Aromatic amine compounds, liquid crystal compositions, liquid crystal elements, display devices, and dimming devices

Abstract

Provided is an aromatic amine compound that can serve as a chiral dopant able to be stably oxidized and reduced in a liquid crystal composition. The aromatic amine compound is represented by formula (1). A1 moieties each independently denote a substitute or unsubstituted alkylene group or a substituted or unsubstituted divalent aromatic group, A2 and A3 moieties each independently denote a substituted or unsubstituted alkyl group or a substituted or unsubstituted aromatic group, and at least one of A1, A2 and A3 denotes an aromatic group. s and t each independently denote an integer between 0 and 6. R1 and R2 each independently denote a substituent group. p+s and q+t each independently denote an integer between 0 and 6. T moieties each independently denote a divalent linking group formed from at least one type selected from the group consisting of a carbonyl group, an oxygen atom, an imino group and an alkylene group. Q denotes a trivalent linking group constituted from at least one type selected from the group consisting of an oxygen atom, a nitrogen atom, a carbon atom, a phosphorus atom, a sulfur atom and a hydrogen atom.

Description

[Technical Field]

[0001] The present invention relates to aromatic amine compounds, liquid crystal compositions, liquid crystal elements, display devices, and dimming devices. [Background technology]

[0002] Liquid crystal display (LCD) devices are used in a variety of applications, not just personal computers and televisions. LCD devices utilize backlights, which are key to further reducing the power consumption of these devices. Cholesteric liquid crystals are liquid crystals capable of selectively reflecting light, and reflective displays using them are devices that can control light with low power consumption. For example, Japanese Patent Publication No. 2019-151597 and J.Am.Chem.Soc., 2018, 140, 10946 propose using a compound in which ferrocene is introduced as a redox site into the binaphthyl skeleton, which is the chiral site, as a chiral dopant for forming cholesteric liquid crystals. Furthermore, it is stated that the reflection wavelength of the cholesteric liquid crystal can be controlled by using a redox reaction induced by applying voltage to a liquid crystal composition layer containing the ferrocene-introduced chiral dopant. [Overview of the Initiative] [Problems that the invention aims to solve]

[0003] One aspect of the present invention aims to provide an aromatic amine compound that can serve as a stably redoxable chiral dopant in a liquid crystal composition. [Means for solving the problem]

[0004] The first embodiment is an aromatic amine compound represented by the following formula (1).

[0005] [ka]

[0006] In formula (1), A 1Each of these independently represents a substituted or unsubstituted alkylene group, or a substituted or unsubstituted divalent aromatic group. 2 and A 3 Each of these independently represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. 1 , A 2 and A 3 At least one of them represents an aromatic group. s and t each independently represent an integer from 0 to 6. R 1 and R 2 Each of the following independently represents a substituent. p+s and q+t each independently represent an integer from 0 to 6. T each independently represents a divalent linking group formed from at least one selected from the group consisting of a carbonyl group, an oxygen atom, an imino group, and an alkylene group. Q represents a trivalent linking group composed of at least one selected from the group consisting of an oxygen atom, a nitrogen atom, a carbon atom, a phosphorus atom, a sulfur atom, and a hydrogen atom.

[0007] A second embodiment is a liquid crystal composition comprising the aromatic amine compound of the first embodiment. A third embodiment is a liquid crystal element comprising a liquid crystal layer comprising the liquid crystal composition of the second embodiment and a pair of electrodes for applying a voltage to the liquid crystal layer. A fourth embodiment is a display device or dimming device comprising the liquid crystal element of the third embodiment. [Effects of the Invention]

[0008] According to one aspect of the present invention, it is possible to provide an aromatic amine compound that can stably act as a chiral dopant in a liquid crystal composition. [Brief explanation of the drawing]

[0009] [Figure 1] (a) is an example of a cyclic voltammogram of the compound according to Example 3 based on ferrocene standards, and (b) is an example of a cyclic voltammogram of the compound according to Comparative Example 1 based on ferrocene standards. [Figure 2](a) is an example of the absorption spectrum of the compound according to Example 3, and (b) is an example of the absorption spectrum of the compound according to Comparative Example 1. [Figure 3] This is an example of the transmission spectrum of a liquid crystal composition containing the compounds described in the examples and comparative examples. [Figure 4] (a) is an example of a transmission spectrum before applying a DC voltage, and (b) is an example of a transmission spectrum after applying a DC voltage. [Modes for carrying out the invention]

[0010] In this specification, the term "process" includes not only independent processes but also processes that cannot be clearly distinguished from other processes, as long as their intended purpose is achieved. Furthermore, the content of each component in a composition refers to the total amount of multiple substances present in the composition, unless otherwise specified, if multiple substances corresponding to each component exist in the composition. In addition, the upper and lower limits of the numerical ranges described herein can be arbitrarily selected and combined from the numerical values ​​exemplified as numerical ranges. Embodiments of the present invention will now be described in detail. However, the embodiments shown below are examples of aromatic amine compounds, liquid crystal compositions, liquid crystal elements, display devices, and dimming devices that embody the technical concept of the present invention, and the present invention is not limited to the aromatic amine compounds, liquid crystal compositions, liquid crystal elements, display devices, and dimming devices shown below.

[0011] Aromatic amine compounds The aromatic amine compound is represented by the following formula (1). The aromatic amine compound contains a binaphthyl skeleton as a chiral site and an aromatic amine skeleton as a redox site, as represented by the following formula (1). The compound represented by the following formula (1) can stably repeat an electrochemical redox reaction in the atmosphere, in a solution, in a liquid crystal composition, etc., by having an aromatic amine skeleton as a redox site. That is, the aromatic amine compound represented by formula (1) can reversibly exhibit ionic and non-ionic properties in response to an electrical stimulus. Such an optically active electro-responsive compound is considered to be able to control the molecular arrangement of the cholesteric liquid crystal's helical structure by electrical stimulation, for example, in a cholesteric liquid crystal. Thereby, the period (pitch) of the helical structure formed by the cholesteric liquid crystal can be controlled, and the wavelength of the circularly polarized light selectively reflected by the cholesteric liquid crystal can be controlled. Specifically, if the pitch of the helical structure becomes longer, light with a longer wavelength can be reflected, and if the pitch becomes shorter, light with a shorter wavelength can be reflected.

[0012] The aromatic amine compound may be configured to have no absorption in the visible light region. Thereby, for example, a colorless liquid crystal composition having no absorption in the visible light region can be constituted. The aromatic amine compound having no absorption in the visible light region can be obtained, for example, by appropriately selecting substituents in the aromatic amine skeleton, substituents in the binaphthyl skeleton, etc.

[0013] [Chemical formula]

[0014] In formula (1), A 1 each independently represents a substituted or unsubstituted alkylene group, or a substituted or unsubstituted divalent aromatic group. A 2 and A 3 each independently represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. At least one of A 1 , A 2 and A 3 represents an aromatic group.

