Application of a viologen coordination compound crystal as a detection material for amine compounds

Abstract

A viologen coordination compound crystal is used as an amine compound detection material. The structure of the viologen coordination compound crystal is shown in formula (I): wherein BTC is pyromellitic acid. The material can be made into a test paper, which changes color in response to ammonia at low concentrations, reacts quickly, and can be reused.

Description

Technical Field

[0001] The invention relates to an application of a novel viologen coordination compound as an amine compound detection material. Background Art

[0002] In recent years, the storage of chemical information in molecules, detection at the molecular level, and conversion into analyzable and detectable signals have attracted increasing research interest. Chemical information analytical sensing materials can detect and identify analytes through color changes, fluorescence properties, photosensitivity, and conductivity. However, some analytes, such as explosives, chemicals, toxic or corrosive gases, radioactive and biologically active agents, can still cause serious damage to human skin and respiratory system at low concentrations. In order to avoid and prevent their potential or actual harm to humans, these substances should be identified or detected at the lowest possible concentration. Based on the actual situation and the problems we face, cationic coordination polymer materials and two-dimensional and three-dimensional metal organic framework materials have entered our sight. These materials generally have pores of a certain size, which are formed by connecting metal centers and organic linking ligands, and have cationic sites. Due to the special and novel structural characteristics of these materials, as well as their excellent reversibility and recyclability in the detection process, they are synthesized and studied by more and more researchers. Cationic coordination polymers are materials with excellent sensing and detection properties. They can identify and detect analytes stored inside compounds through fluorescence detection or color changes of materials. This ability is mainly based on the role played by the functional units provided by organic ligands. In recent years, based on some organic ligands with color-changing properties, such as piperazines, diarylethenes and viologen cations, the synthesized coordination polymers or metal organic frameworks have been increasingly used in light, electricity and thermochemistry. Organic ligands have a real impact on the properties of the complexes, especially as the introduction of functional units or sites, which is decisive for the functionality and potential applications of the synthesized compounds. Therefore, the solubility, stability and functionality of organic ligands are the focus of researchers.

[0003] Viologen cationic ligands / 4,4-bipyridine derivatives are a class of excellent organic ligands that are electron-deficient and can be regarded as Lewis acids. They have good responses to stimuli such as light, electricity, heat, pressure and X-rays and undergo corresponding color changes. In recent reports, viologen cationic ligands, as organic linking media and transition metals, rare earth metals and polyionic metal oxyacids (POM), have been increasingly studied in the field of multifunctional detection materials, and can detect and identify hazardous analytes through visible color changes or changes in fluorescence intensity.

[0004] Organic amines (methylamine, ethylamine, aniline, triethylamine, etc.) have lone pairs of electrons on the nitrogen atom of the amino group, which can act as electron donors to provide electrons to electron acceptors. Such substances can be regarded as a type of Lewis base. The introduction of viologen organic ligands into metal coordination polymers or polyacid compounds can be used as functional units to encapsulate and identify small molecules of organic amines. However, for most coordination polymers, metal organic frameworks, including polyacid compounds, they play the role of "storage" and "detector". During the detection process, some performance has always troubled researchers. This is because most of these materials have irreversible structural collapse after detection or are only one-time detection and cannot be reused multiple times. These two problems have hindered the development of such materials and their further application, which has substantially questioned and affected the value of such materials. Therefore, in the current work, it is a huge and meaningful challenge to synthesize multifunctional and stable crystalline materials based on viologen that can be detected cyclically. Summary of the invention

[0005] The purpose of the present invention is to provide an application of a viologen coordination compound crystal as an amine compound detection material. The material can be made into a test paper, which changes color in response to ammonia at low concentrations, reacts quickly and can be reused.

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

[0007] A viologen coordination compound crystal is used as an amine compound detection material, and the structural formula of the viologen coordination compound crystal is shown in formula (I):

[0008] Among them, BTC is pyromellitic acid.

