Aromatic amine compound, liquid crystal composition, liquid crystal element, display device, and light modulation device

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

Aromatic amine compound, liquid crystal composition, liquid crystal element, display device and light control device

[0001] The present invention relates to an aromatic amine compound, a liquid crystal composition, a liquid crystal device, a display device, and a light control device.

[0002] Liquid crystal display devices are used in a variety of places, including personal computers and televisions. Backlights are used in liquid crystal display devices, and they hold the key to further reducing the power consumption of these devices. Cholesteric liquid crystals are liquid crystals that can selectively reflect light, and reflective displays using these liquid crystals are devices that can control light with low power consumption. For example, Japanese Patent Application Laid-Open No. 2019-151597 and J. Am. Chem. Soc., 2018, 140, 10946 propose using a compound in which ferrocene is introduced as a redox moiety into a binaphthyl skeleton, which is a chiral moiety, as a chiral dopant to form cholesteric liquid crystal. Furthermore, it is said that the reflection wavelength of cholesteric liquid crystals can be controlled by applying a voltage to a liquid crystal composition layer containing a chiral dopant into which ferrocene has been introduced using a redox reaction.

[0003] An object of one embodiment of the present invention is to provide an aromatic amine compound that can serve as a chiral dopant that can be stably oxidized and reduced in a liquid crystal composition.

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

[0005]

[0006] In formula (1), A １ A each independently represents a substituted or unsubstituted alkylene group, or a substituted or unsubstituted divalent aromatic group. ２ and A ３ A each 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 the groups s and t represents an aromatic group. Each of s and t independently represents an integer of 0 to 6. １ and R ２each independently represents a substituent. p + s and q + t each independently represent an integer of 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 aspect is a liquid crystal composition containing the aromatic amine compound of the first aspect. A third aspect is a liquid crystal element comprising a liquid crystal layer containing the liquid crystal composition of the second aspect and a pair of electrodes for applying a voltage to the liquid crystal layer. A fourth aspect is a display device or a light control device comprising the liquid crystal element of the third aspect.

[0008] According to one aspect of the present invention, it is possible to provide an aromatic amine compound that can serve as a chiral dopant that can be stably oxidized and reduced in a liquid crystal composition.

[0009] (a) is an example of a cyclic voltammogram with a ferrocene standard of the compound according to Example 3, and (b) is an example of a cyclic voltammogram with a ferrocene standard of the compound according to Comparative Example 1. (a) is an example of an absorption spectrum of the compound according to Example 3, and (b) is an example of an absorption spectrum of the compound according to Comparative Example 1. (b) is an example of a transmission spectrum of a liquid crystal composition including the compounds according to the Examples and Comparative Examples. (a) is an example of a transmission spectrum before application of a DC voltage, and (b) is an example of a transmission spectrum after application of a DC voltage.

[0010] As used herein, the term "process" refers not only to an independent process, but also to processes that cannot be clearly distinguished from other processes, as long as the intended purpose of the process is achieved. Furthermore, the content of each component in a composition refers to the total amount of the multiple substances present in the composition, unless otherwise specified, when multiple substances corresponding to each component are present in the composition. Furthermore, 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. Hereinafter, embodiments of the present invention will be described in detail. However, the embodiments described below exemplify aromatic amine compounds, liquid crystal compositions, liquid crystal elements, display devices, and light control devices that embody the technical concepts 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 light control devices shown below.

[0011] Aromatic Amine Compound The aromatic amine compound is represented by the following formula (1). As represented by the following formula (1), the aromatic amine compound contains a binaphthyl skeleton as a chiral moiety and an aromatic amine skeleton as a redox moiety. The compound represented by the following formula (1) has an aromatic amine skeleton as a redox moiety, and thus can stably undergo repeated electrochemical redox reactions in the atmosphere, in a solution, in a liquid crystal composition, and the like. That is, the aromatic amine compound represented by formula (1) can reversibly exhibit ionic and nonionic properties in response to an electrical stimulus. It is believed that such an optically active, electrically responsive compound can control the molecular arrangement of the helical structure of cholesteric liquid crystal, for example, by electrical stimulation. This allows the period (pitch) of the helical structure formed by the cholesteric liquid crystal to be controlled, thereby controlling the wavelength of circularly polarized light selectively reflected by the cholesteric liquid crystal. Specifically, a longer pitch of the helical structure reflects longer wavelength light, and a shorter pitch reflects shorter wavelength light.

