Compound, gas sensor material comprising the same, and method for detecting hydrazine or aldehydes using the same

Abstract

To provide a novel compound that can also be used as a gas sensor material.SOLUTION: The present invention is a compound represented by the following general formula (1). A detection target of the compound is aldehydes or hydrazine, and the fluorescence of the compound changes upon exposure thereto. Accordingly, the presence of the detection target can be notified with visually recognizable information. In the general formula (1), each of R1 and R2 is independently a hydrogen atom, an aryl group, a cyano group, a nitro group, a carboxyl group, -(C=O)O-RE, or -O(C=O)-RE; Ra is a hydrogen atom or a C1-10 alkyl group; each R is independently a C1-10 alkyl group; X is -CHO or -CH(NH2)CH2CH=CH2; and each RE is independently a monovalent group.SELECTED DRAWING: Figure 1

Description

[Technical Field]

[0001] The present invention relates to a compound, a gas sensor material comprising the compound, and a method for detecting hydrazine or aldehydes using the compound. [Background technology]

[0002] Gas sensors that detect specific gaseous compounds contained in the air are widely used. Semiconductor-type gas sensors that use metal oxides as their detection sites are widely used, and examples include nitrogen oxide gas sensors (see, for example, Patent Document 1) and ethyl alcohol gas sensors in breath (see, for example, Patent Document 2). These semiconductor-based gas sensors use electrochemical techniques and are highly sensitive, but tend to have problems with power sources and installation locations. Furthermore, many of these gas sensors indicate the presence of a target substance in the form of numerical data, making it difficult to intuitively determine its presence.

[0003] Under these circumstances, the present inventors have proposed the use of organic fluorescent materials as sensors for acidic gases and ammonia (see Patent Documents 3 and 4). These organic fluorescent materials are made of conjugated compounds and have fluorescence, and when exposed to acidic gases or ammonia, they change the color tone and intensity of their fluorescence, making them useful for detecting the presence of these gases by intuitive visual inspection without requiring any dedicated equipment. [Prior art documents] [Patent documents]

[0004] [Patent Document 1] Special Publication No. 2012-504237 [Patent Document 2] Japanese Patent Application Laid-Open No. 2009-025113 [Patent Document 3] Japanese Patent Application Publication No. 2018-076251 [Patent Document 4] Japanese Patent Publication No. 2021-143140 Summary of the Invention [Problem to be solved by the invention]

[0005] The present invention has been made in view of the above circumstances, and an object of the present invention is to provide a novel compound that can also be used as a gas sensor material. [Means for solving the problem]

[0006] The present inventors have conducted extensive research to solve the above problems and have found that an organic fluorescent compound represented by the following general formula (1) can detect aldehydes and hydrazine and change its fluorescence, thereby completing the present invention. Specifically, the present invention provides the following:

[0007] (1) The present invention is a compound represented by the following general formula (1): [ka] (In general formula (1), each R 1 and R 2 are each independently a hydrogen atom, an aryl group, a cyano group, a nitro group, a carboxy group, or -(C=O)OR E or -O(C=O)-R E and R a is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, each R is independently an alkyl group having 1 to 10 carbon atoms, X is -CHO or -CH(NH2)CH2CH=CH2, and each R E are each independently a monovalent group, each m is independently an integer of 0 to 4, and n is an integer of 1 to 4.

[0008] (2) The present invention also provides a compound according to item (1), which is represented by the following general formula (1a): [ka] (In general formula (1a), R 1 and R 2are each independently a hydrogen atom, an aryl group, a cyano group, a nitro group, a carboxy group, or -(C=O)OR E or -O(C=O)-R E and R 3 represents a cyano group, a nitro group, a carboxy group, -(C=O)OR E or -O(C=O)-R E wherein each R is independently an alkyl group having 1 to 10 carbon atoms, X is -CHO or -CH(NH2)CH2CH=CH2, and each R E are each independently a monovalent group, and each m is independently an integer of 0 to 4.

[0009] (3) The present invention also relates to a compound according to item (1) or (2), which is represented by the following general formula (1b): [ka] (In general formula (1b), R 1 and R 2 are each independently a hydrogen atom, an aryl group, a cyano group, a nitro group, a carboxy group, or -(C=O)OR E or -O(C=O)-R E and R 3 represents a cyano group, a nitro group, a carboxy group, -(C=O)OR E or -O(C=O)-R E wherein each R is independently an alkyl group having 1 to 10 carbon atoms, X is -CHO or -CH(NH2)CH2CH=CH2, and each R E are each independently a monovalent group, and each m is independently an integer of 0 to 4.