[0009] For the above application, preferably, the crystallographic parameters of the crystal are as follows: molecular weight is 674.61, belongs to the triclinic system, space group is P-1, unit cell parameters are: α(°)=72.060(3), p(°)=77.983(3), γ(°)=81.530(3), Z=1.

[0010] In the application as described above, preferably, the detection concentration of the amine compound is > 0.01 mg / L.

[0011] In another aspect, the present invention provides a test paper for detecting amine compounds, wherein the test paper is loaded with a viologen coordination compound crystal represented by formula (I) as a detection reagent.

[0012] Among them, BTC is pyromellitic acid.

[0013] As described above, the content of the viologen coordination compound crystals in the amine compound detection test paper is preferably 5-50 mg / cm 2 Paper substrate.

[0014] The 1,1-bis(3-cyanophenyl)-4,4-bipyridyl dichloride (bcnbpy·2C1) used in the present invention is preferably prepared by the following method:

[0015] Add 4,4'-bipyridine and 3-chloromethylbenzoic acid in a molar ratio of 1:(2-3) to N,N-dimethylformamide. 2 Under the protection of gas, the mixture is heated to reflux at a temperature of 110 to 130° C. for 6 to 10 h, then cooled to room temperature, filtered to obtain a yellow precipitate, washed three times with a hot DMF solution, then washed three times with ethanol, and vacuum dried at 60 to 80° C. for 10 to 15 h; and recrystallized with methanol and deionized water in a volume ratio of 1:(1 to 2) to obtain a bcnbpy·2Cl viologen compound with high purity.

[0016] The beneficial effects of the present invention are as follows: the multifunctional viologen coordination compound crystal of the present invention changes color when encountering amine compounds, and changes color rapidly at low concentrations. As an amine detection test paper, it has the characteristics of low response concentration, fast color change speed, simple use method, and reusability. BRIEF DESCRIPTION OF THE DRAWINGS

[0017] Figure 1 This is a diagram of the asymmetric structural unit of the compound prepared in Example 1.

[0018] Figure 2 This is a stacking diagram of the compound prepared in Example 1.

[0019] Figure 3 This is the electron transfer diagram of the compound prepared in Example 1.

[0020] Figure 4 This is the PXRD pattern of the compound prepared in Example 1.

[0021] Figure 5 a is a photograph of the color change of the crystalline compound in detecting organic amines in Experimental Example 1.

[0022] Figure 5 b is a photograph of the color change of the crystalline compound in Experimental Example 1 when detecting low concentration of aniline.

[0023] Figure 6 These are photos of the color change of the test paper in Experimental Example 1 in different organic amine vapors. DETAILED DESCRIPTION

[0024] In order to make the objectives, technical solutions and advantages of the present invention clearer, we will describe the technical solutions and tests of the present invention in more detail. Obviously, the described embodiments are only part of the present invention, not all embodiments.

[0025] Example 1 Viologen coordination compound crystal (I)

[0026] 1. Preparation of the viologen compound 1,1-bis(3-cyanobenzyl)-[4,4′-bipyridine]-1,1′-diium chloride (abbreviated as bcnbpy·2C1)

[0027] 4,4'-bipyridine (1.56g, 10mmol) and 3-chloromethylbenzyl cyanide (3.79g, 25mmol) were added to a 50mL round-bottom flask containing 25mL N,N-dimethylformamide. Under the protection of nitrogen, the mixture was heated to reflux at 110°C for 4-8h, then cooled to 25°C and filtered to obtain a yellow-white precipitate. The precipitate was washed three times with hot DMF solution, then washed three times with ethanol, and vacuum dried at 75°C for 12h. The Bcnbpy·2C1 viologen compound with a high purity was obtained by recrystallization with a methanol and deionized water solution in a volume ratio of 1:1. The hydrogen spectrum and carbon spectrum NMR data are as follows: 1 H-NMR (600 MHz, D 2 O): δ=5.96 (s, 4H), 7.61 (t, J=18Hz, 2H), 7.75 (d, J=6Hz, 2H), 7.82 (d, J=6Hz, 4H), 8.51 (d, J=6Hz, 4H), 9.11 (d, J=6Hz, 4H); 13 C-NMR (600 MHz, D 2O): δ=63.1, 112.5, 118.2, 127.4, 130.5, 132.9, 133.5, 134.0, 145.8, 190.5.

