Binaphthyl derivative, liquid crystal composition, liquid crystal element, display device, and dimming device

Abstract

Provided are a binaphthyl derivative that is capable of forming a liquid crystal composition having a large reflection wavelength change range accompanying voltage application, and a liquid crystal composition. The binaphthyl derivative has a binaphthyl skeleton, a redox functional group that links to the binaphthyl skeleton so as to allow pi-electron conjugation, and a mesogenic group. The liquid crystal composition contains a binaphthyl derivative, a liquid crystalline compound, and an electrolyte.

Description

Binaphthyl derivative, liquid crystal composition, liquid crystal element, display device and light control device

[0001] The present invention relates to a binaphthyl derivative, 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 them can be 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 crystals. Furthermore, Japanese Patent Application Laid-Open No. 2010-132892 proposes a liquid crystal composition in which the selective reflection wavelength changes due to a redox reaction caused by an electric field.

[0003] However, with the conventionally proposed techniques, it has been difficult to obtain a sufficient change range in the reflection wavelength upon application of a voltage when constructing a liquid crystal element. One aspect of the present invention aims to provide a binaphthyl derivative and a liquid crystal composition that can constitute a liquid crystal composition having a large change range in the reflection wavelength upon application of a voltage.

[0004] The first aspect is a binaphthyl derivative having a binaphthyl skeleton, a redox functional group linked to the binaphthyl skeleton so as to be capable of π-electron conjugation, and a mesogenic group.

[0005] The second embodiment is a liquid crystal composition containing the binaphthyl derivative of the first embodiment, a liquid crystal compound, and an electrolyte.

[0006] The third aspect is a liquid crystal element comprising a liquid crystal composition layer containing the liquid crystal composition of the second aspect, a counter electrode material layer containing a substance capable of undergoing an oxidation-reduction reaction, and a first electrode and a second electrode.

[0007] A fourth aspect is a display device or a light control device including the liquid crystal element of the third aspect.

[0008] According to one aspect of the present invention, it is possible to provide a binaphthyl derivative and a liquid crystal composition that can constitute a liquid crystal composition that exhibits a large change in the reflected wavelength upon application of a voltage.

[0009] 1 is a schematic cross-sectional view showing an example of the configuration of a liquid crystal element; FIG. 2 is a schematic cross-sectional view showing another example of the configuration of a liquid crystal element; FIG. 3 is a schematic cross-sectional view showing another example of the configuration of a liquid crystal element; １ 1 is a diagram showing a change in the transmission spectrum of a liquid crystal composition containing the binaphthyl derivative of Example 1 due to voltage application. １ 1 is a diagram showing a change in the transmission spectrum of a liquid crystal composition containing the binaphthyl derivative of Example 3 due to voltage application. １ 1 is a diagram showing a change in the transmission spectrum of a liquid crystal composition containing the binaphthyl derivative of Example 5 when a voltage is applied. １ 1 is a diagram showing a change in the transmission spectrum of a liquid crystal composition containing a binaphthyl derivative of Example 7 upon application of a 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, when a plurality of substances corresponding to each component are present in the composition, the content of each component in the composition refers to the total amount of the plurality of substances present in the composition, unless otherwise specified. 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 binaphthyl derivatives and liquid crystal compositions for embodying the technical concept of the present invention, and the present invention is not limited to the binaphthyl derivatives and liquid crystal compositions shown below.

[0011] Binaphthyl Derivatives Binaphthyl derivatives have a binaphthyl skeleton, a redox functional group linked to the binaphthyl skeleton in a π-electron conjugable manner, and a mesogenic group. The redox functional group linked to the binaphthyl skeleton in a π-electron conjugable manner can increase the range of change in reflection wavelength upon voltage application. This can be thought of as being due to, for example, the π electrons of the redox functional group interacting with the π electrons on the binaphthyl skeleton, increasing the range of change in electron density on the binaphthyl skeleton and enhancing interaction with host liquid crystal molecules. Furthermore, the presence of a mesogenic group in a binaphthyl derivative is thought to enhance interaction with host liquid crystal molecules, thereby further increasing the range of change in reflection wavelength.

[0012] The binaphthyl skeleton in a binaphthyl derivative refers to a residue obtained by removing at least one hydrogen atom from 1,1'-binaphthyl. A redox functional group or a mesogenic group is bound to the position where the hydrogen atom was removed, either directly or via a linking group. The number of redox functional groups in a binaphthyl derivative may be one or more, preferably one to eight, or four or less. In one embodiment, the number of redox functional groups may be two. The redox functional group may be any functional group that can reversibly exhibit, for example, ionic and nonionic properties in response to an electrical stimulus. Specific examples of the redox functional group include functional groups containing structures derived from ferrocene, phenoxazine, phenothiazine, triarylamine, anthraquinone, viologen, and derivatives thereof. The redox functional group may contain a structure derived from at least one selected from the group consisting of ferrocene, phenoxazine, phenothiazine, and derivatives thereof, and preferably contains a structure derived from at least one selected from the group consisting of ferrocene and derivatives thereof. Here, the term "derivative" means that the redox functional group may further have a substituent. Furthermore, the term "structure derived from ferrocene" means a residue formed by removing at least one hydrogen atom from ferrocene. Specific examples of the redox functional group will be described later.

[0013] The redox functional group is linked to the binaphthyl skeleton in a π-electron conjugable manner. The redox functional group and the binaphthyl skeleton are linked via a single bond or a first linking group capable of π-electron conjugation. The first linking group capable of π-electron conjugation may be any linking group having π-electrons that can be conjugated with the π-electrons of the functional group to be linked. Specific examples of the first linking group include an ether bond, a thioether bond, a double bond, a triple bond, a phenylene group, and the like, and combinations thereof may also be used. In one embodiment, the redox functional group and the binaphthyl skeleton may be linked via a single bond.

[0014] The bonding position of the redox functional group to the binaphthyl skeleton is not particularly limited. The bonding position of the redox functional group to the binaphthyl skeleton may be at least one position selected from the group consisting of 2-position, 2'-position, 3-position, 3'-position, 4-position, 4'-position, 5-position, 5'-position, 6-position, 6'-position, 7-position, 7'-position, 8-position, and 8'-position, preferably at least one position selected from the group consisting of 2-position, 2'-position, 3-position, 3'-position, 6-position, 6'-position, 7-position, and 7'-position, and at least one position selected from the group consisting of 6-position and 6'-position. When the binaphthyl derivative has two or more redox functional groups, the redox functional groups may be bonded to symmetric positions or asymmetric positions with respect to the 1,1'-bond of the binaphthyl skeleton. In one embodiment, the bonding positions of the redox functional groups may be symmetric positions with respect to the 1,1'-bond of the binaphthyl skeleton.