[0012] The aromatic amine compound may be configured so as not to have any absorption in the visible light region. This allows, for example, a colorless liquid crystal composition that has no absorption in the visible light region to be formed. The aromatic amine compound that has no absorption in the visible light region can be obtained, for example, by appropriately selecting a substituent on the aromatic amine skeleton, a substituent on the binaphthyl skeleton, or the like.

[0013]

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

[0015] A １ The alkylene group represented by the formula (I) may be linear, branched, or cyclic, or may be a combination thereof. １ The number of carbon atoms in the alkylene group represented by the formula (I) may be, for example, 1 or more and 20 or less, and preferably 1 or more or 10 or less. １ The divalent aromatic group represented by the formula (I) 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 contain at least one heteroatom selected from the group consisting of nitrogen, oxygen, and sulfur atoms. The number of members of 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 the aromatic amine compound, A １When a plurality of alkylene groups or divalent aromatic groups represented by the following formula are present, they may be the same or different.

[0016] A １ The alkylene group or divalent aromatic group represented by the formula (I) may have a substituent. １ The substituent in may be at least one type of substituent selected from the group consisting of a substituted or unsubstituted hydrocarbon group, a nitro group, a cyano group, a halogen atom, a hydroxy group, an alkoxy group, an acyl group, an alkoxycarbonyl group, a carboxy group, an aliphatic amino group, and an aromatic amino group.

[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 aliphatic group may have, for example, 1 to 20 carbon atoms, preferably 1 to 10 or 1 to 6 carbon atoms. Examples of substituents in the aliphatic group include halogen atoms, aryl groups, and alkoxy groups. The aromatic group may have, for example, 6 to 18 carbon atoms, preferably 6. Examples of substituents in the aromatic group include halogen atoms, aliphatic groups having 1 to 20 carbon atoms, alkoxy groups, acyl groups, and alkoxycarbonyl groups.

[0018] The halogen atom in the substituent may include a fluorine atom, a chlorine atom, a bromine atom, 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 carbon number of 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 mono-substituted aliphatic amino group having one aliphatic group, or a di-substituted aliphatic amino group having two aliphatic groups. The aliphatic amino group may further have a substituent in the aliphatic group moiety. Examples of the substituent in the aliphatic group include a halogen atom, an aryl group, an alkoxy group, an alkylamino group, and an arylamino group. 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 contain at least one selected from the group consisting of a phenyl group, a naphthyl group, and an anthracenyl group. The aromatic heterocyclic group may contain 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 contain 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 mono-substituted aromatic amino group having one aromatic group, or a di-substituted aromatic amino group having two aromatic groups. The aromatic amino group may further have a substituent in the aromatic group portion. Examples of substituents in the aromatic group include a halogen atom, an aryl group, an alkoxy group, an alkylamino group, an arylamino group, and an alkyl group. The number of substitutions in the aromatic group may be, for example, 0 or more and 8 or less, and preferably 5 or less.

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

[0022] A ２ or A ３ The alkyl group represented by the formula (I) may be linear, branched, or cyclic, or may be a combination thereof. ２ or A ３ The number of carbon atoms in the alkyl group represented by the formula (I) may be, for example, 1 or more and 20 or less, and preferably 1 or more or 6 or less. ２ or A ３ The aromatic group represented by the formula (I) is formed by removing one hydrogen atom from an aromatic hydrocarbon compound or an aromatic heterocyclic compound. For details of aromatic hydrocarbon compounds and aromatic heterocyclic compounds, see A １ The aromatic hydrocarbon compounds and aromatic heterocyclic compounds in the above are the same as those in the above. ２ or A ３ When a plurality of alkyl groups or aromatic groups represented by the formula (I) are present, they may be the same or different.