[0028] 2. Preparation of Viologen Coordination Compound Crystals [(BTC)(bcnbpy)2Cl]·2H 2 O

[0029] Dissolve pyromellitic acid (50.8 mg, 0.2 mmol) and bcnbpy·2Cl (45.9 mg, 0.1 mmol) in a mixed solution of 2 ml deionized water and 4 ml N, N-dimethylformamide, and dissolve by stirring. Place the dissolved solution in a 20 ml polytetrafluoroethylene liner and synthesize by a solvent thermal method. After being kept at 90° C. for 4 days, cool to room temperature, wash with deionized water, and then obtain orange-yellow block crystals, which are viologen coordination compound crystals, with a yield of 73%.

[0030] 3. Crystal detection

[0031] (1) X-ray single crystal diffraction

[0032] The product obtained in step 2 was analyzed on a Gemini R Ultra diffractometer using the Oxford diffraction method at 296 K and absorption correction using a multi-scan technique with a Mo-Kα ray from a graphite monochromator. Crystal data was collected for the radiation source. Its crystal structure was crystallographically resolved using SHELXTL-2014 and Olex2 programs. Anisotropic refinement was performed on the thermal parameters of all non-hydrogen atoms in the compound, and the positions of hydrogen atoms on the viologen ligands were fixed. The crystallographic parameters were measured as follows: molecular weight is 674.61, belongs to the triclinic system, space group is P-1, unit cell parameters: α(°)=72.060(3), β(°)=77.983(3), γ(°)=81.530(3), Z = 1. Its crystal structure data is shown in Table 1.

[0033] Table 1

[0034]

[0035] Figure 1 is the asymmetric structural unit diagram of the compound, Figure 2 The electron transfer diagram of the compound can be determined as follows:

[0036] BTC is pyromellitic acid (C 10 H 2 O 8 ) 4- .

[0037] (2) UV solid diffuse reflection

[0038] Figure 3 This is the UV solid diffuse reflectance diagram of the compound. The test results show that the compound responds quickly to both UV light and blue light, and generates responsive viologen free radicals through photoinduced electron transfer. The color change process is a process of electron transfer, and the structure of the compound has hardly changed.

[0039] (3) Powder X-ray diffraction

[0040] Figure 4 The PXRD diagram of the compound proves the stability of the compound after discoloration under blue light and UV irradiation. It can be seen from the figure that the PXRD of the compound after light irradiation has almost no change, which shows that the color change response of the compound is caused by the generation of free radicals to change the color of the compound, rather than the result of photoisomerization and photodecomposition. This result supports the potential application prospects of this compound in optical materials.

[0041] Example 2 Viologen coordination compound crystal (II)

[0042] Dissolve pyromellitic acid (76.2 mg, 0.3 mmol) and bcnbpy·2Cl (45.9 mg, 0.1 mmol) prepared in Example 1 in a mixed solution of 4 ml deionized water and 4 ml N, N-dimethylformamide, and dissolve by stirring. Place the dissolved solution in a 20 ml polytetrafluoroethylene liner and synthesize by a solvent thermal method. After being kept at 100°C for 5 days, cool to room temperature, wash with deionized water, and then obtain orange-yellow block crystals, which are viologen coordination compound crystals, with a yield of 75%. Elemental analysis C36 H26 N4 O10 (%): Theoretical value: C, 64.09; H, 3.85; N, 8.30%. Experimental value: C, 63.88; H, 3.88; N, 8.27%.

