Pyridine imidazole derivative as well as preparation method and application thereof

Abstract

The invention discloses a pyridine imidazole derivative as well as a preparation method and application thereof, and relates to the technical field of organic chemistry. The structure of the pyridine imidazole derivative is # imgabs0 #. The fluorescent probe can be used for qualitative or quantitative detection of silver ions in biological samples or environmental samples, has high specific selectivity and sensitivity, is stable in fluorescence performance, can be used for manufacturing a fluorescent molecular recognition system, and has wide application prospects in the fields of fluorescence chemistry, environmental chemistry, life science and the like.

Description

Technical Field

[0001] The present invention relates to the technical field of organic chemistry, and in particular to a pyridine imidazole derivative and a preparation method and application thereof. Background Art

[0002] Silver ions and their compounds play an important role in the fields of metallurgy, pharmaceuticals, electroplating, food, textiles and other industrial life. However, silver ions are also heavy metal ions, which are harmful and toxic to the environment and organisms. Excessive silver ions can cause water pollution and other environmental pollution. Silver ions in the environment accumulate in the human body through the food chain. After being absorbed by the human body, they will be deposited in the skin, eyes and mucous membranes, causing lesions. At the same time, they will also have serious effects on the nervous system, liver, bones, etc.

[0003] In the related technologies, the methods for silver ion determination include test paper method, atomic absorption method, electrochemistry and potentiometric titration, etc. Most of these methods have certain defects, such as low sensitivity, time-consuming, non-specific, cumbersome operation, expensive instruments, etc. Fluorescent probe refers to a molecule in a specific system, when a certain physical or chemical property of a substance or system changes, the fluorescent signal (intensity or wavelength) can change accordingly. Therefore, it is of great significance to develop a highly selective silver ion fluorescent probe. Summary of the invention

[0004] The present invention aims to solve at least one of the technical problems existing in the prior art. To this end, the present invention provides a pyridine imidazole derivative that can specifically recognize Ag + , and has broad application prospects in fields such as environmental chemistry and life sciences.

[0005] The present invention also provides a method for preparing the pyridine imidazole derivative.

[0006] The present invention also provides application of the pyridine imidazole derivatives.

[0007] The invention also provides a method for detecting silver ions.

[0008] A pyridine imidazole derivative according to the first aspect of the present invention has the following structure: .

[0009] The pyridine imidazole derivatives according to the embodiments of the present invention have at least the following beneficial effects: The pyridine imidazole derivatives of the embodiment can exist stably under standard conditions (25°C, one atmosphere) and have good stability; they have high sensitivity, good specificity, and stable fluorescence properties. They can be used to prepare fluorescent molecular recognition systems and have broad application prospects in the fields of fluorescence chemistry, environmental chemistry, and life sciences.

[0010] According to some embodiments of the present invention, the pyridinium imidazole derivative is a pyridinium imidazole derivative fluorescent probe.

[0011] According to some embodiments of the present invention, the pyridinium imidazole derivative is a pyridinium imidazole derivative fluorescent probe for detecting silver ions.

[0012] According to the method for preparing the pyridine imidazole derivative described in the first embodiment of the second embodiment of the present invention, the method comprises the following steps: S1, preparing a first mixture of 2,6-diimidazolylpyridine and 1,4-di(2'-bromoethoxy)-9,10-anthraquinone, reacting, concentrating, and performing a first solid-liquid separation to obtain a first solid phase; S2, prepare the first solid phase and PF6 - The second mixture is reacted, and a second solid phase is obtained through a second solid-liquid separation to obtain the pyridine imidazole derivative.

[0013] The preparation method according to the embodiment of the present invention has at least the following beneficial effects: The preparation method of the embodiment is to react 1,4-bis(2'-bromoethoxy)-9,10-anthraquinone with 2,6-diimidazolylpyridine in an organic solvent to obtain a compound and then perform anion exchange to obtain a pyridine imidazole derivative. The steps are simple and easy to implement.

[0014] According to some embodiments of the present invention, the first mixture includes a first organic solvent; the first organic solvent includes at least one of methanol, ethanol, and tetrahydrofuran (THF).

