A zinc-based molecular crystal blue-green light material and its preparation method

Abstract

A zinc-based molecular crystal blue-green light-emitting material and its preparation method, wherein the chemical formula of the zinc-based molecular crystal blue-green light-emitting material is {[Zn(pcd)]} n In the formula, n is a natural number from 1 to positive infinity; pdc is obtained by deprotonating N′-(pyridine-4-carbonyl)hydrazide. The preparation method is as follows: a 0.1 mol / L solution of zinc nitrate in N,N-dimethylacetamide is mixed with a 0.1 mol / L solution of 2,5-bis(4-pyridyl)-1,3,4-oxadiazole in N,N-dimethylacetamide and sonicated for 10 min. The mixture is then placed in a sealed hydrothermal reactor and reacted at 130℃ for 72 h. After removing the product, the solid is separated and washed three times with N,N-dimethylacetamide to obtain the zinc-based molecular crystal blue-green light material. The zinc-based molecular crystal blue-green light material of this invention has excellent luminous brightness and luminous efficiency, and can replace noble metal blue-green light materials.

Description

Technical Field

[0001] This invention relates to a zinc-based molecular crystal blue-green light material and its preparation method, belonging to the field of light-emitting material technology. Background Technology

[0002] Metallic luminescent molecular crystal materials, due to the heavy atom effect and strong spin-orbit coupling, can fully utilize the energy of all singlet and triplet states, thereby improving luminescence efficiency. Currently, research on metallic luminescent molecular crystal materials mainly focuses on transition metals in period 6 and rare earth metals in period 7, especially noble metals such as ruthenium, osmium, iridium, and platinum in period 6. However, transition metals such as ruthenium, osmium, iridium, and platinum in period 6, and rare earth metals in period 7, are scarce in the Earth's crust and difficult to mine. Therefore, the use cost of these noble metal luminescent molecular crystal materials is high, and these noble metals are non-renewable resources, which would lead to raw material shortages after large-scale production. On the other hand, these noble metals are usually highly toxic, and their large-scale application would also cause serious environmental pollution and health problems. The high cost and environmental unfriendliness of these materials greatly limit their large-scale application. Therefore, it is necessary to find other alternative metals for the synthesis of metallic luminescent molecular crystal materials.

[0003] Compared to the transition noble metals of period 6 and the rare earth metals of period 7, zinc metal of period 4 is not only abundant, inexpensive, and readily available, but also low in toxicity and environmentally friendly. Furthermore, zinc metal exhibits rich fluorescence emission properties, with diverse and abundant emission peaks. Its excellent luminescent performance makes zinc metal luminescent molecular crystal materials show promising potential applications in light-emitting devices, optical sensing, and nonlinear optics.

[0004] Currently, the main luminescent molecular crystal materials reported in the literature are zinc-based 2,5-bis(4-pyridyl)-1,3,4-oxadiazole molecular crystal materials. However, there are currently no publicly available reports on the design and synthesis of zinc-based molecular crystal blue-green light materials by using the hydrolysis reaction of 2,5-bis(4-pyridyl)-1,3,4-oxadiazole to generate N′-(pyridine-4-carbonyl)hydrazide. Summary of the Invention

[0005] The purpose of this invention is to address the shortcomings of existing molecular crystal materials of transition noble metals in period 6 and rare earth metals in period 7, which are characterized by high cost and environmental unfriendliness. The invention seeks alternatives that are resource-rich, inexpensive, low-toxicity, and environmentally friendly, and provides a zinc-based molecular crystal blue-green light material and its preparation method.

[0006] The technical solution implemented by this invention is as follows: a zinc-based molecular crystal blue-green light-emitting material, wherein the chemical formula of the zinc-based molecular crystal blue-green light-emitting material is {[Zn(pcd)]}. n In the formula: n is a natural number from 1 to positive infinity; pdc is obtained by deprotonating N′-(pyridine-4-carbonyl)hydrazide.

[0007] The zinc-based molecular crystal blue-green light material is crystallized in a monoclinic crystal system. P twenty one / c Space group, cell parameters: a = 7.5127(2) Å, b = 14.3973(4) Å, c = 11.1624(3) Å, α = 90°, ß = 94.944(2)°, γ = 90°, crystal volume is 1202.86(6) Å. 3 Z=4.