[0015] A 1 The alkylene group represented by may be linear, branched, or cyclic, or a combination thereof. 1 The number of carbon atoms in the alkylene group represented by may be, for example, 1 to 20, preferably 1 or more, or 10 or less. 1 The divalent aromatic group represented by is formed by removing two hydrogen atoms from an aromatic hydrocarbon compound or an aromatic heterocyclic compound. The aromatic hydrocarbon compound may have 6 to 18 carbon atoms, preferably 6. The aromatic hydrocarbon compound may contain at least one selected from the group consisting of benzene, naphthalene, and anthracene. The aromatic heterocyclic compound may also contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur atoms. The number of members in the aromatic heterocyclic compound may be, for example, 5 to 10, preferably 6 or less. The aromatic heterocyclic compound may contain at least one selected from the group consisting of pyridine, furan, and thiophene. In aromatic amine compounds, A 1 If there are multiple alkylene groups or divalent aromatic groups represented by , they may be the same or different.

[0016] A 1 The alkylene group or divalent aromatic group represented by may have substituents. 1 The substituent in may be at least one substituent selected from the group consisting of substituted or unsubstituted hydrocarbon groups, nitro groups, cyano groups, halogen atoms, hydroxyl groups, alkoxy groups, acyl groups, alkoxycarbonyl groups, carboxyl groups, aliphatic amino groups, and aromatic amino groups.

[0017] The hydrocarbon group in the substituent may be an aliphatic group or an aromatic group. The aliphatic group may be a saturated aliphatic group or an unsaturated aliphatic group. The aliphatic group may be linear, branched, cyclic, or a combination thereof. The number of carbon atoms in the aliphatic group may be, for example, 1 to 20, preferably 1 to 10, or 1 to 6. Examples of substituents in the aliphatic group include halogen atoms, aryl groups, alkoxy groups, etc. The number of carbon atoms in the aromatic group may be, for example, 6 to 18, preferably 6. Examples of substituents in the aromatic group include halogen atoms, aliphatic groups with 1 to 20 carbon atoms, alkoxy groups, acyl groups, alkoxycarbonyl groups, etc.

[0018] The halogen atoms in the substituents may include fluorine atoms, chlorine atoms, bromine atoms, etc. The alkoxy group as a substituent may have an aliphatic group having 1 to 20 carbon atoms, preferably an aliphatic group having 1 to 10 carbon atoms. The acyl group as a substituent may have an aliphatic group having 1 to 20 carbon atoms, preferably an aliphatic group having 1 to 6 carbon atoms. The alkoxycarbonyl group as a substituent may have an aliphatic group having 1 to 20 carbon atoms, preferably an aliphatic group having 1 to 6 carbon atoms.

[0019] The aliphatic group in the aliphatic amino group as a substituent may be a saturated aliphatic group or an unsaturated aliphatic group. The aliphatic group may be linear, branched, cyclic, or a combination thereof. The number of carbon atoms in the aliphatic group may be, for example, 1 to 20, preferably 1 to 10, or 1 to 6. The aliphatic amino group may be a monosubstituted aliphatic amino group having one aliphatic group, or a disubstituted aliphatic amino group having two aliphatic groups. The aliphatic amino group may have further substituents on the aliphatic group portion. Examples of substituents in the aliphatic group include halogen atoms, aryl groups, alkoxy groups, alkylamino groups, arylamino groups, etc. The number of substitutions in the aliphatic group may be, for example, 0 to 20, preferably 10 or less.

[0020] The aromatic group in the aromatic amino group as a substituent may be an aromatic hydrocarbon group or an aromatic heterocyclic group. The number of carbon atoms in the aromatic hydrocarbon group may be, for example, 6 to 18, preferably 6 to 12. The aromatic hydrocarbon group may include at least one selected from the group consisting of a phenyl group, a naphthyl group, and an anthracenyl group. The aromatic heterocyclic group may also include at least one heteroatom selected from the group consisting of a nitrogen atom, an oxygen atom, and a sulfur atom. The number of members in the aromatic heterocyclic group may be, for example, 5 to 10, preferably 6 or less. The aromatic heterocyclic group may include at least one selected from the group consisting of a pyridyl group, a furyl group, and a thienyl group. The aromatic amino group may be a monosubstituted aromatic amino group having one aromatic group, or a disubstituted aromatic amino group having two aromatic groups. The aromatic amino group may have further substituents on the aromatic group portion. Examples of substituents in the aromatic group include halogen atoms, aryl groups, alkoxy groups, alkylamino groups, arylamino groups, alkyl groups, etc. The number of substitutions in the aromatic group may be, for example, 0 to 8, and preferably 5 or less.

[0021] A 1 The number of substitutions in the alkylene group or divalent aromatic group represented by may be, for example, 0 to 20, and preferably 4 or less.

[0022] A 2 Or A 3 The alkyl group represented by may be linear, branched, or cyclic, or a combination thereof. 2 Or A 3 The number of carbon atoms in the alkyl group represented by may be, for example, 1 to 20, preferably 1 or more, or 6 or less. 2 Or A 3 The aromatic group represented by is formed by removing one hydrogen atom from an aromatic hydrocarbon compound or an aromatic heterocyclic compound. For details on aromatic hydrocarbon compounds and aromatic heterocyclic compounds, see A1 This is similar to aromatic hydrocarbon compounds and aromatic heterocyclic compounds in A. 2 Or A 3 If there are multiple alkyl groups or aromatic groups represented by , they may be the same or different.

[0023] A 2 Or A 3 The alkyl group or aromatic group represented by may have substituents. 2 Or A 3 The substituents in A 1 It is similar to the substituents in A. 2 Or A 3 The number of substitutions in the alkyl group or aromatic group represented by may be, for example, 0 to 20, and preferably 5 or less.

[0024] A 2 Or A 3 At least one of the aromatic groups represented by may have a substituent, and may have an aromatic amino group as the substituent. 2 Or A 3 The aromatic amino group that substitutes the aromatic group represented by may be a disubstituted aromatic amino group, and the aromatic group in the aromatic amino group may have further substituents. Examples of substituents in the aromatic group include halogen atoms, aryl groups, alkoxy groups, alkylamino groups, arylamino groups, alkyl groups, etc. The number of substitutions in the aromatic group may be, for example, 0 to 9, and preferably 1 to 5.

[0025] A 1 , A 2 and A 3 At least one of them represents an aromatic group, preferably at least two, and more preferably three. 1 , A 2 and A 3 Of these, at least A 1 A may be an aromatic group, 2 and A3 At least one of them may be an aromatic group.

[0026] s and t each independently represent an integer from 0 to 6. Preferably, they may be integers less than or equal to 5, or integers less than or equal to 2, and may also be integers greater than or equal to 1. Similarly, p and q each independently represent an integer from 0 to 6. Preferably, they may be integers less than or equal to 5, or integers less than or equal to 2, and may also be integers greater than or equal to 1. Furthermore, p+s and q+t each independently represent an integer from 0 to 6. Preferably, they may be integers less than or equal to 5, or integers less than or equal to 2, and may also be integers greater than or equal to 1.

[0027] R 1 and R 2 Each of these independently represents a substituent. 1 or R 2 A substituent is represented by A 1 Similar substituents can be cited in the following example. In aromatic amine compounds, R 1 or R 2 If there are multiple substituents represented by , they may be the same or different.

