A carborane gaschromic luminescent material, its preparation method and use

Abstract

The application belongs to the technical field of fluorescent sensing, and particularly relates to a carborane gaschromic luminescent material, a preparation method and application thereof. The carborane gaschromic material is prepared by subjecting 1-(4-halophenyl)-2-R-1,2-carborane and 2-ethynyl-dibenzothiophene to a Sonogashira coupling reaction. The carborane gaschromic luminescent material can be used for preparing a gaschromic fluorescent detection film, and can be further used for VOCs detection, thereby solving or improving at least one of the problems of large equipment volume, high cost, slow response and complex operation in the current volatile organic compound (VOCs) detection process.

Description

Technical Field

[0001] This invention belongs to the field of fluorescence sensing technology, specifically relating to a carborane gas-induced color-changing luminescent material, its preparation method, and its application. Background Technology

[0002] With the rapid development of my country's industry, the consumption and transformation of fossil energy such as coal and oil are ongoing. Accompanying this process, volatile organic compounds (VOCs) have become a major threat to human health and the environment. VOCs are generated through many pathways, such as the production or storage of chemicals, gas stations, chemical laboratories, interior decoration, and even cooking. They can directly or indirectly damage the human central nervous system, and even cause poisoning or diseases such as cancer. Besides achieving the green conversion and absorption of VOCs, another direction of effort by industry and academia is the quantitative detection of VOCs. Developing a rapid, sensitive, portable, and inexpensive fluorescent sensing membrane capable of detecting VOC gases is extremely urgent. Current research mainly uses mass spectrometry and gas chromatography for sensitive and selective detection of VOC gases, but these methods suffer from drawbacks such as large equipment size, high cost, slow response, and complex operation. In current research, gas-chromic fluorescent membrane detection provides a good alternative for the required VOC gas detection. In this regard, the detection of gas-chromic fluorescent thin films largely depends on the following aspects: 1. the chemical properties of the sensing fluorophore; 2. the selection of the thin film support. These two factors are also crucial for the detection of VOC gases using fluorescent thin films.

[0003] Therefore, there is a need to provide an improved technical solution that addresses the shortcomings of the existing technology. Summary of the Invention

[0004] The purpose of this invention is to provide a carborane gas-induced color-changing luminescent material, its preparation method, and its application, so as to solve or improve at least one of the disadvantages of large equipment size, high cost, slow response, and complex operation in the detection of volatile organic compounds (VOCs).

[0005] To achieve the above objectives, the present invention provides the following technical solution: a carborane gas-induced color-changing luminescent material, wherein the structural formula of the carborane gas-induced color-changing luminescent material is:

[0006] Wherein, R is alkyl, dialkylfluorenyl, or dialkylphenyl.

[0007] Preferably, the alkyl group in the alkyl group, dialkylfluorenyl group, and dialkylphenyl group has 1-4 carbon atoms.

[0008] Preferably, R is butyl, dibutylfluorenyl, or di-tert-butylphenyl.

[0009] The present invention also provides a method for preparing carborane gas-chromatic luminescent materials, which adopts the following technical solution: the method for preparing carborane gas-chromatic luminescent materials as described above includes the following steps: 1-(4-halophenyl)-2-R-1,2-carborane and 2-ethynyl-dibenzothiophene undergo a Sonogashira coupling reaction to prepare the carborane gas-chromatic luminescent material.

[0010] Preferably, the molar ratio of 1-(4-halophenyl)-2-R-1,2-carborane to 2-ethynyl-dibenzothiophene is 1:(1.0-1.2); the catalyst for the Sonogashira coupling reaction comprises tetrakis(triphenylphosphine)palladium and cuprous iodide, wherein the molar equivalent ratio of tetrakis(triphenylphosphine)palladium to 1-(4-halophenyl)-2-R-1,2-carborane is (0.05-0.08):1; the molar equivalent ratio of cuprous iodide to 1-(4-halophenyl)-2-R-1,2-carborane is (0.1-0.16):1; the temperature of the Sonogashira coupling reaction is 70-90℃, and the reaction time is 5-10h; the reaction solvent for the Sonogashira coupling reaction is a mixed solution of tetrahydrofuran and triethylamine, wherein the volume ratio of tetrahydrofuran to triethylamine is (2-3):1.

[0011] Preferably, the preparation method of 1-(4-halophenyl)-2-R-1,2-carborane includes the following steps: A. Preparing BrC6H4-C≡CR using p-bromoiodobenzene and RC≡CH; B. Reacting BrC6H4-C≡CR with a diacetonitrile decaborate complex to obtain 1-(4-halophenyl)-2-R-1,2-carborane.

[0012] The present invention also provides a gas-chromic film, which adopts the following technical solution: a gas-chromic film, wherein the raw materials or components of the gas-chromic film include the carborane gas-chromic luminescent material and the carrier as described above.

[0013] Preferably, the carrier is a nonwoven fabric.

[0014] The present invention also provides a fluorescence sensor, which adopts the following technical solution: a fluorescence sensor, wherein the raw material of the fluorescence sensor includes the carborane gas-chromic luminescent material as described above or the gas-chromic film as described above.

[0015] The present invention also provides a method for detecting gas concentration, which adopts the following technical solution: A method for detecting gas concentration includes the following steps: placing the fluorescence sensor as described above in an environment containing the gas to be tested, detecting the emission wavelength of the fluorescence sensor to realize the detection of the gas to be tested; or, immersing a carrier in a solution containing the carborane gas-chromic luminescent material as described above, drying it to obtain a gas-chromic film, placing the gas-chromic film in an environment containing the gas to be tested to realize the detection of the gas to be tested.

[0016] Preferably, the method further includes the steps of obtaining the linear relationship between the concentration and wavelength provided by the gas standard and / or calculating the concentration of the gas to be tested based on the linear relationship between the concentration and wavelength provided by the gas standard; the gas to be tested is VOCs.