[0023] A ２ or A ３ The alkyl group or aromatic group represented by the formula (I) may have a substituent. ２ or A ３ The substituents in A １ The substituents are the same as those in A. ２ or A ３ The number of substitutions in the alkyl group or aromatic group represented by the formula (I) may be, for example, 0 or more and 20 or less, and preferably 5 or less.

[0024] A ２ or A ３ At least one of the aromatic groups represented by the formula (I) may have a substituent, and may have an aromatic amino group as the substituent. ２ or A ３The aromatic amino group substituting the aromatic group represented by formula (I) may be a disubstituted aromatic amino group, and the aromatic group in the aromatic amino group may further have a substituent. Examples of the substituent in the aromatic group include a halogen atom, an aryl group, an alkoxy group, an alkylamino group, an arylamino group, and an alkyl group. 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 A represents an aromatic group, but preferably at least two may be aromatic groups, and more preferably three may be aromatic groups. １ , A ２ and A ３ At least A １ may be an aromatic group, and A ２ and A ３ At least one of them may be an aromatic group.

[0026] Each of s and t independently represents an integer of 0 to 6. Preferably, it may be an integer of 5 or less, or an integer of 2 or less, or it may be an integer of 1 or more. Furthermore, each of p and q independently represents an integer of 0 to 6. Preferably, it may be an integer of 5 or less, or an integer of 2 or less, or it may be an integer of 1 or more. Furthermore, p + s and q + t independently represent an integer of 0 to 6. Preferably, it may be an integer of 5 or less, or an integer of 2 or less, or it may be an integer of 1 or more.

[0027] R １ and R ２ R each independently represents a substituent. １ or R ２ Examples of the substituent represented by the formula: １ In the aromatic amine compound, R １ or R ２ When a plurality of substituents represented by the following formula are present, they may be the same or different.

[0028] Each 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 substituting the imino group is selected from the group consisting of A １ The alkylene group represented by T may be linear, branched, or cyclic, or a combination thereof. The number of carbon atoms in the alkylene group represented by 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 contain, for example, an ester bond formed by bonding a carbonyl group and an oxygen atom, an amide bond, urea bond, urethane bond, or the like formed by bonding a carbonyl group and an imino group, or an ether bond formed by bonding an oxygen atom and an alkylene group. When a plurality of divalent linking groups represented by T are present in the aromatic amine compound, they may be the same or different.

[0029] The divalent linking group represented by T may be formed containing at least a carbonyl group. Specific 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 the like. Preferred examples of the divalent linking group represented by T include a carbonyloxy group, an oxycarbonyl group, an oxygen atom, and the like.

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

[0031]

[0032] In formulas (2a) and (2b), * indicates the bonding position to other atoms. １ , X ２ and X ３ are each independently an oxygen atom, a sulfur atom, or —C(R ３ ) (R ４ )- and -N(R ５ )-R ３ , R ４ and R ５ each independently represents a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. １ and Y ２ each independently represents one member 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 may be 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 or more and 20 or less, and preferably 6 or less. ３ , R ４ or R ５ The aromatic group represented by R is formed by removing one hydrogen atom from an aromatic hydrocarbon compound or an aromatic heterocyclic compound. The aromatic hydrocarbon compound or aromatic heterocyclic compound is as described above. ３ , R ４ or R ５ The substituents in A １ The substituents are the same as those in

[0034] Y １ or Y ２The alkanetriyl group represented by the formula (I) 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 to 20, preferably 6 or less. １ or Y ２ The substituents in A １ The substituents are the same as those in

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

[0036]

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

[0038]

[0039] The trivalent linking group represented by Q may preferably be represented by formula (2a), and more preferably, X in formula (2a) １ and X ２ may be an oxygen atom, 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 dihaloalkane having a substituent is reacted with 1,1'-bi(2-naphthol) to introduce a trivalent linking group represented by Q, and an aromatic amine derivative is linked to the trivalent linking group represented by Q by a condensation reaction, a substitution reaction, a coupling reaction, or the like, thereby producing the compound represented by formula (1). Alternatively, an aromatic amine derivative can be linked to the naphthyl ring by using 1,1'-bi(2-naphthol) having an appropriate substituent on the naphthyl ring.