[0028] T independently represents a divalent linking group formed from at least one selected from the group consisting of a carbonyl group, an oxygen atom, an imino group, and an alkylene group. The imino group in T may be substituted with a hydrocarbon group. The hydrocarbon group that substitutes the imino group is A 1This is similar to the hydrocarbon group in the substituent. The alkylene group in T may be linear, branched, or cyclic, or a combination thereof. The number of carbon atoms in the alkylene group in T may be, for example, 1 to 20, preferably 10 or less, or 6 or less. The divalent linking group represented by T may be a carbonyl group, an oxygen atom, an imino group, or an alkylene group, and may include, for example, an ester bond formed by the bonding of a carbonyl group and an oxygen atom, an amide bond, urea bond, urethane bond, etc., formed by the bonding of a carbonyl group and an imino group, or an ether bond formed by the bonding of an oxygen atom and an alkylene group. In an aromatic amine compound, if there are multiple divalent linking groups represented by T, they may be the same or different.

[0029] The divalent linking group represented by T may be formed by including at least a carbonyl group. Specifically, examples of the divalent linking group represented by T include a carbonyl group, an oxygen atom, an imino group, an alkylene group, a carbonyloxy group, an oxycarbonyl group, an alkylenecarbonyloxy group, an alkyleneoxycarbonyl group, a carbonyloxyalkylene group, an oxycarbonylalkylene group, an iminocarbonyl group, an alkyleneiminocarbonyl group, a carbonylimino group, a carbonyliminoalkylene group, an alkyleneoxy group, an oxyalkylene group, an iminocarbonylimino group, an oxycarbonylimino group, an iminocarbonyloxy group, and so on. Preferably, the divalent linking group represented by T includes a carbonyloxy group, an oxycarbonyl group, an oxygen atom, and so on.

[0030] Q represents a trivalent linking group composed of at least one atom selected from the group consisting of oxygen, nitrogen, carbon, phosphorus, sulfur, and hydrogen atoms. Q may be a trivalent linking group represented, for example, by formula (2a) or (2b) below.

[0031] [ka]

[0032] In formulas (2a) and (2b), * indicates the bonding position with other atoms. 1 , X 2 and X 3 These are, independently, an oxygen atom, a sulfur atom, and -C(R) 3 )(R 4 )- and -N(R 5 )- Includes at least one selected from the group consisting of R. 3 , R 4 and R 5 Each of these independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. 1 and Y 2 Each of these independently represents one selected from the group consisting of a substituted or unsubstituted alkanetriyl group, a nitrogen atom, and -P(=O)(O-)-.

[0033] R 3 , R 4 or R 5 The alkyl group represented by R may be linear, branched, or cyclic, or a combination thereof. 3 , R 4 or R 5 The number of carbon atoms in the alkyl group represented by R may be, for example, 1 to 20, and preferably 6 or less. 3 , R 4 or R 5 The aromatic group represented by is formed by removing one hydrogen atom from an aromatic hydrocarbon compound or an aromatic heterocyclic compound. Aromatic hydrocarbon compounds and aromatic heterocyclic compounds are as described above. 3 , R 4 or R 5 The substituents in A 1 This is similar to the substituents in [the given expression].

[0034] Y 1 or Y 2The alkanetriyl group represented by is formed by removing three hydrogen atoms from an alkane. The number of carbon atoms in the alkane forming the alkanetriyl group may be, for example, 1 or more and 20 or less, preferably 6 or less. Also, Y 1 or Y 2 The substituents in are the same as the substituents in A 1 .

[0035] Specific examples of the trivalent linking group represented by formula (2a) include the following linking groups, but the present invention is not limited thereto. The trivalent linking group represented by formula (2a) may have X 1 and X 2 bonded to the binaphthyl moiety in formula (1), and Y 1 may be bonded to T in formula (1).

[0036] [Chemical formula]

[0037] Specific examples of the trivalent linking group represented by formula (2b) include the following linking groups, but the present invention is not limited thereto. The trivalent linking group represented by formula (2b) may have X 3 and Y 2 bonded to the binaphthyl moiety in formula (1), and Y 2 may be bonded to T in formula (1).

[0038] [Chemical formula]

[0039] The trivalent linking group represented by Q is preferably represented by formula (2a), and more preferably, X 1 and X 2 in formula (2a) may be oxygen atoms, and Y 1 may be a propane-1,2,3-triyl group.

[0040] The aromatic amine compound represented by formula (1) can be produced, for example, as follows: A trivalent linking group represented by Q is introduced by reacting 1,1'-bi(2-naphthol) with a substituted dihaloalkane, and the aromatic amine derivative is linked to the trivalent linking group represented by Q by a condensation reaction, substitution reaction, coupling reaction, etc., thereby producing the compound represented by formula (1). Alternatively, by using 1,1'-bi(2-naphthol) having a suitable substituent on the naphthyl ring, the aromatic amine derivative can be linked to the naphthyl ring.

[0041] Liquid crystal composition The liquid crystal composition contains at least one aromatic amine compound represented by formula (1) above. A liquid crystal composition containing the aromatic amine compound represented by formula (1) can exhibit, for example, a cholesteric liquid crystal. Furthermore, the liquid crystal composition exhibits selective reflectivity, and the selective reflectivity wavelength can be changed by an oxidation-reduction reaction induced by an electric field. The content of the compound represented by formula (1) in the liquid crystal composition may be, for example, 0.1 mol% to 10 mol%, and preferably 0.5 mol% to 5 mol%.

[0042] The liquid crystal composition may contain the aromatic amine compound represented by formula (1) as a liquid crystalline compound, or it may contain a liquid crystalline compound different from the aromatic amine compound represented by formula (1) as a host liquid crystal, and the aromatic amine compound represented by formula (1) as a chiral dopant.

[0043] Examples of liquid crystalline compounds constituting a liquid crystal composition include liquid crystalline compounds exhibiting the nematic phase and liquid crystalline compounds exhibiting the smectic phase, with liquid crystalline compounds exhibiting the nematic phase being preferred. Specific examples of liquid crystalline compounds include, for example, azomethine compounds, cyanobiphenyl compounds, cyanophenyl ester compounds, fluorine-substituted phenyl ester compounds, cyclohexanecarboxylic acid phenyl ester compounds, fluorine-substituted cyclohexanecarboxylic acid phenyl ester compounds, cyanophenylcyclohexane compounds, fluorine-substituted phenylcyclohexane compounds, cyanophenylpyrimidine compounds, fluorine-substituted phenylpyrimidine compounds, alkoxyphenylpyrimidine compounds, fluorine-substituted alkoxyphenylpyrimidine compounds, phenyldioxane compounds, trans compounds, fluorine-substituted trans compounds, and alkenylcyclohexylbenzonitrile compounds. For further details on liquid crystalline compounds, see, for example, the "Liquid Crystal Device Handbook," edited by the 142nd Committee of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, 1989, pp. 154-192 and 715-722.

