Novel hybridized silver-iodine compound, preparation method thereof and application of novel hybridized silver-iodine compound as fluorescent color-changing sensor

Abstract

The invention discloses a novel hybrid silver iodine compound, the chemical formula of the compound is pIm < 2 > [Ag4I6 (Bpy)], pIm is 1-methyl-3-propyl-imidazolium ion, and Bpy is 4, 4 '-dipyridyl. The structure of the hybrid silver iodine compound is a two-dimensional layered skeleton, the two-dimensional layered [Ag4I6 (Bpy)] 2-anion skeleton is formed by connecting adjacent [Ag4I8] 4-clusters into one-dimensional [Ag4I6] 2-anion chains through a co-edge, and the [Ag4I6] 2-chains are further bridged through Bpy. The pIm < + > cations are discrete and are orderly distributed in gaps among the layers. Tests show that the compound shows remarkable blue and white light emission under the irradiation of an ultraviolet lamp at room temperature, and when the compound is excited by the ultraviolet lamp with the wavelength of 345 nm, the maximum emission peak of the compound is located at 477 nm. Particularly, the compound shows obvious thermochromic fluorescence along with the change of temperature in the temperature range of 77-375 K, is a sensitive fluorescence discoloration temperature sensing material, and provides a new thought for visualization of fluorescence sensing.

Description

Technical Field

[0001] The present invention belongs to the technical field of inorganic solid luminescent materials, and in particular relates to a novel hybrid silver-iodine compound, a preparation method thereof, and an application thereof as a fluorescent color-changing sensor. Background Art

[0002] Luminescent materials and devices have become a research hotspot in both the scientific and industrial communities due to their broad application prospects in white light illumination, flat panel displays, and luminescent sensing [Pan, M.; Liao, W.-M.; Yin, S.-Y.; Sun, S.-S.; Su, C.-Y. Chem. Rev. 2018, 118 , 8889−8935; Yam, VW; Au, VK; Leung, SY Chem. Rev. 2015, 115 , 7589−7728.;Lustig, WP; Mukherjee, S.; Rudd, ND;Desai, AV; Li, J.; Ghosh, SK Chem. Soc. Rev. 2017, 46 , 3242−3285; Fang,M.-H.; Bao, Z.; Huang, W.-T.; Liu, R.-S. Chem. Rev .2022, 122 , 11474-11513.].

[0003] Metal halide luminescent materials, especially Ag-I system, have very complex and varied structures, which are particularly eye-catching. 10 Electronic configuration, can adopt a variety of coordination modes with I - ions form different configurations of AgI x ( x = 1-4) basic structural unit, AgI x The basic structural units can be polymerized with different polymerization degrees to form a variety of different secondary structural units such as [Ag4I4], [Ag4I6] 2- 、[Ag5I6] - 、[Ag 12 I 19 ] 7- 、[Ag8I6] 2+ , [Ag 14 I 19 ] 5-et al. [Song, D.-N.; Li,W.-Y.; Wang, H.-Y.; Zhang, J.; Zhang, D.-J.; Wang, J.-J.; Du, J.-M.; Zhang, R.-C.; An, Y.-L. Inorg. Chem. 2022, 61 , 8662-8669; Song, D.-N.; Zhang, D.-J.;Wang, Y.-L.; Wang, J.-J.; Inorg. Chem. 2020, 59 , 13067-13077; Yu, T.-L.;Guo, Y.-M.; Wu, G.-X.; Yang, X.-F.; Xue, M.; Fu, Y.-L.; Wang, M.-S. Coord. Chem. Rev. 2019, 397 , 91-111; R.-C. Zhang, J.-J. Wang, B.-Q. Yuan, J.-C. Zhang, L. Zhou, H.-B. Yang, D.-J. Zhang, Y.-L. An, Inorg. Chem. 2016, 55, 11593-11599; H.-H. Li, Z.-R. Chen, J.-Q. Li. Eur. J. Inorg. Chem. 2006, 2447-2453.]. These secondary structural units can be assembled into hybrid silver iodide compound skeletons through self-polymerization or organic ligand connection. The formed compounds have high covalency and weak metal-metal interactions between Ag and Ag. This unique bonding feature provides a prerequisite for the synthesis and property exploration of new hybrid silver iodides. For example, as fluorescent materials, this type of new compound has outstanding advantages such as high luminescence intensity, large Stock shift, and long fluorescence lifetime, and has important application prospects in many aspects such as sensing and solid-state lighting [Ford, PC; Cariati, E.; Bourassa, J. Chem. Rev .1999, 99 , 3625-3647;Ford, PC; Ogel, A. Acc. Chem. Res .1993, 26, 220–226; Song, D.-N.; Zhang, D.-J.; Wang, Y.-L.; Wang, J.-J.; Inorg. Chem. 2020, 59 , 13067-13077; Xue, Z.-Z.; Meng, X.-D.; Li, X.-Y.; Han, S.-D.; Pan, J.; Wang, GM Inorg. Chem. 2021, 60 , 4375-4379; Zhang, R.-C.; Wang, J.-J.; Yuan, B.-Q.; Zhang, J.-C.; Zhou, L.;Wang, H.-B.; Zhang, D.-J.; An, Y.-L. Inorg. Chem. 2016, 55 , 11593-11599.].

