An imidazopyridine zinc complex, its preparation method and application

Abstract

The present invention belongs to the technical field of luminescent materials, and particularly relates to an imidazopyridine zinc complex, a preparation method thereof, and an application thereof. The present invention provides an imidazopyridine zinc complex having the structure shown in Formula I. The imidazopyridine zinc complex provided by the present invention can exhibit a dynamic change in afterglow from green to yellow to orange-red respectively as the excitation wavelength changes from 254 to 420 nm, and has a wide fluorescence color gamut.

Description

Technical Field

[0001] The present invention belongs to the technical field of luminescent materials, and particularly relates to an imidazopyridine zinc complex, a preparation method thereof, and an application thereof. Background Art

[0002] Long afterglow luminescent materials are materials that can store the energy of external light radiation such as ultraviolet light and visible light, and then slowly release this stored energy in the form of visible light at room temperature, and have important application values in the fields of information display, information encryption, and biological imaging.

[0003] The long afterglow phenomenon of long afterglow luminescent materials generally originates from the crystal defects of the matrix material, and these crystal defects can be generated by doping. The crystal defects lead to the generation of localized energy levels in the forbidden band energy level of the matrix. In the excitation stage, these localized energy levels can capture holes or electrons. When the excitation ends, these electrons or holes are released under the thermal action of the environment, and the energy is transferred to the activator ions to cause them to emit light. Since the thermal release of energy is a slow process, the luminescence of the activator ions exhibits the characteristics of long afterglow luminescence.

[0004] The existing long afterglow materials in the visible light region are mainly divided into red series, yellow-green series, and blue series. However, the existing long afterglow materials are all static long afterglow materials and have a narrow color gamut, thereby resulting in a single reaction information and restricting the application of long afterglow luminescent materials in the fields of information display, encryption, or imaging. Summary of the Invention

[0005] The purpose of the present invention is to provide an imidazopyridine zinc complex, a preparation method thereof, and an application thereof. The imidazopyridine zinc complex provided by the present invention has a wide fluorescence color gamut and can realize the wide color gamut afterglow fluorescence dynamic change from green - yellow - orange - red.

[0006] In order to achieve the above purpose, the present invention provides the following technical solutions:

[0007] The present invention provides an imidazopyridine zinc complex having the structure shown in Formula I:

[0008]

[0009] Preferably, the imidazopyridine zinc complex is a monoclinic system, the space group is P21 / c, and the unit cell parameters are α = 90°, β = 103.40(2)°, γ = 90°,

[0010] The present invention also provides a preparation method of the imidazopyridine zinc complex according to the above technical solution, including the following steps:

[0011] Mix the compound with the structure shown in Formula II, zinc acetate, and a mixed organic solvent containing N,N-dimethylformamide, and obtain the imidazopyridine zinc complex through a coordination reaction;

[0012]

[0013] Preferably, the molar ratio of the compound with the structure shown in Formula II to zinc acetate is 1:4 to 2:1.

[0014] Preferably, the mixed organic solvent containing N,N-dimethylformamide includes N,N-dimethylformamide and an auxiliary organic solvent;

[0015] The auxiliary organic solvent includes one or more of n-butanol, methanol, ethanol, and acetonitrile.

[0016] Preferably, the volume ratio of N,N-dimethylformamide to the auxiliary organic solvent is 3 to 6:1.

[0017] Preferably, the dosage ratio of the compound with the structure shown in Formula II to the mixed organic solvent containing N,N-dimethylformamide is 0.15 to 0.2 mmol: 4 mL.

[0018] Preferably, the temperature of the coordination reaction is 80 to 120 °C, and the heat preservation time is 48 to 96 h.

[0019] Preferably, the heating rate for raising the temperature to the coordination reaction is 5 to 20 °C / min.

[0020] The present invention also provides the application of the imidazopyridine zinc complex described in the above technical solution or the imidazopyridine zinc complex prepared by the preparation method described in the above technical solution as a long afterglow luminescent material.