[0044] The liquid crystal composition may further contain an electrolyte. The inclusion of an electrolyte can impart conductivity to the liquid crystal composition and facilitate the redox reaction of the compound represented by formula (1). The electrolyte may be a supporting electrolyte constituting the liquid crystal composition and may be selected from compounds with high solubility in the host liquid crystal. The electrolyte can be a supporting electrolyte commonly used in electrochemistry (e.g., nBu4NPF6, nBu4NBF4, nBu4NClO4, etc.), an ionic liquid, etc. Examples of ionic liquids include 1-ethyl-3-methylimidazolium triflate and 1-ethyl-3-methylimidazolium hexafluorophosphate. The liquid crystal composition may contain only one electrolyte or a combination of two or more. The electrolyte content in the liquid crystal composition may be, for example, 0.1 mol% to 30 mol%, preferably 0.5 mol% to 15 mol%.

[0045] Liquid crystal compositions may contain various liquid crystalline and non-liquid crystal compounds to alter the physical properties of the host liquid crystal (e.g., the temperature range of the liquid crystal phase) to a desired range, or to promote oxidation-reduction reactions. Additives such as ultraviolet absorbers and antioxidants may also be included. Furthermore, liquid crystal compositions may contain chiral dopants other than the aromatic amine compound represented by formula (1).

[0046] Click the LCD button The liquid crystal element comprises a liquid crystal layer containing the above-mentioned liquid crystal composition and a pair of electrodes for applying a voltage to the liquid crystal layer. By comprising a liquid crystal layer containing the above-mentioned liquid crystal composition, the liquid crystal element can exhibit a reflected color due to the appearance of cholesteric liquid crystals, for example. Furthermore, the reflected color can be changed by applying a voltage to the liquid crystal layer with the pair of electrodes.

[0047] A liquid crystal element may include a liquid crystal layer, a pair of substrates holding the liquid crystal layer, and electrodes disposed on at least one of the substrates for applying a voltage to the liquid crystal layer. The liquid crystal element may further include, if necessary, a black plate, an anti-reflective film, a brightness-enhancing film, and the like.

[0048] The substrate material constituting the liquid crystal element may be glass, plastic, or the like. Examples of plastics that can be used for the substrate include acrylic resin, polycarbonate resin, epoxy resin, polyester resin, polyamide resin, polyolefin resin, polyether resin, polysulfide resin, polysulfone resin, polyester sulfone resin, polyetherimide resin, and polyimide resin.

[0049] At least one of the pair of substrates constituting the liquid crystal element may be light-transmitting. If the substrate is light-transmitting, its haze value may be, for example, 3% or less, preferably 2% or less, or 1% or less. The total light transmittance of the light-transmitting substrate may be, for example, 70% or more, preferably 80% or more, or 90% or more.

[0050] The substrate may be non-transparent. When using a non-transparent substrate, a black substrate that does not reflect light on the non-display side can be used. Examples of black substrates include plastic substrates to which inorganic pigments such as carbon black have been added.

[0051] The electrodes only need to be arranged in such a way that a voltage can be applied to the liquid crystal layer. The electrodes may be placed on each of a pair of substrates to sandwich the liquid crystal layer, or a pair of electrodes may be placed on one of the substrates.

[0052] The electrodes may be transparent or opaque. Electrodes provided on a translucent substrate may be transparent. Examples of materials for forming transparent electrodes include indium oxide, indium tin oxide (ITO), tin oxide, PEDOT-PSS, silver nanorods, and carbon nanotubes. Transparent electrodes can be formed by sputtering, sol-gel, or printing methods.

[0053] Furthermore, the electrode layer used in the substrate paired with the substrate on which the transparent electrode is formed may be either a transparent electrode or an opaque electrode. For example, a GC electrode can be used as an opaque electrode.

[0054] The surface of the electrode layer of the liquid crystal element may be subjected to a rubbing treatment as needed. The rubbing treatment further improves the orientation of the liquid crystal.

[0055] In liquid crystal elements, a liquid crystal layer can be formed by arranging a pair of substrates with a gap (cell gap) between them via spacers or the like, and then applying a liquid crystal composition to that space. Alternatively, a liquid crystal layer can be placed in the space between substrates by coating or printing the liquid crystal composition onto the substrates.

[0056] The liquid crystal element may also include other components, such as a barrier film, an ultraviolet absorption layer, an anti-reflective layer, a hard coat layer, a dirt-resistant layer, an organic interlayer insulating film, a metal reflector, a phase difference plate, an alignment film, and the like. These may be used individually or in combination of two or more types.

[0057] Liquid crystal elements can be driven using a simple matrix drive system or an active matrix drive system using thin-film transistors (TFTs) or the like.

[0058] In a liquid crystal element, the absolute value of the driving voltage may be, for example, 0.1V or more and 20V or less, preferably 0.3V or more and 15V or less, or 0.5V or more and 1.0V or less. be.

[0059] Next, an example of a color tuning method for liquid crystal elements will be described. A liquid crystal composition containing an aromatic amine compound represented by formula (1) as a chiral dopant, a supporting electrolyte, and a host liquid crystal is injected into a counter electrode cell. The counter electrode cell into which the liquid crystal composition has been injected exhibits selective reflection. Next, color tuning is performed by applying a DC voltage to the counter electrode cell that is equal to or greater than the oxidation-reduction potential of the chiral dopant. The range of change in selective reflection length can be controlled by changing the molecular structure and electronic state of the chiral dopant, or by changing the application time (adjusting the reaction amount of the chiral dopant), etc.

[0060] To return the selective reflection wavelength to its original state, a voltage in the reverse direction is applied. For example, if the selective reflection wavelength was changed by applying a voltage of 1.5V, a voltage of -1.5V is applied to return the selective reflection wavelength to its original state. In this way, the selective reflection wavelength of the liquid crystal composition can be changed, and the reflected light of the liquid crystal element can be color-tuned.

[0061] display device The display device comprises the above-mentioned liquid crystal elements. By including liquid crystal elements configured to be color-adjustable by the voltage applied to the liquid crystal layer, a reflective display device driven by a simple matrix drive or an active matrix drive can be configured.

[0062] Dimming device The dimming device includes the liquid crystal element. By including a liquid crystal element configured to be color - adjustable by the voltage applied to the liquid crystal layer, a dimming device can be configured to exhibit a desired reflected or transmitted circularly polarized light color.

[0063] The present invention may include the following aspects. [1] An aromatic amine compound represented by the following formula (1).

[0064] [Chemical formula]

[0065] In formula (1), A 1 each independently represents a substituted or unsubstituted alkylene group, or a substituted or unsubstituted divalent aromatic group. A 2 and A 3 each independently represents a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. At least one of A 1 , A 2 and A 3 represents an aromatic group. s and t each independently represent an integer from 0 to 6. R 1 and R 2 each independently represent a substituent. p + s and q + t each independently represent an integer from 0 to 6. T represents a divalent linking group formed from at least one selected from the group consisting of a carbonyl group, an oxygen atom, an imino group, and an alkylene group. Q represents a trivalent linking group composed of at least one selected from the group consisting of an oxygen atom, a nitrogen atom, a carbon atom, a phosphorus atom, a sulfur atom, and a hydrogen atom.

[0066] [2] The aromatic amine compound according to [1], wherein T in the formula (1) is a divalent linking group formed including at least a carbonyl group.

[0067] [3] The aromatic amine compound according to [1] or [2], wherein Q in the formula (1) is represented by the following formula (2a) or (2b).

