An aggregation-induced emission material based on benzothiazolium hydrazone, its preparation method and application

Abstract

The present invention belongs to the field of specific light visualization identification technology of dust suppressants for railway coal transportation, and relates to a kind of aggregation-induced luminescence material based on benzothiazole hydrazone and its preparation method and application. Benzothiazole hydrazone is reacted with imidazole formaldehyde to generate a new compound connecting benzothiazole and imidazole ring with hydrazone bond as bridge, and then by protonation of imidazole nitrogen atom and ion exchange reaction, an ionic aggregation-induced luminescence material that emits weak light in solution and emits strong light in solid or viscous liquid is obtained, and the emission wavelength is between 500-700nm. It is added to the dust suppressant for railway coal transportation, and it can emit fluorescence under ultraviolet light, and the fluorescence is enhanced as the water in the dust suppressant evaporates, and the fluorescence intensity is linearly related to the polymer content, dust suppressant concentration, and uniformity in the dust suppressant. Bright green to red light is presented on the surface of coal, and the effect of long-distance naked eye visibility is achieved, which can be applied to remote detection of dust suppressant spraying quality in railway coal transportation.

Description

Technical Field

[0001] The invention belongs to the technical field of specific light visualization identification of dust suppressants for railway coal transportation, and relates to an aggregation-induced luminescence material based on benzothiazole hydrazone, and a preparation method and application thereof. Background Art

[0002] With the rapid development of my country's economy, environmental pollution problems have become increasingly prominent. Among them, dust pollution has become a problem of particular concern to the public. Dust floating in the air may contain a variety of heavy metals and can absorb various toxic substances, even carcinogens, seriously polluting people's living environment. Therefore, effective dust suppression is of great significance. Up to now, the commonly used dust suppressants have no obvious color or state changes on the surface of objects before and after spraying, which makes it more difficult to check the spraying and effect of dust suppressants, and it is also impossible to realize the automatic spraying of dust suppressants through remote identification. Therefore, the research on visual automatic identification of dust suppressants has important environmental significance and economic value.

[0003] Aggregation-induced luminescence material is a new type of luminescent material that emits weak or no light in a dispersed state, but emits strong light in an aggregated state. It has the advantages of weak background signal and strong light in a solid or aggregated state. Ionic aggregation-induced luminescence materials have the characteristics of good water solubility, high melting point, high stability and environmental protection, which meets the requirements of my country's railway industry standard TB / T 3210.1-2020 for environmentally friendly dust suppressants.

[0004] In recent years, fluorescent materials reported are mainly used in the fields of biological imaging, optical materials, fluorescent probes, etc. For example, patent CN110194777A discloses an ionic aggregation-induced luminescence group and its preparation method and application. The structural formula of the ionic aggregation-induced luminescence group is Wherein, each R is independently selected from H, alkyl, unsaturated alkyl, heteroalkyl, cycloalkyl, heterocycloalkyl, aryl and heteroaryl; X is an anion; the ionic aggregation-induced luminophore can be used to distinguish a variety of solvents with different hydrogen bond donation capabilities, and can also be used as a wash-free imaging agent for biological samples and as a fluorescent probe with good photostability. However, the use of fluorescent materials for the identification of dust suppressants for railway coal transportation has not been reported. The use of identifiable dust suppressants for railway coal transportation will greatly reduce the difficulty of dust suppressant spraying quality inspection, reduce the risk of traditional pedaling inspection, reduce labor costs, improve detection efficiency, and realize automated remote detection. Summary of the invention

[0005] In view of the technical problems that the quality inspection of dust suppressant spraying for traditional railway coal transportation is difficult, the risk of traditional pedaling inspection is relatively high, and the labor cost is high, the present invention proposes an aggregation-induced luminescence material based on benzothiazole hydrazone and its preparation method and application. The aggregation-induced luminescence material based on benzothiazole hydrazone is added to the dust suppressant for railway coal transportation and sprayed on the surface of coal. The luminescent material can emit fluorescence under the action of ultraviolet light in the dust suppressant, and the fluorescence is enhanced as the water in the dust suppressant evaporates. The fluorescence intensity is linearly related to the polymer content in the dust suppressant, the concentration of the dust suppressant, and the uniformity. Bright green to red light is presented on the surface of the coal, achieving the effect of being visible to the naked eye at a long distance. The fluorescent identification material has imidazolium ions, exhibits good water solubility and biocompatibility, has the characteristics of high boiling point, high luminescence intensity, no metal ions, low toxicity, simple synthesis, and low price, and can be well applied to the remote detection of the quality of dust suppressant spraying in railway coal transportation.

[0006] In order to achieve the above object, the technical solution of the present invention is achieved as follows:

[0007] A benzothiazole hydrazone-based aggregation-induced emission material, with benzothiazole and its derivatives as fluorescent groups, hydrazone bonds as bridges, and imidazolium ions as electron-withdrawing conjugated groups, having the following structure: Where R1 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; R2 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; R3 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; R4 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; X is any one of Cl, Br, I, F, CH3COO, CF3COO, CF3SO2, (CF3SO2)N, SbF6, BF4, B(C6F6)4 or C4F9.

[0008] Furthermore, the preparation method of the benzothiazole hydrazone-based aggregation-induced emission material comprises the following steps:

[0009] The 3-methylbenzothiazole hydrazone-[2] hydrochloride substituted product and the imidazole-2-carboxaldehyde substituted product are mixed and dissolved in solvent I, and heated under reflux under the action of catalyst I. After the reaction is complete, the mixture is subjected to rotary evaporation and extraction. The organic layer is dried over anhydrous Na2SO4, filtered, and then solid-liquid separation is performed. The solid is separated by silica gel column chromatography or recrystallization to obtain intermediate I.