[0004] Studying the synthesis of new silver-iodine compounds can obtain new structural silver-iodine compounds and new luminescent materials. In-depth research on the relationship between the synthesis, structure, luminescent properties and mechanism of the compounds will greatly enrich inorganic synthetic chemistry, structural chemistry and materials chemistry, and also provide new ideas for the synthesis research of other luminescent materials [Liu, W.; Fang, Y.; Li, J. Adv. Funct. Mater. 2018, 28 , 1705593.; Zhang, R.-C.; Wang, J.-J.;Zhang, J.-C.; Wang, M.-Q.; Sun, M.; Ding, F.; Zhang, D.-J.; An, Y.-L. Inorg. Chem. 2016, 55 , 7556-7563.]. Summary of the Invention

[0005] The present invention aims to overcome the defects of the prior art and provide a novel hybrid silver-iodine compound having a novel skeleton structure and obvious thermochromic fluorescence properties, which can be used as a fluorescent material or a fluorescent color sensor.

[0006] The present invention also provides a preparation method of the novel hybrid silver-iodine compound and its application as a fluorescent material or a fluorescent color-changing sensor.

[0007] To achieve the above object, the present invention adopts the following technical solutions: A novel hybrid silver-iodine compound has the chemical formula pIm2[Ag4I6(Bpy)], wherein pIm is 1-methyl-3-propyl-imidazolium ion and Bpy is 4,4'-bipyridine. The structure of the novel hybrid silver-iodine compound is a two-dimensional layered hybrid skeleton, wherein the two-dimensional layered [Ag4I6(Bpy)] 2- The anion framework consists of adjacent [Ag4I8] 4- Clusters are connected by common edges into one dimension [Ag4I6] 2- Anionic chain, [Ag4I6] 2- The chains are further connected by Bpy bridges. Layers are stacked together to form a three-dimensional supramolecular structure, which appears to be a A one-dimensional channel extending in the axial direction. + The cations are discrete and orderly distributed in the pores between the layers to balance the charge of the skeleton. The novel hybrid silver iodine compound belongs to the triclinic system and has a space group of , the unit cell parameters are: a = 9.420(3) Å, b = 9.466(3) Å, c = 11.420(3) Å, α= 91.0°, β= 106.7°, γ= 92.9°.

[0008] A method for preparing the novel hybrid silver iodide compound comprises the following steps: uniformly mixing silver iodide (AgI), 4,4'-bipyridine (Bpy), 1-methyl-3-propyl imidazolium iodide (pImI, CAS No.: 119171-18-5), and an organic solvent; and then reacting the mixture at a constant temperature of 60-120°C (preferably 85-115°C) for 120-180 hours. After the reaction is completed, the product is washed and dried to obtain the product.

