Mononuclear zinc complex as well as preparation method and application thereof

Abstract

The invention provides a mononuclear zinc complex and a preparation method and application thereof, and belongs to the technical field of luminescent materials, the chemical formula of the mononuclear zinc complex is [Zn (L) 2 (Cl) 2], and L is N-methylbenzimidazole. The preparation method of the mononuclear zinc complex comprises the following steps: by taking N-methylbenzimidazole and a tetrahydrofuran solution of ZnCl2 as raw materials and absolute methanol as a solvent, reacting by a conventional solution method to prepare a target product. The mononuclear zinc complex has the optical properties that white fluorescence is shown under excitation of ultraviolet light with the wavelength of 365 nm, and green afterglow exists after an excitation light source is turned off; the preparation method disclosed by the invention is simple, low in cost and good in repeatability.

Description

Technical Field

[0001] The present invention relates to the technical field of luminescent materials, and in particular to a mononuclear zinc complex and a preparation method and application thereof. Background Art

[0002] Afterglow materials with ultra-long lifetimes have attracted considerable interest among researchers due to their broad application prospects in light-emitting devices and anti-counterfeiting. However, achieving ultra-long afterglow luminescence in low-dimensional microstructures remains an open challenge, limiting the progress of the application of new generation optical materials. Although the novel optoelectronic properties of metal organic halides have been widely used in solar cells and light-emitting devices, the effective ultra-long lifetime afterglow systems of these materials remain underexplored. It is of great significance to develop a new generation of room temperature phosphorescent materials with long lifetime, high efficiency and good stability through a simple, green and economical strategy. Therefore, it is necessary to design a new mononuclear zinc complex and its preparation method. Summary of the invention

[0003] The purpose of the present invention is to provide a mononuclear zinc complex and a preparation method and application thereof, so as to solve the technical problems of the existing luminescent material preparation replication, low cost and difficult control of chemical components.

[0004] In order to achieve the above object, the technical solution adopted by the present invention is as follows:

[0005] A mononuclear zinc complex has a chemical formula of [Zn(L)2(Cl)2], wherein L is N-methylbenzimidazole.

[0006] Furthermore, the zinc complex is a zinc complex with a butterfly-shaped structure.

[0007] Further, the molecular formula of the zinc complex is: C 16 H 16 Cl2N4Zn, molecular weight: 400.60.

[0008] The invention discloses an application of a mononuclear zinc complex in the preparation of optical materials.

[0009] A method for preparing a mononuclear zinc complex comprises the following steps: taking N-methylbenzimidazole, dissolving it in anhydrous methanol, adding the solution into a Pyrex glass tube, adding a 0.5 mol / L ZnCl2 tetrahydrofuran solution, sealing the tube, heating for a set time, taking the tube out and slowly cooling the tube to obtain crystals, separating the crystals, and obtaining a mononuclear zinc complex [Zn(L)2(Cl)2].

[0010] Furthermore, the molar ratio of ZnCl2 to N-methylbenzimidazole is a stoichiometric ratio of 1:2.

[0011] Furthermore, N-methylbenzimidazole is dissolved in anhydrous methanol, and then a tetrahydrofuran solution containing ZnCl2 is added.

[0012] Further, the temperature of the tetrahydrofuran solution of ZnCl2 is room temperature, or -2 to -7°C.

[0013] Furthermore, the heating temperature is 75-85° C. for 72 hours, and the time required for complete crystal precipitation is 0 to 2 weeks.

[0014] Furthermore, if ultrasound is performed after the addition of the tetrahydrofuran solution of ZnCl2, a powdery product of [Zn(L)2(Cl)2] can be obtained without heating.

[0015] The present invention has the following beneficial effects due to the adoption of the above technical solution:

[0016] The optical properties of the mononuclear zinc complex of the present invention are: blue-white fluorescence under the excitation of ultraviolet light with a wavelength of 365nm, and green afterglow after the excitation light source is turned off. The preparation method is simple, the cost is low, the chemical components are easy to control, and the repeatability is good. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 The structure diagram of [Zn(L)2(Cl)2] prepared in the embodiment of the present invention;

[0018] Figure 2 A three-dimensional stacking diagram of [Zn(L)2(Cl)2] prepared in an embodiment of the present invention;

[0019] Figure 3 The room temperature fluorescence spectrum of [Zn(L)2(Cl)2] prepared in the embodiment of the present invention;

[0020] Figure 4 The temperature-variable phosphorescence spectrum of [Zn(L)2(Cl)2] prepared in the embodiment of the present invention;

[0021] Figure 5 This is the infrared spectrum of [Zn(L)2(Cl)2] prepared in the embodiment of the present invention;

[0022] Figure 6 This is the ultraviolet absorption spectrum of [Zn(L)2(Cl)2] prepared in the embodiment of the present invention. DETAILED DESCRIPTION

[0023] In order to make the purpose, technical solution and advantages of the present invention more clearly understood, the present invention is further described in detail below with reference to the accompanying drawings and preferred embodiments. However, it should be noted that many details listed in the specification are only for the purpose of enabling the reader to have a thorough understanding of one or more aspects of the present invention, and these aspects of the present invention can be implemented even without these specific details.

[0024] The mononuclear zinc complex involved in the present invention is [Zn(L)2(Cl)2], wherein L is N-methylbenzimidazole.

[0025] The crystal structure data of the mononuclear zinc complex of the present invention are shown in Table 1, and the bond length and bond angle data are shown in Table 2.

