Compound and electronic component

Abstract

To provide a compound which reversibly changes its color by an external stimulus or the like and can obtain a film having a uniform color even in a film thickness of a fixed value or less, and to provide an electronic component having the compound.SOLUTION: The compound has a structure of Formula (1): In the formula (1), R1 and R2 are each independently an organic group optionally containing an ether bond. R3 is a divalent organic group. X is an aliphatic hydrocarbon group having 5 to 9 carbon atoms.SELECTED DRAWING: None

Description

[Technical Field]

[0001] The present invention relates to a compound and an electronic component. [Background technology]

[0002] Materials that change color in response to external mechanical stimuli such as pressure are called mechanochromic materials, and have attracted attention as new functional materials that can be applied to piezoelectric elements such as sensors and switches.

[0003] In the field of mechanochromic materials, numerous compounds have been studied and reported, including inorganic compounds, organic compounds, complex compounds, etc. For example, Non-Patent Document 1 discloses a compound having a fluorenidene-acridan structure as a main skeleton in which a fluorene moiety and an acridan moiety are conjugated with a double bond. [Prior art documents] [Non-patent literature]

[0004] [Non-Patent Document 1] "A fluorenylidene-acridane that becomes dark in color upon grinding-ground state mechanochromism by conformational change" Chem.Sci., 2018, Vol. 9, pp. 475-482 Summary of the Invention [Problem to be solved by the invention]

[0005] In conventional techniques such as Non-Patent Document 1, a green film is obtained in response to an external stimulus, and by exposing the green film to alcohol vapor, a yellow film can be obtained that has not yet responded to the external stimulus.

[0006] However, with conventional technology, the compounds are randomly formed into a film, which can easily result in uneven color when the compounds aggregate due to exposure to alcohol vapor. In order to create a film with a uniform color, it is necessary to form a film with a certain thickness (4 μm or more), which makes it difficult to apply to piezoelectric element materials that require light weight, flexibility, and thinness.

[0007] The problem to be solved by the present invention is to provide a compound that changes color reversibly in response to an external stimulus or the like and that can provide a film of uniform color even when the film thickness is equal to or less than a certain level, and an electronic component that contains the compound. [Means for solving the problem]

[0008] One aspect of the present invention is a compound having the structure of the following formula (1): [ka] {In formula (1), R1 and R2 are each independently an organic group which may contain an ether bond. R3 is a divalent organic group. X is an aliphatic hydrocarbon group having 5 to 9 carbon atoms.}

[0009] The compound of the above embodiment preferably has a structure of the following formula (2). [ka] {In formula (2), X is an aliphatic hydrocarbon group having 5 to 9 carbon atoms.}

[0010] The compound of the above embodiment preferably has a structure of the following formula (3). [ka]

[0011] In the compound of the above embodiment, it is preferable that the absorption color changes due to molecular orientation.

[0012] In the compound of the above embodiment, it is preferable that the electrical properties change depending on pressure.

[0013] Another aspect of the present invention is an electronic component, which includes the compound of the above aspect. [Effects of the Invention]

[0014] According to the present invention, it is possible to provide a compound that changes color reversibly in response to an external stimulus or the like and that can provide a film of uniform color even when the film thickness is equal to or less than a certain level, and an electronic component that includes the compound. [Brief explanation of the drawings]

[0015] [Figure 1] FIG. 1 shows the results of p-polarized multi-angle incident air-resolved spectroscopy (pMAIRS) measurements on blue and green films of compound (A). [Figure 2] FIG. 2 shows Cole-Cole plots representing the results of AC impedance measurements on blue and green films of Compound (A). [Figure 3] FIG. 3 is a photograph showing the structure of the interdigital electrode used in the AC impedance measurement of the example. DETAILED DESCRIPTION OF THE INVENTION

[0016] Hereinafter, embodiments of the present disclosure will be described in detail. In this specification, the expression "a to b" in the description of a range of values ​​means a to b, unless otherwise specified.

[0017] In this specification, when multiple upper limit values ​​and multiple lower limit values ​​are separately described, all numerical ranges that can be set by freely combining these upper limit values ​​and lower limit values ​​are considered to be described in this specification.