[0017] Preferably, the gas to be tested is any one of n-hexane, carbon tetrachloride, benzene, chloroform, ethyl acetate, tetrahydrofuran, triethylamine, acetone, and acetonitrile.

[0018] Beneficial effects:

[0019] The carborane gas-chromic luminescent material of the present invention can be used to prepare gas-chromic fluorescent detection films, and then used in the detection of VOCs, solving or improving at least one of the problems existing in the current detection process of volatile organic compounds (VOCs), such as large equipment size, high cost, slow response, and complex operation.

[0020] When the carborane gas-chromic luminescent material of the present invention is used for gas (e.g., VOCs) detection, its maximum emission wavelength can be linearly related to the gas (e.g., VOCs) concentration, enabling quantitative detection of gas (e.g., VOCs) (the detection principle is not based on classical fluorescence intensity change, but on the emission wavelength shift generated by gas chromaticity).

[0021] The method for detecting gas concentration of the present invention can achieve quantitative detection, which helps to solve the problem that current methods for detecting VOCs by fluorescence are limited to changes in fluorescence intensity and the response effect depends on complex instruments. Attached Figure Description

[0022] The accompanying drawings, which form part of this application, are used to provide a further understanding of the invention. The illustrative embodiments of the invention and their descriptions are used to explain the invention and do not constitute an undue limitation of the invention. Wherein:

[0023] Figure 1 The structural formula of the carborane gas-induced color-changing material and the optional structural formula of the substituent R are provided in one embodiment of the present invention;

[0024] Figure 2The structural formulas of carborane I, carborane II and carborane III, the carborane gas-induced color-changing luminescent materials provided in Examples 1-3 of this invention;

[0025] Figure 3 The reaction equation for a method of preparing a carborane gas-induced color-changing luminescent material provided in one embodiment of the present invention;

[0026] Figure 4 The reaction equations for the preparation method of the carborane gas-induced color-changing luminescent material provided in Examples 1-3 of the present invention (the products corresponding to Examples 1-3 are "Carborane I", "Carborane II" and "Carborane III" respectively, i.e., carborane I, carborane II and carborane III);

[0027] Figure 5 Photographs of the carborane I, carborane II, and carborane III gas-induced color-changing films of the present invention under no UV light excitation and under 365nm UV light excitation;

[0028] Figure 6 The graph shows the test results of the carborane III gas-induced color-changing membrane of the present invention under different VOC atmospheres;

[0029] Figure 7 The emission spectra of the carborane III gas-induced color-changing film of the present invention under different concentrations of tetrahydrofuran and benzene atmospheres are shown. Figure 7 A shows the emission spectrum measured in a tetrahydrofuran atmosphere (the concentration of tetrahydrofuran gradually increases from top to bottom). Figure 7 B is the emission spectrum test diagram under benzene atmosphere (the concentration of benzene gradually increases from top to bottom);

[0030] Figure 8 This is a linear relationship between the emission wavelength of the carborane III gas-induced color-changing film of the present invention and the atmosphere concentration under different concentrations of tetrahydrofuran and benzene atmospheres; Figure 8 In the middle, the left figure shows the linear relationship between the emission wavelength and the atmosphere concentration under different concentrations of tetrahydrofuran atmosphere, and the right figure shows the linear relationship between the emission wavelength and the atmosphere concentration under different concentrations of benzene atmosphere.

[0031] Figure 9 The emission spectra of the carborane II gas-induced color-changing film of the present invention at different concentrations of tetrahydrofuran are shown below. Figure 9 A, the concentration of tetrahydrofuran gradually increases from top to bottom) and a linear relationship between emission wavelength and atmospheric concentration at different concentrations of tetrahydrofuran ( Figure 9 B);

[0032] Figure 10 The emission spectra of the carborane I gas-induced color-changing film of the present invention under different concentrations of tetrahydrofuran are shown below. Figure 10A, the concentration of tetrahydrofuran gradually increases from top to bottom) and a linear relationship between emission wavelength and atmospheric concentration at different concentrations of tetrahydrofuran ( Figure 10 B). Detailed Implementation

[0033] The technical solutions in the embodiments of the present invention will be clearly and completely described below. Obviously, the described embodiments are only a part of the embodiments of the present invention, and not all of them. All other embodiments obtained by those skilled in the art based on the embodiments of the present invention are within the scope of protection of the present invention.

[0034] The present invention will now be described in detail with reference to embodiments. It should be noted that, unless otherwise specified, the embodiments and features described in the embodiments of the present invention can be combined with each other.

[0035] This invention addresses at least one of the problems existing in current volatile organic compound (VOCs) detection processes, such as large equipment size, high cost, slow response, and complex operation, by providing a carborane gas-chromic luminescent material. The structural formula of the carborane gas-chromic luminescent material is as follows:

[0036] Wherein, R is alkyl, dialkylfluorenyl, or dialkylphenyl.

[0037] Currently, gas-chromatic carborane luminescent materials are scarce, and they have not been used to detect VOC concentrations. This invention selects carborane derivatives as the sensing fluorophore in the gas-chromatic fluorescent film. Carboranes are cluster compounds formed from boron and carbon, achieving high stability (far exceeding that of small-molecule boranes) through the hyperconjugation of their framework atoms. The most representative of these is C2B. 10 H 12 o-Carborane. Because o-carboranes conform to Hückel's rule, they possess aromaticity similar to that of aromatic rings and are quite thermally stable, not decomposing below 250°C. As an inorganic compound, carboranes are similarly reactive to aromatic hydrocarbons and can undergo various forms of substitution, thus yielding carborane materials with various specific functions. In the carborane gas-chromic luminescent material of the present invention, different groups (substituent R is alkyl, dialkylfluorenyl, or dialkylphenyl) are modified on the other carbon terminus of the carborane to adjust the fluorescence response of the sensor, enabling the carborane gas-chromic luminescent material of the present invention to possess gas-chromic properties.