[0041] Liquid crystal composition The liquid crystal composition contains at least one aromatic amine compound represented by the above formula (1). A liquid crystal composition containing the aromatic amine compound represented by formula (1) can exhibit, for example, cholesteric liquid crystal. Furthermore, the liquid crystal composition exhibits selective reflection and can change the selective reflection wavelength by a redox reaction caused 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 % or more and 10 mol % or less, and preferably 0.5 mol % or more and 5 mol % or less.

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

[0043] The liquid crystal compound constituting the liquid crystal composition can be a liquid crystal compound showing a nematic phase or a liquid crystal compound showing a smectic phase, and preferably a liquid crystal compound showing a nematic phase.Specific examples of the liquid crystal compound include 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, tolan compounds, fluorine-substituted tolan compounds, and alkenylcyclohexylbenzonitrile compounds.For details of the liquid crystal compound, refer to, for example, the description in Liquid Crystal Device Handbook, edited by the 142nd Committee of the Japan Society for the Promotion of Science, Nikkan Kogyo Shimbun, 1989, pages 154-192 and 715-722.

[0044] The liquid crystal composition may further contain an electrolyte. By including an electrolyte, the liquid crystal composition can be made conductive, and the oxidation-reduction reaction of the compound represented by formula (1) can be facilitated. The electrolyte may be a supporting electrolyte constituting the liquid crystal composition, and may be selected from compounds that are highly soluble in the host liquid crystal. The electrolyte may be a supporting electrolyte commonly used in electrochemistry (e.g., nBu ４ NPF ６ , nBu ４ NBF ４ , nBu ４ NClO ４ Examples of the ionic liquid 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 electrolytes. The content of the electrolyte in the liquid crystal composition may be, for example, 0.1 mol % or more and 30 mol % or less, and preferably 0.5 mol % or more and 15 mol % or less.

[0045] Various liquid crystal and non-liquid crystal compounds can be added to the liquid crystal composition for the purposes of changing the physical properties of the host liquid crystal (e.g., the temperature range of the liquid crystal phase) to a desired range and promoting the oxidation-reduction reaction. Additives such as ultraviolet absorbers and antioxidants may also be added. Furthermore, the liquid crystal composition may contain a chiral dopant other than the aromatic amine compound represented by formula (1).

[0046] Liquid crystal element The liquid crystal element is configured to include a liquid crystal layer containing the above liquid crystal composition and a pair of electrodes for applying a voltage to the liquid crystal layer. By including a liquid crystal layer containing the above liquid crystal composition, the liquid crystal element can exhibit, for example, a reflected color due to the development of cholesteric liquid crystal. Furthermore, by applying a voltage to the liquid crystal layer via the pair of electrodes, the reflected color can be changed.

[0047] The liquid crystal element may include a liquid crystal layer, a pair of substrates that support the liquid crystal layer, and an electrode that is disposed on at least one of the substrates and applies a voltage to the liquid crystal layer. The liquid crystal element may further include a black plate, an anti-reflection film, a brightness enhancement film, etc., as necessary.

[0048] The material of the substrate constituting the liquid crystal element may be glass, plastic, etc. 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. When 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-light-transmitting. When a non-light-transmitting substrate is used as the substrate, a black substrate that does not have light reflectivity 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 may be disposed on each of a pair of substrates so as to sandwich the liquid crystal layer, or a pair of electrodes may be disposed on one of the substrates so as to be able to apply a voltage to the liquid crystal layer.

[0052] The electrode may be a transparent electrode or a non-transparent electrode. The electrode provided on the light-transmitting substrate may be a transparent electrode. Examples of materials for forming the transparent electrode include indium oxide, indium tin oxide (ITO), tin oxide, PEDOT-PSS, silver nanorods, and carbon nanotubes. The transparent electrode can be formed by a sputtering method, a sol-gel method, or a printing method.

[0053] The electrode layer of the substrate paired with the substrate on which the transparent electrode is formed may be a transparent electrode or a non-transparent electrode. For example, a GC electrode or the like can be used as the non-transparent electrode.