[0010] (2) mixing the intermediate I with sodium hydroxide and solvent II and reacting them at room temperature with stirring, treating in an ice bath and rotary evaporating after the reaction to obtain a solid, adding chloroform to dissolve the solid, and extracting the solid with ultrapure water to obtain an organic phase, adding sodium sulfate to dry the organic phase, rotary evaporating the solid, and drying the solid to obtain an intermediate II;

[0011] (3) The intermediate II is mixed with a halogenated hydrocarbon and dissolved in a solvent III, and a catalyst II is added and stirred. After the reaction is completed, the mixture is cooled and separated by silica gel column chromatography or recrystallized to obtain an imidazole aldehyde hydrazone fluorescent organic salt 1, i.e., an aggregation-induced emission material based on benzothiazole hydrazone.

[0012] Further, the reaction equation of step (1) is:

[0013]

[0014] Furthermore, in step (1), the solvent I is any one or more of anhydrous methanol, anhydrous ethanol, acetonitrile, chloroform, n-propanol or N,N-dimethylformamide; the catalyst I is acetic acid; the structural formula of the 3-methylbenzothiazole hydrazone-[2] hydrochloride substitution is Where R1 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; R2 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; the structural formula of the imidazole-2-carboxaldehyde substituted product is Wherein R4 is H, CH3 or CH3(CH2) n Any one of the above, wherein n is 1-17; the molar ratio of the 3-methylbenzothiazole hydrazone-[2] hydrochloride substitute to the imidazole-2-carboxaldehyde substitute is 1:(1-1.5); and the amount of catalyst I added is 0.5-15 mol% of the 3-methylbenzothiazole hydrazone-[2] hydrochloride substitute.

[0015] Furthermore, in the step (1), the heating reflux temperature is 80-130° C., and the heating reflux time is 5-72 h.

[0016] Further, the reaction equation in step (2) is:

[0017]

[0018] Further, in step (2), intermediate I is The molar ratio of intermediate I to sodium hydroxide is 1:(1-1.2), the solvent II is anhydrous methanol, the reaction time is 12-15 hours under stirring at room temperature, the temperature of the ice bath is 0°C, and the treatment time of the ice bath is 1 hour.

[0019] Further, the reaction equation in step (3) is:

[0020]

[0021] Furthermore, the structural formula of intermediate II in step (3) is The halogenated hydrocarbon is R3-X, where R3 is H, CH3 or CH3(CH2) n any one of, n is 1-17, X is any one of Cl, Br, I, F, C.H3COO, CF3COO, CF3SO2, (CF3SO2)N, SbF6, BF4, B(C6F6)4 or C4F9; catalyst II is acetic acid, and the structural formula of the aggregation-induced emission material based on benzothiazole hydrazone is The solvent III is any one or more of anhydrous methanol, acetonitrile, ethanol or N,N-dimethylformamide.

[0022] Furthermore, in step (3), the stirring temperature is 20-160° C., and the stirring time is 4-48 h. The molar ratio of intermediate II, halogenated hydrocarbon, and catalyst II is 1:(1-2):(0.001-0.006), and the developing solvent of silica gel column chromatography is a mixed solvent of dichloromethane and methanol in a volume ratio of 30:1.

[0023] Furthermore, the benzothiazole hydrazone-based aggregation-induced luminescence material is used as an identification agent in the field of visual detection of dust suppressants used in storage yards or in deserts.

[0024] Further, the application steps are:

[0025] (1) adding water to a benzothiazole hydrazone-based aggregation-induced emission material and stirring and mixing the mixture to obtain an aqueous solution of the benzothiazole hydrazone-based aggregation-induced emission material;

[0026] (2) adding water to the dust suppressant for railway coal transportation, stirring and mixing, to obtain an aqueous solution of the dust suppressant for railway coal transportation;

[0027] (3) mixing the aqueous solution of the benzothiazolehydrazone-based aggregation-induced emission material obtained in step (1) with the aqueous solution of the dust suppressant for railway coal transportation obtained in step (2), and stirring to obtain a visualized dust suppressant for railway coal transportation;

[0028] (4) The visualized railway coal transportation dust suppressant obtained in step (3) was heated at 2 L / m 3 The spray amount is sprayed onto the coal surface. After spraying, it is irradiated with a 365nm ultraviolet lamp. The spraying uniformity of the dust suppressant is observed based on the fluorescence intensity and distribution of the dust suppressant.

[0029] Furthermore, in the step (1), the concentration of the aqueous solution of the benzothiazole hydrazone-based aggregation-induced luminescence material is 0.0012 kg / kg, and the stirring time is 10-20 min; the concentration of the aqueous solution of the dust suppressant for railway coal transportation in the step (2) is 0.01 kg / kg, and the stirring time is 20-40 min; in the step (3), the mass ratio of the benzothiazole hydrazone-based aggregation-induced luminescence material to the dust suppressant for railway coal transportation is 1:(16-500), and the stirring time is 30-60 min. To avoid excessive local concentration, steps (1), (2), and (3) cannot be combined into one step.

[0030] The present invention has the following beneficial effects:

[0031] 1. The benzothiazole hydrazone-based aggregation-induced luminescence material prepared by the present invention is a new type of green fluorescent material with good light / thermal stability and small background fluorescence interference, and the synthetic route of the material molecule is short, the process is simple, and it is easy to operate.

[0032] 2. The benzothiazole hydrazone-based aggregation-induced luminescence material of the present invention has obvious advantages when applied to the detection of dust suppressants for railway coal transportation: the existing detection of dust suppressants for railway coal transportation requires boarding inspection, which is risky, time-consuming and labor-intensive, and is not conducive to remote rapid detection; while the benzothiazole hydrazone-based aggregation-induced luminescence material prepared by the present invention can emit bright green fluorescence when reacting with dust suppressants with a certain viscosity, and the emission wavelength is generally between 520nm and 560nm, does not emit light under natural light, emits strong light under ultraviolet light, has little light damage, is easy to identify, and common substances emit blue light or no light, with less interference. Therefore, green fluorescent materials are less affected by environmental factors.