[0009] Specifically, during the preparation process, the molar ratio of silver iodide (AgI), 4,4'-bipyridine (Bpy), and 1-methyl-3-propyl imidazolium iodide (pImI) can be 1:0.5-3.5:2-5.

[0010] Furthermore, the organic solvent is preferably composed of a mixture of acetonitrile and ethanol in a volume ratio of 1: 1-3. It is appropriate to add 0.3-2.0 mL of the organic solvent for every 0.1 mmol of silver iodide.

[0011] The present invention provides the use of the novel hybrid silver-iodine compound as a fluorescent material. Experiments have shown that the novel silver-iodine compound exhibits fluorescent properties and can be used as a fluorescent material. Furthermore, it exhibits thermoluminescent color change and can be used as a temperature sensing material.

[0012] The present invention also provides the use of the novel hybrid silver-iodine compound as a fluorescence colorimetric sensor, particularly an intensity-type fluorescence thermometer. Experiments have further revealed that within the temperature range of 77-375 K, the luminescence intensity of the novel hybrid silver-iodine compound gradually decreases with increasing temperature. The compound's luminescence color exhibits a significant dependence on temperature, indicating significant thermochromic fluorescence behavior. In particular, within the temperature range of 125-325 K, the emission intensity at 414 nm exhibits a significant linear relationship with temperature, making it a typical intensity-type fluorescence thermometer. Combined with the material's unique thermochromic properties, the compound is also a sensitive fluorescence colorimetric temperature sensing material, suitable for use as a fluorescence colorimetric temperature sensor in the field of fluorescence temperature sensing.

[0013] Compared with the prior art, the present invention has the following beneficial effects: This invention uses the ionic liquid 1-methyl-3-propylimidazolium iodide, which has a high boiling point, excellent solubility, and high thermal and chemical stability, as a reaction raw material to synthesize a novel hybrid silver iodide compound under mild conditions. The preparation method is simple, employs mild conditions, exhibits good reproducibility, and produces high yields, injecting new vitality into the field of inorganic synthesis and preparation. Furthermore, the silver iodide prepared by this invention exhibits thermochromic fluorescence and can be used in applications such as fluorescent materials and fluorescent color-changing temperature sensors. BRIEF DESCRIPTION OF THE DRAWINGS

[0014] Figure 1 This is a structural unit diagram of the novel hybrid silver-iodine compound of the present invention; Figure 2 This is a spatial structure diagram of the novel hybrid silver-iodine compound of the present invention; Figure 3 is the XRD pattern of the novel hybrid silver-iodine compound of the present invention; Figure 4 This is a fluorescence spectrum of the novel hybrid silver iodine compound of the present invention at room temperature; Figure 5 This is a fluorescence spectrum of the novel hybrid silver iodine compound of the present invention at 77 K; Figure 6 This is a temperature-dependent fluorescence diagram of the novel hybrid silver-iodine compound of the present invention; Figure 7 The fluorescence color coordinate diagram of the novel hybrid silver iodine compound of the present invention at different temperatures; Figure 8 This is a fitting diagram of the fluorescence intensity temperature sensing of the novel hybrid silver-iodine compound described in the present invention. DETAILED DESCRIPTION

[0015] In order to make the technical purpose, technical solution and beneficial effects of the present invention clearer, the technical solution of the present invention is further described below in conjunction with the accompanying drawings and specific embodiments. However, the embodiments are intended to explain the present invention and should not be understood as limiting the present invention.

[0016] If no specific techniques or conditions are specified in the examples, the procedures were carried out according to the techniques or conditions described in the literature in the field or according to the product instructions. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be obtained commercially.

[0017] Room temperature refers to 25±5°C.