[0015] The binaphthyl derivative has a mesogenic group. The presence of the mesogenic group improves compatibility with host liquid crystal molecules and strengthens the intermolecular interaction between the binaphthyl derivative and the host liquid crystal molecules. The number of mesogenic groups in the binaphthyl derivative may be one or more, preferably one to four. In one embodiment, the number of mesogenic groups may be two. The mesogenic group is not particularly limited as long as it contains a structure that exhibits a liquid crystal phase and interacts with the host liquid crystal molecules to produce a cholesteric phase. The mesogenic group may contain a cyclic structure such as a cyclohexane ring or a benzene ring, and the cyclic structure may be a fused ring structure such as a naphthalene ring or anthracene. The mesogenic group may contain at least one cyclic structure and a chain-like aliphatic group (e.g., an alkyl group) having 1 to 20 carbon atoms. The aliphatic group may preferably have 1 to 12 carbon atoms, or 3 to 6 carbon atoms. When the mesogenic group contains two or more cyclic structures, the two cyclic structures may be linked by a single bond, an ethenediyl group, an ester bond, an imine bond, an azo bond, or the like. Specific examples of the cyclic structure contained in the mesogenic group include a biphenyl group, a phenylbenzoate group, a cyclohexylphenyl group, a stilbenyl group, an anthracenyl group, and a diphenylazo group. In one embodiment, the mesogenic group may contain one or two cyclic structures and a chain aliphatic group having 3 to 6 carbon atoms. Specific examples of the mesogenic group will be described later.

[0016] The mesogenic group may be bonded to the binaphthyl skeleton via a single bond or a second linking group. The second linking group is not particularly limited, and examples thereof include an ester bond and an ether bond.

[0017] The bonding position of the mesogenic group to the binaphthyl skeleton is not particularly limited. The bonding position of the mesogenic group to the binaphthyl skeleton may be at least one position selected from the group consisting of 2-, 2'-, 3-, 3'-, 4-, 4'-, 5-, 5'-, 6-, 6'-, 7-, 7'-, 8-, and 8'-positions, preferably at least one position selected from the group consisting of 2-, 2'-, 3-, 3'-, 6-, 6'-, 7-, and 7'-positions, and at least one position selected from the group consisting of 2-, 2'-, 3-, and 3'-positions. When the binaphthyl derivative has two or more mesogenic groups, the mesogenic groups may be bonded to positions symmetrical with respect to the 1,1'-bond of the binaphthyl skeleton, or may be bonded to positions asymmetrical with respect to the 1,1'-bond of the binaphthyl skeleton. In one embodiment, the bonding positions of the mesogenic groups may be positions symmetrical with respect to the 1,1'-bond of the binaphthyl skeleton.

[0018] The binaphthyl derivative may have, for example, a structure represented by the following formula (1).

[0019]

[0020] In formula (1), L １ represents a single bond or a first linking group capable of π-electron conjugation. Rd represents a redox functional group. L ２ represents a single bond or a second linking group, M represents a mesogenic group, R represents a substituent, i and j each represent a number from 1 to 12, k represents a number from 0 to 12, and i + j + k ≦ 14. In addition, in formula (1), -L １ a group represented by —Rd, L ２ The group represented by -M and the substituent R may each be substituted at any position on the binaphthyl skeleton, i.e., they may be substituted at either of the two naphthyl groups constituting the binaphthyl skeleton, and the substitution position may also be arbitrary.

[0021] L １ Examples of the π-electron conjugable first linking group represented by the formula (I) include an ether bond, a thioether bond, a double bond, a triple bond, a phenylene group, and the like, and may be a combination of these. １may be a single bond. Specific examples of the redox functional group represented by Rd ​​include functional groups represented by any of the following formulas (2a) to (2d), but the redox functional group represented by Rd ​​is not limited thereto.

[0022]

[0023] In the formula, R ７ , R ８ , R ９ , R １０ , R １１ , R １２ , R １３ , R １４ and R １５ each independently represents a hydrogen atom or a substituent, R １６ , R １７ and R １８ each independently represents a substituent. x and y each independently represent a number from 0 to 10, and z each independently represent a number from 0 to 5. * indicates the bonding position to the binaphthyl skeleton or the first linking group that bonds to the binaphthyl skeleton.

[0024] R ７ From R １８ (Hereafter, collectively referred to as R ７ Examples of the substituent represented by R include an alkyl group, a halogen atom, and an alkoxy group. ７ The alkyl group represented by R may be linear, branched, or cyclic, or may be a combination thereof. The number of carbon atoms in the alkyl group may be, for example, 1 or more and 20 or less, preferably 1 to 10, or 1 to 8. ７ The halogen atoms represented by R include fluorine atoms, chlorine atoms, bromine atoms, iodine atoms, etc. ７ The alkyl group portion of the alkoxy group represented by R may be linear, branched, cyclic, or a combination thereof, and may further have a substituent. The number of carbon atoms in the alkyl group portion of the alkoxy group may be, for example, 1 or more and 20 or less, preferably 1 to 10, or 1 to 8. Examples of the substituent in the alkoxy group include an alkoxy group having 1 to 6 carbon atoms, an aryloxy group, etc. Furthermore, R ７Two adjacent substituents selected from the group consisting of x, y, y- ...

[0025] In the binaphthyl skeleton, -L １ The position to which the group represented by -Rd is bonded may be at least one position selected from the group consisting of 2-position, 2'-position, 3-position, 3'-position, 4-position, 4'-position, 5-position, 5'-position, 6-position, 6'-position, 7-position, 7'-position, 8-position, and 8'-position, preferably at least one position selected from the group consisting of 2-position, 2'-position, 3-position, 3'-position, 6-position, 6'-position, 7-position, and 7'-position, and may be at least one position selected from the group consisting of 6-position and 6'-position. １ -Rd, and -L １ The groups represented by -Rd may be bonded to the 6- and 6'-positions of the binaphthyl skeleton.

[0026] L ２ Examples of the second linking group represented by the formula (I) include an ester bond and an ether bond. ２ may be an ester bond. Specific examples of the mesogenic group represented by M include functional groups represented by any of the following formulae (3a) to (3f), but the mesogenic group represented by M is not limited to these.

[0027]

[0028] In the formula, * indicates the bonding position of the binaphthyl skeleton or the second linking group that links to the binaphthyl skeleton.

[0029] In the binaphthyl skeleton, -L ２The position at which the group represented by -M is bonded may be at least one position selected from the group consisting of 2-position, 2'-position, 3-position, 3'-position, 4-position, 4'-position, 5-position, 5'-position, 6-position, 6'-position, 7-position, 7'-position, 8-position, and 8'-position, preferably at least one position selected from the group consisting of 2-position, 2'-position, 3-position, 3'-position, 6-position, 6'-position, 7-position, and 7'-position, and may be at least one position selected from the group consisting of 2-position, 2'-position, 3-position, and 3'-position. ２ -M groups, and -L ２ The group represented by -M may be bonded to the 2-position and 2'-position of the binaphthyl skeleton.