[0068] [ka]

[0069] In formulas (2a) and (2b), * indicates the bonding position with other atoms. 1 , X 2 and X 3 These are, independently, an oxygen atom, a sulfur atom, and -C(R) 3 )(R 4 )- and -N(R 5 )- and includes at least one selected from the group consisting of R 3 , R 4 and R 5 Each of these independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. 1 and Y 2 Each of these independently represents one selected from the group consisting of a substituted or unsubstituted alkanetriyl group, a nitrogen atom, and -P(=O)(O-)-.

[0070] [4] Q in equation (1) above is expressed by equation (2a) above, X 1 and X 2 [3] Aromatic amine compounds, which represent an oxygen atom.

[0071] [5] Q in equation (1) is expressed by equation (2a) above, and Y 1 [3] or [4] is an aromatic amine compound representing a propane-1,2,3-triyl group.

[0072] [6] In formula (1), T is an aromatic amine compound according to any one of [1] to [5], where T is independently a carbonyloxy group or an oxycarbonyl group.

[0073] A liquid crystal composition comprising an aromatic amine compound as described in any of [7] [1] to [6].

[0074] [8] The liquid crystal composition according to [7], further comprising a liquid crystal compound and an electrolyte.

[0075] A liquid crystal element comprising a liquid crystal layer containing the liquid crystal composition described in [9] [7] or [8], and a pair of electrodes for applying a voltage to the liquid crystal layer.

[0076]

[10] [9] A display device or dimming device comprising the liquid crystal elements described above.

[0077] The present invention, in other embodiments, includes the use of an aromatic amine compound represented by formula (1) in the production of a liquid crystal composition containing the aromatic amine compound, the use of an aromatic amine compound represented by formula (1) in the production of a liquid crystal element containing the liquid crystal composition, and the use of an aromatic amine compound represented by formula (1) in the production of a liquid crystal display device or dimming device containing the liquid crystal element. In yet another embodiment, the present invention includes an aromatic amine compound represented by formula (1) used in a liquid crystal composition containing the aromatic amine compound, and an aromatic amine compound represented by formula (1) used in a liquid crystal element, liquid crystal display device or dimming device containing the liquid crystal composition. [Examples]

[0078] The present invention will be described in detail below with reference to examples, but the present invention is not limited to these examples.

[0079] Reference example 1

[0080] [ka]

[0081] As shown in the scheme above, BN-OH was synthesized using a known method (e.g., J.Am.Chem.Soc.,2018,140,10946).

[0082] Example 1 Synthesis of the precursor TPA-OMe-COOH

[0083] [ka]

[0084] As shown in the scheme above, under a nitrogen atmosphere, 1.15 g (5.0 mmol) of 4,4'-dimethoxydiphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 1.40 g (5.2 mmol) of methyl 4-iodobenzoate (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.72 g (7.5 mmol) of sodium tert-butoxide (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.15 g (0.5 mmol) of tri-tert-butylphosphonium tetrafluoroborate (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.15 g (0.25 mmol) of bis(dibenzylideneacetone)palladium(0) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 100 mL of toluene (super-dehydrated) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a three-necked flask, and the mixture was stirred under heating and reflux for 7 hours, after which it was stirred at room temperature. After 1 day, the reaction solution was slowly added to 250 mL of 1 M aqueous ammonia solution to stop the reaction. The mixture was then filtered using Celite and washed with toluene. After removing the aqueous layer by liquid-liquid separatory, the organic layer was further separated with saturated brine, dehydrated with magnesium sulfate, and the solvent was removed using an evaporator. The mixture was then dried under reduced pressure to obtain a reddish-brown oily substance called TPA-OMe-COOMe.

[0085] Oily TPA-OMe-COOMe was dissolved in 50 mL of THF (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 50 mL of ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). 50 mL of 2 M potassium hydroxide aqueous solution was added, and the mixture was heated under reflux for 1 hour. After cooling, the THF and ethanol were removed using an evaporator. 100 mL of ultrapure water was added, and 2 M HCl aqueous solution was slowly added until the solution became acidic, forming a yellowish-white precipitate. 200 mL of dichloromethane (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added to dissolve the yellowish-white precipitate, and the aqueous layer was removed by liquid-liquid extraction. Subsequently, liquid-liquid extraction was performed with saturated saline solution, and the organic layer was dehydrated with magnesium sulfate. The solvent was removed using an evaporator, and the mixture was dried under reduced pressure to obtain a yellowish-brown oily substance. The target compound was isolated from the oily substance using a silica gel column with ethyl acetate:hexane = 1:1 as the developing solvent (Rf = 0.5). After removing the solvent with an evaporator, 400 mg of the precursor TPA-OMe-COOH was obtained as a white powder by vacuum drying. For identification of the obtained compound, 1 It surpasses H-NMR.

[0086] 1 H-NMR (400 MHz, CDCl3): δ(ppm) 7.84(d, 2H), 7.11(d, 4H), 6.88(d, 4H), 6.81(d, 2H), 3.82(s, 6H).

[0087] Synthesis of compound BN-TPA-OMe

[0088] [ka]

[0089] Under a nitrogen atmosphere, 0.18 g (0.5 mmol) of compound TPA-OMe-COOH, 0.18 g (0.5 mmol) of BN-OH, 0.14 g (0.75 mmol) of 1-(3-dimethylaminopropyl)-3-ethylcarbodiimide hydrochloride (Tokyo Chemical Industries), 0.06 g (0.5 mmol) of 4-dimethylaminopyridine (Tokyo Chemical Industries), and 30 mL of dichloromethane (Fujifilm Wako) were added to a three-necked flask and stirred at room temperature for 1 day. Dichloromethane was added to the reaction solution for extraction, and after liquid-liquid extraction with saturated saline, the organic layer was dehydrated with magnesium sulfate. After removing the solvent with an evaporator, the mixture was dried under reduced pressure to obtain a pale yellow powder. The target compound BN-TPA was purified using a silica gel column with ethyl acetate:hexane = 1:1 as the developing solvent (Rf = 0.5). After removing the solvent with an evaporator, 0.22 g of the target compound BN-TPA was obtained as a yellowish-white powder by vacuum drying. For identification, 1 1H-NMR and ESI-MS were used.

[0090] 1 H-NMR(400 MHz, CDCl3):δ(ppm) 7.96(dd, 2H), 7.88(d, 2H), 7.74(d, 2H), 7.56(d, 1H), 7.41(d, 1H) 7.35-7.39(m, 2H), 7.21-7.25(m, 2H+2H), 7.10(d, 4H), 6.87(d, 4H), 6.79(d, 2H), 4.73(dd, 1H), 4.61(d, 1H), 4.10-4.33(m, 4H), 3.81(s, 6H), 2.61-2.66(m, 1H); ESI-MS: m / z calc for C 45 H 37 NO6: 688.27 [M+H] + ; found 688.27.