[0018] Example 1 A method for preparing a novel hybrid silver iodine compound, specifically comprising: First, 0.1 mmol AgI, 0.1 mmol Bpy (Aladdin Reagent Co., Ltd.), 0.25 mmol pImI (Aladdin Reagent Co., Ltd.) and 0.5 mL of a mixed solvent of acetonitrile and ethanol (V CH3CN : V CH3CH2OH = 1:2) (Sinopharm Group Chemical Reagent Co., Ltd.), with a glass tube filling ratio of 10%. Ultrasonic dispersion was then performed uniformly, and the tube was sealed over an alcohol burner (i.e., the glass tube was sealed to ensure the reaction was carried out in a sealed state). The mixture was placed in a reactor and then placed in a drying oven at 85°C (no vacuum required) for 120 hours. After cooling naturally to room temperature, light yellow rhombus-shaped flaky crystals were observed in the glass tube. These were washed with acetonitrile and dried.

[0019] The yield of the resulting novel hybrid silver-iodine compound was 78%, and its molecular formula was (pIm)2[Ag4I6(Bpy)]. Scanning electron microscopy (EDS) revealed an Ag:I ratio of 2:3. Elemental analysis revealed 17.87% carbon, 2.14% hydrogen, and 5.36% nitrogen. The theoretical values ​​for structural analysis were 18.02% carbon, 2.13% hydrogen, and 5.25% nitrogen, consistent with theoretical calculations.

[0020] The structure of the obtained new hybrid silver iodine compound is determined as follows: Single crystals of the silver iodide compound of appropriate size were selected under a microscope and were analyzed on a Bruker APEX II CCD surface diffractometer at room temperature using a Mo-K diffractometer monochromated with a graphite monochromator. α ray( = 0.71073 Å), with Diffraction data were collected using the SADABS program. All diffraction data were semi-empirical absorption corrected using the least squares method. Data reduction and structure analysis were performed using the SAINT and SHELXTL programs, respectively. The crystal structure was solved using the direct method, and the positions of the metal atoms were determined by the direct method. E -map, while other non-hydrogen atoms were determined using the difference Fourier function method and least squares method, followed by anisotropic refinement. Detailed crystallographic data of the obtained compounds are shown in Table 1.

[0021] Structure such as Figure 1 and 2 As shown, the structure of the obtained compound belongs to the triclinic system and the space group is The crystallographic data are shown in Table 1. The XRD pattern is shown in Table 1. Figure 3 As shown, the characteristic peaks of the experimental sample spectrum correspond to the characteristic peaks of the simulated spectrum, indicating that the crystals of the compound are pure phase.

[0022] Table 1 Crystallographic data of compound: (pIm)2[Ag4I6(Bpy)] The novel hybrid silver-iodine compound belongs to the triclinic system and has a space group of , the unit cell parameters are: a = 9.420(3)Å, b = 9.466(3) Å, c = 11.420(3) Å, α= 91.0°, β= 106.7°, γ= 92.9°.

[0023] Figure 1 、 2 The structural unit and spatial structure diagram of the novel hybrid silver iodine compound are given respectively. Figure 1 、 2 As shown, the structure of the silver iodine compound is one-dimensional infinite [Ag4I6] 2- The two-dimensional layered anion framework formed by the 4,4'-bpy bridging ligand and the discrete pIm + Composition. In Infinity [Ag4I6] 2- The secondary structural unit of the compound is a tetrameric [Ag4I8] 4- Cluster. Among them, I - use μ 2 and μ 3-key connection mode, all Ag + All adopt tetrahedral coordination and can be divided into two categories: 2 Ag+ With 3 μ 2-I - and 1 μ 3-I - Coordination, 2 Ag + With 2 μ 3-I - , 1 μ 2-I - Coordinated with one nitrogen atom of bpy. There is a weak interaction between Ag…Ag. Each [Ag4I8] 4- Clusters pass through the periphery μ 2-I - With the adjacent [Ag4I8] 4- Clusters connect and expand to form infinity [Ag4I6] 2- Anion chain. Adjacent [Ag4I6] 2- The chains are connected to the 4,4'-bpy bridging ligand through Ag-N, further expanding to form 2D layers, and the layers are stacked to form the 3D spatial stacking structure of the compound. + Located in the gaps between layers, it plays a role in balancing the charge of the compound.