[0033] 3. The dust suppressant raw material used in the present invention and the dust suppressant / water mixed in proportion for the final solution before spraying (excluding the identification machine) have no fluorescence in the range of 400nm-600nm under the excitation of 400nm light, and the coal seam is black. After adding the prepared aggregation-induced luminescence material based on benzothiazole hydrazone, green fluorescence appears at 530nm, and the fluorescence increases as the dust suppressant gradually loses water. The fluorescence wavelength does not change with the change of dust suppressant concentration, and it can be seen by naked eyes, making it easy for remote instruments to identify the dust suppressant spraying effect.

[0034] 4. The benzothiazolehydrazone-based aggregation-induced luminescence material prepared by the present invention is suitable for various scenarios such as daytime, nighttime, indoors and outdoors during railway coal transportation. It exhibits the characteristics of constant luminescence color, strong anti-interference ability, high sensitivity (within 0.2 seconds), and fast response, and can be well applied to the detection of dust suppressants for railway coal transportation. BRIEF DESCRIPTION OF THE DRAWINGS

[0035] In order to more clearly illustrate the embodiments of the present invention or the technical solutions in the prior art, the drawings required for use in the embodiments or the description of the prior art will be briefly introduced below. Obviously, the drawings described below are only some embodiments of the present invention. For ordinary technicians in this field, other drawings can be obtained based on these drawings without paying creative work.

[0036] Figure 1 This is the hydrogen nuclear magnetic resonance spectrum of the intermediate I prepared in Example 1 of the present invention, wherein the solvent is DMSO-d 6 .

[0037] Figure 2 The carbon NMR spectrum of the intermediate I prepared in Example 1 of the present invention, wherein the solvent is DMSO-d 6 .

[0038] Figure 3 This is the hydrogen nuclear magnetic resonance spectrum of the intermediate II prepared in Example 1 of the present invention, wherein the solvent is DMSO-d 6 .

[0039] Figure 4 The carbon NMR spectrum of the intermediate II prepared in Example 1 of the present invention, wherein the solvent is DMSO-d 6 .

[0040] Figure 5 This is a hydrogen nuclear magnetic resonance spectrum of the aggregation-induced emission material based on benzothiazole hydrazone prepared in Example 1 of the present invention, wherein the solvent is DMSO-d 6 .

[0041] Figure 6 This is the carbon NMR spectrum of the aggregation-induced emission material based on benzothiazole hydrazone prepared in Example 1 of the present invention, wherein the solvent is DMSO-d 6 .

[0042] Figure 7 This is the mass spectrum of the benzothiazolehydrazone-based aggregation-induced emission material prepared in Example 1 of the present invention.

[0043] Figure 8 These are photos of a coal seam sprayed with a common dust suppressant (left) and a coal seam sprayed with a recognizable dust suppressant (right) in Application Example 1 under natural light and 400nm ultraviolet light.

[0044] Fig. 9 For Application Example 1, the fluorescence emission spectrum of the dust suppressant under 400nm light excitation can be identified.

[0045] Fig.10For Application Example 1, the coal seam sprayed with identifiable dust suppressants is exposed to ultraviolet light in a natural environment and emits fluorescence images from different angles, including: 1. The image of the coal seam without ultraviolet light; 2. The fluorescence image of the coal seam when ultraviolet light is irradiated from the far lower left corner; 3. The fluorescence image of the coal seam when ultraviolet light is slowly approaching from the lower left corner to the top; 4. The fluorescence image of the coal seam when ultraviolet light is irradiated from the top; 5. The fluorescence image of the coal seam when ultraviolet light is irradiated from the far upper right corner; 6. The image after the ultraviolet light is far away from the coal seam. DETAILED DESCRIPTION

[0046] The following will be combined with the drawings in the embodiments of the present invention to clearly and completely describe the technical solutions in the embodiments of the present invention. Obviously, the described embodiments are only part of the embodiments of the present invention, not all of the embodiments. Based on the embodiments of the present invention, all other embodiments obtained by ordinary technicians in this field without creative work are within the scope of protection of the present invention.

[0047] The reagents and materials used in the embodiments of the present invention were purchased from Beijing Inokai Reagent Co., Ltd.

[0048] Example 1

[0049] A method for preparing an aggregation-induced emission material based on benzothiazole hydrazone, comprising the following steps:

[0050] (1) Preparation of Intermediate I

[0051]

[0052] In a 100 mL round-bottom flask, 551 mg (5 mmol) of 1-methyl-1H-imidazole-2-carbaldehyde, 1.079 g (5 mmol) of 3-methyl-2-benzothiazolone hydrazone hydrochloride hydrate, 20 mL of anhydrous ethanol, and 0.04 mL of acetic acid were added. The mixture was heated to reflux at 90° C. for 6 h, cooled, and the solvent was removed by rotary evaporation. The residue was extracted with dichloromethane and 2% sodium bicarbonate solution. The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated. The residue was passed through a silica gel column (PE:EtOAc=3:1) to obtain 1.235 g of a yellow solid, namely intermediate I, with a yield of 80%.

[0053] Melting point Mp = 261 ° C. The nuclear magnetic resonance hydrogen spectrum of intermediate I is as follows Figure 1 As shown, 1 H NMR (400 MHz, DMSO-d 6)δ8.44(s,1H),7.79(d,J=1.6Hz,1H),7.75(d,J=7.26Hz,1H),7.72(d,J=1.6Hz,1H),7.41-7.48(m,2H),4.04(s,3H),3.68(s,3H)ppm.

[0054] The carbon NMR spectrum of intermediate I is as follows Figure 2 As shown, 13 C NMR (100MHz, DMSO-d6): δ170.84,140.49,139.45,126.95,125.64,123.4,122.92,122.62,111.35,36.22and 31.45ppm.

[0055] MALDI TOF-MS, C 13 H 14 N5S[M] + : Calculated value 272.0964, found value 272.0967.