[0038] The carborane gas-chromic luminescent material of the present invention can be used to prepare gas-chromic fluorescent detection films, and then used in the detection of VOCs, solving at least one of the problems existing in the current detection process of volatile organic compounds (VOCs), such as large equipment size, high cost, slow response, and complex operation.

[0039] When the carborane gas-chromic luminescent material of the present invention is used for gas (e.g., VOCs) detection, its maximum emission wavelength can be linearly related to the gas (e.g., VOCs) concentration, enabling quantitative detection of gas (e.g., VOCs) (the detection principle is not based on classical fluorescence intensity change, but on the emission wavelength shift generated by gas chromaticity).

[0040] In a preferred embodiment of the carborane gas-chromic material of the present invention, the alkyl group in the alkyl, dialkylfluorenyl, and dialkylphenyl groups has 1-4 carbon atoms. (See reference...) Figure 1 , Figure 1 The structural formula of R is listed (where C1-C4 alkyl groups can be straight-chain alkyl groups or branched alkyl groups). As the number of carbon atoms in the alkyl group, dialkylfluorenyl group, and dialkylphenyl group increases, the gas-induced discoloration phenomenon may weaken or disappear.

[0041] In a preferred embodiment of the carborane gas-chromic material of the present invention, the substituent R in the carborane gas-chromic luminescent material is butyl, dibutylfluorenyl, or di-tert-butylphenyl. Their complete structural formulas are as follows: Figure 2 (I, II, and III). When R is butyl, dibutylfluorenyl, or di-tert-butylphenyl, the carborane gas-chromic material of the present invention has good film-forming properties (relatively speaking, when the butyl or tert-butyl in butyl, dibutylfluorenyl, or di-tert-butylphenyl is replaced by a C1-C3 alkyl group (e.g., methyl, ethyl, or propyl), the film-forming properties of the corresponding carborane gas-chromic material may be affected, making it difficult to form a film, and its practical application will be affected to some extent), making it easy to use for the production of gas-chromic films, and its practical application performance is good.

[0042] This invention also proposes a method for preparing a carborane gas-chromic luminescent material. The method for preparing the carborane gas-chromic luminescent material according to embodiments of this invention includes the following steps: 1-(4-halophenyl)-2-R-1,2-carborane and 2-ethynyl-dibenzothiophene undergo a Sonogashira coupling reaction to prepare the carborane gas-chromic luminescent material (see reference). Figure 3 (step 3 in the text). Preferably, the halogen in 1-(4-halophenyl)-2-R-1,2-carborane is bromine or iodine.

[0043] In a preferred embodiment of the method for preparing the carborane gas-chromic luminescent material of the present invention, the molar ratio of 1-(4-iodophenyl)-2-R-1,2-carborane and 2-ethynyl-dibenzothiophene is 1:(1.0-1.2) (e.g., 1:1.0, 1:1.05, 1:1.1, 1:1.15 or 1:1.2); the catalyst for the Sonogashira coupling reaction includes tetrakis(triphenylphosphine)palladium and cuprous iodide, wherein tetrakis(triphenylphosphine)palladium and 1-(4-iodophenyl) The molar equivalent ratio of 1-(4-iodophenyl)-2-R-1,2-carborane is (0.05-0.08):1 (e.g., 0.05:1, 0.06:1, 0.07:1 or 0.08:1); the molar equivalent ratio of cuprous iodide to 1-(4-iodophenyl)-2-R-1,2-carborane is (0.1-0.16):1 (e.g., 0.1:1, 0.11:1, 0.12:1, 0.13:1, 0.14:1, 0.15:1 or 0.16:1).

[0044] The Sonogashira coupling reaction temperature of the carborane gas-induced color-changing luminescent material of the present invention is 70-90°C (e.g., 70°C, 75°C, 80°C, 85°C or 90°C), and the reaction time is 5-10h (e.g., 5h, 6h, 7h, 8h, 9h or 10h).

[0045] In a preferred embodiment of the method for preparing the carborane gas-chromic luminescent material of the present invention, the method for preparing 1-(4-halophenyl)-2-R-1,2-carborane includes the following steps: A. Preparing BrC6H4-C≡CR using p-bromoiodobenzene and RC≡CH; B. Reacting BrC6H4-C≡CR with a diacetonitrile decaborate complex to obtain 1-(4-halophenyl)-2-R-1,2-carborane (i.e., BrC6H4-C2B). 10 H 10 -R)(refer to Figure 3 (step 1 - step 2 in the text).

[0046] In a preferred embodiment of the method for preparing the carborane gas-induced color-changing luminescent material of the present invention, in step A, the molar ratio of p-bromoiodobenzene to RC≡CH is (1.0-1.1):1 (e.g., 1.0:1, 1.02:1, 1.04:1, 1.06:1, 1.08:1 or 1.1:1), the reaction solvent is a mixed solution of tetrahydrofuran and triethylamine, and the catalyst is bis(triphenylphosphine)palladium dichloride and cuprous iodide. More preferably, in step A, the volume ratio of tetrahydrofuran to triethylamine in the reaction solvent is (2-3):1 (e.g., 2:1, 2.2:1, 2.4:1, 2.6:1, 2.8:1 or 3:1), the molar equivalent ratio of bis(triphenylphosphine)palladium dichloride to RC≡CH is (0.01-0.02):1 (e.g., 0.01:1, 0.012:1, 0.014:1, 0.016:1, 0.018:1 or 0.02:1), and the molar equivalent ratio of cuprous iodide to RC≡CH is (0.02-0.04):1 (e.g., 0.02:1, 0.025:1, 0.03:1, 0.035:1 or 0.04:1).