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

[0055] In a liquid crystal element, a pair of substrates are arranged with a gap (cell gap) between them via a spacer or the like, and a liquid crystal composition is applied to the space to form a liquid crystal layer. Alternatively, a liquid crystal layer can be disposed in the space between the substrates by applying or printing the liquid crystal composition onto the substrates.

[0056] The liquid crystal element may also include other members such as a barrier film, an ultraviolet absorbing layer, an anti-reflection layer, a hard coat layer, an anti-fouling layer, an organic interlayer insulating film, a metal reflector, a retardation film, an alignment film, etc. These may be used alone or in combination of two or more.

[0057] The liquid crystal element can be driven by a simple matrix driving method or an active matrix driving method using thin film transistors (TFTs) or the like.

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

[0059] Next, an example of a method for toning the color of a liquid crystal element 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 toning is performed by applying a DC voltage equal to or higher than the redox potential of the chiral dopant to the counter electrode cell. The change in the selective reflection length can be controlled by changing the molecular structure or electronic state of the chiral dopant, or by changing the application time (adjusting the reaction amount of the chiral dopant), etc.

[0060] To restore the selective reflection wavelength to its original state, a voltage in the opposite direction is applied. For example, if a voltage of 1.5 V is applied to change the selective reflection wavelength, a voltage of −1.5 V is applied to restore 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 color of the reflected light of the liquid crystal element can be adjusted.

[0061] A display device includes the above-described liquid crystal element. By including a liquid crystal element configured to be able to adjust the color by changing the voltage applied to the liquid crystal layer, a reflective display device driven by a simple matrix drive system or an active matrix drive system can be configured.

[0062] A light control device includes the liquid crystal element described above. By including a liquid crystal element configured to be able to adjust the color by applying a voltage to the liquid crystal layer, it is possible to configure a light control device that exhibits a desired reflected light color or transmitted light color of circularly polarized light.

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

[0064]

[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; A １ , A ２ and A ３ At least one of the groups s and t represents an aromatic group. Each of s and t independently represents an integer of 0 to 6. １ and R ２ each independently represents a substituent. p + s and q + t each independently represent an integer of 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.

[0066] [2] The aromatic amine compound according to [1], wherein T in the formula (1) is a divalent linking group formed by containing 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]

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

[0070] [4] Q in the formula (1) is represented by the formula (2a), and X １ and X ２ represents an oxygen atom.

[0071] [5] Q in the formula (1) is represented by the formula (2a), and Y １ represents a propane-1,2,3-triyl group.

[0072] [6] The aromatic amine compound according to any one of [1] to [5], wherein T in the formula (1) each independently represents a carbonyloxy group or an oxycarbonyl group.

[0073] [7] A liquid crystal composition containing the aromatic amine compound according to any one of [1] to [6].

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

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

[0076]

[10] A display device or a light control device comprising the liquid crystal element according to [9].

[0077] Other aspects of the present invention include 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 light control device containing the liquid crystal element. Still other aspects of the present invention include the aromatic amine compound represented by formula (1) used in a liquid crystal composition containing the aromatic amine compound, and the aromatic amine compound represented by formula (1) used in a liquid crystal element, liquid crystal display device, or light control device containing the liquid crystal composition.

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

[0079] Reference example 1

[0080]

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

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

[0083]

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

[0085] The oily TPA-OMe-COOMe was dissolved in 50 mL of THF (FUJIFILM Wako Pure Chemical Industries, Ltd.) and 50 mL of ethanol (FUJIFILM Wako Pure Chemical Industries, Ltd.). 50 mL of 2M aqueous potassium hydroxide solution was added, and the mixture was heated to reflux for 1 hour. After cooling, the THF and ethanol were removed using an evaporator, 100 mL of ultrapure water was added, and 2M aqueous HCl was slowly added until the solution became acidic, producing a yellow-white precipitate. 200 mL of dichloromethane (FUJIFILM Wako Pure Chemical Industries, Ltd.) was added to dissolve the yellow-white precipitate, and the aqueous layer was removed by separation. The mixture was then separated with saturated saline, and the organic layer was dehydrated with magnesium sulfate. The solvent was then removed using an evaporator and dried under reduced pressure, yielding a yellow-brown oily substance. The oily substance was then purified using a silica gel column with a 1:1 ethyl acetate:hexane mixture as a developing solvent, and the target compound was isolated (Rf = 0.5). After removing the solvent with an evaporator, the product was dried under reduced pressure to obtain 400 mg of the precursor TPA-OMe-COOH as a white powder. １ H-NMR was used.