[0015] According to some embodiments of the present invention, in step S1, the ratio of the total mass of the 2,6-diimidazolylpyridine and 1,4-bis(2'-bromoethoxy)-9,10-anthraquinone to the volume of the first organic solvent is (13-15) g: 1 L. For example, it may be 13 g: 1 L, 13.2 g: 1 L, 13.4 g: 1 L, 13.6 g: 1 L, 13.8 g: 1 L, 14 g: 1 L, 14.2 g: 1 L, 14.4 g: 1 L, 14.6 g: 1 L, 14.8 g: 1 L or 15 g: 1 L.

[0016] According to some embodiments of the present invention, in step S1, the reaction temperature is 66°C-70°C. For example, it can be 66°C, 66.5°C, 67°C, 67.5°C, 68°C, 68.5°C, 69°C, 69.5°C or 70°C.

[0017] According to some embodiments of the present invention, in step S1, the reaction time is 96 h-100 h. For example, it can be 96 h, 96.5 h, 97 h, 97.5 h, 98 h, 98.5 h, 99 h, 99.5 h or 100 h.

[0018] According to some embodiments of the present invention, in step S1, the molar ratio of 2,6-diimidazolylpyridine to 1,4-bis(2'-bromoethoxy)-9,10-anthraquinone is (2-14): 1. For example, it can be 2: 1, 3: 1, 4: 1, 5: 1, 6: 1, 7: 1, 8: 1, 9: 1, 10: 1, 11: 1, 12: 1, 13: 1 or 14: 1.

[0019] According to some embodiments of the present invention, in step S1, the concentration includes: concentrating to a volume of 8%-12% of the first organic solvent, for example, 8%, 8.5%, 9%, 9.5%, 10%, 10.5%, 11%, 11.5% or 12%.

[0020] According to some embodiments of the present invention, in step S2, the PF6 - The source includes at least one of ammonium hexafluorophosphate (NH4PF6) and NaPF6.

[0021] According to some embodiments of the present invention, in step S2, the first solid phase and PF6 - The molar ratio is 1: (2-10). For example, it can be 1: 2, 1: 2.5, 1: 3, 1: 3.5, 1: 4, 1: 4.5, 1: 5, 1: 5.5, 1: 6, 1: 6.5, 1: 7, 1: 7.5, 1: 8, 1: 8.5, 1: 9, 1: 9.5 or 1: 10.

[0022] According to some embodiments of the present invention, the second mixture includes a second organic solvent; the second organic solvent includes at least one of methanol, ethanol, and THF.

[0023] According to some embodiments of the present invention, in step S2, the first solid phase and PF6 - The ratio of the total mass of the source to the volume of the second organic solvent is (15 g-25 g): 1 L. For example, it can be 15 g: 1 L, 16 g: 1 L, 17 g: 1 L, 18 g: 1 L, 19 g: 1 L, 20 g: 1 L, 21 g: 1 L, 22 g: 1 L, 23 g: 1 L, 24 g: 1 L or 25 g: 1 L.

[0024] According to some embodiments of the present invention, in step S2, the mass volume ratio of the first solid phase to the second organic solvent is (5 g-9 g):1 L. For example, it can be 5 g:1 L, 5.5 g:1 L, 6 g:1 L, 6.5 g:1 L, 7 g:1 L, 7.5 g:1 L, 8 g:1 L, 8.5 g:1 L or 9 g:1 L.

[0025] According to some embodiments of the present invention, in step S2, the reaction temperature is 20°C-30°C. For example, it can be 20°C, 21°C, 22°C, 23°C, 24°C, 25°C, 26°C, 27°C, 28°C, 29°C or 30°C.

[0026] According to some embodiments of the present invention, in step S2, the reaction time is 72 h-75 h. For example, it can be 72 h, 72.5 h, 73 h, 73.5 h, 74 h, 74.5 h, 75 h.

[0027] According to some embodiments of the present invention, the first solid-liquid separation and the second solid-liquid separation are independently selected from at least one of centrifugation, filtration, and filter pressing.

[0028] According to some embodiments of the present invention, the method for preparing 1,4-bis(2'-bromoethoxy)-9,10-anthraquinone comprises the following steps: A third mixture of 1,4-dihydroxy-9,10-anthraquinone and potassium carbonate is prepared, 1,2-dibromoethane is added dropwise after the reaction, the reaction is continued, and the solvent is removed after a third solid-liquid separation to obtain a third solid phase; the third solid phase is recrystallized to obtain the 1,4-di(2'-bromoethoxy)-9,10-anthraquinone.