[0047] In a preferred embodiment of the method for preparing the carborane gas-chromic luminescent material of the present invention, in step B, the molar equivalent ratio of the BrC6H4-C≡CR raw material to the diacetonitrile decaborate complex is 1:(1.0-1.2) (e.g., 1:1.0, 1:1.05, 1:1.1, 1:1.15 or 1:1.2); the synthesis reaction in step B is carried out under nitrogen protection, the solvent is anhydrous toluene, the reaction temperature is 100-120℃ (e.g., 100℃, 105℃, 110℃, 115℃ or 120℃), and the reaction time is 40-72h (e.g., 40h, 45h, 50h, 55h, 60h, 65h, 70h or 72h).

[0048] This invention also proposes a gas-chromic film. The raw materials or composition of the gas-chromic film in this embodiment include the carborane gas-chromic luminescent material and the carrier as described above. The carrier can be any one of non-woven fabric, filter paper, frosted glass, and silicone plate.

[0049] In a preferred embodiment of the gas-chromic film of the present invention, the film fabric is a non-woven fabric. The carborane gas-chromic luminescent material of the present invention exhibits strong adhesion and good film-forming properties on non-woven fabrics, allowing for more uniform distribution. Simultaneously, the non-woven fabric possesses good double-sided air permeability, resulting in a better response when VOCs gases come into contact with the gas-chromic film. Preferably, the dimensions of the non-woven fabric are: 3cm in length and 1cm in width.

[0050] The method for preparing the gas-chromic film of the present invention includes the following steps: immersing a carrier in a solution containing the carborane gas-chromic luminescent material as described above, and then removing and drying it to obtain the gas-chromic film of the present invention. Preferably, the carborane gas-chromic luminescent material is dispersed in a toluene solution, and the concentration of the carborane gas-chromic material is 4 mg / mL.

[0051] This invention also proposes a fluorescence sensor, which, according to embodiments of the invention, comprises the carborane gas-chromic luminescent material or the gas-chromic film described above. The working principle of the fluorescence sensor of this invention, that is, its application in the quantitative detection of gases (e.g., VOCs), is not based on classical fluorescence intensity changes, but rather on the emission wavelength shift caused by gas chromaticity. In other words, the fluorescence sensor of this invention can be used for the quantitative detection of gas (e.g., VOCs) concentration primarily because the maximum emission wavelength of the carborane gas-chromic luminescent material or the gas-chromic film it contains has a linear relationship with the gas (e.g., VOCs) concentration.

[0052] This invention also proposes a method for detecting gas concentration. The method for detecting gas concentration according to an embodiment of this invention includes the following steps: placing the fluorescence sensor described above in an environment containing the gas to be measured, detecting the emission wavelength of the fluorescence sensor, and thus detecting the gas to be measured; or,

[0053] The carrier is immersed in a solution containing the carborane gas-chromic luminescent material as described above, and dried to obtain a gas-chromic film. The gas-chromic film is placed in an environment containing the gas to be tested, and the emission wavelength of the gas-chromic film is detected to achieve the detection of the gas to be tested.

[0054] In a preferred embodiment of the method for detecting gas concentration of the present invention, the method further includes the steps of obtaining the linear relationship between the concentration and wavelength provided by the gas standard to be tested and / or calculating the concentration of the gas to be tested based on the linear relationship between the concentration and wavelength provided by the gas standard to be tested.

[0055] In a preferred embodiment of the method for detecting gas concentration of the present invention, the gas to be tested is VOCs.

[0056] In a preferred embodiment of the method for detecting gas concentration of the present invention, the gas to be tested includes any one of n-hexane, carbon tetrachloride, benzene, chloroform, ethyl acetate, tetrahydrofuran, triethylamine, acetone, and acetonitrile.

[0057] The carborane gas-induced color-changing luminescent material of the present invention, its preparation method, and its application are described in detail below through specific embodiments.

[0058] Example 1

[0059] The carborane gas-induced color-changing luminescent material in this embodiment is carborane I, the structural formula of which is detailed in [link to structural formula]. Figure 2 Compound I in the compound.

[0060] The specific preparation method of the carborane gas-induced color-changing luminescent material in this embodiment is as follows (refer to...). Figure 4 Preparation of "Carborane I" in China:

[0061] (1) 1-(4-iodophenyl)-2-n-butyl-1,2-carborane was prepared according to the method in Dalton Transactions (2019), 48(33), 12549-12559.

[0062] (2) Sonogashira coupling reaction

[0063] Weigh 0.67 g (3.2 mmol) of 2-ethynyl-dibenzothiophene and 1-(4-iodophenyl)-2-n-butyl-1,2-carborane (1.21 g (3 mmol)) into a 100 mL Schlenk reaction tube, add 20 mL of tetrahydrofuran and 10 mL of triethylamine and stir to dissolve.

[0064] Assemble the condenser tube in the reaction tube and place it in an alcohol coolant at -80°C. Use a diaphragm pump to evacuate the solution until no obvious bubbles escape. Then, purge with nitrogen.

[0065] Tetra(triphenylphosphine)palladium (0.17 g, 0.15 mmol) and cuprous iodide (0.057 g, 0.30 mmol) were added under nitrogen protection, and the reaction mixture was slowly heated to 80 °C and kept under reflux for 5 hours.

[0066] After cooling to room temperature, the reaction mixture was transferred to a spherical flask, and the solvent was removed by rotary evaporation. The solid residue was subjected to alkaline alumina column chromatography with petroleum ether / benzene (3 / 1 v / v) as the eluent to separate the crude carborane I product. The crude product was then washed with methanol to give 0.95 g of a white solid.