[0010] (4) The present invention also provides a compound according to any one of items (1) to (3), which is represented by the following general formula (1c): [ka] (In general formula (1c), X is —CHO or —CH(NH)CHCH═CH.)

[0011] (5) The present invention also provides a gas sensor material for detecting hydrazine, which comprises a compound represented by the following chemical formula (1c-A): [ka]

[0012] (6) The present invention also provides a gas sensor material for detecting aldehydes, which comprises a compound represented by the following chemical formula (1c-B): [ka]

[0013] (7) The present invention also provides a method for detecting hydrazine or aldehydes, which comprises exposing a gas to be measured to a gas sensor containing the compound according to any one of (1) to (4) and observing a change in fluorescence of the compound. [Effects of the Invention]

[0014] According to the present invention, a novel compound is provided which can also be used as a gas sensor material. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 is a spectrum showing the change in fluorescence wavelength when TPR-NH2, one of the compounds of the present invention, is exposed to aldehyde gas. [Figure 2] FIG. 2 is a spectrum showing the change in fluorescence wavelength when TPR-CHO, one of the compounds of the present invention, is exposed to hydrazine gas. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, an embodiment of the compound of the present invention, an embodiment of the gas sensor material for detecting hydrazine, an embodiment of the gas sensor material for detecting aldehydes, and an embodiment of the method for detecting hydrazine or aldehydes will be described. Note that the present invention is not limited to the following embodiments and implementations, and can be practiced with appropriate modifications within the scope of the present invention.

[0017] <Compound> First, one embodiment of the compound of the present invention will be described. The compound of the present invention is a π-conjugated compound represented by the following general formula (1), which emits fluorescence upon irradiation with ultraviolet light. When aldehydes or hydrazines are present in the vicinity, this compound bonds with them and changes the color tone of the fluorescence. Here, aldehydes are known as everyday malodorous substances, such as isovaleric aldehyde and nonenal, as well as health hazards, such as formaldehyde, which is a causative agent of sick building syndrome. Hydrazine is used as rocket fuel, but leakage poses a risk of explosion and is known to be harmful to the human body. When coated as a thin film on a substrate, the compound of the present invention detects the presence of these aldehydes or hydrazines in the form of a change in fluorescence and notifies their presence as visible information.

[0018] [ka]

[0019] In general formula (1), X is -CHO or -CH(NH2)CH2CH=CH2. When X is -CHO, the compound of the present invention detects hydrazine and changes its fluorescence. When X is -CH(NH2)CH2CH=CH2, the compound of the present invention detects aldehydes and changes its fluorescence. In either case, the electronic state of the π-conjugated system changes when the aldehyde or hydrazine to be detected binds to the substituent represented by X, and this change in electronic state can be visually perceived as a change in the color tone of the fluorescence. The chemical change that occurs is shown below. For ease of explanation, an example in which X is bonded to the para position of the benzene ring is shown below, but the position at which X is bonded is not limited to this. In general formula (1), the n double bonds are expressed as trans-type, but the double bonds may also be cis-type. This also applies to the general formulas described below.

[0020] [ka]

[0021] As described above, the electronic state of the π-conjugated system changes when -CHO or -CH(NH2)CH2CH=CH2, which is the substituent represented by X, binds to an aldehyde or hydrazine. Therefore, X may be bound to any substitution position of the benzene ring, which is one of the elements forming the π-conjugated system. Note that this chemical reaction is irreversible, so once the compound of the present invention binds to the target substance and changes its fluorescence, the fluorescence remains changed even if the target substance is removed from the surroundings.

[0022] In general formula (1), each R 1 and R 2 are each independently a hydrogen atom, an aryl group, a cyano group, a nitro group, a carboxy group, or -(C=O)OR E or -O(C=O)-R E "Each R 1 and R 2 "R" is determined by the value of n, which is the number of repeating units. 1 or R2 There will be multiple instances of each, but each of the multiple R 1 or R 2 is determined independently. In this case, each R 1 may be the same or different from each other, and each R 2 may be the same or different from each other. This also applies to other parts of this specification. E are each independently a monovalent group. Examples of such groups include a hydrogen atom and monovalent organic groups. Examples of monovalent organic groups include alkyl groups having 1 to 10 carbon atoms, aryl groups, and aralkyl groups.

[0023] R a is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms. Each R is independently an alkyl group having 1 to 10 carbon atoms. These alkyl groups may be branched. Examples of such alkyl groups include a methyl group, an ethyl group, a propyl group, an isopropyl group, a butyl group, a pentyl group, a hexyl group, a 2-ethylhexyl group, an octyl group, and a decyl group.