[0056] (2) Preparation of Intermediate II

[0057]

[0058] 0.562g (1.8mmol) of intermediate I, 88mg (2.2mmol) of sodium hydroxide and 30mL of anhydrous methanol were added to a 100mL round-bottom flask. After reacting at room temperature 20°C for 12h, the mixture was placed in an ice bath for 1h. The reaction was complete. The obtained reaction solution was spin-dried, 30mL of chloroform was added to dissolve, and ultrapure water (10mL×3) was used to extract the organic phase. Sodium sulfate was added to dry the organic phase, and the obtained organic phase was spin-dried and vacuum dried to obtain 0.431g of colorless solid, namely intermediate II, with a yield of 87%.

[0059] Melting point Mp = 151 ° C. The nuclear magnetic resonance hydrogen spectrum of intermediate II is as follows Figure 3 As shown, 1 H NMR (400MHz, CDCl3): δ8.74(s,1H),7.7(d,J=6.8Hz,1H),7.58-7.60(d,J=8Hz,1H),7.43(s,H),7.30-7.39(m,2H),4.34(s,3H),3.91(s,3H),and 3.95(s,3H)ppm.

[0060] The carbon NMR spectrum of intermediate II is as follows Figure 4 As shown, 13C NMR (100MHz, CDCl3): δ143.40, 140.72, 129.32, 124.27, 121.28, 118.65, 118.56, 113.22, and 35.69ppm.

[0061] MALDI TOF-MS:m / z[M+H] + Calculated value: C 13 H 16 N5 272.0964, found value: 272.0972.

[0062] (3) Aggregation-induced emission materials based on benzothiazole hydrazone III

[0063]

[0064] Take intermediate II (0.300g, 1.10mmol) and add it to a 100mL flask. Add a magnet and dissolve it in 20mL acetonitrile solution. Add ethyl bromide (0.082mL, 1.10mmol) and acetic acid (0.0011mmol). After heating and reflux at 100℃ for 12h, cool it to room temperature. Detection by thin layer chromatography shows that intermediate II disappears completely, proving that the reaction is complete. Column chromatography is performed for separation and purification. The developing solvent is dichloromethane: methanol (30:1) to obtain 0.255g of yellow powder, i.e., aggregation-induced emission material III based on benzothiazole hydrazone, with a yield of 60.73%.

[0065] Melting point Mp = 241 ° C. The nuclear magnetic resonance hydrogen spectrum of the aggregation-induced emission material III based on benzothiazole hydrazone is as follows Figure 5 As shown, 1 H NMR (400MHz, DMSO-d6) δ8.57(s,1H),7.93(d,J=1.8Hz,1H),7.88(d,J=1.6Hz,1H),7.75(d,J=7.8Hz,1H),7.49(d,J=8.2Hz ,1H),7.41(t,J=7.8Hz,1H),7.21(t,J=7.6Hz,1H),4.50(q,J=7.1Hz,2H),4.02(s,3H),3.70(s,3H),1.45(t,J=7.2Hz,3H).

[0066] The carbon NMR spectrum of the aggregation-induced emission material III based on benzothiazole hydrazone is as follows Figure 6 As shown, 13C NMR (101MHz, DMSO-d6) δ171.50,140.47,137.50,134.52,126.99,124.74,123.23,123.06,122.96,122.67,111.51,44.47,36.69,31.56,15.32.

[0067] The mass spectrum of the benzothiazole hydrazone-based aggregation-induced emission material III is as follows Figure 7 As shown, MALDI TOF-MSC 15 H 18 N5S[M] + , calculated value: 300.1277, actual value: 300.1280.

[0068] According to the preparation method in Example 1, the conditions of step (1), step (2) and step (3) are controlled, and R1, R2, R3, R4, and X are replaced by CH3 or CH3(CH2) from H, H, ethyl, methyl, and bromine in Example 1, respectively. n (n is 1-17) and other halogenated hydrocarbons (X is any one of Cl, Br, I or F), aggregation-induced emission materials based on benzothiazole hydrazone containing different anions X (Cl, Br, I or F) and R1, R2, R3, R4 can be prepared.

[0069] Example 2

[0070] A method for preparing an aggregation-induced emission material based on benzothiazole hydrazone, comprising the following steps:

[0071] (1) Preparation of intermediate I-1

[0072] In a 100 mL round-bottom flask, 689 mg (6.25 mmol) of 1H-imidazole-2-carboxaldehyde, 1.079 g (5 mmol) of 3-methyl-2-benzothiazolone hydrazone hydrochloride, 20 mL of acetonitrile, and 0.0014 mL of acetic acid were added. The mixture was heated to reflux at 80°C for 60 h, cooled, and the solvent was removed by rotary evaporation. The residue was extracted with dichloromethane and 2% sodium bicarbonate solution. The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated. The residue was passed through a silica gel column (PE:EtOAc=3:1) to give a solid, namely intermediate I-1.

[0073] (2) Preparation of intermediate II-1

[0074] In a 100 mL round-bottom flask, add intermediate I-1 (1.8 mmol), sodium hydroxide (1.8 mmol), and 30 mL of anhydrous methanol. After reacting at room temperature 25°C for 13 h, place in an ice bath for 1 h. When the reaction is complete, spin dry the obtained reaction solution, add 30 mL of chloroform to dissolve, extract with ultrapure water (10 mL×3), obtain an organic phase, add sodium sulfate to dry, spin dry the obtained organic phase, and vacuum dry to obtain a solid, namely intermediate II-1.

[0075] (3) Aggregation-induced emission material based on benzothiazole hydrazone III-1

[0076] Take the intermediate II-1 (1.10mmol) and add it to a 100mL flask, add a magnetic particle, dissolve it in 20mL of anhydrous methanol, add 1-chlorobutane (0.88mmol) and acetic acid (0.0011mmol), heat and stir at 20℃ for 10h, cool to room temperature, and detect with thin layer chromatography. The intermediate II-1 disappears completely, proving that the reaction is complete. Column chromatography is performed for separation and purification, and the developing solvent is dichloromethane: methanol (30:1) to obtain a powder, i.e., the aggregation-induced emission material III-1 based on benzothiazole hydrazone.