[0067] The NMR characterization results of the product carborane I are as follows:

[0068] 1 H NMR (400MHz, CDCl3): δ (ppm) 8.32 (s, 1H), 8.18 ~ 8.13 (m, 1H), 7.88 ~ 7.81 (m, 2H), 7.64 ~ 7.58 (m, 3H), 7.58 ~ 7.54 (m, 2H) ,7.51~7.45(m,2H),3.5~1.5(br,10H),1.77(t,J=8Hz,2H),1.42~1.32(m,2H),1.15~1.04(m,2H),0.75(t,J=7Hz,3H). 13C NMR (101MHz, CDCl3): δ (ppm) 140.10, 139.71, 135.69, 134.77, 131.77, 131.10, 130.41, 129.68, 127.26, 125.9 1,124.86,124.71,122.87,122.85,121.70,118.55,92.52,87.81,82.99,82.75,34.79,31.51,22.10,13.49. 11 B NMR (128MHz, CDCl3): δ (ppm) -3.67 (2B), -10.23 (8B).

[0069] The mass spectrometric characterization results of the product carborane I are as follows:

[0070] HRMS: m / z theoretical [M+H] 482.3084, measured 482.3066.

[0071] Example 2

[0072] The carborane luminescent material in this embodiment is carborane II, the structural formula of which is detailed in [link to structural formula]. Figure 2 Compound II in the compound.

[0073] The preparation method of the carborane luminescent material in this embodiment (refer to...) Figure 4 The preparation of "Carborane II" includes the following steps:

[0074] (1) Sonogashira coupling reaction one:

[0075] 9,9-Dibutyl-2-acetylene-9H-fluorene was prepared according to the method provided in the literature Chemistry-A European Journal (2020), 26(53), 12150-12157. 4.53 g (16 mmol) of p-bromoiodobenzene and 4.54 g (15 mmol) of 9,9-dibutyl-2-acetylene-9H-fluorene were weighed and dissolved in a 100 mL Schlenk reaction tube. 30 mL of tetrahydrofuran and 10 mL of triethylamine were added to dissolve them.

[0076] Assemble the condenser tube in the reaction tube and place it in ethanol coolant at -80°C. Use a diaphragm pump to evacuate the solution until no obvious bubbles escape. Then, purge with nitrogen.

[0077] Under nitrogen protection, palladium dichloride (0.14 g, 0.2 mmol) and cuprous iodide (0.076 g, 0.4 mmol) were added, and the reaction mixture was slowly heated to 80 °C and kept under reflux for 3 h.

[0078] After cooling to room temperature, the reaction mixture was transferred to a round-bottom flask, and the solvent was removed by rotary evaporation. The solid residue was subjected to silica gel column chromatography with petroleum ether as the eluent to separate the crude product. The crude product was then washed with methanol to give 5.77 g of 2-((4-bromophenyl)ethynyl)-9,9-dibutyl-9H-fluorene.

[0079] The NMR characterization results of the product (2-((4-bromophenyl)ethynyl)-9,9-dibutyl-9H-fluorene) are as follows:

[0080] 1 H NMR (400MHz, CDCl3): δ (ppm) 7.72 ~ 7.68 (m, 1H), 7.67 (d, J = 8.5Hz, 1H), 7.50 (tt, J1 = 7Hz, J2 = 1.7Hz, 4H), 7.42 (dt, J 1=8.5Hz,J2=1.7Hz,2H),7.36~7.30(m,3H),1.97(t,J=8.5Hz,4H),1.07(m,4H),0.66(t,J=7.5Hz,6H),0.58(m,4H). 13 C NMR (101MHz, CDCl3): δ (ppm): 150.98, 150.76, 141.67, 140.29, 132.94, 131.61, 130.59, 127.59, 126.88, 1 25.89,122.86,122.38,122.31,120.95,120.01,119.66,91.67,88.27,55.03,40.18,25.87,23.04,13.81.

[0081] The mass spectrometric characterization results of the product (2-((4-bromophenyl)ethynyl)-9,9-dibutyl-9H-fluorene) are as follows:

[0082] HRMS: Theoretical m / z [M+H] 457.1531, measured 457.1525.

[0083] Preparation of 1-(4-bromophenyl)-2-(2-9,9-dibutyl-9H-fluorene)-1,2-carborane by boron cluster addition reaction:

[0084] Weigh out 5.00 g (11 mmol) of 2-((4-bromophenyl)ethynyl)-9,9-dibutyl-9H-fluorene and B 10 H 12 (CH3CN)2 (2.43 g, 12 mmol) was added to a 100 mL dry reaction tube, and nitrogen gas was introduced after evacuation.

[0085] Add 30 mL of freshly distilled anhydrous toluene under nitrogen protection, connect a condenser, mix the reactants and heat to 110 °C, and continue the reaction for 48 hours.

[0086] After the reactants have cooled to room temperature, 1 mL of methanol is added and the mixture is stirred for 1 minute. Then, the solvent is removed by rotary evaporation to obtain the crude product.

[0087] The crude product solid was separated by silica gel column chromatography, and after removing the solvent by vacuum distillation with petroleum ether as the eluent, 3.90 g of colorless oily 1-(4-bromophenyl)-2-(2-9,9-dibutyl-9H-fluorene)-1,2-carborane was obtained.

[0088] The NMR characterization results of 1-(4-bromophenyl)-2-(2-9,9-dibutyl-9H-fluorene)-1,2-carborane are as follows:

[0089] 1 H NMR (400MHz, CDCl3): δ (ppm) 7.63 ~ 7.58 (m, 1H), 7.47 ~ 7.39 (m, 2H), 7.37 (d, J = 1Hz, 1H), 7.33 ~ 7.26 (m, 5H), 7.20 (d ,J=8.5Hz,2H),4.0~1.6(br,10H),1.92~1.76(m,4H),1.07~0.94(m,4H),0.65(t,J=7.5Hz,6H),0.50~0.19(m,4H). 11 C NMR (101MHz, CDCl3): δ (ppm) 151.24, 150.83, 143.38, 139.28, 132.01, 131.39, 130.03, 129.87, 128.84, 12 8.18,127.02,125.09,125.03,122.95,120.39,119.41,86.54,84.31,55.04,39.74,25.75,22.88,13.79. 11 B NMR (128MHz, CDCl3): δ (ppm) -2.11 (2B), -9.08, -10.24 (8B).