[0024] Each m is independently an integer of 0 to 4. Of these, m is preferably 0. Furthermore, n is an integer of 1 to 4. Of these, n is preferably 2.

[0025] More specifically, the compound represented by the general formula (1) above includes a compound represented by the following general formula (1a): In the following general formula (1a), n in the general formula (1) is specified to be 2.

[0026] [ka]

[0027] In general formula (1a), R 1 and R 2 each independently represents a hydrogen atom, an aryl group, a cyano group, a nitro group, a carboxy group, or -(C=O)ORE or -O(C=O)-R E Among these, R 1 and R 2 are preferably hydrogen atoms. In general formula (1a), each R, each m, and each X are the same as R, m, and X in general formula (1). E are each independently a monovalent group. Examples of such groups include a hydrogen atom and monovalent organic groups. Examples of monovalent organic groups include alkyl groups having 1 to 10 carbon atoms, aryl groups, and aralkyl groups.

[0028] In general formula (1a), R 3 represents a cyano group, a nitro group, a carboxy group, -(C=O)OR E or -O(C=O)-R E R 3 R is preferably an electron-withdrawing group, and a cyano group is particularly preferred. E is a monovalent group. Examples of such groups include a hydrogen atom and monovalent organic groups. Examples of monovalent organic groups include alkyl groups having 1 to 10 carbon atoms, aryl groups, and aralkyl groups.

[0029] More specifically, the compound represented by the general formula (1a) above includes a compound represented by the following general formula (1b): In the general formula (1b), the bonding position of the substituent represented by X on the benzene ring is specified relative to the general formula (1a).

[0030] [ka]

[0031] In general formula (1b), R 1 , R 2 , R 3 , R, X and m are the same as those in general formula (1a).

[0032] A more specific example of the compound represented by the above general formula (1b) is the compound represented by the following general formula (1c): It goes without saying that the compounds of the present invention are not limited to this.

[0033] [ka]

[0034] In general formula (1c), X is the same as X in general formula (1). That is, X is selected from -CHO and -CH(NH2)CH2CH=CH2, and when X is -CHO, the compound represented by general formula (1c) detects hydrazine present in its vicinity and changes its fluorescence, and when X is -CH(NH2)CH2CH=CH2, the compound represented by general formula (1c) detects aldehydes present in its vicinity and changes its fluorescence.

[0035] The following scheme can be shown as an example of a route for synthesizing the compound of the present invention. In the scheme below, the compound represented by "TPE-CHO" corresponds to the compound in which X is -CHO in the above general formula (1), and the compound represented by "TPE-NH" corresponds to the compound in which X is -CH(NH)CHCH=CH. In the scheme below, the compounds represented by "TPE-CHO" and "TPE-NH" are examples of the present invention, and the present invention is not limited to these compounds. In the scheme below, the compound represented by "Pd(dppf)Cl" is [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II), the compound represented by "NaOMe" is sodium methoxide, the compound represented by "THF" is tetrahydrofuran, the compound represented by "MeOH" is methanol, and the compound represented by "EtOH" is ethanol.

[0036] [ka]

[0037] <Gas sensor material for hydrazine detection> The present invention also includes a gas sensor material for detecting hydrazine, which is one of the compounds of the present invention, and is represented by the following chemical formula (1c-A):

[0038] [ka]

[0039] The compound represented by chemical formula (1c-A) is a compound in which X in the above general formula (1) is -CHO, and as already explained, the fluorescence of this compound changes when hydrazine binds to this -CHO group. Therefore, the compound represented by chemical formula (1c-A) can be used as a gas sensor material that notifies the presence of hydrazine as visual information, namely, a change in fluorescence.

[0040] Specifically, the compound represented by chemical formula (1c-A) can be dissolved in an appropriate solvent, and then coated on a substrate and dried to form a thin film, which can then be used as a highly sensitive hydrazine gas sensor.

[0041] <Gas sensor material for detecting aldehydes> The present invention also includes a gas sensor material for detecting aldehydes, which is one of the compounds of the present invention and is represented by the following chemical formula (1c-B):

[0042] [ka]

[0043] The compound represented by chemical formula (1c-B) is a compound in which X in the above general formula (1) is -CH(NH2)CH2CH=CH2, and as already explained, the fluorescence of this compound changes when aldehydes bind to this -CH(NH2)CH2CH=CH2 group. Therefore, the compound represented by chemical formula (1c-B) can be used as a gas sensor material that notifies the presence of aldehydes as visual information, namely, a change in fluorescence.