[0029] According to some embodiments of the present invention, the molar ratio of 1,4-dihydroxy-9,10-anthraquinone to potassium carbonate is 1:(4-7). For example, it can be 1:4, 1:4.5, 1:5, 1:5.5, 1:6, 1:6.5 or 1:7.

[0030] According to some embodiments of the present invention, the reaction temperature of 1,4-dihydroxy-9,10-anthraquinone and potassium carbonate is 58°C-65°C. For example, it may be 58°C, 59°C, 60°C, 61°C, 62°C, 63°C, 64°C or 65°C.

[0031] According to some embodiments of the present invention, the reaction time of 1,4-dihydroxy-9,10-anthraquinone and potassium carbonate is 0.4 h-1 h. For example, it can be 0.4 h, 0.45 h, 0.5 h, 0.55 h, 0.6 h, 0.65 h, 0.7 h, 0.75 h, 0.8 h, 0.85 h, 0.9 h or 1 h.

[0032] According to some embodiments of the present invention, the third mixture includes a third organic solvent; the third organic solvent is selected from acetone and tetrahydrofuran.

[0033] According to some embodiments of the present invention, the mass volume ratio of the 1,4-dihydroxy-9,10-anthraquinone to the third organic solvent is (10-15) g: 1 L. For example, it can be 10 g: 1 L, 10.5 g: 1 L, 11 g: 1 L, 11.5 g: 1 L, 12 g: 1 L, 12.5 g: 1 L, 13 g: 1 L, 13.5 g: 1 L, 14 g: 1 L, 14.5 g: 1 L or 15 g: 1L.

[0034] According to some embodiments of the present invention, the molar ratio of 1,4-dihydroxy-9,10-anthraquinone to 1,2-dibromoethane is 1: (8-12). For example, it can be 1: 8, 1: 8.5, 1: 9, 1: 9.5, 1: 10, 1: 10.5, 1: 11, 1: 11.5 or 1: 12.

[0035] According to some embodiments of the present invention, the reaction temperature of dripping 1,2-dibromoethane is 58° C.-65° C. For example, it can be 58° C., 58.5° C., 59° C., 59.5° C., 60° C., 60.5° C., 61° C., 61.5° C., 62° C., 62.5° C., 63° C., 63.5° C., 64° C., 64.5° C. or 65° C.

[0036] According to some embodiments of the present invention, the reaction time of dripping 1,2-dibromoethane is 70 h-75 h. For example, it can be 70 h, 70.5 h, 71 h, 71.5 h, 72 h, 72.5 h, 73 h, 73.5 h, 74 h, 74.5 h or 75 h.

[0037] According to some embodiments of the present invention, the recrystallization solvent includes at least one of ethyl acetate and petroleum ether.

[0038] According to the third aspect of the present invention, the pyridine imidazole derivative as described in the first aspect of the present invention is used in the detection of silver ions or the preparation of products for detecting silver ions.

[0039] According to some embodiments of the present invention, the application is for purposes other than disease diagnosis and treatment.

[0040] According to some embodiments of the present invention, the product is selected from a test paper, a reagent, a kit or a chip.

[0041] A method for detecting silver ions according to a fourth aspect of the present invention comprises the following steps: A fourth mixture of the pyridine imidazole derivative and the sample to be tested described in the first embodiment is prepared, and the change in the emission peak wavelength of the fourth mixture is measured as a detection index of silver ions. Since the detection method adopts all the technical solutions of the pyridine imidazole derivatives of the above embodiment, it at least has all the beneficial effects brought by the technical solutions of the above embodiment.

[0042] According to some embodiments of the present invention, the working medium for the detection of silver ions is water and / or an organic medium.

[0043] According to some embodiments of the present invention, the organic medium includes at least one of C2H5OH and CH3OH.

[0044] According to some embodiments of the present invention, the working medium is a mixture of water and an organic medium. The volume ratio of water to organic medium is 1:(0.9-1.1). For example, it can be 1:0.9, 1:0.92, 1:0.94, 1:0.96, 1:0.98, 1:1, 1:1.02, 1:1.04, 1:1.06, 1:1.08 or 1:1.1.

[0045] According to some embodiments of the present invention, the concentration of silver ions in the fourth mixture is (0-90)×10 -6 mol / L. For example, it can be 1×10 -6 mol / L、10×10 -6 mol / L、20×10 -6 mol / L、30×10 -6 mol / L、40×10 -6 mol / L、50×10 -6 mol / L、60×10 -6 mol / L、70×10 -6 mol / L、80×10 -6 mol / L or 90×10 -6 mol / L.