[0008] The N′-(pyridin-4-carbonyl)hydrazide was prepared by hydrolysis of 2,5-bis(4-pyridyl)-1,3,4-oxadiazole.

[0009] The zinc-based molecular crystal blue-green light material can emit blue-green light under 365nm ultraviolet light excitation, and its blue light CIE coordinates are (0.1742, 0.2778), which can be applied to the field of blue-green light materials.

[0010] This invention discloses a method for preparing a zinc-based molecular crystal blue-green light-emitting material, the method comprising the following steps:

[0011] (1) The organic compound 2,5-bis(4-pyridyl)-1,3,4-oxadiazole and Zn(NO3)2 . 6H2O was dissolved in N,N-dimethylacetamide to obtain a mixed solution;

[0012] (2) Place the mixed solution into a hydrothermal reactor and react at a constant temperature of 90-130℃ for 1-96 hours. After taking out the product, separate the solid and wash the solid multiple times with N,N-dimethylacetamide to obtain zinc-based molecular crystal blue-green light material.

[0013] The 2,5-bis(4-pyridyl)-1,3,4-oxadiazole, Zn(NO3)2 . The molar ratio of 6H2O to N,N-dimethylacetamide is 1:1:322.

[0014] The beneficial effects of this invention are as follows: The zinc-based molecular crystal blue-green light material prepared by this invention is simple to synthesize, easy to implement, has high yield, and high reproducibility. The zinc-based molecular crystal blue-green light material of this invention has excellent luminous brightness and luminous efficiency, can replace noble metal blue-green light materials, and can be applied on a large scale. The zinc-based molecular crystal blue-green light material of this invention has good blue-green light characteristics, with blue light CIE coordinates of (0.1742, 0.2778), and can be applied in the field of blue-green light materials. Attached Figure Description

[0015] Figure 1 This is a schematic diagram of the synthesis steps of the zinc-based molecular crystal blue-green light material of the present invention;

[0016] Figure 2 This is a crystal structure diagram of the zinc-based molecular crystal blue-green light material of the present invention;

[0017] Figure 3 A three-dimensional structural diagram of a zinc-based molecular crystal blue-green light-emitting material;

[0018] Figure 4 X-ray powder diffraction pattern of zinc-based molecular crystal blue-green light material;

[0019] Figure 5 The fluorescence spectrum of a zinc-based molecular crystal blue-green light-emitting material;

[0020] Figure 6 The CIE chromaticity diagram for zinc-based molecular crystal blue-green light-emitting materials. Detailed Implementation

[0021] The preparation method of the zinc-based molecular crystal blue-green light material in this embodiment includes the following synthesis steps:

[0022] A 0.1 mol / L solution of zinc nitrate in N,N-dimethylacetamide was mixed with a 0.1 mol / L solution of 2,5-bis(4-pyridyl)-1,3,4-oxadiazole in N,N-dimethylacetamide and sonicated for 10 min. The mixture was then placed in a sealed hydrothermal reactor and reacted at 130 °C for 72 h. After removing the product, the solid was separated and washed three times with N,N-dimethylacetamide to obtain the zinc-based molecular crystal blue-green light material.

[0023] The properties of the zinc-based molecular crystal blue-green light material prepared in this embodiment are characterized as follows:

[0024] (1) Structural determination of the zinc-based molecular crystal blue-green light material in this embodiment:

[0025] The crystal structure in this embodiment was determined using a Supernova X-ray single-crystal diffractometer. Mo-Kα rays (λ = 0.71073 Å) monochromated with graphite were used as the incident radiation source. Diffraction points were collected using an ω-φ scanning method. Cell parameters were obtained after least-squares correction. The crystal structure was then solved directly from the difference Fourier electron density map using the SHELXL-97 method, and corrected for Lorentz and polarization effects. All H atoms were synthesized using difference Fourier methods and determined by ideal position calculations. Detailed crystal measurement data are shown in Table 1.

[0026]

[0027] Figure 1 This describes the synthesis steps of zinc-based molecular crystal blue-green light-emitting materials. As shown in the figure, 2,5-bis(4-pyridyl)-1,3,4-oxadiazole is hydrolyzed to generate N′-(pyridin-4-carbonyl)hydrazide.