[0044] Specifically, the compound represented by chemical formula (1c-B) can be dissolved in an appropriate solvent, and then coated on a substrate and dried to form a thin film, which can then be used as a highly sensitive hydrazine gas sensor.

[0045] In the present invention, aldehydes refer to compounds that have a formyl group and can be gasified at room temperature. Such compounds can cause unpleasant odors and health problems, so the gas sensor material of the present invention, which can detect these compounds in the air, is useful. Examples of such aldehydes include formaldehyde, acetaldehyde, isovaleric aldehyde, and nonanal.

[0046] <Method for detecting hydrazine or aldehyde> The present invention also includes a method for detecting hydrazine or aldehyde, which comprises exposing a gas to be measured to a gas sensor containing the compound of the present invention and observing a change in the fluorescence of the compound. As this method has already been described, further description will be omitted here. [Example]

[0047] The present invention will be described in more detail below with reference to examples, but the present invention is not limited to these examples. The compound numbers shown in the chemical reaction formulas shown in the following synthesis examples correspond to the compound numbers shown in the synthesis scheme of the compounds of the present invention.

[0048] Synthesis of 2-(4-(1,2,2-triphenylvinyl)phenyl)acetonitrile (Compound 1) [ka]

[0049] (2-Bromoethene-1,1,2-triyl)tribenzene (1.0 g, 2.98 mmol) and 4-cyanomethylphenylboronic acid (0.58 g, 3.58 mmol) were dissolved in a mixed solvent of toluene (10 mL) and ethanol (10 mL). The resulting solution was added with 8 mL of aqueous sodium carbonate (2 mol / L) and reacted at room temperature for 30 minutes under a nitrogen stream. Then, [1,1'-bis(diphenylphosphino)ferrocene]dichloropalladium(II) (0.22 g, 0.298 mmol) was added and stirred at 90°C for 16 hours under a nitrogen stream. The reaction solution was cooled to room temperature, extracted with ethyl acetate, and the organic phase was washed three times with saturated brine (50 mL). The organic phase was concentrated under reduced pressure and recrystallized from dichloromethane / methanol to give compound 1 as a pale yellow solid (yield: 1.00 g, 90%).

[0050] Synthesis of 3-(4-(diethoxymethyl)phenyl)-2-(4-(1,2,2-triphenylvinyl)phenyl)acrylonitrile (Compound 2) [ka]

[0051] Compound 1 (0.70 g, 1.88 mmol) and 4-(diethoxymethyl)benzaldehyde (0.47 g, 2.26 mmol) were dissolved in tetrahydrofuran (THF, 5 mL). 2 mL of a 5 mol / L solution of sodium methoxide in methanol was added to this solution and stirred at room temperature for 12 hours. The reaction mixture was then extracted with chloroform, and the organic phase was washed three times with saturated brine (50 mL). The organic phase was concentrated under reduced pressure and recrystallized from dichloromethane / methanol to give compound 2 as a yellow solid (yield 0.90 g, 85%).

[0052] Synthesis of 3-(4-(formylphenyl)-2-(4-(1,2,2-triphenylvinyl)phenyl)acrylonitrile (TPE-CHO) [ka]

[0053] Compound 2 (0.50 g, 0.890 mmol) was dissolved in chloroform (5 mL), 3 mL of hydrochloric acid was added, and the mixture was stirred at 60 °C for 12 hours. 1-Bromo-2-octyldodecane (2.0 g, 5.53 mmol) was added to the mixture, and the mixture was stirred at 120 °C for 24 hours. The reaction mixture was then extracted with chloroform, and the organic phase was washed three times with saturated brine (50 mL). The organic phase was concentrated under reduced pressure and recrystallized from hexane to obtain TPE-CHO as a yellow solid (yield 0.40 g, 93%).

[0054] Synthesis of 3-(4-(1-aminobut-3-en-1-yl)phenyl)-2-(4-(1,2,2-triphenylvinyl)phenyl)acrylonitrile (TPE-NH2) [ka]

[0055] TPE-CHO (0.30 g, 0.615 mmol) was added to an ethanol solution of ammonia (10 mL) and stirred. The mixture was cooled to 0 °C, and CH═CHBF═K (0.14 g, 0.923 mmol) was added. The mixture was then returned to room temperature and reacted for 16 hours. The reaction mixture was then poured into ice and extracted with chloroform. The organic phase was washed twice with water and once with saturated brine. The organic phase was dried over magnesium sulfate, concentrated under reduced pressure, and recrystallized from dichloromethane / hexane to give TPE-NH═ as a yellow solid (0.25 g, 76% yield).