[0046] According to some embodiments of the present invention, the change in the emission peak wavelength is the change in the emission peak wavelength at 550 nm.

[0047] According to some embodiments of the present invention, the excitation wavelength is 400 nm.

[0048] According to some embodiments of the present invention, the sample to be tested includes at least one of an environmental sample and a biological sample.

[0049] According to some embodiments of the present invention, the detection is qualitative detection or quantitative detection.

[0050] According to some embodiments of the present invention, the detection is a quantitative detection; the detection method further comprises: Prepare silver ion standard solutions of different concentrations and the probe standard solution of the pyridine imidazole derivative described in the first aspect embodiment, mix the silver ion standard solution and the probe standard solution, measure the fluorescence intensity corresponding to the silver ion concentrations of different concentrations, draw a standard curve, fit the functional relationship between the change in fluorescence intensity and the silver ion concentration, and calculate the concentration of silver ions in the sample to be tested according to the functional relationship.

[0051] Other features and advantages of the present invention will be set forth in the description which follows, and in part will be apparent from the description, or may be learned by practice of the present invention. BRIEF DESCRIPTION OF THE DRAWINGS

[0052] Figure 1 is the fluorescence spectrum of different cations detected in the pyridine imidazole derivative of Example 1; Figure 2 The pyridine imidazole derivatives of Example 1 are + Detection fluorescence spectrum of Ag + The concentration increases in the direction of the arrow. DETAILED DESCRIPTION

[0053] The following will be combined with the embodiments to clearly and completely describe the concept of the present invention and the technical effects produced, so as to fully understand the purpose, characteristics and effects of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of them. Based on the embodiments of the present invention, other embodiments obtained by those skilled in the art without creative work are all within the scope of protection of the present invention.

[0054] If the specific conditions are not specified in the examples, the experiments were carried out under conventional conditions or conditions recommended by the manufacturer. If the manufacturers of the reagents or instruments are not specified, they are all conventional products that can be purchased commercially.

[0055] In the description of the present invention, if there is a description of first, second, third, fourth, etc., it is only for the purpose of distinguishing the technical features, and cannot be understood as indicating or implying the relative importance or implicitly indicating the number of the indicated technical features or implicitly indicating the sequence of the indicated technical features.

[0056] "And / or" is used to indicate that one or both of the stated situations may occur, for example, A and / or B includes (A and B) and (A or B).

[0057] Unless otherwise specified, "room temperature" in the present invention means (25±5)°C.

[0058] Unless otherwise specified, the reagents used in the present invention are all from Tianjin Kress Chemical Co., Ltd. and are of analytical grade. All solvents are purified by standard procedures, and all reagents used for synthesis and analysis are of analytical grade without further treatment.

[0059] If not otherwise specified, the melting point in the present invention is measured by a Boetius zone intercept machine. 1 H NRM and 13 C NRM spectra were recorded on a Mercury Variant Vx400 spectrophotometer, measuring between 400 MHz and 100 MHz. Chemical shifts, δ, were determined with reference to the international standard TMS. Fluorescence spectra were measured on a Cary Eclipse fluorescence spectrophotometer.

[0060] Preparation Example 1 This example provides a method for preparing 1,4-bis(2'-bromoethoxy)-9,10-anthraquinone, the steps are as follows: A suspension of 1,4-dihydroxy-9,10-anthraquinone (2.000 g, 8.2 mmol, CAS: 81-64-1) and K2CO3 (6.790 g, 49.2 mmol, CAS: 584-08-7) in acetone (150 mL) was stirred at 60°C for 0.5 h, and then 1,2-dibromoethane (15.400 g, 82.0 mmol, CAS: 106-93-4) was added dropwise to the mixture. The mixture was stirred at 60°C for 72 h, and the solvent in the liquid phase was removed by vacuum after filtration to obtain a brown solid. The brown solid was recrystallized from ethyl acetate to obtain orange needle-shaped crystals of 1,4-di(2'-bromoethoxy)-9,10-anthraquinone.

[0061] Yield: 2.978 g (80%). Melting point: 114°C–116°C.