[0021] The present invention provides an imidazopyridine zinc complex with the structure shown in Formula I. The imidazopyridine zinc complex provided by the present invention can respectively exhibit a dynamic change in afterglow from green-yellow-orange-red as the excitation wavelength changes from 254 to 420 nm, and has a wide fluorescence color gamut. Through crystal structure analysis, variable temperature phosphorescence testing, solid-state ultraviolet absorption, and singlet and triplet energy level calculations, it can be known that the generation of this dynamic afterglow comes from the triplets generated by different aggregation states of the organic light-emitting body in the crystal and the triplets induced by intermolecular charge transfer, proving that charge transfer plays an important role in the generation and stabilization of the triplets. Description of the Drawings

[0022] Figure 1 Schematic diagram of the coordination environment structure of Zn in the imidazopyridine zinc complex obtained in Example 1;

[0023] Figure 2Schematic diagram of the one-dimensional chain structure of the imidazopyridine zinc complex obtained in Example 1;

[0024] Figure 3 Schematic diagram of the three-dimensional network structure of the imidazopyridine zinc complex obtained in Example 1;

[0025] Figure 4 Schematic diagram of the TOPOs structure of the imidazopyridine zinc complex obtained in Example 1;

[0026] Figure 5 XRD pattern of the imidazopyridine zinc complex obtained in Example 1;

[0027] Figure 6 Thermogravimetric curve of the imidazopyridine zinc complex obtained in Example 1;

[0028] Figure 7 Fluorescence spectrum of the imidazopyridine zinc complex obtained in Example 1;

[0029] Figure 8 Lifetime diagram of the imidazopyridine zinc complex obtained in Example 1;

[0030] Figure 9 Phosphorescence spectra of the imidazopyridine zinc complex obtained in Example 1 under different excitation peaks;

[0031] Figure 10 Phosphorescence spectra of the imidazopyridine zinc complex obtained in Example 1 under different excitation peaks;

[0032] Figure 11 Phosphorescence color development spectra of the imidazopyridine zinc complex obtained in Example 1 under different excitation peaks. Detailed implementation mode

[0033] The present invention provides an imidazopyridine zinc complex having the structure shown in Formula I:

[0034]

[0035] In the present invention, the imidazopyridine zinc complex is preferably monoclinic, with the space group P21 / c and the unit cell parameters being α = 90°, β = 103.40(2)°, γ = 90°,

[0036] In the present invention, the basic structure of the imidazopyridine zinc complex is a three-dimensional supramolecular structure, and the basic structural unit contains a tetracoordinated Zn II ion, and these four coordinating atoms are respectively from the nitrogen atoms of two 1H-1,2,3-triazole[4,5-b]pyridines and the oxygen atoms of two acetate groups. Adjacent two ZnII The ions are respectively connected to two nitrogen atoms of the same 1H-1,2,3-triazole[4,5-b]pyridine and the oxygen atom in the acetate group. Zn II The Zn ions form a one-dimensional chain through this connection mode, and there are π-π interactions between the 1H-1,2,3-triazole[4,5-b]pyridines, and the distance between the ring centers is It realizes the connection of the one-dimensional chain into a three-dimensional supramolecular structure.

[0037] The present invention also provides a preparation method of the imidazopyridine zinc complex described in the above technical solution, including the following steps:

[0038] Mix the compound with the structure shown in formula II, zinc acetate and a mixed organic solvent containing N,N-dimethylformamide, and obtain the imidazopyridine zinc complex through a coordination reaction;

[0039]

[0040] In the present invention, unless otherwise specified, all preparation raw materials are commercially available products well-known to those skilled in the art.

[0041] In the present invention, the zinc acetate is preferably zinc acetate dihydrate.

[0042] In the present invention, the mixed organic solvent containing N,N-dimethylformamide preferably includes N,N-dimethylformamide and an auxiliary organic solvent; the auxiliary organic solvent preferably includes one or more of n-butanol, methanol, ethanol and acetonitrile. In the present invention, the volume ratio of the N,N-dimethylformamide to the auxiliary organic solvent is preferably 3-6:1.

[0043] In the present invention, the molar ratio of the compound with the structure shown in formula II to the water-soluble zinc salt is 1:4-2:1. In the present invention, the dosage ratio of the compound with the structure shown in formula II to the mixed organic solvent containing N,N-dimethylformamide is preferably 0.15-0.2 mmol:4 mL.

[0044] The present invention has no special limitation on the mixing process, and those well-known to those skilled in the art can be used.

[0045] In the present invention, the temperature of the coordination reaction is 80-120 °C, further preferably 90-110 °C, more preferably 100 °C; the heating rate to the coordination reaction is 5-20 °C / min; the heat preservation time is 48-96 h. In the present invention, the coordination reaction is preferably carried out in a hydrothermal reaction kettle.

[0046] After the coordination reaction, the present invention preferably further includes successively cooling, filtering, washing, and drying the obtained reaction liquor. In the present invention, the cooling rate of temperature reduction is preferably the same as the heating rate. In the present invention, the washing is preferably carried out using ethanol. In the present invention, the drying method is preferably natural air drying at room temperature.

[0047] In the present invention, the yield of the imidazopyridine zinc complex is preferably above 62%.