[0056] [Exposure test to aldehyde gases] 10.0 mg of TPE-NH2 synthesized by the above procedure was weighed out and dissolved in 1.0 mL of dichloromethane. This solution was dropped onto a glass substrate and spin-coated (3000 rpm, 30 seconds) to form a thin film. This thin film was used to observe changes in the fluorescence spectrum when exposed to aldehyde gas, and the recognition ability of the compound of the present invention for aldehyde compounds was investigated.

[0057] As a result, the TPE-NH2 thin film before exposure to aldehyde gases exhibited fluorescence with a peak wavelength of 515 nm, whereas the TPE-NH2 thin film exposed to formaldehyde, isovaleric aldehyde, or nonanal gases exhibited a fluorescence peak shift to 530 nm, 535 nm, or 520 nm, respectively, as shown in Figure 1. The color of the fluorescence also changed from green to yellow. This demonstrates that the compound of the present invention is useful as a gas sensor material that can visually confirm the presence of aldehyde gases.

[0058] [Hydrazine gas exposure test] 10.0 mg of TPE-CHO synthesized by the above procedure was weighed and dissolved in 1.0 mL of dichloromethane. This solution was dropped onto a glass substrate and spin-coated (3000 rpm, 30 seconds) to form a thin film. This thin film was used to observe the change in fluorescence spectrum upon exposure to hydrazine gas, and the recognition ability of the compound of the present invention for hydrazine was examined.

[0059] As a result, the TPE-CHO thin film before exposure to hydrazine gas emitted fluorescence with a peak wavelength of 545 nm, whereas the TPE-CHO thin film exposed to hydrazine gas exhibited a fluorescence peak shift to 515 nm and a color change from yellow to green, as shown in Figure 2. This demonstrates that the compound of the present invention is useful as a gas sensor material that can visually confirm the presence of hydrazine gas.

Claims

1. A compound represented by the following general formula (1): 【Chemical 1】 (In general formula (1), each R １ and R ２ each independently represents a hydrogen atom, an aryl group, a cyano group, a nitro group, a carboxy group, or —(C═O)O—R Ｅ or -O(C=O)-R Ｅ and R ａ is a hydrogen atom or an alkyl group having 1 to 10 carbon atoms, each R is independently an alkyl group having 1 to 10 carbon atoms, and X is —CHO or —CH(NH ２ ) CH ２ CH=CH ２ and each R Ｅ are each independently a monovalent group, each m is independently an integer from 0 to 4, and n is an integer from 1 to 4.

2. The compound according to claim 1, which is represented by the following general formula (1a): 【Chemistry 2】 (In general formula (1a), R １ and R ２ each independently represents a hydrogen atom, an aryl group, a cyano group, a nitro group, a carboxy group, or —(C═O)O—R Ｅ or -O(C=O)-R Ｅ and R ３ represents a cyano group, a nitro group, a carboxy group, -(C=O)O-R ｅ or -O(C=O)-R ｅ wherein each R is independently an alkyl group having 1 to 10 carbon atoms, and X is —CHO or —CH(NH ２ ) CH ２ CH=CH ２ and each R Ｅ are each independently a monovalent group, and each m is independently an integer from 0 to 4.

3. The compound according to claim 1, represented by the following general formula (1b): 【Chemistry 3】 (In general formula (1b), R １ and R ２ each independently represents a hydrogen atom, an aryl group, a cyano group, a nitro group, a carboxy group, or —(C═O)O—R Ｅ or -O(C=O)-R Ｅ and R ３ represents a cyano group, a nitro group, a carboxy group, -(C=O)O-R Ｅ or -O(C=O)-R Ｅ wherein each R is independently an alkyl group having 1 to 10 carbon atoms, and X is —CHO or —CH(NH ２ ) CH ２ CH=CH ２ and each R Ｅ are each independently a monovalent group, and each m is independently an integer from 0 to 4.

4. The compound according to claim 1, which is represented by the following general formula (1c): 【Chemistry 4】 (In the general formula (1c), X is —CHO or —CH(NH ２ ) CH ２ CH=CH ２ It is.)

5. A gas sensor material for detecting hydrazine or aldehydes, comprising the compound according to any one of claims 1 to 4.

6. A gas sensor material for detecting hydrazine, comprising a compound represented by the following chemical formula (1c-A): 【Chemistry 5】

7. A gas sensor material for detecting aldehydes, comprising a compound represented by the following chemical formula (1c-B): 【Chemistry 6】

8. A method for detecting hydrazine or aldehydes, comprising exposing a gas to be measured to a gas sensor containing the compound according to any one of claims 1 to 4, and observing a change in fluorescence of the compound.

Images