[0026] Table 1 Crystallographic parameters of Zn(L)2(Cl)2

[0027]

[0028] Table 2 Bond lengths of Zn(L)2(Cl)2 and bond angle (°)

[0029]

[0030] The photophysical property study of the mononuclear zinc complex of the present invention shows that the complex has fluorescence and phosphorescence behavior. Therefore, the present invention also includes the use of the mononuclear complex in the preparation of optical materials.

[0031] The preparation method of the mononuclear zinc complex [Zn(L)2(Cl)2] is:

[0032] Weigh N,-methylbenzimidazole (0.2mmol, 0.0264g) and add it to a 25cm Pyrex glass tube, then add 0.5mL of anhydrous methanol solution to the glass tube, shake the glass tube thoroughly to dissolve it, then add 200μL (0.1mmol) of ZnCl2 tetrahydrofuran solution, then add 1.5mL of anhydrous methanol solution, seal the glass tube, place it in an 80℃ oven for 72 hours, slowly cool the heated glass tube, transparent block crystals will be generated after 0 to 2 weeks, separate the crystals and dry them in the air. Yield: 32.9mg, yield: 82.30%.

[0033] The products obtained in the examples were further characterized:

[0034] 1) Crystal structure analysis:

[0035] The crystal structure of the bulk transparent crystal with intact surface structure was determined by single crystal diffraction. The crystal structure data obtained are shown in Table 1 above, the bond length and bond angle data are shown in Table 2 above, and the chemical structure of the bulk transparent crystal is shown in Figure 1As shown, the obtained blocky transparent crystals are determined to be a mononuclear zinc complex [Zn(L)2(Cl)2] with a butterfly-shaped structure, wherein L is N-methylbenzimidazole, and the molecular formula of the complex is: C 16 H 16 Cl2N4Zn, molecular weight: 400.60. The three-dimensional j stacking diagram of the above blocky transparent crystal is as follows Figure 2 shown.

[0036] 2) Optical property determination:

[0037] Take an appropriate amount of the crystals prepared in this embodiment and test them on a QuantaMater 8000 spectrum test instrument to obtain fluorescence and phosphorescence spectra as shown in Figure 3 (Fluorescence spectrum of [Zn(L)2(Cl)2]), Figure 4 (Thermal phosphorescence spectrum of [Zn(L)2(Cl)2]).

[0038] Depend on Figures 3-4 It can be seen that the mononuclear zinc complex [Zn(L)2(Cl)2] described in the present invention emits blue-white fluorescence under 365nm excitation light. In addition, the phosphorescence test results show that the intensity of the phosphorescence characteristic peak of [Zn(L)2(Cl)2] decreases with increasing temperature, indicating that [Zn(L)2(Cl)2] is a typical phosphorescent material.

[0039] 3) Infrared characterization:

[0040] The mononuclear zinc complex [Zn(L)2(Cl)2] prepared in this example was analyzed by infrared spectroscopy using a PE Spectrum Two FT-IR Fourier transform infrared spectrometer (KBr pellet) in the range of 400 to 4000 cm -1 The infrared spectrum obtained is as follows Figure 5 shown.

[0041] 3) UV characterization:

[0042] The mononuclear zinc complex [Zn(L)2(Cl)2] prepared in this example was subjected to ultraviolet absorption analysis using a Shimadzu UV-2600i ultraviolet absorption spectrometer in the range of 200 to 550 nm. The obtained ultraviolet absorption spectrum is shown in the figure below: Figure 6 shown.

[0043] Matters not covered by the present invention are known technologies.

[0044] The above is only a preferred embodiment of the present invention. It should be pointed out that for ordinary technicians in this technical field, several improvements and modifications can be made without departing from the principle of the present invention. These improvements and modifications should also be regarded as the scope of protection of the present invention.

Claims

1. A mononuclear zinc complex, characterized in that: Its chemical formula is: [Zn(L)2(Cl)2], wherein L is N-methylbenzimidazole.

2. A mononuclear zinc complex according to claim 1, characterized in that: The zinc complex is a zinc complex with a butterfly-shaped structure.

3. A mononuclear zinc complex according to claim 2, characterized in that: The molecular formula of zinc complex is: C 16 H 16 Cl2N4Zn, molecular weight: 400.

60.

4. The use of a mononuclear zinc complex according to claims 1-3, characterized in that: Used in the preparation of optical materials.

5. A method for preparing a mononuclear zinc complex, characterized in that: Take N-methylbenzimidazole, dissolve it in anhydrous methanol, add it to a Pyrex glass tube, then add 0.5 mol / L ZnCl2 tetrahydrofuran solution, then seal it, heat for a set time, take it out and slowly cool it to obtain crystals, separate the crystals, and obtain a mononuclear zinc complex [Zn(L)2(Cl)2].

6. The method for preparing a mononuclear zinc complex according to claim 5, characterized in that: The molar ratio of ZnCl2 and N-methylbenzimidazole is a stoichiometric ratio of 1:

2.

7. The method for preparing a mononuclear zinc complex according to claim 5, characterized in that: After dissolving N-methylbenzimidazole in anhydrous methanol, add a tetrahydrofuran solution containing ZnCl2.

8. The method for preparing a mononuclear zinc complex according to claim 1, characterized in that: The temperature of the tetrahydrofuran solution of ZnCl2 is room temperature, or -2 to -7°C.

9. The method for preparing a mononuclear zinc complex according to claim 5, characterized in that: The heating temperature is 75-85°C for 72 hours, and the time required for complete crystal precipitation is 0 to 2 weeks.

10. The method for preparing a mononuclear zinc complex according to claim 5, characterized in that: If ultrasound is performed after adding the tetrahydrofuran solution of ZnCl2, the powdery product [Zn(L)2(Cl)2] can be obtained without heating.

Images