[0077] Example 3

[0078] A method for preparing an aggregation-induced emission material based on benzothiazole hydrazone, comprising the following steps:

[0079] (1) Preparation of intermediate I-2

[0080] In a 100 mL round-bottom flask, 761.3 mg (6.5 mmol) of 1-isopropyl-1H-imidazole-2-carbaldehyde, 1.079 g (5 mmol) of 3-methyl-2-benzothiazolone hydrazone hydrochloride, 20 mL of chloroform, and 0.014 mL of acetic acid were added. The mixture was heated to reflux at 100 °C for 72 h, cooled, and the solvent was removed by rotary evaporation. The residue was extracted with dichloromethane and 2% sodium bicarbonate solution. The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated. The residue was passed through a silica gel column (PE:EtOAc=3:1) to give a solid, namely intermediate I-2.

[0081] (2) Preparation of intermediate II-2

[0082] 1.8 mmol of intermediate I-2, sodium hydroxide (2 mmol), and 30 mL of anhydrous methanol were added to a 100 mL round-bottom flask. After reacting at room temperature 30°C for 14 h, the mixture was placed in an ice bath for 1 h. When the reaction was complete, the obtained reaction solution was spin-dried, 30 mL of chloroform was added to dissolve, and extracted with ultrapure water (10 mL×3) to obtain an organic phase, which was dried by adding sodium sulfate. The obtained organic phase was spin-dried and vacuum dried to obtain a solid, namely intermediate II-2.

[0083] (3) Aggregation-induced emission material III-2 based on benzothiazole hydrazone

[0084] Take the intermediate II-2 (1.10mmol) and add it to a 100mL flask, add a magnetic particle, dissolve it in 20mL of anhydrous ethanol solution, add CH3(CH2)8CF3SO2H (1.8mmol) and acetic acid (0.0033mmol), heat and reflux at 50℃ for 48h, cool it to room temperature, and detect it by thin layer chromatography. The intermediate II-2 disappears completely, proving that the reaction is complete. Column chromatography is performed for separation and purification, and the developing solvent is dichloromethane: methanol (30:1) to obtain a powder, that is, the aggregation-induced emission material III-2 based on benzothiazole hydrazone.

[0085] Example 4

[0086] A method for preparing an aggregation-induced emission material based on benzothiazole hydrazone, comprising the following steps:

[0087] (1) Preparation of intermediate I-3

[0088] In a 100 mL round-bottom flask, 771 mg (7 mmol) of N-ethylimidazole-2-carboxaldehyde, 1.079 g (5 mmol) of 3-methyl-2-benzothiazolone hydrazone hydrochloride, 20 mL of n-propanol, and 0.028 mL of acetic acid were added. The mixture was heated to reflux at 120° C. for 22 h, cooled, and the solvent was removed by rotary evaporation. The residue was extracted with dichloromethane and 2% sodium bicarbonate solution. The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated. The residue was passed through a silica gel column (PE:EtOAc=3:1) to give a solid, namely intermediate I-3.

[0089] (2) Preparation of intermediate II-3

[0090] Add intermediate I-3 (1.8 mmol), sodium hydroxide (2.2 mmol), and 30 mL of anhydrous methanol to a 100 mL round-bottom flask. After reacting at room temperature 24°C for 15 h, place in an ice bath for 1 h. When the reaction is complete, spin dry the obtained reaction solution, add 30 mL of chloroform to dissolve, extract with ultrapure water (10 mL×3), obtain an organic phase, add sodium sulfate to dry, spin dry the obtained organic phase, and vacuum dry. A solid, namely intermediate II-3, is obtained.

[0091] (3) Aggregation-induced emission material based on benzothiazole hydrazone III-3

[0092] Take the intermediate II-3 (1.10mmol) and add it to a 100mL flask, add a magnetic particle, dissolve it in 20mL DMF solution, add 1-bromooctadecane (2mmol) and acetic acid (0.0044mmol), heat and reflux at 160℃ for 18h, cool it to room temperature, and detect it by thin layer chromatography. The intermediate II-3 disappears completely, proving that the reaction is complete. Column chromatography is performed for separation and purification, and the developing solvent is dichloromethane: methanol (30:1) to obtain a powder, that is, the aggregation-induced emission material III-3 based on benzothiazole hydrazone.

[0093] Example 5

[0094] A method for preparing an aggregation-induced emission material based on benzothiazole hydrazone, comprising the following steps:

[0095] (1) Preparation of intermediate I-4

[0096] In a 100 mL round-bottom flask, 826.5 mg (7.5 mmol) of 1-butyl-1H-imidazole-2-carbaldehyde, 1.079 g (5 mmol) of 3-methyl-2-benzothiazolone hydrazone hydrochloride, 20 mL of DMF, and 0.04 mL of acetic acid were added. The mixture was heated to reflux at 130° C. for 5 h, cooled, and the solvent was removed by rotary evaporation. The residue was extracted with dichloromethane and 2% sodium bicarbonate solution. The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated. The residue was passed through a silica gel column (PE:EtOAc=3:1) to give a solid, namely intermediate I-4.

[0097] (2) Preparation of intermediate II-4

[0098] In a 100 mL round-bottom flask, add intermediate I-4 (1.8 mmol), sodium hydroxide (1.9 mmol), and 30 mL of anhydrous methanol. After reacting at room temperature 26°C for 10 h, place in an ice bath for 1 h. When the reaction is complete, spin dry the obtained reaction solution, add 30 mL of chloroform to dissolve, extract with ultrapure water (10 mL×3), obtain an organic phase, add sodium sulfate to dry, spin dry the obtained organic phase, and vacuum dry to obtain a solid, namely intermediate II-4.