[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]

[0089] Under a nitrogen atmosphere, 0.18 g (0.5 mmol) of the 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 Industry Co., Ltd.), 0.06 g (0.5 mmol) of 4-dimethylaminopyridine (Tokyo Chemical Industry Co., Ltd.), and 30 mL of dichloromethane (Fujifilm Wako Co., Ltd.) were added to a three-neck flask and stirred at room temperature for one day. The reaction solution was extracted with dichloromethane and separated with saturated saline, after which 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 pale yellow powder. The target compound BN-TPA was purified using a silica gel column with a 1:1 mixture of ethyl acetate and hexane as a developing solvent (Rf = 0.5). After removing the solvent with an evaporator, the residue was dried under reduced pressure to obtain 0.22 g of the final target compound BN-TPA as a yellowish white powder. １ H-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 37NO6: 688.27 [M+H] + ; found 688.27.

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

[0092]

[0093] As shown in the above scheme, the precursor TPA-OMe-COOH was synthesized in the same manner as in the synthesis of precursor TPA-OMe-COOH, except that bis[4-(hexyloxy)phenyl]amine (Tokyo Chemical Industry Co., Ltd.) was used instead of 4,4'-dimethoxydiphenylamine, and methyl 4-bromobenzoate (Tokyo Chemical Industry Co., Ltd.) was used instead of methyl 4-iodobenzoate. The resulting precursor TPA-OC6-COOH was identified as follows: １ H-NMR was used.

[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]

[0097] As shown in the above scheme, the compound BN-TPA-OC6 was synthesized in the same manner as in the synthesis of the 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 the compound BN-TPA-OMe. １ H-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 precursor TPA-Me-COOH

[0100]

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

[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]

[0105] As shown in the above scheme, the compound BN-TPA-Me was synthesized in the same manner as in the synthesis of the 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 the compound BN-TPA-OMe. １ H-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 precursor TPA-tBu-COOH

[0108]

[0109] As shown in the above scheme, the precursor TPA-tBu-COOH was synthesized in the same manner as in the synthesis of the compound TPA-OMe-COOH, except that bis(4-tert-butylphenyl)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. １ H-NMR was used.

[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]

[0113] As shown in the above scheme, the compound BN-TPA-tBu was synthesized in the same manner as in the synthesis of the 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 the compound BN-TPA-OMe. １ H-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]

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

[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]

[0121] As shown in the above scheme, 0.96 g (2.3 mmol) of the synthesized N2-H, 1.1 g (4.2 mmol) of methyl 4-iodobenzoate (Tokyo Chemical Industry Co., Ltd.), 0.40 g (4.2 mmol) of sodium tert-butoxide (Tokyo Chemical Industry Co., Ltd.), 0.10 g (0.35 mmol) of tri-tert-butylphosphonium tetrafluoroborate (Tokyo Chemical Industry Co., Ltd.), 0.10 g (0.35 mmol) of bis(dibenzylideneacetone)palladium(0) (Fujifilm Wako Pure Chemical Industries, Ltd.), and 50 mL of toluene (ultra-dehydrated) (Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a three-neck flask under a nitrogen atmosphere, and the mixture was stirred under reflux for 7 hours, followed by stirring at room temperature. After one day, the reaction solution was slowly added to 250 mL of 1 M aqueous ammonia to quench the reaction. The mixture was then filtered through Celite and washed with toluene. After the aqueous layer was removed by separation, the organic layer was further separated with saturated brine, dehydrated with magnesium sulfate, and then the solvent was removed with an evaporator. The residue was dried under reduced pressure to obtain a reddish-brown oily substance, N2-COOMe.