[0018] In this specification, when a compound is described, its isomers are also described unless otherwise specified.

[0019] As used herein, "aromatic" also includes "heteroaromatic."

[0020] In this specification, the term "substituent" is not particularly limited, and unless otherwise specified, examples thereof include a hydroxyl group, a phenoxy group, an alkoxy group, a phenyl group, a halogen group, a thiol group, a sulfo group, an amino group, an imino group, a hydroxyamino group, a nitro group, a nitroso group, a carboxy group, a thiocarboxy group, an ester group, a thioester group, an aldehyde group, an acetyl group, and the like.

[0021] In this specification, the term "solid content" refers to the components other than the solvent (particularly the organic solvent) among the components constituting the composition or each raw material, and is based on mass unless otherwise specified.

[0022] 1. Compound (A) The compound (A) of this embodiment has a structure of the following formula (1). [ka] {In formula (1), R1 and R2 are each independently an organic group which may contain an ether bond. R3 is a divalent organic group. X is an aliphatic hydrocarbon group having 5 to 9 carbon atoms.}

[0023] Compound (A) of this embodiment is a novel compound, and X in the above formula (1) described below is an aliphatic hydrocarbon group having 5 to 9 carbon atoms. It is believed that the number of carbon atoms in the aliphatic hydrocarbon group affects the orientation of compound (A). By making X an aliphatic hydrocarbon group having 5 to 9 carbon atoms in compound (A) of this embodiment, the orientation of compound (A) during film formation can be improved and uniform aggregation can be promoted upon exposure to alcohol vapor. Therefore, even when compound (A) is formed into a thin film with a thickness of 400 nm or less, it is possible to obtain a uniform film of two colors before and after pressure response. The above formula (1) will be described in detail below.

[0024] R1 and R2 in formula (1) are not particularly limited as long as they are mutually independent organic groups. Examples of the organic groups include alkyl groups, heteroalkyl groups, alkenyl groups, heteroalkenyl groups, alkynyl groups, heteroalkynyl groups, cycloalkyl groups, heterocycloalkyl groups, aryl groups, heteroaryl groups, alkoxy groups (e.g., methoxy groups, ethoxy groups), carbonyl groups, acetyl groups, carboxy groups, cyano groups, hydroxy groups, thiol groups, amino groups, imino groups, nitro groups, halogen groups, and combinations thereof.

[0025] Among the organic groups mentioned above, R1 and R2 in formula (1) preferably have an ether bond. As the organic group having an ether bond, for example, an alkoxy group (such as a methoxy group or an ethoxy group) is more preferable, and a methoxy group is even more preferable.

[0026] In formula (1), R1 and R2 may be the same group or different groups.

[0027] R3 in formula (1) is not particularly limited as long as it is a divalent organic group. The divalent organic group may be, for example, a divalent organic group containing an aromatic hydrocarbon group (arylene group), an aliphatic hydrocarbon group (alkylene group), an ether group, a ketone group, an ester group, a sulfonyl group, or the like.

[0028] Among the divalent organic groups mentioned above, R3 in formula (1) preferably contains an aromatic hydrocarbon group. Examples of the divalent organic group containing an aromatic hydrocarbon group include divalent organic groups containing a biphenyl skeleton, a diphenyl ether skeleton, a diphenyl thioether skeleton, a benzophenone skeleton, a diphenylmethane skeleton, a diphenylpropane skeleton, a diphenylhexafluoropropane skeleton, a diphenyl sulfoxide skeleton, a diphenyl sulfone skeleton, and a benzene skeleton.

[0029] Among the divalent organic groups described above, R3 in formula (1) is more preferably a divalent organic group containing an aromatic hydrocarbon group, further preferably a divalent organic group containing a benzene skeleton structure, and particularly preferably a phenylene group.

[0030] R3 in formula (1) may or may not have a substituent.

[0031] The compound (A) of this embodiment preferably has, for example, a structure of the following formula (2). [ka] {In formula (2), X is an aliphatic hydrocarbon group having 5 to 9 carbon atoms.}

[0032] X in formula (1) or (2) is not particularly limited as long as it is an aliphatic hydrocarbon group having 5 to 9 carbon atoms. X may be linear or branched, and is preferably linear. X may be saturated or unsaturated, and is preferably saturated.