[0030] In formula (1), examples of the substituent represented by R include an alkyl group, a halogen atom, an alkoxy group, and the like. The alkyl group represented by R may be linear, branched, or cyclic, or a combination thereof. The number of carbon atoms in the alkyl group may be, for example, 1 to 20, preferably 1 to 10, or 1 to 8. The halogen atom represented by R includes a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, and the like. The alkyl group portion of the alkoxy group represented by R may be linear, branched, cyclic, or a combination thereof, and may further have a substituent. The number of carbon atoms in the alkyl group portion of the alkoxy group may be, for example, 1 to 20, preferably 1 to 10, or 1 to 8. Examples of the substituent in the alkoxy group include an alkoxy group having 1 to 6 carbon atoms, an aryloxy group, and the like.

[0031] In formula (1), i may preferably represent a number from 1 to 8, more preferably from 1 to 4. j may preferably represent a number from 1 to 10, more preferably from 1 to 4. k may preferably represent a number from 0 to 12, more preferably from 0 to 4. i + j + k may preferably be 8 or less, or 2 or more and 4 or less.

[0032] In one embodiment, the binaphthyl derivative may have a structure represented by the following formula (1a): The symbols in formula (1a) have the same meanings as those in formula (1).

[0033]

[0034] Specific examples of the binaphthyl derivative represented by formula (1) are shown below, but the present invention is not limited to these.

[0035]

[0036]

[0037] In the formula, Fc represents a ferrocenyl group, and C ３ H ８ is an n-propyl group, C ４ H １０ represents an n-butyl group.

[0038] Binaphthyl derivatives can function as chiral dopants (chiral agents) that form a cholesteric liquid crystal phase. That is, binaphthyl derivatives can induce a helical structure in the liquid crystal phase. The helical induction power of the binaphthyl derivative may be, for example, 100 to 500, preferably 200 to 400, or 200 to 300. When the helical induction power is within the above range, the change in the reflection wavelength upon voltage application tends to be larger. The helical induction power of the binaphthyl derivative can be evaluated by adding the binaphthyl derivative to a host liquid crystal to prepare a cholesteric liquid crystal, introducing the liquid crystal into a wedge-shaped cell, and measuring the helix length using a polarizing microscope.

[0039] Liquid Crystal Composition The liquid crystal composition includes the binaphthyl derivative described above, a liquid crystalline compound, and an electrolyte. The binaphthyl derivative functions as a chiral agent having a partial structure that serves as an asymmetric source and a partial structure capable of reversibly undergoing redox reaction, and can reversibly exhibit, for example, ionic and nonionic properties in response to electrical stimulation. Such optically active, electrically responsive compounds can control the molecular arrangement of the helical structure of cholesteric liquid crystal in a liquid crystal composition (e.g., cholesteric liquid crystal) 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 wavelengths of light, and a shorter pitch reflects shorter wavelengths of light. In the binaphthyl derivative, the partial structure capable of redox reaction is bonded to the binaphthyl skeleton in a π-electron conjugable manner, thereby conjugating the π electrons of the partial structure capable of redox reaction, thereby increasing the electron density on the binaphthyl skeleton. It is believed that the electron-densified binaphthyl skeleton has a stronger interaction with the host liquid crystal molecules, resulting in a shorter reflection wavelength. Furthermore, when the partial structure capable of redox reactions is ionized by the application of voltage, π electrons move toward the partial structure capable of redox reactions, and the electron density on the binaphthyl skeleton becomes lower than before the application of voltage. It is believed that the electron-densified binaphthyl skeleton has a weaker interaction with the host liquid crystal molecules, resulting in a shift to longer wavelengths. In binaphthyl derivatives, the presence of a mesogenic group in addition to the partial structure capable of redox reactions increases the compatibility between the binaphthyl derivative and the host liquid crystal molecules. Furthermore, the presence of a mesogenic group with a structure similar to that of the host liquid crystal molecules near the asymmetric source strengthens the intermolecular interaction with the host liquid crystal molecules, thereby increasing the range of change in the reflection wavelength.

[0040] At least one of the binaphthyl derivatives contained in the liquid crystal composition may have liquid crystallinity by itself to constitute the liquid crystal composition. The liquid crystal composition may further contain at least one liquid crystal compound in addition to the binaphthyl derivative. That is, the liquid crystal composition may contain a liquid crystal compound other than the binaphthyl derivative as host liquid crystal molecules and the binaphthyl derivative as a chiral dopant (chiral agent). The content of the binaphthyl derivative in the liquid crystal composition may be, for example, 0.1 mol % to 10 mol %, and preferably 0.5 mol % to 5 mol %, relative to the liquid crystal compound.

[0041] 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.

[0042] Specific examples of the liquid crystal compound include liquid crystal compounds exhibiting a nematic phase, such as 4-cyano-4'-pentyloxybiphenyl (5OCB), 4-cyano-4'-pentylbiphenyl (5CB), 4-cyano-4'-propyloxybiphenyl (3OCB), 4-cyano-4'-octyloxybiphenyl (8OCB), and 4-cyano-4''-pentylterphenyl (5CT). The content of the liquid crystal compound in the liquid crystal composition may be, for example, the balance other than the binaphthyl derivative, the electrolyte, and additives contained as necessary.

[0043] The liquid crystal composition may further contain an electrolyte. By including an electrolyte, the liquid crystal composition can be given sufficient conductivity, and the oxidation-reduction reaction of the binaphthyl derivative 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 host liquid crystal molecules. 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 electrolyte include ionic liquids, such as 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, relative to the liquid crystal compound.

[0044] 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, promoting the oxidation-reduction reaction, etc. Furthermore, additives such as ultraviolet absorbers and antioxidants may also be added.

[0045] Liquid crystal element The liquid crystal element comprises a liquid crystal composition layer containing a binaphthyl derivative, a liquid crystalline compound, and an electrolyte, a counter electrode material layer containing a substance capable of redox reaction, and a first electrode and a second electrode. The liquid crystal element may further comprise a reverse reaction suppression layer separating the liquid crystal composition layer and the counter electrode material layer, as necessary. The liquid crystal element may also comprise a pair of substrates that support the liquid crystal composition layer and the counter electrode material layer. Furthermore, the liquid crystal element may further comprise a black plate, an anti-reflection film, a brightness enhancement film, etc., as necessary.

[0046] In a liquid crystal element comprising a liquid crystal composition layer containing a binaphthyl derivative and a counter electrode material layer, application of a voltage causes the binaphthyl derivative to undergo an oxidation-reduction reaction with a redox-reactive substance contained in the counter electrode material layer, resulting in a significant change in the period (pitch) of the helical structure formed by the liquid crystal composition, and a significant change in the wavelength of the selectively reflected circularly polarized light.