[0091] Example 2 Synthesis of the precursor TPA-OC6-COOH

[0092] [ka]

[0093] As shown in the scheme above, the precursor TPA-OMe-COOH was synthesized in the same manner as the precursor TPA-OMe-COOH, except that bis[4-(hexyloxy)phenyl]amine (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 4,4'-dimethoxydiphenylamine, and methyl 4-bromobenzoate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of methyl 4-iodobenzoate. For the identification of the obtained precursor TPA-OC6-COOH, 1 It surpasses H-NMR.

[0094] 1 H-NMR(400 MHz, CDCl3):δ(ppm) 7.83(d, 2H), 7.10(d, 4H), 6.86(d, 4H), 6.80(d, 2H), 3.93(t, 4H), 1.74-1.81(m, 4H), 1.42-1.50(m, 4H), 1.30-1.40(m, 4H+4H), 0.91(t, 6H).

[0095] Synthesis of compound BN-TPA-OC6

[0096] [ka]

[0097] As shown in the scheme above, compound BN-TPA-OC6 was synthesized in the same manner as the synthesis of compound BN-TPA-OMe, except that the precursor TPA-OC6-COOH was used instead of the precursor TPA-OMe-COOH used in the synthesis of compound BN-TPA-OMe. For identification, 1 1H-NMR and ESI-MS were used.

[0098] 1H-NMR(400 MHz, CDCl3):δ(ppm) 7.96(dd, 2H), 7.88(d, 2H), 7.71(d, 2H), 7.55(d, 1H), 7.41(d, 1H) 7.33-7.40(m, 2H), 7.23-7.26(m, 2H+2H), 7.08(d, 4H), 6.84(d, 4H), 6.79(d, 2H), 4.73(dd, 1H), 4.61(d, 1H), 4.10-4.33(m, 4H), 3.93(s, 4H), 2.62-2.66(m, 1H), 1.74-1.81(m, 4H), 1.42-1.48(m, 4H), 1.40-1.31(m, 4H+4H), 0.91(t, 6H); ESI-MS: m / z calc for C 55 H 57 NO6: 828.43 [M+H] + ; found 828.43.

[0099] Example 3 Synthesis of the precursor TPA-Me-COOH

[0100] [ka]

[0101] As shown in the scheme above, the precursor TPA-Me-COOH was synthesized in the same manner as the precursor TPA-OMe-COOH, except that p,p'-ditolylamine (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of 4,4'-dimethoxydiphenylamine in the synthesis of the precursor TPA-OMe-COOH, and methyl 4-bromobenzoate (manufactured by Tokyo Chemical Industry Co., Ltd.) was used instead of methyl 4-iodobenzoate. For identification, 1 It surpasses H-NMR.

[0102] 1 H-NMR (400 MHz, CDCl3): δ(ppm) 7.86(d, 2H), 7.13(d, 4H), 7.05(d, 4H), 6.91(d, 2H), 2.34(s, 6H).

[0103] Synthesis of compound BN-TPA-Me

[0104] [ka]

[0105] As shown in the scheme above, compound BN-TPA-Me was synthesized in the same manner as the synthesis of compound BN-TPA-OMe, except that the precursor TPA-Me-COOH was used instead of the precursor TPA-OMe-COOH used in the synthesis of compound BN-TPA-OMe. For identification, 1 1H-NMR and ESI-MS were used.

[0106] 1 H-NMR(400 MHz, CDCl3):δ(ppm) 7.96(dd, 2H), 7.88(d, 2H), 7.75(d, 2H), 7.56(d, 1H), 7.41(d, 1H) 7.35-7.39(m, 2H), 7.23-7.26(m, 2H+2H), 7.12(d, 4H), 7.03(d, 4H), 6.89(d, 2H), 4.73(dd, 1H), 4.61(d, 1H), 4.10-4.31(m, 4H), 2.61-2.66(m, 1H), 2.33(s, 6H); ESI-MS: m / z calc for C 45 H 37 NO4: 656.28 [M+H] + ; found 656.28.

[0107] Example 4 Synthesis of the precursor TPA-tBu-COOH

[0108] [ka]

[0109] As shown in the scheme above, the precursor TPA-tBu-COOH was synthesized in the same manner as the synthesis of the precursor TPA-OMe-COOH, except that bis(4-tert-butylphenyl)amine (Tokyo Chemical Industries Co., Ltd.) was used instead of 4,4'-dimethoxydiphenylamine and methyl 4-bromobenzoate (Tokyo Chemical Industries Co., Ltd.) was used instead of methyl 4-iodobenzoate. For identification, 1 It surpasses H-NMR.

[0110] 1 H-NMR (400 MHz, CDCl3): δ(ppm) 7.87(d, 2H), 7.32(d, 4H), 7.08(d, 4H), 6.93(d, 2H), 1.32(s, 18H).

[0111] Synthesis of compound BN-TPA-tBu

[0112] [ka]

[0113] As shown in the scheme above, compound BN-TPA-tBu was synthesized in the same manner as the synthesis of compound BN-TPA-OMe, except that the precursor TPA-tBu-COOH was used instead of the precursor TPA-OMe-COOH used in the synthesis of compound BN-TPA-OMe. For identification, 1 1H-NMR and ESI-MS were used.

[0114] 1 H-NMR(400 MHz, CDCl3):δ(ppm) 7.96(dd, 2H), 7.88(d, 2H), 7.76(d, 2H), 7.56(d, 1H), 7.41(d, 1H) 7.35-7.39(m, 2H), 7.31(d, 4H),7.21-7.25(m, 2H+2H), 7.06(d, 4H), 6.91(d, 2H), 4.73(dd, 1H), 4.61(d, 1H), 4.11-4.31(m, 4H), 2.61-2.67(m, 1H), 1.32(s, 18H); ESI-MS: m / z calc for C 51 H 49 NO4: 740.37 [M+H] + ; found 740.37.

[0115] Example 5 Synthesis of precursor N2-H

[0116] [ka]

[0117] As shown in the scheme above, under a nitrogen atmosphere, 1.18 g (3.0 mmol) of 4-bromo-4,4'-dimethoxytriphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.40 g (3.2 mmol) of para-anisidine (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.43 g (4.5 mmol) of sodium tert-butoxide (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.17 g (0.3 mmol) of 1,1'-bis(diphenylphosphino)ferrocene (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.09 g (0.15 mmol) of bis(dibenzylideneacetone)palladium(0) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 30 mL of toluene (super-dehydrated) (manufactured by Fujifilm Wako) were added to a three-necked flask. The mixture was heated under reflux and stirred for 7 hours, and then stirred at room temperature. After 1 day, the reaction was stopped, filtered by Celite, and washed with toluene. The organic layer was separated with saturated brine, dehydrated with magnesium sulfate, the solvent was removed using an evaporator, and the mixture was dried under reduced pressure to obtain a reddish-brown oily substance. The target compound was isolated from the oily substance using a silica gel column with ethyl acetate:hexane = 1:3 as the developing solvent (Rf = 0.4). After removing the solvent with an evaporator, the mixture was dried under reduced pressure to obtain 0.96 g of the precursor N2-H as the target yellowish-brown oily substance. For identification, 1 It surpasses H-NMR.

[0118] 1 H-NMR (400 MHz, DMSO): δ(ppm) 7.71(s, 1H), 7.00(d, 2H), 6.80-6.89(m, 14H), 3.74(s, 6H), 3.71(s,3H).

