A single crystal of a Cd(II) complex, a preparation method thereof, and an application thereof

Abstract

The present invention relates to the fields of coordination chemistry and detection, and discloses a cadmium complex single crystal, a preparation method thereof and an application thereof. Its chemical formula is: [Cd2(H3BTB)2L] n , where H3BTB = 1,3,5-tris(4-carboxyphenyl)benzene and L = 1,4-bis(1-imidazolyl)benzene; it belongs to the triclinic system, and the space group is 'P‑1' , a = 9.6452(19) Å, b = 14.733(3) Å, c = 16.824(3) Å, α = 66.14(3)°, β = 76.10(3)°, γ = 83.76(3)°, V = 2122.1(9) Å 3 . Cadmium nitrate tetrahydrate, the ligand 1,3,5-tris(4-carboxyphenyl)benzene and 1,4-bis(1-imidazolyl)benzene are dissolved in N,N'-dimethylformamide and distilled water, sealed in a reaction flask, and ultrasonically prepared at room temperature. This complex can stably exist in water and can be used as a sensor to detect norfloxacin and chlortetracycline hydrochloride in water to achieve qualitative and quantitative detection.

Description

Technical Field

[0001] The present invention relates to the fields of coordination chemistry and detection, and particularly relates to a cadmium(II) complex single crystal, a preparation method thereof, and a fluorescence detection application. Background Art

[0002] In recent years, due to the overuse of norfloxacin antibiotics, there has been an abuse phenomenon. Moreover, norfloxacin is difficult to completely degrade in animals, and most of it will accumulate and remain in animals. The accumulation of norfloxacin in animals can cause gastrointestinal reactions and central nervous system reactions when people consume meat products and dairy products containing norfloxacin antibiotics, affecting people's physical health. Chlortetracycline hydrochloride is a widely used broad-spectrum antibiotic that can promote the growth of fish and prevent aquaculture diseases. The aquaculture technology generates a large amount of aquaculture wastewater, which is directly discharged into the natural environment, causing serious environmental pollution. When people consume meat products containing chlortetracycline hydrochloride antibiotics, it can lead to liver damage, double infections, teratogenesis, etc., seriously interfering with the normal physiological mechanisms of the human body. Chlortetracycline hydrochloride contains many hydroxyl groups and is easy to form insoluble chelates with polyvalent metal ions. Moreover, it can also complex with calcium salts and iron salts in water, resulting in difficult degradation. Therefore, the monitoring of norfloxacin and chlortetracycline hydrochloride in drinking water is of great significance.

[0003] For this reason, many novel methods for detecting norfloxacin and chlortetracycline hydrochloride have been developed by chemists. Fluorescence analysis has been widely used due to its characteristics such as short response time, simple operation, high sensitivity, and good selectivity, which has led researchers to be committed to constructing various fluorescence sensors. Metal-organic framework materials have received great attention in the sensing field in recent years due to their tunable luminescence properties. The luminescence properties of MOFs are affected by various factors, such as metal ions, coordination environment, pore surface properties, and organic ligands with different functional groups. Therefore, it is easy to adjust the luminescence of the material by changing the structure of MOFs. In particular, various functional groups can be reasonably introduced to modify the microporous structure of metal ligands, thereby generating more active sites and being widely used in the detection of various antibiotics. The N in the imino group of norfloxacin and the amino group of chlortetracycline hydrochloride can undergo electrophilic reactions. Therefore, the design and synthesis of a metal-organic framework probe with a fast response speed, simple operation, high sensitivity, and wide detection range is more conducive to detecting the concentrations of norfloxacin and chlortetracycline hydrochloride in water. Summary of the Invention

[0004] The object of the present invention is to provide a cadmium functional complex with high sensitivity, wide detection range, good stability, and convenient use, and use it as a sensor for detecting norfloxacin and chlortetracycline hydrochloride. Another object is to provide a preparation method thereof.

[0005] To achieve the above invention object, the technical solutions are as follows:

[0006] The single crystal of the cadmium (II) complex has the chemical formula: [Cd2(H3BTB)2L] n , where H3BTB = 1,3,5-tris(4-carboxyphenyl)benzene and L = 1,4-bis(1-imidazolyl)benzene; it belongs to the triclinic system with the space group 'P-1', α = 66.14(3)°, β = 76.10(3)°, γ = 83.76(3)°,

[0007] The preparation method of the sensor of the present invention: Dissolve cadmium nitrate tetrahydrate, the ligand 1,3,5-tris(4-carboxyphenyl)benzene and 1,4-bis(1-imidazolyl)benzene in N,N'-dimethylformamide and distilled water, seal them in a reaction flask, ultrasonicate at room temperature, place them in a constant-temperature oven, and then cool to room temperature to obtain transparent block crystals, thus obtaining the target product, namely the single crystal sensor of the Cd(II) complex.

[0008] This complex can be used as a sensor for detecting norfloxacin and chlortetracycline hydrochloride in water to achieve qualitative and quantitative detection.