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

[0123] 1H-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]

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

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

[0131] Synthesis of precursor N3-COOH

[0132]

[0133] As shown in the above scheme, 2.5 g (4 mmol) of the synthesized N3-H, 1.1 g (4 mmol) of methyl 4-iodobenzoate (Tokyo Chemical Industry Co., Ltd.), 0.58 g (6 mmol) of sodium tert-butoxide (Tokyo Chemical Industry Co., Ltd.), 0.12 g (0.4 mmol) of tri-tert-butylphosphonium tetrafluoroborate (Tokyo Chemical Industry Co., Ltd.), 0.12 g (0.2 mmol) of bis(dibenzylideneacetone)palladium(0) (Fujifilm Wako Pure Chemical Industries, Ltd.), and 100 mL of toluene (ultra-dehydrated) (Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a three-neck flask under a nitrogen atmosphere, and the mixture was stirred under reflux for 7 hours, followed by stirring at room temperature. After one day, the reaction solution was slowly added to 250 mL of 1 M aqueous ammonia to quench the reaction. The mixture was then filtered through Celite and washed with toluene. After the aqueous layer was removed by separation, the organic layer was further separated with saturated brine, dehydrated with magnesium sulfate, and then the solvent was removed with an evaporator. The residue was dried under reduced pressure to obtain a reddish-brown oily substance, N3-COOMe.

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

[0135] 1 H-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]

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

[0139] 1H-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 calculation for C 71 H 59 N3O8: 1082.4375 [M+H] + ; found 1082.4302.

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

[0141]

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

[0143] Measurement The prepared sample solution was subjected to CV measurement using an electrochemical measurement device (Model 660E; manufactured by BAS). ＋ Measurements were performed using a reference electrode RE-7 (manufactured by BAS), a GC electrode as the working electrode, and a platinum electrode as the counter electrode. The sweep voltage was −0.2 to 1.3 V (vs. Ag / Ag ＋CV measurements were performed at a scan rate of 0.05 V / sec and 10 scans. Figure 1(a) shows the cyclic voltammograms of the compound BN-TPA-Me and Figure 1(b) shows the cyclic voltammograms of the comparative compound BN-Fc, both based on ferrocene. Table 1 also shows the oxidation-reduction potentials of the compounds and their variances at 1 V (vs. Ag / Ag). ＋ The evaluation results of the stability against the redox reaction in the above are shown in Table 1. The stability was evaluated based on the change in the waveform of the cyclic voltammogram in CV measurement with 10 sweeps. Specifically, when no change was observed between the waveform after the first sweep and the waveform after the tenth sweep, the sample was evaluated as "stable."

[0144]

[0145] 1 and Table 1, it can be seen that the compounds according to the examples are stable to oxidation-reduction reactions. It can also be seen that compounds having multiple aromatic amine moieties exhibit multiple oxidation-reduction potentials.

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

[0147] Measurement The prepared sample solution was placed in a quartz cell with an optical path length of 0.1 cm, and the absorption spectrum was measured using an ultraviolet-visible spectrophotometer (UV1800, manufactured by Shimadzu Corporation). Figure 2(a) shows the absorption spectrum of compound BN-TPA-Me, and Figure 2(b) shows the absorption spectrum of comparative compound BN-Fc. Table 2 also shows the absorption edge wavelength and the color tone of the liquid crystal composition. The color tone of the liquid crystal composition was evaluated by visual observation of a liquid crystal composition sample for transmission spectrum measurement, which will be described later.

[0148]

[0149] It can be seen that the compounds according to the examples can be used to form colorless liquid crystal compositions.

[0150] Evaluation Measurement of transmission spectrum of liquid crystal composition In a methylene chloride solution of host liquid crystal molecules, which was a 7:3 mixture of 4-cyano-4'-pentyloxybiphenyl and 4-cyano-4'-pentylbiphenyl, compounds BN-TPA-OMe, BN-TPA-OC6, BN-TPA-Me, BN-TPA-tBu, and comparative compound BN-Fc were each dissolved to a final concentration of 3 mol %, and 3 mol % of 1-ethyl-3-methylimidazolium triflate was added, followed by concentration under reduced pressure to prepare a liquid crystal composition sample.