[0047] An example of the configuration of a liquid crystal element will now be described with reference to the drawings. FIG. 1 is a schematic cross-sectional view showing an example of the configuration of a liquid crystal element. The liquid crystal element 100 includes a first electrode 22, a counter electrode material layer 30 disposed on the first electrode 22, a liquid crystal composition layer 50 disposed on the counter electrode material layer 30, and a second electrode 24 disposed on the liquid crystal composition layer 50. The first electrode 22 is disposed on a first substrate 12, and the second electrode 24 is disposed on a second substrate 14. As shown in FIG. 1, the first electrode 22 and the second electrode 24 are disposed opposite each other. The first electrode 22 and the second electrode 24 are each connected to a power source.

[0048] 2 is a schematic cross-sectional view showing another example of the configuration of a liquid crystal element. The liquid crystal element 200 includes a first electrode 22, a counter electrode material layer 30 disposed on the first electrode 22, a reverse reaction suppression layer 40 disposed on the counter electrode material layer 30, a liquid crystal composition layer 50 disposed on the reverse reaction suppression layer 40, and a second electrode 24 disposed on the liquid crystal composition layer 50. The first electrode 22 is disposed on a first substrate 12, and the second electrode 24 is disposed on a second substrate 14. As shown in FIG. 2, the first electrode 22 and the second electrode 24 are disposed opposite each other. The counter electrode material layer 30 disposed in contact with the first electrode 22 and the liquid crystal composition layer 50 disposed in contact with the second electrode 24 are stacked with the reverse reaction suppression layer 40 interposed therebetween.

[0049] 3 is a schematic cross-sectional view showing another example of the configuration of a liquid crystal element. The liquid crystal element 300 includes a first electrode 22, a counter electrode material layer 30 disposed on the first electrode 22, a second electrode 24, a liquid crystal composition layer 50 disposed on the second electrode 24, and a reverse reaction suppression layer 40 disposed to separate the counter electrode material layer 30 and the liquid crystal composition layer 50. The first electrode 22 and the second electrode 24 are disposed on a first substrate 12 and separated by the reverse reaction suppression layer 40. The second substrate 14 is disposed on the liquid crystal composition layer 50. The reverse reaction suppression layer 40 is disposed extending on the side and top surfaces of the counter electrode material layer 30, separating the counter electrode material layer 30 disposed in contact with the first electrode 22 from the liquid crystal composition layer 50 disposed in contact with the second electrode 24. The liquid crystal composition layer 50 is disposed extending on the second electrode layer 24 and the reverse reaction suppression layer 40.

[0050] The liquid crystal composition layer includes a liquid crystal composition containing a binaphthyl derivative, a liquid crystal compound, and an electrolyte. Details of the liquid crystal composition are as described above. The thickness of the liquid crystal composition layer in the liquid crystal element may be, for example, 1 μm or more and 100 μm or less, and preferably 1 μm or more or 50 μm or less.

[0051] The counter electrode layer is composed of a counter electrode material, which is a substance capable of undergoing a redox reaction. The counter electrode material may be a substance that is oxidized and reduced in response to the redox reaction of the chiral agent. The counter electrode material may be any substance capable of undergoing a reversible redox reaction, and may be organic or inorganic. Specific examples of the counter electrode material include organic substances such as poly(3,4-ethylenedioxythiophene) (PEDOT), polypyrrole, and polyaniline, and inorganic substances such as Prussian blue and tungsten oxide. Preferably, the counter electrode material may contain at least one selected from the group consisting of poly(3,4-ethylenedioxythiophene) (PEDOT) and Prussian blue. The organic substance such as PEDOT used as the counter electrode material may be a block copolymer with polyethylene glycol (PEG) or the like. Examples of block copolymers of PEDOT and PEG include Aedotron ＴＭ (Sigma-Aldrich Co.) and the like.

[0052] The counter electrode layer may further contain a conductive material in addition to the counter electrode material, which is a substance capable of undergoing an oxidation-reduction reaction. Examples of the conductive material include conductive polymers such as polystyrene sulfonate (PSS), polypyrrole, and polyaniline, and supporting electrolytes commonly used in electrochemistry (e.g., nBu). ４ NPF ６ , nBu ４ NBF ４ , nBu ４ NClO ４ etc.) etc.

[0053] When the counter electrode material layer contains a substance capable of undergoing a redox reaction and a conductive substance, they may be contained in the counter electrode material layer as a composite. An example of the composite is PEDOT / PSS. A commercially available product may be used for the composite such as PEDOT / PSS. An example of a commercially available product is Orgacon. ＴＭ , Aedotron ＴＭ (all manufactured by Sigma-Aldrich Corporation) etc. In one embodiment, the counter electrode layer may be made of a composite of a substance capable of redox reaction and a conductive substance.

[0054] The thickness of the counter electrode material layer in the liquid crystal element may be, for example, 10 nm or more and 1 mm or less, and preferably 100 nm or more or 100 μm or less.

[0055] The liquid crystal element may further include a reverse reaction suppression layer separating the liquid crystal composition layer and the counter electrode material layer. In the liquid crystal element, when the applied voltage is removed, the binaphthyl derivative, whose structure has changed due to the oxidation-reduction reaction, returns to its original structure due to a reverse reaction, thereby restoring the period of the helical structure to its original state. By including the reverse reaction suppression layer in the liquid crystal element, the reverse reaction after the voltage is removed is suppressed, the period of the helical structure in the state when the voltage is applied is maintained, and the memory property of the reflected color is obtained. Here, the memory property of the reflected color means that the reflected color changed by the application of a voltage is maintained even after the application of the voltage is stopped. The maintenance time of the changed reflected color may be, for example, 3 seconds or more, or 30 seconds or more.

[0056] The reverse reaction suppression layer prevents the binaphthyl derivative, whose structure has changed due to the oxidation-reduction reaction, from returning to its original structure due to the reverse reaction. The reverse reaction suppression layer may be configured to suppress contact between the binaphthyl derivative and the counter electrode material. For example, the reverse reaction suppression layer may be configured to suppress permeation of the binaphthyl derivative. The reverse reaction suppression layer may be configured from a porous material or a non-porous material (e.g., a solid material). The reverse reaction suppression layer may be configured to contain a resin, or may be configured to contain a resin that can be applied to the counter electrode material layer to form a reverse reaction suppression layer. Examples of resins that can form the reverse reaction suppression layer include insulating resins such as polyethylene, polypropylene, epoxy resin, and acrylic resin, cationic or anionic ion exchange resins, and covalent organic frameworks. Specific examples of ion exchange resins include Nafion. ＴＭ , polyallylamine, etc. The reverse reaction suppression layer may be configured to contain a gel electrolyte material, a solid electrolyte material, etc.