[0119] Synthesis of precursor N2-COOH

[0120] [ka]

[0121] As shown in the scheme above, under a nitrogen atmosphere, 0.96 g (2.3 mmol) of synthesized N2-H, 1.1 g (4.2 mmol) of methyl 4-iodobenzoate (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.40 g (4.2 mmol) of sodium tert-butoxide (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.10 g (0.35 mmol) of tri-tert-butylphosphonium tetrafluoroborate (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.10 g (0.35 mmol) of bis(dibenzylideneacetone)palladium(0) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 50 mL of toluene (super-dehydrated) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a three-necked flask. The mixture was heated under reflux and stirred for 7 hours, and then stirred at room temperature. After 1 day, the reaction solution was slowly added to 250 mL of 1 M aqueous ammonia to stop the reaction. The mixture was then filtered by Celite and washed with toluene. After removing the aqueous layer by liquid-liquid separatory, the organic layer was further separated with saturated saline solution, dehydrated with magnesium sulfate, the solvent was removed using an evaporator, and the reddish-brown oily substance N2-COOMe was obtained by vacuum drying.

[0122] Oily N2-COOMe was dissolved in 50 mL of THF (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 50 mL of ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). 50 mL of 2 M potassium hydroxide aqueous solution was added, and the mixture was heated under reflux for 1 hour. After cooling, the THF and ethanol were removed using an evaporator. 100 mL of ultrapure water was added, and 2 M HCl aqueous solution was slowly added until the solution became acidic. 200 mL of dichloromethane (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the aqueous layer was removed by liquid-liquid separation. Subsequently, liquid-liquid separation was performed with saturated saline solution, and the organic layer was dehydrated with magnesium sulfate. The solvent was removed using an evaporator, and the mixture was dried under reduced pressure to obtain a yellowish-brown oily substance. The oily substance was isolated using a silica gel column with ethyl acetate:hexane = 1:1 as the developing solvent (Rf = 0.35). After removing the solvent using an evaporator, the mixture was dried under reduced pressure to obtain 0.19 g of the precursor N2-COOH as a yellowish-white powder. For identification, 1 It surpasses H-NMR.

[0123] 1 H-NMR(400 MHz, DMSO):δ(ppm) 12.31(s, 1H), 7.71(d, 2H), 7.14 (d, 2H), 7.10(d, 4H), 7.04(d, 2H), 6.98(d, 2H), 6.92(d, 4H), 6.78(d, 2H), 6.70(d, 2H), 3.77(s, 3H), 3.74(s, 6H).

[0124] Synthesis of compound BN-N2

[0125] [ka]

[0126] As shown in the scheme above, compound BN-N2 was synthesized in the same manner as the synthesis of compound BN-TPA-OMe, except that the precursor N2-COOH was used instead of the precursor TPA-OMe-COOH. For identification, 1 1H-NMR and ESI-MS were used.

[0127] 1 H-NMR(400 MHz, CDCl3):δ(ppm) 7.96(dd, 2H), 7.88(d, 2H), 7.74(d, 2H), 7.56(d, 1H), 7.41(d, 1H) 7.33-7.39(m, 2H), 7.21-7.25(m, 2H+2H), 7.11(d, 2H), 7.05(d, 4H), 6.94(d, 2H), 6.81-6.89(m, 10H), 4.73(dd, 1H), 4.61(d, 1H), 4.10-4.30(m, 4H), 3.81(s, 3H), 3.78(s, 6H), 2.60-2.65 (m, 1H); ESI-MS: m / z calc for C 58 H 48 N2O7: 885.3534 [M+H] + ; found 885.3477.

[0128] Example 6 Synthesis of precursor N3-H

[0129] [ka]

[0130] As shown in the scheme above, the precursor N3-H was synthesized using a known method (J.Mater.Chem.C.2018,6,6429.).

[0131] Synthesis of precursor N3-COOH

[0132] [ka]

[0133] As shown in the scheme above, under a nitrogen atmosphere, 2.5 g (4 mmol) of the synthesized N3-H, 1.1 g (4 mmol) of methyl 4-iodobenzoate (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.58 g (6 mmol) of sodium tert-butoxide (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.12 g (0.4 mmol) of tri-tert-butylphosphonium tetrafluoroborate (manufactured by Tokyo Chemical Industry Co., Ltd.), 0.12 g (0.2 mmol) of bis(dibenzylideneacetone)palladium(0) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.), and 100 mL of toluene (super-dehydrated) (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a three-necked flask. The mixture was stirred under heating and reflux for 7 hours, and then stirred at room temperature. After 1 day, the reaction solution was slowly added to 250 mL of 1 M aqueous ammonia solution to stop the reaction. The mixture was then filtered by Celite and washed with toluene. After removing the aqueous layer by liquid-liquid separatory, the organic layer was further separated with saturated saline solution, dehydrated with magnesium sulfate, the solvent was removed using an evaporator, and the reddish-brown oily substance N3-COOMe was obtained by vacuum drying.

[0134] Oily N3-COOMe was dissolved in 50 mL of THF (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) and 50 mL of ethanol (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.). 50 mL of 2 M sodium hydroxide aqueous solution was added, and the mixture was heated under reflux for 1 hour. After cooling, the THF and ethanol were removed using an evaporator. 100 mL of ultrapure water was added, and 2 M HCl aqueous solution was slowly added until the solution became acidic. 200 mL of dichloromethane (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) was added, and the aqueous layer was removed by liquid-liquid extraction. Liquid-liquid extraction was then performed using a brine, and the organic layer was dehydrated with magnesium sulfate. The solvent was removed using an evaporator, and the mixture was dried under reduced pressure to obtain a yellowish-brown oily substance. The oily substance was isolated using a silica gel column with ethyl acetate:hexane = 1:1 as the developing solvent (Rf = 0.35). After removing the solvent using an evaporator, the mixture was dried under reduced pressure to obtain 0.47 g of the precursor N3-COOH as a yellowish-white powder. For identification, 1 It surpasses H-NMR.

[0135] 1H-NMR (400 MHz, CDCl3): δ(ppm) 7.84(d, 2H), 7.06 (d, 8H), 6.98(d, 4H), 6.87(d, 2H), 6.86(d, 4H), 6.82(d, 8H), 3.80(s, 12H).

[0136] Synthesis of compound BN-N3

[0137] [ka]

[0138] As shown in the scheme above, compound BN-N3 was synthesized in the same manner as the synthesis of compound BN-TPA-OMe, except that the precursor N3-COOH was used instead of the precursor TPA-OMe-COOH. For identification, 1 1H-NMR and ESI-MS were used.

[0139] 1 H-NMR(400 MHz, CDCl3):δ(ppm) 7.95(dd, 2H), 7.87(d, 2H), 7.75(d, 2H), 7.55(d, 1H), 7.41(d, 1H) 7.33-7.39(m, 2H), 7.21-7.25(m, 2H+2H), 7.05(d, 8H), 6.95(d, 4H), 6.87(d, 2H), 6.86(d, 4H), 6.82(d, 8H), 4.72(dd, 1H), 4.60(d, 1H), 4.09-4.32(m, 4H), 3.78(s, 12H), 2.60-2.65(m, 1H); ESI-MS: m / z calc for C 71 H 59 N3O8: 1082.4375 [M+H] + ; found 1082.4302.