[0048] The preparation method provided by the present invention has the advantages of simple synthesis method, easy operation, good stability, high yield, and good reproducibility.

[0049] The present invention also provides the application of the imidazopyridine zinc complex described in the above technical solution or the imidazopyridine zinc complex prepared by the preparation method described in the above technical solution as a long afterglow luminescent material. The present invention has no special limitation on the specific implementation manner of the application, and those well-known to those skilled in the art can be adopted.

[0050] In the present invention, under ultraviolet lamp excitation, the imidazopyridine zinc complex emits blue-white fluorescence. After turning off the ultraviolet lamp, with the change of the excitation wavelength from 254 nm to 420 nm, it respectively shows afterglow dynamic changes from green - yellow - orange - red, and has a wide fluorescence color gamut. The peak position of its emission peak gradually redshifts from 550 nm to 650 nm.

[0051] To further illustrate the present invention, the following describes in detail an imidazopyridine zinc complex provided by the present invention, its preparation method, and application with reference to the accompanying drawings and embodiments, but they cannot be understood as limiting the protection scope of the present invention.

[0052] Example 1

[0053] Dissolve the compound with the structure shown in formula II (24 mg, 0.2 mmol) and zinc acetate dihydrate (44 mg, 0.2 mmol) in a mixed solvent of 4 mL of DMF and n-butanol (where the volume ratio of DMF to n-butanol is 3:1); place the obtained mixed system in a hydrothermal reaction kettle, heat it to 100 °C at a heating rate of 20 °C / h, and keep it warm for 2 days for coordination reaction; cool it to room temperature at a cooling rate of 20 °C / h, and brown flaky crystals can be obtained by filtration. Wash the collected flaky crystals with ethanol and dry them naturally at room temperature to obtain the imidazopyridine zinc complex, and the yield is about 62%.

[0054] Example 2

[0055] Dissolve the compound with the structure shown in Formula II (18 mg, 0.15 mmol) and zinc acetate dihydrate (66 mg, 0.3 mmol) in a mixed solvent of 4 mL of DMF and methanol (where the volume ratio of DMF to methanol is 3:1); place the resulting mixed system in a hydrothermal reaction kettle, heat it to 120 °C at a heating rate of 10 °C / h, and keep it warm for 3 days for the coordination reaction; cool it to room temperature at a cooling rate of 10 °C / h, and obtain brown flaky crystals by filtration. Wash the collected flaky crystals with ethanol and air-dry them at room temperature to obtain the imidazopyridine zinc complex with a yield of about 73%.

[0056] Performance Test

[0057] Test Example 1

[0058] Determine the crystal structure of the imidazopyridine zinc complex obtained in Example 1;

[0059] Stick the transparent crystal of the complex obtained in Example 1 on a capillary glass rod, place it on a SuperNova, Singlesource at offset, Eos S2 X-ray single crystal diffractometer at room temperature for testing, and use Mo-Kα rays filtered by a graphite monochromator as the incident light source, collect diffraction intensity data in a certain angular range in the ω-scan mode, use Olex2, and analyze the structure using Intrinsic Phasing in the ShelXT program package, and refine the structure using the least squares method in the ShelXL program package;

[0060] The detailed crystal determination data obtained are shown in Table 1;

[0061] Table 1 Crystallographic data of the imidazopyridine zinc complex obtained in Example 1

[0062]

[0063]

[0064] where R = [∑||F0| – |F c || / ∑|F0|], R W = ∑ W [|F0 2 – Fc 2 | 2 / ∑ W (|F w | 2 ) 2 1 / 2 . The important bond length data in the complex are shown in Table 2;

[0065] ​Table 2 Important bond length data of the imidazopyridine zinc complex obtained in Example 1

[0066]

[0067]

[0068] The important bond angle data in the complex are shown in Table 3;

[0069] Table 3 Important bond angle data of the imidazopyridine zinc complex obtained in Example 1

[0070]

[0071]

[0072] Symmetry codes: A: x, -y, z - 1 / 2; B: -x + 1 / 2, -y + 1 / 2, -z.

[0073] The schematic diagram of the coordination environment structure of Zn in the obtained imidazopyridine zinc complex is as Figure 1 shown; the schematic diagram of the structure of the one-dimensional chain diagram of the complex is as Figure 2 shown; the schematic diagram of the three-dimensional structure of the complex is as Figure 3 shown; the schematic diagram of the TOPOs structure of the complex is as Figure 4 shown; from Figures 1 - 4 it can be seen that: the complex is a three-dimensional supramolecular compound formed by stacking two-dimensional layers.