[0057] The thickness of the reverse reaction suppression layer in the liquid crystal element may be, for example, 10 nm or more and 1 mm or less, and preferably 100 nm or more or 100 μm or less.

[0058] The electrode includes a first electrode disposed in contact with the counter electrode material layer and a second electrode disposed in contact with the liquid crystal composition layer. The electrode may be formed, for example, on a substrate described below. The electrode may be a transparent electrode or a non-transparent electrode. Examples of materials for forming the transparent electrode include indium oxide, indium tin oxide (ITO), tin oxide, silver nanorods, carbon nanotubes, and conductive resins such as polystyrene sulfonate. The transparent electrode can be formed by a sputtering method, a sol-gel method, or a printing method. Examples of the non-transparent electrode that can be used include a GC electrode.

[0059] The surface of the electrode placed in contact with the liquid crystal composition layer may be subjected to a rubbing treatment, if necessary, to further improve the alignment of the liquid crystal.

[0060] The liquid crystal element may further include a pair of substrates, which may be arranged to hold, for example, a liquid crystal composition layer and a counter electrode material layer.

[0061] 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.

[0062] 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.

[0063] One of the substrates 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 can be used on the non-display side. Examples of black substrates include plastic substrates to which inorganic pigments such as carbon black have been added.

[0064] Display device 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, it is possible to configure a reflective display device driven by a simple matrix driving method or an active matrix driving method.

[0065] 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.

[0066] The invention according to the present disclosure may include, for example, the following aspects: [1] A binaphthyl derivative having a binaphthyl skeleton, a redox functional group linked to the binaphthyl skeleton so as to be capable of π-electron conjugation, and a mesogenic group.

[0067] [2] The binaphthyl derivative according to [1], wherein the redox functional groups are located at the 6-position and the 6′-position of the binaphthyl skeleton.

[0068] [3] The binaphthyl derivative according to [1] or [2], wherein the redox functional group is linked to the binaphthyl skeleton via a single bond.

[0069] [4] The binaphthyl derivative according to any one of [1] to [3], wherein the redox functional group contains a partial structure derived from ferrocene.

[0070] [5] The binaphthyl derivative according to any one of [1] to [4], which has the mesogenic groups at at least two positions selected from the group consisting of the 2-position, the 2'-position, the 3-position, and the 3'-position of the binaphthyl skeleton.

[0071] [6] A binaphthyl derivative according to any one of [1] to [5], represented by the following formula (1):

[0072]

[0073] In the ceremony, L １ represents a single bond or a linking group capable of π-electron conjugation, and Rd represents a redox functional group. ２ represents a single bond or a linking group, M represents a mesogenic group, R represents a substituent, i and j each represent a number from 1 to 12, k represents a number from 0 to 12, and i + j + k ≦ 14.

[0074] [7] In formula (1), -L １ The binaphthyl derivative according to [6], which has groups represented by -Rd at the 6-position and the 6'-position of the binaphthyl skeleton.

[0075] [8] In formula (1), L １ The binaphthyl derivative according to [6] or [7], wherein is a single bond.

[0076] [9] The binaphthyl derivative according to any one of [6] to [8], wherein in formula (1), Rd contains a partial structure derived from ferrocene.

[0077]

[10] In formula (1), -L ２The binaphthyl derivative according to any one of [6] to [9], having a group represented by -M at at least two positions selected from the group consisting of the 2-position, the 2'-position, the 3-position, and the 3'-position of the binaphthyl skeleton.

[0078]

[11] A liquid crystal composition comprising the binaphthyl derivative according to any one of [1] to

[10] , a liquid crystal compound, and an electrolyte.

[0079]

[12] A liquid crystal element comprising a liquid crystal composition layer containing the liquid crystal composition according to

[11] , a counter electrode material layer containing a substance capable of undergoing an oxidation-reduction reaction, a first electrode, and a second electrode.

[0080]

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

[12] .

[0081] Other aspects of the present invention include use of the binaphthyl derivative of the first aspect in the production of the liquid crystal composition of the second aspect, the binaphthyl derivative of the first aspect used in the liquid crystal composition of the second aspect, use of the binaphthyl derivative of the first aspect or the liquid crystal composition of the second aspect in the production of a liquid crystal device of the third aspect, use of the binaphthyl derivative of the first aspect or the liquid crystal composition of the second aspect used in the liquid crystal device of the third aspect, use of the binaphthyl derivative of the first aspect, the liquid crystal composition of the second aspect, or the liquid crystal device of the third aspect in the production of a display device or light control device of the fourth aspect, and the binaphthyl derivative of the first aspect, the liquid crystal composition of the second aspect, or the liquid crystal device of the third aspect used in the display device or light control device of the fourth aspect.

[0082] The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples.

[0083] Example 1

[0084]

[0085] A three-neck flask was charged with 532 mg (1 mmol) of (R)-6,6'-dibromo-2,2'-bis(methoxymethoxy)-1,1'-binaphthyl (Tokyo Chemical Industry Co., Ltd.), 919 mg (4 equivalents, 4 mmol) of ferroceneboronic acid (Tokyo Chemical Industry Co., Ltd.), 760 mg (5.5 equivalents, 13.75 mmol) of potassium carbonate (Tokyo Chemical Industry Co., Ltd.), 115 mg (10 mol%, 0.1 mmol) of tetrakis(triphenylphosphine)palladium(0) (Tokyo Chemical Industry Co., Ltd.), 10 mL of 1,4-dioxane (Fujifilm Wako Pure Chemical Industries Co., Ltd.), and 5 mL of ultrapure water, and the mixture was stirred at 110°C for 24 hours. The reaction solution was separated twice with ethyl acetate and 2 M HCl (Fujifilm Wako Pure Chemical Industries Co., Ltd.), and then once with ethyl acetate and saturated brine. The collected organic layer was dehydrated over magnesium sulfate. The magnesium sulfate was then filtered off, and the organic solvent was removed using an evaporator, yielding a reddish-brown oily substance. The target compound was isolated using a silica gel column with a developing solvent of ethyl acetate:hexane = 1:3 (Rf value = 0.49). After removing the solvent using an evaporator, the product was dissolved in a small amount of ethyl acetate or acetone and recrystallized with methanol. The product was then dried under reduced pressure to yield 274 mg (0.37 mmol, 37% yield) of the target orange powder, Fc-BN-MOM.