[0062] Anal. Calculation for C 18 H 14 O4Br2: C, 47.60; H, 3.10. Found: C, 47.48; H, 3.23.v0.4 / 0.44. 1 H NMR (400 MHz, DMSO- d6): δ 3.87(t, J =5.6Hz,4H,C H 2), 4.47 (t, J = 5.8 Hz,4H, C H 2), 7.60 (s, 2H, Ph H ), 7.86-7.88 (m, 2H, Ph H ), 8.07-8.10 (m, 2H, Ph H ). 13 C NMR (100 MHz, DMSO- d 6): δ 181.8 ( C =O), 152.7 (Ar C ), 133.6 (Ar C ), 133.6(Ar C ), 125.8 (Ar C ), 124.1 (Ar C ), 123.0 (Ar C ), 70.3 (O C H2CH2Br), 31.1(OCH2 C H2Br). Example 1 This example provides a pyridine imidazole derivative, as shown in Formula I:

[0063] Formula Ⅰ.

[0064] This example also provides a method for preparing the pyridine imidazole derivative shown in formula I, the steps are as follows: S1. Dissolve 2,6-diimidazolylpyridine (1.120 g, 5.3 mmol, CAS: 39242-17-6) and 1,4-bis(2'-bromoethoxy)-9,10-anthraquinone (0.200 g, 0.4 mmol) in THF (100 mL), reflux under stirring at 66°C-70°C for 4 days, concentrate to 10 mL to precipitate solid, and filter to obtain 0.701 g of solid (yield 68%, molecular weight 876.55, purity 100%).

[0065] S2. The solid obtained in step S1 (0.701 g, 0.8 mmol) and NH4PF6 (1.270 g, 7.8 mmol, CAS: 16941-11-0) were dissolved in CH3OH (100 mL), and the mixture was reacted at room temperature for 3 days under stirring to generate a precipitate, which was filtered to obtain a pyridine imidazole derivative (1).

[0066] Yield: 0.225 g (56%). Melting point: 193°C-195°C.

[0067] HRMS (ESI) m / z: calcd for C 40 H 32 O4N 10 P2F 12 (1) [(1- 2PF6 - ) / 2] + ,358.3735;found, 358.3730. 1 H NMR (400 MHz, DMSO- d 6): δ 4.60(t, 4H, C H 2), 4.83 (t, 4H, C H 2), 7.13(s, 2H, imi H ), 7.64-7.68 (m, 4H, Ph H ), 7.72-7.76(m, 2H, Ph H ), 8.04(dd, J = 8.0Hz, 4H, Ph H ), 8.20 (s, 2H, imi H ), 8.29 (s, 2H, imi H ), 8.43(t, J = 8.0 Hz, 2H,Ph H ), 8.77 (s, 2H, imi H ), 8.83 (s, 2H, imi H ), 10.48(s, 2H, imi H ). 13 C NMR (DMSO- d 6, 100 MHz): δ 187.6 ( C =O), 157.5 (Ar C ), 153.0 (Ar C), 150.5 (Ar C ), 149.2(Ar C ), 141.8(Ar C ), 138.7 (Ar C ), 135.8 (Ar C ), 130.9 (Ar C ), 129.4 (Ar C ), 128.0(Ar C ), 127.4 (Ar C ), 124.4(Ar C ), 124.2 (Ar C ), 122.1 (Ar C ), 118.3 (Ar C ),116.3(Ar C ), 115.2 (Ar C ), 72.6 ( C H2), 54.4 ( C H2).

[0068] Application Example 1 At 25°C, the pyridinium imidazole derivative of Example 1 (5 × 10 -6 mol / L) H2O / C2H5OH (v / v = 1:1) solution was added with different types of the same concentration (25 × 10 -6 mol / L) cation H2O / C2H5OH (v / v = 1:1) solution (Li + , Na + , K + , Ag + , Cu 2+ , Co 2+ , Ni 2+ , NH 4+ , Ca 2+ , Zn 2+ , Cr 3+ , Cd 3+ , Al 3+ , Mn 2+ ,Pb 2+ , the anions were all nitrate), and their fluorescence spectra were measured.

[0069] The results are as follows Figure 1 shown.

[0070] The pyridine imidazole derivatives of Example 1 are effective for Ag +, with the ability of selective recognition.