[0099] (3) Aggregation-induced emission material based on benzothiazole hydrazone III-4

[0100] Take the intermediate II-4 (1.10mmol) and add it to a 100mL flask, add a magnetic particle, dissolve it in 20mL acetonitrile solution, add trifluorosulfonic acid (2.2mmol) and acetic acid (0.0066mmol), heat and reflux at 100℃ for 4h, cool it to room temperature, and detect it by thin layer chromatography. The intermediate II-4 disappears completely, proving that the reaction is complete. Column chromatography is performed for separation and purification, and the developing solvent is dichloromethane: methanol (30:1) to obtain a powder, that is, the aggregation-induced emission material III-4 based on benzothiazole hydrazone.

[0101] Example 6

[0102] A method for preparing an aggregation-induced emission material based on benzothiazole hydrazone, comprising the following steps:

[0103] (1) Preparation of Intermediate I

[0104] In a 100 mL round-bottom flask, 441 mg (4 mmol) of n-dodecyl-1H-imidazole-2-carbaldehyde, 1.079 g (5 mmol) of 3-methyl-2-benzothiazolone hydrazone hydrochloride hydrate, 20 mL of ethanol, and 0.0028 mL of acetic acid were added. The mixture was heated to reflux at 90°C for 14 h, cooled, and the solvent was removed by rotary evaporation. The residue was extracted with dichloromethane and 2% sodium bicarbonate solution. The organic layer was dried over anhydrous Na2SO4, filtered, and concentrated. The residue was passed through a silica gel column (PE:EtOAc=3:1) to obtain a solid, namely intermediate I-5.

[0105] (2) Preparation of Intermediate II-5

[0106] In a 100 mL round-bottom flask, add intermediate I-5 (1.8 mmol), sodium hydroxide (2.5 mmol), and 30 mL of anhydrous methanol. After reacting at room temperature 20°C for 11 h, place in an ice bath for 1 h. When the reaction is complete, spin dry the obtained reaction solution, add 30 mL of chloroform to dissolve, extract with ultrapure water (10 mL×3), obtain an organic phase, add sodium sulfate to dry, spin dry the obtained organic phase, and vacuum dry to obtain a solid, namely intermediate II-5.

[0107] (3) Aggregation-induced emission material based on benzothiazole hydrazone III-5

[0108] Take intermediate II-5 (1.10mmol) and add it to a 100mL flask, add a magnetic particle, dissolve it in 20mL of anhydrous ethanol solution, add n-dodecyl bromide (1.54mmol) and acetic acid (0.0011mmol), heat and reflux at 90℃ for 12h, cool to room temperature, and detect with thin layer chromatography. Intermediate II disappears completely, proving that the reaction is complete. Column chromatography is performed for separation and purification, and the developing solvent is dichloromethane: methanol (30:1) to obtain a powder, i.e., the aggregation-induced emission material III-5 based on benzothiazole hydrazone.

[0109] According to the preparation method in this embodiment, the conditions of step (1), step (2) and step (3) are controlled, and R1, R2, R3, R4, and X are replaced by CH3 or CH3(CH2) respectively. n (n is 1-17) and other X (X is any one of (CF3SO2)N, SbF6, BF4, B(C6F6)4 or C4F9), aggregation-induced emission materials based on benzothiazole hydrazone containing different anions and different alkyl substituent configurations can be prepared.

[0110] Application Example 1

[0111] The application of the benzothiazole hydrazone-based aggregation-induced luminescence material prepared in Example 1 as an identification agent in the field of visual detection of dust suppressants for storage yards or deserts is as follows:

[0112] (1) Take 10 kg of dust suppressant (polyvinyl alcohol) and add it to a stirring tank, add 1000 kg of tap water, and stir for 30 minutes to obtain a dust suppressant aqueous solution;

[0113] (2) Add 240 g of the identification agent to 200 kg of water and stir for 15 min to obtain an identification agent aqueous solution;

[0114] (3) adding 100 g of the identification agent solution of step (2) to 1000 kg of the dust suppressant solution of step (1), stirring for 45 min, to obtain an automatic identification type dust suppressant aqueous solution (at this time, the mass ratio of the identification agent to the dust suppressant is 1:417);

[0115] (4) According to 2L / m 2 Spraying amount: Spray the dust suppressant aqueous solution onto the surface of the coal carried by the train. Irradiate with a 365nm ultraviolet lamp and judge whether the dust suppressant is sprayed and whether the spraying is uniform based on the fluorescence intensity and distribution of the dust suppressant.

[0116] (5) Fluorescence spectrum test method

[0117] Use a pipette to transfer 3mL of the aqueous solution of benzothiazole hydrazone-based aggregation-induced luminescence material and dust suppressant into a 1cm cuvette, and use a microinjector to add different volumes of anion solution to meet different concentration requirements. Mix thoroughly and let stand for 2 minutes before testing. The excitation wavelength of all test objects is set to 365-460nm. Use a Cary Eclipse absolute quantum efficiency tester for detection.

[0118] Application Example 2

[0119] The application of the benzothiazole hydrazone-based aggregation-induced luminescence material prepared in Example 1 as an identification agent in the field of visual detection of dust suppressants for storage yards or deserts is as follows:

[0120] (1) Take 10 kg of dust suppressant and add it to a stirring tank, add 1000 kg of tap water, and stir for 40 minutes to obtain a dust suppressant aqueous solution;

[0121] (2) Add 240 g of the identification agent to 200 kg of water and stir for 20 min;

[0122] (3) adding the identification agent solution of step (2) to the dust suppressant solution of step (1) (the volume ratio of the identification agent to the dust suppressant is 1:16), stirring for 60 minutes, and obtaining an automatic identification type dust suppressant aqueous solution;

[0123] (4) According to 2L / m 2 Spraying amount: Spray the dust suppressant aqueous solution onto the surface of the coal carried by the train. Irradiate with a 365nm ultraviolet lamp and judge whether the dust suppressant is sprayed and whether the spraying is uniform based on the fluorescence intensity and distribution of the dust suppressant.