[0090] The mass spectrometric characterization results of 1-(4-bromophenyl)-2-(2-9,9-dibutyl-9H-fluorene)-1,2-carborane are as follows:

[0091] HRMS: m / z theoretical [M+H] 574.3261, measured 574.3233.

[0092] (2) Sonogashira coupling reaction to prepare carborane II:

[0093] Weigh 0.60 g (2.9 mmol) of 2-ethynyl-dibenzothiophene and 1-(4-bromophenyl)-2-(2-9,9-dibutyl-9H-fluorene)-1,2-carborane (1.38 g (2.4 mmol) into a 100 mL Schlenk reaction tube, and add 20 mL of tetrahydrofuran and 10 mL of triethylamine to dissolve them.

[0094] Assemble the condenser tube in the reaction tube and cool it in ethanol coolant at -80°C. Use a diaphragm pump to evacuate the solution until no obvious bubbles escape. Then purge with nitrogen.

[0095] Tetraphenylphosphine palladium (0.18 g, 0.16 mmol) and cuprous iodide (0.076 g, 0.4 mmol) were added under nitrogen protection, and the reaction mixture was slowly heated to 80 °C and kept under reflux for 5 hours.

[0096] After cooling to room temperature, the reaction mixture was transferred to a round-bottom flask, and the solvent was removed by rotary evaporation. The solid residue was subjected to silica gel column chromatography, using petroleum ether / benzene (3 / 1 v / v) as the eluent to separate the crude product. After washing with methanol, carborane II, 1.48 g, was obtained.

[0097] The NMR characterization results of the product (carborane II) are as follows:

[0098] 1 H NMR (400MHz, CDCl3): δ (ppm) 8.19 (s, 1H), 8.12 ~ 8.06 (m, 1H), 7.85 ~ 7.80 (m, 1H), 7.76 (d, J = 8Hz, 1H), 7.63 ~ 7.58 (m, 1H), 7 .49~7.39(m,8H),7.30~7.25(m,5H),3.8~1.6(br,10H),1.86(m,4H),1.05(m,4H),0.70(t,J=7Hz,6H),0.5~0.25(m,4H). 13 C NMR (101MHz, CDCl3): δ (ppm) 151.19,150.71,143.24,139.89,139.64,139.31,13 5.57,134.73,131.12,130.53,130.44,129.90,129.53,128.92,128.09,127.18,1 26.95, 125.40, 124.97, 124.69, 124.65, 122.90, 122.82, 122.74, 121.63, 120.34, 119.34, 118.57, 92.23, 87.83, 86.64, 84.88, 55.01, 39.80, 25.74, 22.94, 13.85.11 B NMR (128MHz, CDCl3): δ (ppm) -2.09 (2B), -10.32 (8B).

[0099] The mass spectrometry characterization results of the product (carborane II) are as follows:

[0100] HRMS: m / z theoretical [M+H] 703.4319, measured 703.4311.

[0101] Example 3

[0102] The carborane luminescent material in this embodiment is carborane III, and its structural formula is as follows: Figure 2 Compound III in the compound.

[0103] The preparation method of the carborane luminescent material in this embodiment (refer to...) Figure 4 The preparation of "Carborane III" includes the following steps:

[0104] (1) 1-[2-(4-bromophenyl)ethynyl]-3,5-bis(1,1-dimethylethyl)-benzene was prepared according to the method provided in the Journal of Materials Chemistry C:Materials for Optical and Electronic Devices (2015), 3(3), 521-529.

[0105] (2) Addition reaction of boron clusters

[0106] 1-[2-(4-bromophenyl)ethynyl]-3,5-bis(1,1-dimethylethyl)benzene (3.70 g, 10 mmol) and B 10 H 12 (CH3CN)2 (2.23 g, 11 mmol) was added to a 100 mL dry reaction tube, and nitrogen gas was introduced after evacuation.

[0107] Add 30 mL of freshly distilled anhydrous toluene under nitrogen protection, connect a condenser, mix the reactants and heat to 110 °C, and continue the reaction for two days.

[0108] After the reactants have cooled to room temperature, 1 mL of methanol is added and the mixture is stirred for 1 minute. Then, the solvent is removed by rotary evaporation to obtain the crude product.

[0109] The crude product solid was separated by silica gel column chromatography. Petroleum ether was used as the eluent, and the solvent was removed by vacuum distillation to obtain a colorless oily substance, denoted as 1-(4-bromophenyl)-2-(3,5-di-tert-butylphenyl)-1,2-carborane, 3.38 g.

[0110] The NMR characterization results of 1-(4-bromophenyl)-2-(3,5-di-tert-butylphenyl)-1,2-carborane are as follows:

[0111] 1 H NMR (400MHz, CDCl3): δ (ppm) 7.44 (d, J = 8.5Hz, 2H), 7.27 (t, J = 1Hz, 1H), 7.17 (t, J = 1Hz, 2H), 7.07 (d, J = 8.5Hz, 2H), 3.9 ~ 1.6 (br, 10H), 1.17 (s, 18H). 13 C NMR (101Hz, CDCl3): δ (ppm) 150.77, 137.23, 132.11, 130.76, 129.22, 125.01, 123.89, 96.84, 86.11, 83.75, 34.80, 31.12. 11 B NMR (128Hz, CDCl3): δ (ppm) -2.48 (2B), -10.41 (8B).

[0112] The mass spectrometric characterization results of 1-(4-bromophenyl)-2-(3,5-di-tert-butylphenyl)-1,2-carborane are as follows:

[0113] HRMS: m / z theory [M+H]C 22 H 35 B 10 Br 487.2922, measured 487.2903.