[0071] Application Example 2 Fluorescence titration experiments were performed using a Cary Eclipse fluorescence spectrophotometer with a quartz cell of 1 cm path length. The pyridinium imidazole derivative of Example 1 (5 × 10 -6 mol / L) H2O / C2H5OH (v / v = 1:1) solution was placed in a 4 mL cuvette, and increasing concentrations of Ag were added using a microsyringe. + H2O / C2H5OH (v / v = 1:1) solution (0-90 × 10 -6 mol / L). The excitation wavelength was 400 nm, and the emission peak intensity of the pyridine imidazole derivatives at 550 nm gradually increased. After each addition, the reaction equilibrium was reached in 8-10 minutes and the fluorescence intensity was measured. Data analysis was performed using Origin8.0.

[0072] The results are as follows Figure 2 shown.

[0073] With Ag + As the concentration increases, the intensity of the emission peak increases. + When the concentration reaches a certain value, the fluorescence no longer increases significantly.

[0074] The embodiments of the present invention are described in detail above in conjunction with the embodiments, but the present invention is not limited to the above embodiments, and various changes can be made within the knowledge scope of ordinary technicians in the relevant technical field without departing from the purpose of the present invention.

Claims

1. A pyridine imidazole derivative, characterized in that: The structure is as follows: 。 2. The method for preparing the pyridine imidazole derivative according to claim 1, characterized in that: The following steps are involved: S1, preparing a first mixture of 2,6-diimidazolylpyridine and 1,4-di(2'-bromoethoxy)-9,10-anthraquinone, reacting, concentrating, and performing a first solid-liquid separation to obtain a first solid phase; S2, prepare the first solid phase and PF6 - The second mixture is reacted, and a second solid phase is obtained through a second solid-liquid separation to obtain the pyridine imidazole derivative.

3. The preparation method according to claim 2, characterized in that: The first mixture includes a first organic solvent; the first organic solvent includes at least one of methanol, ethanol, and THF; and / or, in step S1, the molar ratio of 2,6-diimidazolylpyridine to 1,4-di(2'-bromoethoxy)-9,10-anthraquinone is (2-13):1; And / or, in step S1, the reaction temperature is 66°C-70°C; And / or, in step S1, the reaction time is 96 h-100 h.

4. The preparation method according to claim 2, characterized in that: In step S2, the second mixture includes a second organic solvent; the second organic solvent includes at least one of methanol, ethanol, and THF; And / or, in step S2, the PF6 - The source includes at least one of NH4PF6 and NaPF6; And / or, in step S2, the first solid phase and PF6 - The molar ratio is (2-5):1; And / or, in step S2, the reaction temperature is 20°C-30°C; And / or, in step S2, the reaction time is 72 h-75 h.

5. The preparation method according to claim 2, characterized in that: The preparation method of 1,4-bis(2'-bromoethoxy)-9,10-anthraquinone comprises the following steps: A third mixture of 1,4-dihydroxy-9,10-anthraquinone and potassium carbonate is prepared, 1,2-dibromoethane is added dropwise after the reaction, the reaction is continued, and the solvent is removed after a third solid-liquid separation to obtain a third solid phase; the third solid phase is recrystallized to obtain the 1,4-di(2'-bromoethoxy)-9,10-anthraquinone.

6. The preparation method according to claim 5, characterized in that: The molar ratio of 1,4-dihydroxy-9,10-anthraquinone to potassium carbonate is 1: (4-7); and / or, the reaction temperature of the 1,4-dihydroxy-9,10-anthraquinone and potassium carbonate is 58° C.-65° C.; And / or, the molar ratio of 1,4-dihydroxy-9,10-anthraquinone to 1,2-dibromoethane is 1: (8-12); And / or, the reaction temperature for dropping 1,2-dibromoethane is 58°C-65°C.

7. The preparation method according to claim 2, characterized in that: The recrystallization solvent includes at least one of ethyl acetate and petroleum ether.

8. Use of the pyridine imidazole derivative according to claim 1 in the detection of silver ions or in the preparation of products for detecting silver ions.

9. A method for detecting silver ions, characterized in that: The steps include: A fourth mixture of the pyridine imidazole derivative according to claim 1 and a sample to be tested is prepared, and a change in the emission peak wavelength of the fourth mixture is measured as a detection index of silver ions.

10. The detection method according to claim 9, characterized in that: When used for the detection of silver ions, the working medium is water and / or an organic medium; Preferably, the organic medium includes at least one of C2H5OH and CH3OH; Preferably, the working medium is a mixture of water and an organic medium; the volume ratio of the water to the organic medium is 1:(0.9-1.1); Preferably, the concentration of silver ions in the fourth mixture is (0-90) × 10 -6 mol / L.

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