[0140] Comparative Example 1 Referring to J.Am.Chem.Soc.2018,140,10946., we prepared a comparative compound BN-Fc, represented by the following structural formula, which has a ferrocene skeleton instead of an aromatic amine skeleton.

[0141] [ka]

[0142] Evaluation by electrochemical measurement Preparation of sample solutions The compounds BN-TPA-OMe, BN-TPA-OC6, BN-TPA-Me, BN-TPA-tBu, BN-N2, BN-N3, and the comparative compound BN-Fc prepared above were each dissolved in a 100 mM tetrabutylammonium tetrafluoroborate / dichloromethane solution to a concentration of 1 mM to prepare sample solutions for electrochemical measurement.

[0143] measurement The prepared sample solutions were subjected to CV measurements using an electrochemical analyzer (Model 660E; BAS). A non-aqueous Ag / Ag was used as the reference electrode. + Measurements were taken using a reference electrode RE-7 (BAS Corporation), a GC electrode as the working electrode, and a platinum electrode as the counter electrode. The sweep voltage ranged from -0.2 to 1.3V (vs. Ag / Ag). + CV measurements were performed with a sweep rate of 0.05 V / sec and 10 sweeps. Figure 1(a) shows the cyclic voltammogram of compound BN-TPA-Me, and Figure 1(b) shows the cyclic voltammogram of the comparative compound BN-Fc relative to ferrocene. Table 1 also shows the redox potential and 1V(vs.Ag / Ag) of each compound. + Table 1 shows the results of the evaluation of the stability against redox reactions in the above conditions. Stability was evaluated by the waveform change of the cyclic voltammogram during CV measurements with 10 sweeps. Specifically, "stable" was evaluated when no change was observed between the waveform after 1 sweep and the waveform after 10 sweeps.

[0144] [Table 1]

[0145] As shown in Figure 1 and Table 1, the compounds in the examples are stable against redox reactions. Furthermore, compounds having multiple aromatic amine moieties exhibit multiple redox potentials.

[0146] Evaluation: Absorption spectrum measurement Preparation of sample solutions The compounds BN-TPA-OMe, BN-TPA-OC6, BN-TPA-Me, BN-TPA-tBu, BN-N2, BN-N3, and the comparative compound BN-Fc prepared above were each dissolved in dichloromethane to a concentration of 0.1 mM to prepare sample solutions for absorption spectrum measurement.

[0147] measurement The prepared sample solutions were placed in a quartz cell with a path length of 0.1 cm, and the absorption spectra were measured using a UV-Vis spectrophotometer (UV1800, Shimadzu Corporation). Figure 2(a) shows the absorption spectrum of compound BN-TPA-Me, and Figure 2(b) shows the absorption spectrum of the comparative example compound BN-Fc. Table 2 shows the absorption edge wavelengths and the color tones of the liquid crystal compositions. The color tones of the liquid crystal compositions were evaluated by visual observation of liquid crystal composition samples used for transmission spectrum measurement, which will be described later.

[0148] [Table 2]

[0149] It can be seen that by using the compounds described in the examples, a colorless liquid crystal composition can be constructed.

[0150] Evaluation: Measurement of the transmission spectrum of a liquid crystal composition. A methylene chloride solution of a host liquid crystal molecule, prepared by mixing 4-cyano-4'-pentyloxybiphenyl and 4-cyano-4'-pentylbiphenyl in a 7:3 ratio, was then mixed with compounds BN-TPA-OMe, BN-TPA-OC6, BN-TPA-Me, BN-TPA-tBu, and comparative compound BN-Fc, each dissolved to a final concentration of 3 mol%. After adding 3 mol% of 1-ethyl-3-methylimidazolium triflate, the solution was concentrated under reduced pressure to prepare a liquid crystal composition sample.

[0151] measurement The liquid crystal composition samples prepared above were introduced into glass cells (manufactured by EHC) with a cell thickness of 5 μm and a polyimide alignment film that had been rubbed. Cholesteric liquid crystals were then formed at room temperature, and the transmission spectra were measured. The results are shown in Figure 3 and Table 3. Note that the reflection wavelengths in Table 3 are median values, and the reflection colors were evaluated by visual observation.

[0152] [Table 3]

[0153] It can be seen that by using the compounds described in the examples to construct a liquid crystal element exhibiting cholesteric liquid crystals, a wide range of reflective colors from red to blue-violet can be produced.

[0154] Evaluation: Change in reflected color due to voltage application Liquid crystal elements were fabricated by introducing the liquid crystal composition samples prepared above into a cell with a cell thickness of 10 μm, consisting of ITO glass and ITO glass spin-coated with Prussian blue nanoparticles. The transmission spectrum changes of the fabricated liquid crystal elements were measured before and after the application of a DC voltage (2V), and the change in reflected color due to voltage application was measured. Figure 4 shows the results for a liquid crystal element using BN-TPA-OMe as a chiral dopant as a representative example. Figure 4(a) is the transmission spectrum before the application of a DC voltage (2V), and Figure 4(b) is the transmission spectrum after the application of a DC voltage (2V). In Figure 4(a), the median reflection wavelength was 499 nm and the color was blue-green, and in Figure 4(b), the median reflection wavelength was 535 nm and the color was green.

[0155] Figure 4 shows that by using the compounds of the examples, a liquid crystal element in which the reflection wavelength changes when a voltage is applied can be constructed.

[0156] The disclosure of Japanese Patent Application No. 2022-177592 (filing date: November 4, 2022) is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards described herein are incorporated herein by reference to the same extent as if each individual document, patent application, and technical standard had been specifically and individually noted as being incorporated by reference.

Claims

1. An aromatic amine compound represented by the following formula (1). 【Chemistry 1】 (In formula (1), A １ Each of these independently represents a substituted or unsubstituted divalent aromatic group, A ２ and A ３ Each of these independently represents a substituted or unsubstituted aromatic group. s and t each independently represent an integer from 0 to 6. １ and R ２ Each of the following independently represents a substituent. p+s and q+t each independently represent an integer from 0 to 6. T each independently represents a divalent linking group that is either a methylenecarbonyloxy group or a methyleneoxycarbonyl group. Q represents a trivalent linking group represented by formula (2a). 【Chemistry 2】 In formula (2a), * indicates the bonding position with other atoms. １ and X ２ Y represents an oxygen atom. １ (This represents the propane-1,2,3-triyl group.)

2. The aromatic amine compound according to claim 1, wherein s and t in formula (1) are 0.

3. The aromatic amine compound according to claim 1, wherein p+s and q+t in formula (1) are 0.

4. A liquid crystal composition comprising the aromatic amine compound according to any one of claims 1 to 3.

5. The liquid crystal composition according to claim 4, further comprising a liquid crystal compound and an electrolyte.

6. A liquid crystal element comprising a liquid crystal layer containing the liquid crystal composition described in claim 4, and a pair of electrodes for applying a voltage to the liquid crystal layer.

7. A display device or dimming device comprising the liquid crystal element described in claim 6.

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