[0114] (3) Sonogashira Coupling Reaction II: Preparation of Carborane III

[0115] Weigh 0.73 g (3.5 mmol) of 2-ethynyl-dibenzothiophene and 1-(4-bromophenyl)-2-(3,5-di-tert-butylphenyl)-1,2-carborane (1.56 g (3.2 mmol)) into a 100 mL Schlenk reaction tube, and add 20 mL of tetrahydrofuran and 10 mL of triethylamine to dissolve them.

[0116] Assemble the condenser tube in the reaction tube and cool it in ethanol coolant at -80°C. Use a diaphragm pump to evacuate the solution until no obvious bubbles escape. Then purge with nitrogen.

[0117] Tetraphenylphosphine palladium (0.18 g, 0.16 mmol) and cuprous iodide (0.076 g, 0.4 mmol) were added under nitrogen protection, and the reaction mixture was slowly heated to 80 °C and kept under reflux for 5 hours.

[0118] After cooling to room temperature, the reaction mixture was transferred to a spherical flask, and the solvent was removed by rotary evaporation. The solid residue was subjected to silica gel column chromatography, using petroleum ether / benzene (3 / 1 v / v) as the eluent to separate the crude product. Recrystallization from petroleum ether yielded carborane III, a white powder, 1.48 g.

[0119] The NMR characterization results of carborane III are as follows:

[0120] 1 H NMR (500MHz, CDCl3): δ (ppm) 8.26 (s, 1H), 8.13 (m, 1H), 7.84 (m, 1H), 7.79 (d, J = 8.5Hz, 1H), 7.53 (dd, J1 = 8.5 Hz, J2=1.5Hz,1H),7.47(m,2H),7.37(d,J=8.5Hz,2H),7.32~7.22(m,5H),3.8~1.6(br,10H),1.18(s,18H). 13 CNMR (126MHz, CDCl3): δ (ppm) 150.72, 139.98, 139.71, 135.66, 134.78, 131.05, 130.62, 130.56, 129.66, 129.37, 127.2 4,125.24,125.15,124.80,124.70,123.85,122.88,122.81,121.68,118.62,91.95,87.89,86.54,84.39,34.83,31.17. 11 B NMR: δ(ppm)-3.07(2B),-10.96(8B).

[0121] The mass spectrometry characterization results of carborane III are as follows: HRMS: theoretical m / z [M+H] 614.4028, measured 614.4021.

[0122] Example 4

[0123] The gas-chromic membrane of this embodiment is prepared by dissolving carborane I-III in toluene to form a mixed solvent of 4 mg / mL (concentration of carborane I-III). The nonwoven fabric (the size of the nonwoven fabric strip is 3 cm long and 1 cm wide) is immersed in the mixed solvent. After complete immersion, it is removed and the solvent is allowed to evaporate completely to obtain the carborane I gas-chromic membrane, carborane II gas-chromic membrane and carborane III gas-chromic membrane of this embodiment.

[0124] Experimental Example 1

[0125] 1. Observe the carborane I, carborane II, and carborane III gas-induced color-changing films under no UV light excitation and under 365nm UV light excitation, respectively:

[0126] Observation results as follows Figure 5 As shown:

[0127] Figure 5 In the image, IA is a photograph of the carborane I gas-induced color-changing film without UV excitation, and IB is a photograph of the carborane I gas-induced color-changing film excited under 365nm UV light.

[0128] II-A is a photograph of the carborane II gas-induced color-changing film under no UV excitation. II-B is a photograph of the carborane II gas-induced color-changing film excited under 365nm UV light.

[0129] III-A is a photograph of the carborane III gas-induced color-changing film under no UV light excitation, and III-B is a photograph of the carborane III gas-induced color-changing film under 365nm UV light excitation.

[0130] Experimental Example 2

[0131] The carborane III gas-induced color-changing membrane from Example 4 was placed in a sealed cuvette (4.8 mL) containing air and 4 μL of vapor generated from different liquid VOCs. VOC testing was performed under 365 nm UV excitation, and the results are attached. Figure 6 As shown.

[0132] Depend on Figure 6 It can be seen that the carborane III gas-induced color-changing membrane has a certain response to different VOC gases, and the response effects are different.

[0133] Experimental Example 3

[0134] The carborane III gas-induced color-changing film (prepared in Example 4) was subjected to VOCs testing under different concentrations of tetrahydrofuran and benzene. We used a Shimadzu UV-2600 spectrometer, excited under 350 nm ultraviolet light, and performed fluorescence emission spectral scanning. The resulting spectra are shown in the attached figure. Figure 7 As shown ( Figure 7 A shows the emission spectra of the carborane III gas-induced color-changing film under different concentrations of tetrahydrofuran atmosphere. Figure 7 B shows the emission spectra of the carborane III gas-induced color-changing film under benzene atmospheres of different concentrations.

[0135] We obtained a linear relationship between the emission wavelength of the carborane III gas-induced color-changing film at different gas concentrations by fitting the data, such as... Figure 8 As shown.

[0136] ( Figure 8 A represents the linear relationship between emission wavelength and atmosphere concentration under different concentrations of tetrahydrofuran atmosphere. Figure 8 B. Linear relationship between emission wavelength and atmosphere concentration under different concentrations of benzene atmosphere.

[0137] in Figure 8 A is present at a tetrahydrofuran concentration of 89-890 g / m³. 3 The linear relationship equation at concentration is:

[0138] C = -2500.71 * E PM +6223.13;

[0139] In the above formula, C represents the concentration of tetrahydrofuran, in g / m³. 3 E pM E represents the energy value corresponding to the spectral wavelength at which the measured intensity reaches its maximum in the spectrum. PM =1240 / λ M .