[0086]

[0087] A three-neck flask was charged with 100 mg (0.14 mmol) of Fc-BN-MOM, 128 mg (5 equivalents, 0.67 mmol) of p-toluenesulfonic acid (Tokyo Chemical Industry Co., Ltd.), 7 mL of tetrahydrofuran (Fujifilm Wako Pure Chemical Industries, Ltd.), and 10 mL of ethanol (Fujifilm Wako Pure Chemical Industries, Ltd.), and the mixture was stirred at 70°C for 3 hours. The organic solvent from the reaction solution was removed using an evaporator, and the mixture was separated three times with ethyl acetate and ultrapure water. The recovered organic layer was dehydrated using magnesium sulfate. The magnesium sulfate was then filtered off, the organic solvent was removed using an evaporator, and the mixture was dried under reduced pressure to obtain a dark brown oily substance. After removing the solvent using an evaporator, the product was dissolved in a small amount of ethyl acetate and reprecipitated with hexane. The product was then dried under reduced pressure to obtain 80 mg (0.12 mmol, 88% yield) of the desired glassy Fc-BN-OH.

[0088]

[0089] Under ice bath conditions at 0°C, 19 mg (0.2 mmol) of Fc-BN-OH, 143 mg (2 equivalents, 0.58 mmol) of 4-(trans-4-propylcyclohexyl)benzoic acid (Tokyo Chemical Industry Co., Ltd.), 35 mg (1 equivalent, 0.29 mmol) of 4-dimethylaminopyridine (Tokyo Chemical Industry Co., Ltd.), 111 mg (2 equivalents, 0.58 mmol) of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (Tokyo Chemical Industry Co., Ltd.), and 15 mL of dichloromethane (Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a three-neck flask and stirred for 24 hours at room temperature. The reaction solution was separated twice with ethyl acetate and ultrapure water, and then separated once with saturated saline. The recovered organic layer was dehydrated with magnesium sulfate. The magnesium sulfate was then filtered off, the organic solvent was removed using an evaporator, and the mixture was dried under reduced pressure to obtain a dark brown oily substance. The target compound was isolated using a silica gel column with a developing solvent of ethyl acetate:hexane = 1:3 (Rf value = 0.65). After removing the solvent with an evaporator, the product was dissolved in a small amount of ethyl acetate and reprecipitated with ethanol. The product was then dried under reduced pressure to obtain 170 mg (0.15 mmol, 53% yield) of the target orange powder 2Fc-BN-LC.

[0090] The obtained 2Fc-BN-LC was dissolved in deuterated chloroform. １ The structure was confirmed by H-NMR measurement. １ The H-NMR spectrum is shown in FIG.

[0091] １ H-NMR (400MHz, CDCl ３ ): δ (ppm) 7.92 (d, 2H), 7.89 (d, 2H), 7.58 (d, 2H), 7.53 (d, 2H), 7.49-7.51 (dd, 2H), 7.39 (d, 2H), 7.07 (d, 4H) , 4.71 (s, 4H), 4.34 (s, 4H), 3.96 (s, 10H), 2.39 (t, 2H), 1.78 (t, 8H), 1.16-1.37 (m, 16H), 0.85-1.02 (m, 10H).

[0092] Example 2 A host liquid crystal was prepared by mixing 4-cyano-4'-pentylbiphenyl (5CB), 4-cyano-4'-propyloxybiphenyl (3OCB), 4-cyano-4'-pentyloxybiphenyl (5OCB), 4-cyano-4'-octyloxybiphenyl (8OCB), and 4-cyano-4''-pentylterphenyl (5CT) in a molar ratio of 43:17:13:17:10. 2Fc-BN-LC was dissolved as a binaphthyl derivative to a concentration of 1.0 mol %, and 1-ethyl-3-methylimidazolium trifluoromethylsulfonate (EMI.OTf) was dissolved as an electrolyte in the host liquid crystal to a concentration of 3 mol %, to prepare a liquid crystal composition.

[0093] Using the liquid crystal composition obtained above, a liquid crystal element having the configuration shown in Figure 1 was fabricated. ITO glass was used as the substrate and electrodes. Liquid crystal composition was introduced into a cell having a cell thickness of 10 μm, which was made of ITO glass and on which a counter electrode layer had been formed by spin-coating PEDOT / PSS and Prussian blue nanoparticles, to fabricate liquid crystal element 1.

[0094] The transmission spectrum of the fabricated liquid crystal element 1 was measured before application of a DC voltage, when a DC voltage of 1.5 V was applied, and when a DC voltage of 2 V was applied. The results are shown in FIG.

[0095] Figure 5 also shows the center wavelength of the reflection peak in the transmission spectrum in each state. As shown in Figure 5, it can be seen that the reflection peak wavelength changes depending on the applied voltage. The change in the reflection wavelength when 1.5 V was applied was 35 nm, and the change in the reflection wavelength when 2 V was applied was 70 nm.

[0096] Example 3

[0097]

[0098] In a three-neck flask, 200 mg (0.3 mmol) of Fc-BN-OH obtained in the same manner as in Example 1, 98.5 mg (2 equivalents, 0.6 mmol) of 4-propylbenzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 36 mg (1 equivalent, 0.3 mmol) of 4-dimethylaminopyridine (manufactured by Tokyo Chemical Industry Co., Ltd.), 115 mg (2 equivalents, 0.58 mmol) of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (manufactured by Tokyo Chemical Industry Co., Ltd.), and 15 mL of dichloromethane (manufactured by Fujifilm Wako Pure Chemical Industries) were added under ice bath conditions at 0°C, and the mixture was stirred at room temperature for 24 hours. The reaction solution was separated twice with ethyl acetate and ultrapure water, and then separated once with saturated saline. The recovered organic layer was dehydrated with magnesium sulfate. The magnesium sulfate was then filtered off, the organic solvent was removed using an evaporator, and the mixture was dried under reduced pressure to obtain a dark brown oily substance. The target compound was isolated using a silica gel column with a developing solvent of ethyl acetate:hexane = 1:3 (Rf value = 0.64). After removing the solvent with an evaporator, the product was dissolved in a small amount of ethyl acetate and reprecipitated with ethanol. The target compound, 2Fc-BN-Be, was obtained as an orange powder in an amount of 174 mg (0.16 mmol, yield: 52%) by drying under reduced pressure.

[0099] The obtained 2Fc-BN-Be was dissolved in deuterated chloroform. １ The structure was confirmed by H-NMR measurement. １ The H-NMR spectrum is shown in FIG.

[0100] １ H-NMR (400MHz, CDCl ３ ): δ (ppm) 7.92 (d, 2H), 7.90 (d, 2H), 7.53-7.57 (m, 6H), 7.50 (dd, 2H), 7.40 (d, 2H), 7.03 (d, 4H), 4.71 (s, 4H), 4.34 (s, 4H), 3.97 (s, 10H), 2.50 (t, 4H), 1.54 (t, 4H), 0.86 (t, 6H).