[0033] The number of carbon atoms in X in formula (1) or (2) is preferably 6 to 8, more preferably 7 to 8, and particularly preferably 8. It is presumed that the larger the number of carbon atoms in X, the more improved the alignment of compound (A) during film formation. On the other hand, the larger the number of carbon atoms in X, the lower the melting point of compound (A), which causes problems with handleability at room temperature. By setting the number of carbon atoms in X to 8, compound (A) becomes solid at room temperature while exhibiting good alignment during film formation, and is therefore easy to handle.

[0034] The compound (A) of this embodiment preferably has a structure of the following formula (3), for example. [ka]

[0035] 2. Physical properties of compound (A) 2-1. Change in absorption color (mechanochromism) The compound (A) of this embodiment preferably changes its absorption color due to molecular orientation. The change in absorption color of the compound (A) will be described below.

[0036] The compound (A) of this embodiment exists in a blue solid state at room temperature, and the film produced by vacuum deposition is green. Subsequent exposure to alcohol vapor changes the color from green to blue. This color change is reversible and can be repeated many times.

[0037] The change in absorption color of the compound (A) of this embodiment is due to molecular orientation. Molecular orientation occurs when the blue solid compound (A) is vacuum-deposited. This allows the formation of a uniform green or blue film with a thickness of 1 / 10 or less (400 nm or less) of that of conventional films.

[0038] 2-2. Changes in electrical characteristics The orientation of compound (A) relative to the substrate can be observed by p-polarized multi-angle incident resolution spectroscopy (pMAIRS). Figure 1 shows the results of pMAIRS measurements for compound (A). From the above measurements, it can be seen that when compound (A) is blue, it exhibits edge-on orientation that stands up relative to the substrate compared to when it is green (see Figure 1). In general, when compound (A) exhibits edge-on orientation that stands up relative to the substrate, it is suggested that horizontal charge transfer is improved, resulting in lower electrical resistance. From this, it can be inferred that there is a difference in the electrical properties of compound (A) when it is blue and when it is green.

[0039] The compound (A) of this embodiment preferably changes its electrical properties in response to pressure. The blue compound (A) has a more uniform molecular arrangement due to crystallization than the green compound (A). Therefore, the blue compound (A) has a lower resistance than the green compound (A) and different electrical properties from the green compound (A). Furthermore, the resistance of the green compound (A) decreases when pressure is applied, and the electrical properties change to those of the blue compound (A).

[0040] The change in the electrical properties of compound (A) can be observed by AC impedance measurement. Figure 2 shows a Cole-Cole plot of compound (A), which is the result of AC impedance measurement. The horizontal axis represents the real component of impedance (Z'), and the vertical axis represents the imaginary component of impedance (Z'').

[0041] As shown in FIG. 2, the AC impedance measurement results show that the blue compound (A) shows almost no change in the real component of the impedance, indicating that it has a lower electrical resistance than the green compound (A).

[0042] The results of measuring the AC impedance of green compound (A) after applying normal stresses of 150 MPa and 200 MPa by nanoimprinting or other methods are shown in Figure 2. As shown in Figure 2, the resistance of green compound (A) after pressure application decreases, and its electrical properties approach those of blue compound (A).

[0043] From this, it can be inferred that the electrical properties of compound (A) differ between blue and green, and that the electrical properties change depending on the pressure.

[0044] 3. Method for producing compound (A) An example of a method for producing compound (A) is a method of reacting a compound represented by the following formula (4) with a compound represented by the following formula (5) as raw materials. [ka] {In formula (4), R1 and R2 are as defined above.} [ka] {In formula (5), R3 and X are as defined above.}

[0045] The compound represented by formula (4) is not particularly limited, and known compounds can be used. For example, a compound represented by the following formula (4-1) (dimethoxydiazofluorene) can be mentioned. [ka]

[0046] The compound represented by formula (5) is not particularly limited, and known compounds can be used, such as the compound represented by the following formula (5-1) (p-octylphenyl acridan). [ka]

[0047] In the reaction of the compound represented by formula (4) with the compound represented by formula (5), an organic solvent may be used, if necessary.