[0140] in Figure 8 B is present when the benzene concentration is 88-704 g / m³. 3 The linear relationship equation at concentration is:

[0141] C = -2333.23 * E PM +5842.25;

[0142] After obtaining the linear equation between concentration and wavelength, we can use a fluorescence detector to read the emission wavelength of the carborane III gas-induced color-changing film under different VOC atmospheres to determine the concentration of VOCs gas in the environment.

[0143] Experiment Example 4

[0144] The carborane II gas-induced color-changing film (prepared in Example 4) was subjected to VOCs testing under different concentrations of tetrahydrofuran. Using a Shimadzu UV-2600 spectrometer, excitation was performed under 350 nm ultraviolet light, and fluorescence emission spectroscopy was scanned. The resulting spectra are shown below. Figure 9 As shown in Figure A.

[0145] We obtained a linear relationship between the emission wavelength of the carborane II gas-induced color-changing film at different gas concentrations by fitting the data, such as... Figure 9 As shown in B.

[0146] in Figure 9 B is present at a tetrahydrofuran concentration of 89-712 g / m³. 3 The linear relationship equation at concentration is:

[0147] C = -3377.77 * E PM+8236.47;

[0148] After obtaining the linear relationship between concentration and wavelength, we can use a fluorescence detector to read the emission wavelength of the carborane II gas-induced color-changing film under different VOC atmospheres to determine the concentration of VOCs gas in the environment.

[0149] Experimental Example 5

[0150] The carborane I gas-induced color-changing film (prepared in Example 4) was subjected to VOCs testing under different concentrations of tetrahydrofuran. Using a Shimadzu UV-2600 spectrometer, excitation was performed under 350 nm ultraviolet light, and fluorescence emission spectroscopy was scanned. The resulting spectra are shown below. Figure 10 As shown in Figure A.

[0151] We obtained a linear relationship between the emission wavelengths of the carborane I gas chromatic film at different tetrahydrofuran concentrations and the concentration, such as... Figure 10 As shown in B.

[0152] in Figure 10 B is present at a tetrahydrofuran concentration of 89-712 g / m³. 3 The following linear relationship equation is:

[0153] C = -2982.58 * E PM +7371.45;

[0154] After obtaining the linear equation between concentration and wavelength, we can use a fluorescence detector to read the emission wavelength of the carborane I gas chromogenic film under different VOC atmospheres to determine the concentration of VOC gas in the environment.

[0155] The above description is merely a preferred embodiment of the present invention and is not intended to limit the invention. Various modifications and variations can be made to the present invention by those skilled in the art. Any modifications, equivalent substitutions, improvements, etc., made within the spirit and principles of the present invention should be included within the scope of protection of the present invention.

Claims

1. A carborane gas-induced color-changing luminescent material, characterized in that, The structural formula of the carborane gas-induced color-changing luminescent material is: ； Wherein, R is an alkyl, dialkylfluorenyl, or dialkylphenyl; the alkyl group in the alkyl, dialkylfluorenyl, and dialkylphenyl groups has 1-4 carbon atoms.

2. The carborane gas-induced color-changing luminescent material according to claim 1, characterized in that, R is butyl, dibutylfluorenyl, or di-tert-butylphenyl.

3. The method for preparing the carborane gas-induced color-changing luminescent material according to claim 1 or 2, characterized in that, Includes the following steps: and The carborane gas-induced color-changing luminescent material was prepared by undergoing a Sonogashira coupling reaction.

4. The method for preparing the carborane gas-induced color-changing luminescent material according to claim 3, characterized in that, The and The molar ratio is 1:(1.0-1.2); The catalyst for the Sonogashira coupling reaction comprises tetra(triphenylphosphine)palladium and cuprous iodide, wherein the tetra(triphenylphosphine)palladium and... The molar equivalent ratio is (0.05-0.08):1; the cuprous iodide and The molar equivalent ratio is (0.1-0.16):1; The Sonogashira coupling reaction is carried out at a temperature of 70-90℃ for 5-10 hours. The reaction solvent for the Sonogashira coupling reaction is a mixed solution of tetrahydrofuran and triethylamine, with a volume ratio of (2-3):

1.

5. The method for preparing the carborane gas-induced color-changing luminescent material according to claim 3, characterized in that, The The preparation method includes the following steps: A. Using p-bromoiodobenzene and preparation ; B. The reaction with the diacetonitrile decaborate complex yields .

6. A gas-induced color-changing film, characterized in that, The raw materials or components of the gas-induced color-changing film include the carborane gas-induced color-changing luminescent material and carrier as described in claim 2.

7. The gas-induced color-changing film according to claim 6, characterized in that, The carrier is non-woven fabric.

8. A fluorescence sensor, wherein the raw material of the fluorescence sensor comprises a carborane gas-chromic luminescent material as described in any one of claims 1-2 or a gas-chromic film as described in any one of claims 6-7.

9. A method for detecting gas concentration, characterized in that, Includes the following steps: The fluorescence sensor as described in claim 8 is placed in an environment containing the gas to be measured, and the emission wavelength of the fluorescence sensor is detected to achieve the detection of the gas to be measured; or, The carrier is immersed in a solution containing the carborane gas-chromic luminescent material as described in claim 2, and dried to obtain a gas-chromic film. The gas-chromic film is then placed in an environment containing the gas to be tested to achieve the detection of the gas to be tested.

10. The method for detecting gas concentration according to claim 9, characterized in that, It also includes the steps of obtaining the linear relationship between the concentration and wavelength provided by the gas standard to be tested and calculating the concentration of the gas to be tested based on the linear relationship between the concentration and wavelength provided by the gas standard to be tested; The gas to be tested is VOCs.

11. The method for detecting gas concentration as described in claim 10, characterized in that, The gas to be tested is any one of n-hexane, carbon tetrachloride, benzene, chloroform, ethyl acetate, tetrahydrofuran, triethylamine, acetone, and acetonitrile.

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