[0009] The advantages of the present invention are as follows: The single crystal of the Cd(II) complex can stably exist in water, and its three-dimensional framework structure pores contain N atoms, which is conducive to interacting with norfloxacin and chlortetracycline hydrochloride, and thus quickly and sensitively detecting the concentrations of norfloxacin and chlortetracycline hydrochloride in water. When detecting the concentration of norfloxacin in water, it has a wide detection range (1 - 130 μM), a low detection limit (0.073 μM) and a short response time (1 minute). When detecting the concentration of chlortetracycline hydrochloride in water, it has a wide detection range (1 - 30 μM), a low detection limit (0.560 μM) and a short response time (1 minute). Moreover, the synthesis process of the present invention is simple and has a high yield, showing good application prospects. Description of the Drawings

[0010] Figure 1 It is the coordination environment diagram of cadmium in the cadmium complex crystal of the present invention;

[0011] Figure 2 It is the single crystal structure diagram of the sensor of the present invention;

[0012] Figure 3 It is the experimental powder diffraction pattern and simulated powder diffraction pattern of the cadmium complex of the present invention; 1 is the simulated powder diffraction pattern of the single crystal, 2 is the powder diffraction pattern of the cadmium complex of the present invention, and 3 is the powder diffraction pattern of the cadmium complex after being soaked in water for 24 hours.

[0013] Figure 4Fluorescence intensity change diagram of the sensor of the present invention for detecting the concentration of norfloxacin in water (excitation peak: 287 nm, emission peak: 310 - 500 nm);

[0014] Figure 5 Linear range of the sensor of the present invention for detecting the concentration of norfloxacin in water;

[0015] Figure 6 Fluorescence intensity change diagram of the sensor of the present invention for detecting the concentration of chlortetracycline hydrochloride in water (excitation peak: 287 nm, emission peak: 310 - 500 nm)

[0016] Figure 7 Linear range of the sensor of the present invention for detecting the concentration of chlortetracycline hydrochloride in water. Detailed implementation mode

[0017] The present invention will be further described below through examples:

[0018] Example 1: Synthesis of Cd(II) single crystal sensor

[0019] Dissolve cadmium nitrate tetrahydrate (18.5 mg, 0.06 mmol), 1,3,5-tris(4-carboxyphenyl)benzene (13.2 mg, 0.03 mmol) and 1,4-bis(1-imidazolyl)benzene (6.3 mg, 0.03 mmol) in N,N'-dimethylformamide (3 mL) and water (3 mL), seal in a reaction flask, ultrasonicate at room temperature, keep at a constant temperature of 100 °C for three days, and then cool to room temperature to obtain transparent block crystals. The molecular formula of the transparent block crystals is: [Cd2(H3BTB)2L] n , that is, the Cd(II) single crystal sensor.

[0020] Select single crystals of appropriate size under a microscope for X-ray diffraction experiments at room temperature. On a Bruker SmartApex-II CCD diffractometer, use Mo-Kα radiation monochromatized by a graphite monochromator Collect diffraction data in the φ–ω mode. Use the Bruker SAINT program for data reduction. Absorption correction of diffraction data for some structures is carried out using the SADABS program. The crystal structure is solved by direct methods combined with difference Fourier synthesis. All non-hydrogen atom coordinates and anisotropic parameters are refined by full-matrix least-squares methods, and the positions of C–H atoms are determined according to the theoretical model. The coordination environment diagram of the metal cadmium in the complex is shown in Figure 1 ; the crystal structure diagram of the complex is shown in Figure 2 ; the detailed crystal determination data are shown in Table 1.

[0021] Table 1 Main crystallographic data of the complex

[0022]

[0023]

[0024] Example 2: Application of the Cd(II) single crystal sensor of the present invention in detecting the concentrations of norfloxacin and chlortetracycline hydrochloride in water

[0025] First, grind the Cd(II) single crystal sensor synthesized in the present invention in an agate mortar for 1 hour, and then add 3 mg of the ground sample to 10 mL of distilled water to obtain a 0.3 mg mL -1 suspended Cd(II) sensor. Secondly, add norfloxacin with different concentrations to the 0.3 mg mL -1 suspended Cd(II) sensor. After equilibration for 1 minute, detect the fluorescence change with an Edinburgh fluorescence spectrometer, as shown in Figure 4 . And a good linear curve is shown, as shown in Figure 5 . This sensor can well detect the concentration of 1-130 μM norfloxacin in water. Then, add chlortetracycline hydrochloride with different concentrations to the 0.3 mg mL -1 suspended Cd(II) sensor. After equilibration for 1 minute, detect the fluorescence change with an Edinburgh fluorescence spectrometer, as shown in Figure 6 . And a good linear curve is shown, as shown in Figure 7 . This sensor can well detect the concentration of 1-30 μM chlortetracycline hydrochloride in water.

Claims

1. A single crystal of a cadmium (II) complex, characterized in that, Chemical formula: [Cd2(H3BTB)2L] n , where H3BTB is 1,3,5-tris(4-carboxyphenyl)benzene and L is 1,4-bis(1-imidazolyl)benzene; it belongs to the triclinic system, and the space group is 'P -1' , a = 9.6452(19) Å, b = 14.733(3) Å, c = 16.824(3) Å, α = 66.14(3)°, β = 76.10(3)°, γ = 83.76(3)°, V = 2122.1(9) Å 3 .

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