[0043] Example 3 Viologen coordination compound crystal (III)

[0044] The pyromellitic acid and bcnbpy·2Cl prepared in Example 1 were dissolved in a mixed solution of deionized water and N,N-dimethylformamide in a volume ratio of 1:1 in a molar ratio of 3:1, and dissolved by stirring. The dissolved solution was placed in a 20ml polytetrafluoroethylene liner and synthesized by a solvent thermal method. After being kept at 100°C for 5 days, it was cooled to room temperature and washed with deionized water to obtain orange-yellow block crystals, which were viologen coordination compound crystals with a yield of 75%. Elemental analysis C36 H26N4O10 (%): Theoretical value: C, 64.09; H, 3.85; N, 8.30%. Experimental value: C, 63.62; H, 3.90; N, 8.24%.

[0045] Experimental Example 1 Amine adsorption color change experiment

[0046] 1. Crystal adsorption color change experiment

[0047] Weigh ethylamine, mono-n-propylamine, di-n-propylamine, diethylamine, tert-butylamine, and diisopropylamine to a concentration of 100 mg / m 3 Amine ethanol solution; take aniline and prepare 10M, 1M, 10 -1 M, 10 -2 M, 10 -3 M, 10 -4 Each solution was placed in a beaker, and the amine solution was evaporated by slight heating. The viologen coordination compound crystal prepared in Example 1 was placed on top of the beaker. Figure 5 As shown, Figure 5 a is a photo of the color change of crystals in different organic amine vapors when the experiment was carried out for 5 seconds; Figure 5 b is the color change of the crystal in different aniline concentrations. -4 The crystals can still respond to aniline under the condition of M concentration. In each test, the crystals can return to their original color (cp) about 1-2 minutes after leaving the gas environment.

[0048] 2. Test paper adsorption color change experiment

[0049] Take 0.05g of the viologen coordination compound crystal prepared in Example 1, dissolve it with 5ml of water and 5ml of DM, and ultrasonicate it for 30 minutes. Then add 1g of polystyrene sulfonic acid and stir it evenly. Then add 0.5g of polyethyleneimine and continue stirring until it becomes a pale yellow-white gel. Apply it evenly on the filter paper for 3 times. The total amount of application is 10mg / cm 2 , and dried to obtain a rapid organic amine detection test paper.

[0050] The beaker experiment under the condition of slight heating and evaporation of amines was carried out by the same method as the above crystal adsorption color change experiment. Figure 6The following is a photo of the color change of the test paper in different organic amine vapors at 5 seconds of the experiment. The test paper can return to its original color (cp) about 1-2 minutes after leaving the gas environment. The color change of the test paper is reversible and can be used repeatedly.

[0051] The above experimental results indicate that the compounds of the present invention are sensitive to primary amines and therefore have potential applications in leak detection and adsorption of toxic gases.

Claims

1. An application of a viologen coordination compound crystal as an amine compound detection material, characterized in that: The structural formula of the viologen coordination compound crystal is shown in formula (I): （I） ， Among them, BTC is pyromellitic acid; The crystallographic parameters of the crystal are as follows: molecular weight is 674.61, belongs to the triclinic system, and the space group is P-1 , unit cell parameters: a(Å)=8.3995(7), b(Å)= 9.7400(10), c(Å)=10.5279(9), α(°)=72.060(3), β(°)= 77.983(3), γ(°)= 81.530(3), V(Å 3 )=798.26(13), Z= 1.

2. The use according to claim 1, characterized in that The detection concentration of the amine compounds is >0.01 mg / L.

3. A test paper for detecting amine compounds, characterized in that: The test paper is loaded with a viologen coordination compound crystal represented by formula (I) as a detection reagent. （I） ， Among them, BTC is pyromellitic acid; The crystallographic parameters of the crystal are as follows: molecular weight is 674.61, belongs to the triclinic system, and the space group is P-1 , unit cell parameters: a(Å)=8.3995(7), b(Å)= 9.7400(10), c(Å)=10.5279(9), α(°)=72.060(3), β(°)= 77.983(3), γ(°)= 81.530(3), V(Å 3 )=798.26(13), Z= 1.

4. The amine compound detection test paper as claimed in claim 3, characterized in that: The content of the viologen coordination compound crystals in the amine compound detection test paper is 5-50 mg / cm 2 Paper substrate.

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