[0028] Figure 2 This is the crystal structure of a zinc-based molecular crystal blue-green light-emitting material. As can be seen from the figure, there is one Zn atom in the smallest asymmetric structural unit. 2+ The ion is one N′-(pyridin-4-carbonyl)hydrazide, in which Zn 2+ The ion adopts a five-coordinate trigonal bipyramidal coordination mode, coordinating with two oxygen atoms from two N′-(pyridine-4-carbonyl)hydrazides and three nitrogen atoms from three N′-(pyridine-4-carbonyl)hydrazides.

[0029] Figure 3 This is a structural diagram of a zinc-based molecular crystal blue-green light-emitting material. As can be seen from the diagram, this zinc-based molecular crystal blue-green light-emitting material is connected into a three-dimensional structure by N′-(pyridine-4-carbonyl)hydrazide.

[0030] (2) Used for phase purity testing of zinc-based molecular crystal blue-green light materials:

[0031] The X-ray powder diffraction pattern of this zinc-based molecular crystal blue-green light-emitting material was tested at room temperature, as shown below. Figure 4 As shown.

[0032] from Figure 4 It can be seen that, compared with its simulation pattern, the measured powder diffraction pattern matches well in terms of peak position and peak shape, except for slight differences in the intensity of some peaks, indicating that the zinc-based molecular crystal blue-green light material has high phase purity.

[0033] (3) Characterization of fluorescence properties of zinc-based molecular crystal blue-green light materials:

[0034] The method for measuring the fluorescence data of the zinc-based molecular crystal blue-green light material in this embodiment is as follows: The solid-state fluorescence performance of the zinc-based molecular crystal blue-green light material under the excitation wavelength of 365 nm was measured at room temperature using an Edinburgh FLS920.

[0035] from Figure 5 It can be seen that, under room temperature and 365 nm ultraviolet light excitation, the zinc-based hybrid material used for blue light emission exhibits a characteristic fluorescence peak at 474 nm. This characteristic peak originates from the π* → π and / or π* → n transitions of the ligands, which is a result of the ligands transitioning to Zn. 2+ Effective energy transfer of ions.

[0036] from Figure 6 It can be seen that the CIE coordinates corresponding to the fluorescence spectrum of the zinc-based molecular crystal blue-green light material are (0.1742, 0.2778), which are in the blue-green light region and can be applied to the field of blue-green light materials.

Claims

1. A zinc-based molecular crystal blue-green light material, characterized in that, The chemical formula of the zinc-based molecular crystal blue-green light material is {[Zn(pcd)]} n In the formula: n is a natural number from 1 to positive infinity; pdc is obtained by deprotonation of N′-(pyridine-4-carbonyl)hydrazide; the zinc-based molecular crystal blue-green light material is crystallized in a monoclinic crystal system. P twenty one / c Space group, cell parameters: a = 7.5127(2) Å, b = 14.3973(4) Å, c = 11.1624(3) Å, α = 90°, ß = 94.944(2)°, γ = 90°, crystal volume is 1202.86(6) Å. 3 Z=4; The zinc-based molecular crystal blue-green light material can emit blue-green light when excited by 365nm ultraviolet light, and its blue light CIE coordinates are (0.1742, 0.2778).

2. A method for preparing a zinc-based molecular crystal blue-green light-emitting material, characterized in that, The method steps are as follows: (1) The organic compound 2,5-bis(4-pyridyl)-1,3,4-oxadiazole and Zn(NO3)2 . 6H2O was dissolved in N,N-dimethylacetamide to obtain a mixed solution; (2) Place the mixed solution into a hydrothermal reactor and react at a constant temperature of 90-130℃ for 1-96 hours. After taking out the product, separate the solid and wash the solid multiple times with N,N-dimethylacetamide to obtain zinc-based molecular crystal blue-green light material.

3. The zinc-based molecular crystal blue-green light material according to claim 1, characterized in that, The N′-(pyridin-4-carbonyl)hydrazide was prepared by hydrolysis of 2,5-bis(4-pyridyl)-1,3,4-oxadiazole.

4. The method for preparing a zinc-based molecular crystal blue-green light material according to claim 2, characterized in that, The 2,5-bis(4-pyridyl)-1,3,4-oxadiazole, Zn(NO3)2 . The molar ratio of 6H2O to N,N-dimethylacetamide is 1:1:322.

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