[0074] Test Example 2

[0075] The imidazopyridine zinc complex obtained in Example 1 was subjected to X-ray diffraction testing, and the obtained XRD pattern is as Figure 5 shown. From Figure 5 it can be seen that the imidazopyridine zinc complex provided by the present invention coincides with the diffraction pattern simulated in the experiment, indicating that it has reliable phase purity, providing a guarantee for its application as an optical material.

[0076] Test Example 3

[0077] The thermal stability of the imidazopyridine zinc complex obtained in Example 1 was tested;

[0078] A thermogravimetric analyzer with the instrument model SII EXStar6000 TG / DTA6300 was used to perform thermogravimetric analysis on the complex, and the obtained thermogravimetric analysis curve is as Figure 6 shown; from Figure 6It can be seen that the skeleton of the complex can still stably exist at about 250 °C, having a certain thermal stability, which provides a thermal stability guarantee for its further development and application as a material. As the temperature increases, all the organic ligands are finally lost, and the final product is a metal oxide.

[0079] Test Example 4

[0080] After the imidazopyridine zinc complex obtained in Example 1 was subjected to enrichment treatment, the complex was subjected to solid fluorescence testing using an Edinburgh FLS1000 steady-state transient fluorescence spectrometer, and the test results obtained were as Figure 7 and Figure 8 shown; among them Figure 7 is the fluorescence spectrum of the imidazopyridine zinc complex obtained in Example 1; Figure 8 is the lifetime graph of the imidazopyridine zinc complex obtained in Example 1;

[0081] From Figure 7 and Figure 8 it can be seen that the complex is excited at 280 - 310 nm, and an emission peak is obtained at 344 nm. When excited at 320 - 370 nm, a new peak appears at 405 nm, and its lifetimes are 1.99 ns and 8.47 ns respectively.

[0082] Test Example 5

[0083] After the imidazopyridine zinc complex obtained in Example 1 was subjected to enrichment treatment, the complex was subjected to solid phosphorescence testing using an Edinburgh FLS1000 steady-state transient fluorescence spectrometer, and the test results obtained were as Figures 9 - 11 shown; among them, Figure 9 is the phosphorescence spectrum of the imidazopyridine zinc complex under different excitation peaks; Figure 10 is the phosphorescence spectrum of the imidazopyridine zinc complex under different excitation peaks; Figure 11 is the phosphorescence color display spectrum of the imidazopyridine zinc complex under different excitation peaks;

[0084] As Figure 9 shown, the complex is excited at 330 nm, and a strong emission peak is obtained at 510 nm. After turning off the ultraviolet lamp, green luminescence is shown;

[0085] As Figure 10 shown, when the excitation is changed to 360 nm, 390 nm, and 420 nm, its emission peak gradually redshifts from 535 nm to 640 nm, and gradually changes from yellow-green afterglow to red afterglow;

[0086] As Figure 11As shown, in the chromaticity coordinate diagram of the International Commission on Illumination, the phosphorescent colors of the complex at 330 nm, 360 nm, 390 nm, and 420 nm.

[0087] Although the above embodiments have described the present invention in detail, they are only a part of the embodiments of the present invention, not all embodiments. Other embodiments can also be obtained according to this embodiment without creative work, and these embodiments all fall within the protection scope of the present invention.

Claims

1. A zinc complex, characterized in that, The zinc complex is obtained by the following preparation method: A compound having the structure shown in Formula II, zinc acetate and a mixed organic solvent containing N,N-dimethylformamide are mixed, and through a coordination reaction, the zinc complex is obtained; Formula II; The molar ratio of the compound having the structure shown in Formula II to zinc acetate is 1:4 to 2:1; The mixed organic solvent containing N,N-dimethylformamide is N,N-dimethylformamide and an auxiliary organic solvent; the auxiliary organic solvent is one or more of n-butanol, methanol, ethanol and acetonitrile; The volume ratio of N,N-dimethylformamide to the auxiliary organic solvent is 3 to 6:1; The dosage ratio of the compound having the structure shown in Formula II to the mixed organic solvent containing N,N-dimethylformamide is 0.15 to 0.2 mmol: 4 mL; The temperature of the coordination reaction is 80 to 120 °C, and the heat preservation time is 48 to 96 h; The heating rate for raising the temperature to the coordination reaction is 5 to 20 °C / min; The zinc complex is monoclinic, with the space group P21 / c. The unit cell parameters are a = 10.762(2) Å, b = 9.3931(16) Å, c = 8.9593(19) Å, α = 90°, β = 103.40(2)°, γ = 90°, and V = 881.0(3) Å 3 .

2. Use of the zinc complex according to claim 1 as a long afterglow luminescent material.

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