for preparing metal halides based on 2-(p-tolyl)pyridine as described in claim 3, characterized in that: In step S5, the cooling rate is 0.004-50℃ / h.

8. An application of a 2-(p-tolyl)pyridine-based metal halide as described in any one of claims 1 or 2, characterized in that: The metal halide based on 2-(p-tolyl)pyridine is used as a luminescent material in photoluminescent devices.

9. The application of 2-(p-tolyl)pyridine-based metal halides as described in claim 8, characterized in that: The photoluminescent device is a light-emitting diode.

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