[0048] The organic solvent is not particularly limited, and known organic solvents can be used. Examples include amide organic solvents such as pyridine, N-methyl-2-pyrrolidone (NMP), N,N-dimethylacetamide (DMAc), and N,N-dimethylformamide (DMF); alcohol organic solvents such as methanol, ethanol, isopropanol, butanol, and octanol; ketone organic solvents such as acetone, methyl ethyl ketone, methyl isobutyl ketone, and cyclohexanone; ester organic solvents such as ethyl acetate, butyl acetate, and ethyl lactate; ether organic solvents such as ethylene glycol monomethyl ether, diethylene glycol monobutyl ether, and tetrahydrofuran (THF); and aromatic hydrocarbon compound organic solvents such as benzene, toluene, and xylene. Among the above, aromatic hydrocarbon compound organic solvents are preferred.

[0049] The amount of organic solvent is not particularly limited as long as it allows the reaction to proceed efficiently, and is preferably about 50 to 500 parts by mass per 100 parts by mass of the total amount of the compound represented by formula (4) above and the compound represented by formula (5) above.

[0050] The reaction temperature and reaction time for the above reaction can be appropriately selected from conventionally known reaction conditions, and for example, the reaction can be carried out at 25°C to 150°C for 1 to 5 hours.

[0051] The compound (A) obtained by the above-mentioned production method may be dispersed in a poor solvent, and the dispersion solution may be vacuum-deposited onto a substrate such as cloth or fiber to form a film. The vacuum-deposited film is green in color and changes to blue when exposed to vapors of alcohol or the like.

[0052] The substrate may be made of any material such as fiber, paper, cloth, fabric, cloth product, clothing, etc. The substrate may be in any shape such as a plate, string, wire, etc. The substrate may have holes or irregularities on the surface to which fine particles of compound (A) can be adsorbed.

[0053] The anti-solvent may be a lower alcohol such as ethanol or methanol, or a lower hydrocarbon such as hexane, etc. To facilitate evaporation of the anti-solvent, an anti-solvent with a low boiling point, such as methanol, may be used.

[0054] The compound (A) may be dispersed in a poor solvent in a state where it has been pulverized using a wet pulverizer such as a bead mill or a ball mill.

[0055] The particle size of the fine particles of compound (A) may be adjusted depending on the type, shape, and use of the object, the area where compound (A) is applied, the type of poor solvent, the type of tool or device, and the like.

[0056] After the film formation, the surface of the film may be covered with a protective layer to protect the film, or the film may be peeled off from the substrate and laminated so that the film is sandwiched between protective layers.

[0057] The protective portion may be made of a transparent or semi-transparent PET film, a metal mesh, or the like.

[0058] The thickness of the film may be adjusted as appropriate depending on the type of compound (A), the intended use, etc. As described above, molecular orientation occurs when compound (A) is vacuum-deposited. This allows the formation of a uniform film of two colors, green and blue, with a film thickness of 1 / 10 or less (400 nm or less) of that of conventional films.

[0059] 4. Electronic Components The electronic component of this embodiment includes the above-described compound (A). Compound (A) reversibly changes color in response to an external stimulus or the like, and can form a film with a uniform color even at a film thickness of a certain level or less (400 nm or less). Therefore, compound (A) is suitable for use in electronic components such as pressure-responsive elements. [Example]

[0060] Next, the present embodiment will be described in detail with reference to examples and comparative examples, but the present invention is not limited to these examples.