[0101] Example 4 A liquid crystal composition was prepared in the same manner as in Example 2, except that 2Fc-BN-Be was used as the binaphthyl derivative. In addition, a liquid crystal element 2 was fabricated in the same manner as in Example 2, except that the obtained liquid crystal composition was used.

[0102] The transmission spectrum of the fabricated liquid crystal element 2 was measured before application of a DC voltage, when a DC voltage of 1.5 V was applied, and when a DC voltage of 2 V was applied. The results are shown in FIG.

[0103] Figure 7 also shows the central wavelength of the reflection peak in the transmission spectrum in each state. As shown in Figure 7, it can be seen that the reflection peak wavelength changes depending on the applied voltage. Furthermore, the change in the reflection wavelength when 1.5 V was applied was 25 nm, and the change in the reflection wavelength when 2 V was applied was 80 nm.

[0104] Example 5

[0105]

[0106] In a three-neck flask, 200 mg (0.3 mmol) of Fc-BN-OH obtained in the same manner as in Example 1, 159 mg (2 equivalents, 0.6 mmol) of trans,trans-4'-butylbicyclohexyl-4-carboxylic acid (Tokyo Chemical Industry Co., Ltd.), 115 mg (2 equivalents, 0.6 mmol) of 4-dimethylaminopyridine (Tokyo Chemical Industry Co., Ltd.), 36 mg (2 equivalents, 0.6 mmol) of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (Tokyo Chemical Industry Co., Ltd.), and 15 mL of dichloromethane (Fujifilm Wako Pure Chemical Industries, Ltd.) were placed in an ice bath at 0°C and stirred at room temperature for 24 hours. The reaction solution was separated twice with ethyl acetate and ultrapure water, and then once with saturated saline. The collected organic layer was dehydrated over magnesium sulfate. The magnesium sulfate was then filtered off, the organic solvent was removed using an evaporator, and the residue was dried under reduced pressure to obtain a dark brown oily substance. The target compound was isolated using a developing solvent of ethyl acetate:hexane = 1:9 and a silica gel column (Rf value = 0.65). After removing the solvent using an evaporator, the product was dissolved in a small amount of hexane and reprecipitated with methanol. The target orange powder 2Fc-BN-Bicyclolo was obtained in an amount of 260 mg (0.23 mmol, 75% yield) by drying under reduced pressure.

[0107] The obtained 2Fc-BN-Bicyclolo was dissolved in deuterated chloroform. １The structure was confirmed by H-NMR measurement. １ The H-NMR spectrum is shown in FIG.

[0108] １ H-NMR (400MHz, CDCl ３ ): δ (ppm) 7.92 (d, 4H), 7.48 (dd, 2H), 7.36 (d, 2H), 7.25 (d, 2H), 4.73 (dd, 4H), 4.35 (s, 4H), 4.01 (s, 10H), 2.02 (t, 2H), 0.71-1.99 (m, 56H)

[0109] Example 6 A liquid crystal composition was prepared in the same manner as in Example 2, except that 2Fc-BN-Bicyclolo was used as the binaphthyl derivative. Furthermore, a liquid crystal element 3 was fabricated in the same manner as in Example 2, except that the obtained liquid crystal composition was used.

[0110] The transmission spectrum of the fabricated liquid crystal element 3 was measured before application of a DC voltage, when a DC voltage of 1.5 V was applied, and when a DC voltage of 2 V was applied. The results are shown in FIG.

[0111] Figure 9 also shows the central wavelength of the reflection peak in the transmission spectrum in each state. As shown in Figure 9, it can be seen that the reflection peak wavelength changes depending on the applied voltage. The change in the reflection wavelength when 1.5 V was applied was 50 nm, and the change in the reflection wavelength when 2 V was applied was 89 nm.

[0112] Example 7

[0113]

[0114] A three-neck flask was charged with 500 mg (0.94 mmol) of (R)-6,6'-dibromo-2,2'-bis(methoxymethoxy)-1,1'-binaphthyl (manufactured by Tokyo Chemical Industry Co., Ltd.), 540 mg (2.5 equivalents, 2.3 mmol) of 4,4'-dimethoxydiphenylamine (manufactured by Tokyo Chemical Industry Co., Ltd.), 663 mg (6.9 mmol) of sodium tert-butoxide (manufactured by Tokyo Chemical Industry Co., Ltd.), 133 mg (0.46 mmol) of tri-tert-butylphosphonium tetrafluoroborate (manufactured by Tokyo Chemical Industry Co., Ltd.), 69 mg (0.12 mmol) of bis(dibenzylideneacetone)palladium(0) (manufactured by Tokyo Chemical Industry Co., Ltd.), and 35 mL of toluene (manufactured by Fujifilm Wako Pure Chemical Industries Co., Ltd.), and the mixture was stirred at 110°C for 24 hours. Palladium removal treatment was performed using Celite, and the reaction solution was separated twice with ethyl acetate and 2 M HCl (Fujifilm Wako Pure Chemical Industries, Ltd.), and then once with ethyl acetate and saturated saline. The recovered organic layer was dehydrated with magnesium sulfate. The magnesium sulfate was then filtered off, and the organic solvent was removed using an evaporator to obtain a reddish-brown oily substance. This was dissolved in a small amount of tetrahydrofuran and recrystallized with hexane. The product was then dried under reduced pressure to obtain 578 mg (0.7 mmol, 74% yield) of the desired white powder DAB-BN-MOM.

[0115]

[0116] 550 mg (0.66 mmol) of DAB-BN-MOM, 631 mg (5 equivalents, 3.32 mmol) of p-toluenesulfonic acid (Tokyo Chemical Industry Co., Ltd.), 15 mL of tetrahydrofuran (Fujifilm Wako Pure Chemical Industries, Ltd.), and 10 mL of ethanol (Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a three-neck flask and stirred for 24 hours at room temperature. The organic layer was recovered by three phase separation using ethyl acetate and ultrapure water and dehydrated with magnesium sulfate. The magnesium sulfate was then filtered off, the organic solvent was removed using an evaporator, and the residue was dried under reduced pressure to obtain a dark brown oily substance. After removing the solvent using an evaporator, the residue was dissolved in a small amount of tetrahydrofuran and recrystallized with hexane. 383 mg (0.52 mmol, 78% yield) of the target DAB-BN-OH was obtained by drying under reduced pressure.