[0124] (5) Fluorescence spectrum test method

[0125] Use a pipette to transfer 3mL of the aqueous solution of benzothiazole hydrazone-based aggregation-induced luminescence material and dust suppressant into a 1cm cuvette, and use a microinjector to add different volumes of anion solution to meet different concentration requirements. Mix thoroughly and let stand for 2 minutes before testing. The excitation wavelength of all test objects is set to 365-460nm. Use a Cary Eclipse absolute quantum efficiency tester for detection.

[0126] Application Example 3

[0127] The application of the benzothiazole hydrazone-based aggregation-induced luminescence material prepared in Example 1 as an identification agent in the field of visual detection of dust suppressants for storage yards or deserts is as follows:

[0128] (1) Take 10 kg of dust suppressant and add it to a stirring tank, add 1000 kg of tap water, and stir for 20 minutes to obtain a dust suppressant aqueous solution;

[0129] (2) Add 240 g of the identification agent to 200 kg of water and stir for 10 min;

[0130] (3) adding the identification agent solution of step (2) to the dust suppressant solution of step (1) (the ratio of identification agent to dust suppressant is 1:500), stirring for 30 minutes, and obtaining an automatic identification type dust suppressant aqueous solution;

[0131] (4) According to 2L / m 2 Spraying amount: Spray the dust suppressant aqueous solution onto the surface of the coal carried by the train. After 0.2s of spraying, irradiate with a 365nm ultraviolet lamp to judge whether the dust suppressant has been sprayed and whether the spraying is uniform based on the fluorescence intensity and distribution of the dust suppressant.

[0132] (5) Fluorescence spectrum test method

[0133] Use a pipette to transfer 3mL of the aqueous solution of benzothiazole hydrazone-based aggregation-induced luminescence material and dust suppressant into a 1cm cuvette, and use a microinjector to add different volumes of anion solution to meet different concentration requirements. Mix thoroughly and let stand for 2 minutes before testing. The excitation wavelength of all test objects is set to 365-460nm. Use a Cary Eclipse absolute quantum efficiency tester for detection.

[0134] Figure 8 The following are photos of a coal seam sprayed with a common dust suppressant (left) and a coal seam sprayed with a recognizable dust suppressant (right) in Application Example 1 under natural light and 400nm ultraviolet light. Figure 8 It can be seen that the ordinary dust suppressant used has no fluorescence in the range of 400nm-600nm under the excitation of 400nm light in a solution with a dust suppressant / water volume ratio of 1:49, and the coal seam is black; after adding the prepared benzothiazole hydrazone-based aggregation-induced luminescence material as an identification agent, green fluorescence appears at 530nm, and the fluorescence increases as the identifiable dust suppressant gradually loses water, and the fluorescence wavelength does not change with the dust suppressant concentration, so it is visible to the naked eye, making it easy for remote instruments to identify the dust suppressant spraying effect.

[0135] Fig. 9 For Application Example 1, the fluorescence emission spectrum of dust suppressant under 400nm light excitation can be identified. Fig. 9 It can be seen that under the excitation of 400nm light, the dust suppressant can be identified to emit fluorescence in the range of 400nm-600nm

[0136] Fig.10For Application Example 1, the coal seam sprayed with identifiable dust suppressants emits fluorescence images when stimulated by ultraviolet light in a natural environment and illuminated from different angles, including: 1. The coal seam image without ultraviolet light; 2. The fluorescence image of the coal seam illuminated by ultraviolet light from the far lower left corner; 3. The fluorescence image of the coal seam illuminated by ultraviolet light slowly approaching from the lower left corner; 4. The fluorescence image of the coal seam illuminated by ultraviolet light from above; 5. The fluorescence image of the coal seam illuminated by ultraviolet light from the far upper right corner; 6. The image after the ultraviolet light is far away from the coal seam. Fig.10 It can be seen that after the benzothiazole hydrazone-based aggregation-induced luminescence material reacts with the dust suppressant, it does not emit light under natural light, but can emit bright green fluorescence under ultraviolet light, which is easy to identify. In addition, based on the fluorescence intensity and distribution emitted by the dust suppressant, it can be judged whether the dust suppressant is sprayed and whether the spraying is uniform.

[0137] The benzothiazole hydrazone-based aggregation-induced luminescence material prepared by the present invention has obvious advantages when applied to the detection of dust suppressants for railway coal transportation: the existing detection of dust suppressants for railway coal transportation requires boarding inspection, which is high-risk, time-consuming and labor-intensive, and is not conducive to remote rapid detection; while the benzothiazole hydrazone-based aggregation-induced luminescence material prepared by the present invention can emit bright green fluorescence when reacting with a dust suppressant with a certain viscosity, and the emission wavelength is generally between 520nm and 560nm, does not emit light under natural light, emits strong light under the action of ultraviolet light, has little light damage, is easy to identify, and common substances emit blue light or no light, with less interference. Therefore, green fluorescent materials are less affected by environmental factors.

[0138] The benzothiazolehydrazone-based aggregation-induced luminescence material prepared by the present invention is suitable for various scenes such as daytime, nighttime, indoors and outdoors during railway coal transportation, and exhibits the characteristics of constant luminescence color, strong anti-interference ability, high sensitivity (within 0.2 seconds), and fast response, and can be well applied to the detection of dust suppressants for railway coal transportation.

[0139] The above description is only a preferred embodiment of the present invention and is not intended to limit the present invention. Any modifications, equivalent substitutions, improvements, etc. made within the spirit and principle of the present invention should be included in the protection scope of the present invention.

Claims

1. An aggregation-induced emission material based on benzothiazole hydrazone, characterized in that: The aggregation-induced luminescence material of benzothiazole hydrazone has benzothiazole and its derivatives as fluorescent groups, hydrazone bonds as bridges, and imidazolium ions as electron-withdrawing conjugated groups. It has the following structure: , wherein R1 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; R2 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; R3 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; R4 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; X is any one of Cl, Br, I, F, CH3COO, CF3COO, CF3SO2, (CF3SO2)N, SbF6, BF4, B(C6F6)4 or C4F9.