[0061] <Synthesis of Compound (A)> p-Octylphenylacridan (3139 mg, 7.86 mmol) and triphenylphosphine (PPh3) (2474 mg, 9.43 mmol) were placed in a 100 mL two-neck flask and stirred at 140 °C. 99.0 mL of a solution of dimethoxydiazofluorene in dehydrated o-xylene (1984 mg, 7.86 mmol) was added dropwise via a dropping funnel over 1 h. After the addition, the mixture was stirred at 140 °C for an additional 1 h, and then the solvent was removed under reduced pressure. The resulting reaction mixture was purified by silica gel column chromatography using dichloromethane as the developing solvent to remove unreacted materials. The target product adsorbed on the silica gel was then completely recovered by flushing with triethylamine. Next, a silica gel column was prepared using a mixed solvent of dichloromethane:triethylamine = 5:1, and the crude product was further purified using a developing solvent of dichloromethane:hexane = 1:3. The solvent of the resulting blue fraction was removed under reduced pressure, and the resulting product was irradiated with ultrasound in a methanol solution to obtain a deep blue powdery solid (1720 mg, 2.91 mmol).

[0062] [ka]

[0063] [evaluation] The compound (A) thus formed into a film was evaluated as follows.

[0064] (p-polarized multi-angle incident resolved spectroscopy (pMAIRS) measurement) Compound (A) was deposited on a substrate. More specifically, compound (A) was deposited by vacuum deposition on a substrate whose surface had been plasma-treated, yielding a green organic film. The resulting green film was then exposed to methanol vapor and crystallized for approximately 5 hours to yield a blue film. p-Polarized Multi-Angle Incidence Resolution Spectroscopy (pMAIRS) measurements were performed on the resulting green and blue films. The sample was deposited on a silicon substrate, and infrared light whose polarization direction was changed using a polarizer was incident on the film, resulting in measurements. Figure 1 shows the measurement results.

[0065] As shown in Figure 1, the above measurements showed that the blue film had an edge-on orientation that stood up relative to the substrate compared to the green film. Generally, when an edge-on orientation that stands up relative to the substrate is observed, it is suggested that the horizontal charge transfer is improved, resulting in a lower electrical resistance. This revealed that there is a difference in the electrical properties between the blue and green films.

[0066] (AC impedance measurement) An element substrate (20 mm × 20 mm) was prepared for measuring AC impedance. More specifically, a comb-shaped electrode having the following dimensions was prepared as the electrode (see Figure 3). The electrode was prepared by a maskless photolithography method. A film of compound (A) was formed on the obtained element substrate in the same manner as above. The film thickness of compound (A) was set to 2 μm. The impedance of the obtained blue film and green film of compound (A) was measured. ·electrode Material: gold Shape: Comb type Thickness: 200 μm Width: 10μm Interelectrode distance: 5μm Number of combs: 500

[0067] A nanoprint (X-300 manufactured by SCIVAX Corporation) was used to apply normal stresses of 150 MPa and 200 MPa to the green film of compound (A). A silicon mold (20 mm x 20 mm) was used for pressure application.

[0068] FIG. 2 shows the Cole-Cole plots when normal stresses of 150 MPa and 200 MPa are applied to the blue film, the green film, and the green film.

[0069] As shown in Figure 2, after applying a pressure of 150 MPa, the resistance of the green film decreases, and the electrical properties approach those of the blue film. Furthermore, after applying a pressure of 200 MPa, the electrical properties approach those of the blue film even more. This demonstrates that the electrical properties of compound (A) differ between the blue and green cases, and that the electrical properties change depending on the pressure. [Industrial Applicability]

[0070] The compound of the present invention reversibly changes color in response to external stimuli or the like, and can form a film of uniform color even at a film thickness below a certain level, and therefore can be used in electronic components such as pressure-responsive elements.

Claims

1. A compound having a structure of the following formula (1): 【Chemistry 1】 {In formula (1), R １ , R ２ are each independently an organic group which may contain an ether bond. ３ is a divalent organic group. X is an aliphatic hydrocarbon group having 5 to 9 carbon atoms.}

2. The compound according to claim 1, having the structure of the following formula (2): 【Chemistry 2】 {In formula (2), X is an aliphatic hydrocarbon group having 5 to 9 carbon atoms.}

3. The compound according to claim 1, having a structure of the following formula (3): 【Transformation 3】

4. The compound of claim 1 , wherein the absorption color changes due to molecular orientation.

5. The compound of claim 1, wherein the electrical properties change with pressure.

6. An electronic component comprising the compound according to any one of claims 1 to 5.

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