[0117]

[0118] Under ice bath conditions at 0°C, 135 mg (0.182 mmol) of DAB-BN-OH, 112 mg (2.5 equivalents, 0.46 mmol) of 4-(trans-4-propylcyclohexyl)benzoic acid (manufactured by Tokyo Chemical Industry Co., Ltd.), 22.2 mg (2.5 equivalents, 0.46 mmol) of 4-dimethylaminopyridine (manufactured by Tokyo Chemical Industry Co., Ltd.), 88 mg (2.5 equivalents, 0.46 mmol) of N-(3-dimethylaminopropyl)-N'-ethylcarbodiimide hydrochloride (manufactured by Tokyo Chemical Industry Co., Ltd.), and 15 mL of dichloromethane (manufactured by Fujifilm Wako Pure Chemical Industries, Ltd.) were added to a three-neck flask and stirred for 24 hours at room temperature. The reaction solution was separated three times with tetrahydrofuran and ultrapure water, and the recovered organic layer was dehydrated with magnesium sulfate. Thereafter, the magnesium sulfate was filtered off, the organic solvent was removed using an evaporator, and the residue was dried under reduced pressure to obtain a pale yellow oily substance. The target compound was isolated using a developing solvent of ethyl acetate:hexane = 1:3 and a silica gel column (Rf value = 0.46). After removing the solvent using an evaporator, the product was dissolved in a small amount of tetrahydrofuran and reprecipitated with methanol. The target compound, DAB-BN-LC, was obtained as a white powder in an amount of 157.6 mg (0.13 mmol, yield 72%) by drying under reduced pressure.

[0119] The obtained DAB-BN-LC was dissolved in deuterated chloroform. １ The structure was confirmed by H-NMR measurement. １ The H-NMR spectrum is shown in FIG.

[0120] １ H-NMR (400MHz, CDCl ３ ): δ (ppm) 7.59 (d, 2H), 7.57 (d, 4H), 7.41 (d, 2H), 7.26 (d, 2H), 7.21 (dd, 2H), 7.12 (d, 4H), 7.02 (d, 2H), 6.97-7.00 (m, 8H), 6.77-6.81 (m, 8H), 3.79 (s, 12H), 1.85 (d, 8H), 1.17-1.45 (m, 16H), 0.98-1.07 (m, 4H), 0.88 (t, 6H).

[0121] Example 8 A liquid crystal composition was prepared in the same manner as in Example 2, except that DAB-BN-LC was used as the binaphthyl derivative. Furthermore, a liquid crystal element 4 was fabricated in the same manner as in Example 2, except that the obtained liquid crystal composition was used.

[0122] The transmission spectrum of the fabricated liquid crystal element 4 was measured before application of a DC voltage, when a DC voltage of 1.5 V was applied, and when a DC voltage of 2 V was applied. The results are shown in FIG.

[0123] The central wavelength of the reflection peak in the transmission spectrum in each state is also shown in Figure 11. As shown in Figure 11, it can be seen that the reflection peak wavelength changes depending on the applied voltage. The change in the reflection wavelength when 1.5 V was applied was 23 nm, and the change in the reflection wavelength when 2 V was applied was 75 nm.

[0124] Comparative Example 1 Comparative liquid crystal elements were prepared in the same manner as in Example 2, except that compounds represented by the following chemical formulas C1 to C4 were used instead of the binaphthyl derivative 2Fc-BN-LC. The transmission spectrum of the prepared liquid crystal element was measured before and after application of a DC voltage of 2 V, and the change in the reflection wavelength Δλ (nm) was evaluated. The results are shown in Table 1. Note that the binaphthyl derivative, which is the chiral dopant, precipitated in C2, making it impossible to measure the transmission spectrum.

[0125]

[0126]

[0127] As shown in Table 1, by using the binaphthyl derivative according to this embodiment, the range of change in reflection wavelength can be increased.

[0128] The helical induction power (β Ｍ) was determined. A binaphthyl derivative was added as a chiral dopant to the host liquid crystal E-8 (LCC Corporation) at a concentration of 1.0% by mass or 0.5% by mass. These were dissolved in dichloromethane, ultrasonically stirred, and the solvent was evaporated to prepare a liquid crystal composition. The solution was added to a glass vial and annealed on a hot plate at 90°C for 30 minutes. A wedge-shaped cell (KCRK-07, manufactured by EHC Corporation) was then heated on a hot plate at 90°C, and the liquid crystal composition was introduced via capillary action. The hot plate was then turned off, and the cell was slowly cooled to room temperature on the hot plate to develop cholesteric liquid crystals. The wedge-shaped cell containing the cholesteric liquid crystal was observed under a polarizing microscope to measure the helical pitch length, and the helical potential was calculated from the concentration of the chiral dopant added. The relationship between the helical potential and the change in reflection wavelength (Δλ) is shown in Table 2.

[0129]

[0130] The disclosure of Japanese Patent Application No. 2024-114214 (filing date: July 17, 2024) is incorporated herein by reference in its entirety. All documents, patent applications, and technical standards mentioned 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. A binaphthyl derivative having a binaphthyl skeleton, a redox functional group linked to the binaphthyl skeleton so as to be capable of π-electron conjugation, and a mesogenic group.

2. The binaphthyl derivative according to claim 1, wherein the redox functional groups are located at the 6- and 6'-positions of the binaphthyl skeleton.

3. The binaphthyl derivative according to claim 1 or 2, wherein the redox functional group is linked to the binaphthyl skeleton by a single bond.

4. A binaphthyl derivative according to any one of claims 1 to 3, wherein the redox functional group contains a partial structure derived from ferrocene.

5. The binaphthyl derivative according to any one of claims 1 to 4, which has the mesogenic group at at least one position selected from the group consisting of the 2-position, 2'-position, 3-position and 3'-position of the binaphthyl skeleton.

6. A binaphthyl derivative according to any one of claims 1 to 5, which is represented by the following formula (1): (In the formula, L １ represents a single bond or a linking group capable of π-electron conjugation, and Rd represents a redox functional group. ２ represents a single bond or a linking group, M represents a mesogenic group, R represents a substituent, i and j each represent a number from 1 to 12, k represents a number from 0 to 12, and i + j + k ≦ 14.

7. In formula (1), -L １ 7. The binaphthyl derivative according to claim 6, which has groups represented by -Rd at the 6- and 6'-positions of the binaphthyl skeleton.

8. In formula (1), L １ The binaphthyl derivative according to claim 6 or 7, wherein is a single bond.

9. A binaphthyl derivative according to any one of claims 6 to 8, wherein in formula (1), Rd contains a partial structure derived from ferrocene.

10. In formula (1), -L ２ 10. The binaphthyl derivative according to claim 6, wherein a group represented by -M is present at at least two positions selected from the group consisting of the 2-position, the 2'-position, the 3-position, and the 3'-position of the binaphthyl skeleton.

11. A liquid crystal composition comprising the binaphthyl derivative according to any one of claims 1 to 10, a liquid crystal compound, and an electrolyte.

12. A liquid crystal device comprising a liquid crystal composition layer containing the liquid crystal composition according to claim 11, a counter electrode material layer containing a substance capable of undergoing an oxidation-reduction reaction, and a first electrode and a second electrode.

13. A display device or a light control device comprising the liquid crystal element according to claim 12.

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