[0024] The obtained novel hybrid silver iodine compound was determined by powder X-ray diffraction pattern: After the sample is ground evenly, the powder X-ray diffraction data of the compound is measured using a powder X-ray diffractometer, such as Figure 3 As shown, the diffraction characteristic peaks of the experimentally synthesized sample are consistent with the characteristic peaks simulated by single crystal data, indicating that the crystals of the compound are pure phase.

[0025] Determination of fluorescence properties of the obtained new hybrid silver iodine compound: Take an appropriate amount of sample and measure its luminescence properties using FLS980 steady-state fluorescence spectrometer. At room temperature, the compound shows a significant blue-white light under ultraviolet light. When excited by 345 nm ultraviolet light, the maximum emission peak of the compound is located at 477 nm. Figure 4 As shown, the luminous color is blue-white.

[0026] Temperature-dependent fluorescence determination of the obtained novel hybrid silver iodine compound: Take appropriate amount of sample and measure its temperature-dependent luminescence properties using FLS980 fluorescence spectrometer. The results show (see Figure 5): At 77 K, when excited by 345 nm ultraviolet light, the compound emits multiple obvious emission peaks, located at 414 nm, 437 nm, 443 nm, 464 nm and 470 nm, respectively. The maximum emission peak is located at 414 nm, and the emission color is blue. As the temperature rises from 77 K to 200 K, the intensity of the emission peak decreases significantly, the emission peaks at 437 nm and 443 nm gradually merge, and the emission peaks at 464 nm and 470 nm gradually merge. As the temperature continues to rise, the emission peak intensity gradually weakens, and above 375 K, the luminescence is quenched (see Figure 6 The fluorescence color coordinate diagram of this compound at different temperatures is shown in Figure 7 Its luminescent color gradually changes from light blue to blue, then to blue-white, white, and finally to yellow, with significant thermoluminescent color-changing behavior.

[0027] Example 2 A method for preparing a novel hybrid silver iodine compound, specifically comprising: First, 0.1 mmol AgI, 0.15 mmol Bpy (Aladdin Reagent Co., Ltd.), 0.35 mmol pImI (Aladdin Reagent Co., Ltd.) and 0.5 mL of a mixed solvent of acetonitrile and ethanol (V CH3CN : V CH3CH2OH = 1:2) (Sinopharm Group Chemical Reagent Co., Ltd.), with a glass tube filling ratio of 10%. Ultrasonic dispersion was then performed uniformly, and the tube was sealed over an alcohol burner (i.e., the glass tube was sealed to ensure the reaction was carried out in a sealed state). The mixture was placed in a reactor and then placed in a drying oven at 95°C (no vacuum required) for 140 hours. After cooling naturally to room temperature, light yellow rhombus-shaped flaky crystals were observed in the glass tube. These were washed with acetonitrile and dried.

[0028] Example 3 A method for preparing a novel hybrid silver iodine compound, specifically comprising: First, 0.1 mmol AgI, 0.35 mmol Bpy (Aladdin Reagent Co., Ltd.), 0.5 mmol pImI (Aladdin Reagent Co., Ltd.) and 0.5 mL of a mixed solvent of acetonitrile and ethanol (V CH3CN : V CH3CH2OH = 1:2) (Sinopharm Group Chemical Reagent Co., Ltd.), with a glass tube filling ratio of 10%. Ultrasonic dispersion was then performed uniformly, and the tube was sealed over an alcohol burner (i.e., the glass tube was sealed to ensure the reaction was carried out in a sealed state). The mixture was placed in a reactor and then placed in a drying oven at 115°C (no vacuum required) for 180 hours. After cooling naturally to room temperature, light yellow rhombus-shaped flaky crystals were observed in the glass tube. These crystals were washed with acetonitrile and dried.