2. The method for preparing the aggregation-induced emission material based on benzothiazole hydrazone according to claim 1, characterized in that: Here are the steps: (1) Mixing a 3-methylbenzothiazole hydrazone-[2] hydrochloride substitute and an imidazole-2-carboxaldehyde substitute, dissolving the mixture in solvent I, heating under reflux in the presence of catalyst I, and performing rotary evaporation and extraction after the reaction is complete. The organic layer is dried over anhydrous Na2SO4, filtered, and then separated into solid and liquid. The solid is separated by silica gel column chromatography or recrystallized to obtain intermediate I; wherein the structural formula of the 3-methylbenzothiazole hydrazone-[2] hydrochloride substitute is , wherein R1 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; R2 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; the structural formula of the imidazole-2-carboxaldehyde substituted product is , wherein R4 is H, CH3 or CH3(CH2) n Any one of, n is 1-17; (2) Intermediate I is mixed with sodium hydroxide and solvent II and stirred at room temperature for reaction. After the reaction is completed, the mixture is treated in an ice bath and rotary evaporated to obtain a solid. Chloroform is added to the solid to dissolve it and then extracted with ultrapure water to obtain an organic phase. The organic phase is added with sodium sulfate and dried, and then rotary evaporated and dried to obtain Intermediate II; wherein Intermediate I is ; (3) Intermediate II is mixed with a halogenated hydrocarbon and dissolved in a solvent III, and a catalyst II is added and stirred. After the reaction is completed, the mixture is cooled and separated by silica gel column chromatography or recrystallized to obtain an imidazole aldehyde hydrazone fluorescent organic salt 1, i.e., an aggregation-induced emission material based on benzothiazole hydrazone; wherein the structural formula of intermediate II is .

3. The method for preparing the aggregation-induced emission material based on benzothiazolehydrazone according to claim 2, characterized in that: In the step (1), the solvent I is any one or more of anhydrous methanol, anhydrous ethanol, acetonitrile, chloroform, n-propanol or N,N-dimethylformamide; the catalyst I is acetic acid; the molar ratio of the 3-methylbenzothiazole hydrazone-[2] hydrochloride substitute to the imidazole-2-carboxaldehyde substitute is 1:(0.8-1.5); and the amount of the catalyst I added is 0.5-15 mol% of the 3-methylbenzothiazole hydrazone-[2] hydrochloride substitute.

4. The method for preparing the aggregation-induced emission material based on benzothiazolehydrazone according to claim 2 or 3, characterized in that: The heating reflux temperature in step (1) is 80-130° C., and the heating reflux time is 5-72 h.

5. The method for preparing the aggregation-induced emission material based on benzothiazolehydrazone according to claim 2, characterized in that: In the step (2), the molar ratio of intermediate I to sodium hydroxide is 1:(1-1.4), the solvent II is anhydrous methanol, the stirring reaction time at room temperature is 10-15 hours, the temperature of the ice bath is 0°C, and the treatment time of the ice bath is 1 hour.

6. The method for preparing the aggregation-induced emission material based on benzothiazolehydrazone according to claim 5, characterized in that: In step (3), the halogenated hydrocarbon is R3-X, wherein R3 is H, CH3 or CH3(CH2) n any one of, n is 1-17, X is any one of Cl, Br, I, F, CH3COO, CF3COO, CF3SO2, (CF3SO2)N, SbF6, BF4, B(C6F6)4 or C4F9; catalyst II is acetic acid, and the structural formula of the aggregation-induced emission material based on benzothiazole hydrazone is ; Solvent III is any one or more of anhydrous methanol, acetonitrile, anhydrous ethanol or N,N-dimethylformamide.

7. The method for preparing the aggregation-induced emission material based on benzothiazolehydrazone according to claim 5 or 6, characterized in that: The stirring temperature in step (3) is 20-160°C, and the stirring time is 4-48 h. The molar ratio of intermediate II, halogenated hydrocarbon, and catalyst II is 1:(0.8-2):(0.001-0.006), and the developing solvent of silica gel column chromatography is a mixed solvent of dichloromethane and methanol in a volume ratio of 30:

1.

8. Use of the benzothiazolehydrazone-based aggregation-induced luminescence material according to claim 1 as an identification agent in the field of visual detection of dust suppressants for storage yards or deserts.

9. The use according to claim 8, characterized in that: Here are the steps: (1) adding water to a benzothiazole hydrazone-based aggregation-induced emission material and stirring and mixing the mixture to obtain an aqueous solution of the benzothiazole hydrazone-based aggregation-induced emission material; (2) adding water to the dust suppressant for railway coal transportation, stirring and mixing, to obtain an aqueous solution of the dust suppressant for railway coal transportation; (3) mixing the aqueous solution of the benzothiazolehydrazone-based aggregation-induced emission material obtained in step (1) with the aqueous solution of the dust suppressant for railway coal transportation obtained in step (2), and stirring to obtain a visualized dust suppressant for railway coal transportation; (4) The visualized railway coal transportation dust suppressant obtained in step (3) was heated to 2 L / m 3 The spray amount is sprayed onto the coal surface. After spraying, it is irradiated with a 365nm ultraviolet lamp. The spraying uniformity of the dust suppressant is observed based on the fluorescence intensity and distribution of the dust suppressant.

10. The use according to claim 9, characterized in that: In the step (1), the concentration of the aqueous solution of the benzothiazole hydrazone-based aggregation-induced luminescence material is 0.0012 kg / kg, and the stirring time is 10-20 min. In the step (2), the concentration of the aqueous solution of the dust suppressant for railway coal transportation is 0.01 kg / kg, and the stirring time is 20-40 min. In the step (3), the mass ratio of the benzothiazole hydrazone-based aggregation-induced luminescence material to the dust suppressant for railway coal transportation is 1:(16-500), and the stirring time is 30-60 min.

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