[0151] The liquid crystal composition sample prepared above was introduced into a glass cell (manufactured by EHC) with a cell thickness of 5 μm and a rubbed polyimide alignment film, and cholesteric liquid crystal was expressed at room temperature, and the transmission spectrum was measured. The results are shown in Figure 3 and Table 3. Note that the reflection wavelength in Table 3 is the median value, and the reflection color was evaluated by visual observation.

[0152]

[0153] It can be seen that by using the compounds according to the examples to construct a liquid crystal device that exhibits cholesteric liquid crystal, it is possible to exhibit a wide variety of reflected colors ranging from red to blue-purple.

[0154] Evaluation: Change in Reflected Color with Voltage Application. A liquid crystal composition sample prepared as described above was introduced into a 10 μm-thick cell consisting of ITO glass and ITO glass spin-coated with Prussian blue nanoparticles to prepare a liquid crystal device. The change in transmission spectrum of the prepared liquid crystal device was measured before and after application of a DC voltage (2 V), and the change in reflected color with voltage application was measured. Figure 4 shows the results of a representative example of a liquid crystal device using BN-TPA-OMe as the chiral dopant. Figure 4(a) shows the transmission spectrum before application of a DC voltage (2 V), and Figure 4(b) shows the transmission spectrum after application of a DC voltage (2 V). The reflected wavelength (median) in Figure 4(a) was 499 nm, a blue-green color, and the reflected wavelength (median) in Figure 4(b) was 535 nm, a green color.

[0155] It can be seen from FIG. 4 that by using the compounds of the examples, it is possible to construct a liquid crystal element in which the reflection wavelength changes when a voltage is applied.

[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 was specifically and individually indicated to be incorporated by reference.

Claims

1. An aromatic amine compound represented by the following formula (1). 【Chemical 1】 (In formula (1), A １ independently represents a substituted or unsubstituted alkylene group or a substituted or unsubstituted divalent aromatic group, and A ２ and A ３ independently represent a substituted or unsubstituted alkyl group or a substituted or unsubstituted aromatic group, and 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 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 represented by formula (2a). 【Chemical 2】 In formula (2a), * indicates the bonding position with other atoms. X1 and X2 each independently contain at least one selected from the group consisting of an oxygen atom, a sulfur atom, -C(R3)(R4)-, and -N(R5)-, and R3, R4, and R5 each independently represent a hydrogen atom, a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group. Y1 represents a propane-1,2,3-triyl group.)

2. The aromatic amine compound according to claim 1, wherein T in the formula (1) is a divalent linking group formed by containing at least a carbonyl group.

3. X in the formula (2a) １ and X ２ is an aromatic amine compound according to claim 1, which represents an oxygen atom.

4. The aromatic amine compound according to claim 1, wherein T in the formula (1) each independently represents a carbonyloxy group or an oxycarbonyl group.

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

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

7. A liquid crystal element including a liquid crystal layer containing the liquid crystal composition according to claim 5, and a pair of electrodes for applying a voltage to the liquid crystal layer.

8. A display device or a dimming device including the liquid crystal element according to claim 7.

9. A liquid crystal composition containing an aromatic amine compound represented by the following formula (1). 【Chemical 1】 (In formula (1), A1 each independently represents a substituted or unsubstituted alkylene group, or a substituted or unsubstituted divalent aromatic group, A2 and A3 each independently represent a substituted or unsubstituted alkyl group, or a substituted or unsubstituted aromatic group, and at least one of A1, A2, and A3 represents an aromatic group. s and t each independently represent an integer from 0 to 6. R1 and R2 each independently represent 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 by 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.)

10. A liquid crystal element comprising a liquid crystal layer containing the liquid crystal composition according to Claim 9, and a pair of electrodes for applying a voltage to the liquid crystal layer.

11. A display device or a light control device comprising the liquid crystal element according to Claim 10.

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