[0029] Example 4 A method for preparing a novel hybrid silver iodine compound, specifically comprising: First, 0.1 mmol AgI, 0.2 mmol Bpy (Aladdin Reagent Co., Ltd.), 0.5 mmol pImI (Aladdin Reagent Co., Ltd.) and 0.5 mL of a mixed solvent of acetonitrile and ethanol (V CH3CN : V CH3CH2OH = 1:2) (Sinopharm Group Chemical Reagent Co., Ltd.), with a glass tube filling ratio of 10%. Ultrasonic dispersion was then performed uniformly, and the tube was sealed over an alcohol burner (i.e., the glass tube was sealed to ensure the reaction was carried out in a sealed state). The mixture was placed in a reactor and then placed in a drying oven at 65°C (no vacuum required) for 180 hours. After cooling naturally to room temperature, light yellow rhombus-shaped flaky crystals were observed in the glass tube. These were washed with acetonitrile and dried.

[0030] Application test The novel hybrid silver iodine compound obtained in Example 1 of the present invention (i.e., the following sample) was used as a luminescent material to conduct temperature sensing research: The variable temperature fluorescence behavior of the compound was studied using a fluorescence spectrometer. The results showed that the compound responded significantly differently to temperature at different temperatures. At 77 K, the luminescence of the compound contained multiple obvious emission peaks, with the strongest peak located at 414 nm. As the temperature rose from 77 K to 375 K, the intensity of the emission peak decreased significantly, and the emission peak intensity gradually weakened. Above 375 K, the luminescence was quenched, and its luminescence color gradually changed from blue to white and then to yellow, showing significant thermochromic fluorescence behavior. In particular, in the temperature range of 125-325 K, the luminescence intensity at 414 nm showed a linear relationship with the change of temperature, and the fitting equation was: y = -0.0059 x +1.92, R 2 Reached 0.99391 (see Figure 8 ), indicating that the compound can be constructed into an intensity-based fluorescence thermometer. Combined with the compound's unique luminescence behavior, the material can be constructed into a visual color-changing temperature sensor for application in the field of fluorescence temperature sensing. This invention provides new ideas for the development of new temperature sensors.

[0031] Finally, it should be noted that the above embodiments are only used to illustrate and not to limit the technical solutions of the present invention. Any equivalent substitutions of the present invention and any modifications or partial substitutions that do not depart from the spirit and scope of the present invention should be included in the scope of protection of the claims of the present invention.

Claims

1. A hybrid silver-iodine compound, characterized in that The chemical formula is pIm2[Ag4I6(Bpy)], where pIm is 1-methyl-3-propyl-imidazolium ion and Bpy is 4,4'-bipyridine.

2. The method for preparing the hybrid silver iodine compound according to claim 1, wherein Silver iodide, 4,4'-bipyridine, 1-methyl-3-propyl imidazole iodide and an organic solvent are uniformly mixed, and then reacted at a constant temperature of 60-120°C for 120-180 hours. After the reaction is completed, the product is washed and dried to obtain the product.

3. The method for preparing the hybrid silver iodine compound according to claim 2, wherein: The molar ratio of the silver iodide, 4,4'-bipyridine and 1-methyl-3-propyl imidazolium iodide is 1:0.5-3.5:2-5.

4. The method for preparing the hybrid silver iodine compound according to claim 2, wherein: The organic solvent is composed of a mixture of acetonitrile and ethanol in a volume ratio of 1:1-3.

5. Use of the hybrid silver iodine compound according to claim 1 as a fluorescent material.

6. Use of the hybrid silver-iodine compound according to claim 1 as a fluorescent color-changing sensor.

7. Use of the hybrid silver-iodine compound according to claim 1 as an intensity-type fluorescence thermometer.

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