Azobenzene derivative, method for producing azobenzene derivative, photothermal storage material, adhesive, optical element, and actuator material

Abstract

Provided is an azobenzene derivative represented by formula (1). (In formula (1), R1 represents a C1-18 alkoxy group, R2 each independently represent a hydrogen atom or a C1-4 alkyl group, R3 represents a hydrogen atom, a C1-4 alkyl group, or a C1-4 alkoxy group, R3 represents a functional group different than R1, X1 to X4 each independently represent a halogen atom or a C1-2 alkyl group, and one or more of X1 to X4 represents a halogen atom.)

Description

Azobenzene derivative, method for producing azobenzene derivative, photothermal storage material, adhesive, optical element and actuator material

[0001] The present invention relates to an azobenzene derivative, a method for producing an azobenzene derivative, and a photothermal storage material, adhesive, optical element, and actuator material containing the azobenzene derivative.

[0002] Compounds and materials that can reversibly change phase between solid and liquid using light are being researched for applications such as reversible adhesives, actuators, and light-storage materials. Patent Document 1 discloses a macrocyclic azobenzene having a specific structure as a photoresponsive liquid crystal compound. Patent Documents 2 and 3 disclose azobenzene derivatives having a specific structure. Non-Patent Documents 1, 2, 3, and 4 disclose halogen-substituted azobenzene derivatives.

[0003] Patent No. 5618272 Patent No. 5765751 Patent No. 6938063

[0004] Angew. Chem. Int. Ed. 2016, 55, 13514-13518Chem. Eur. J. 2016, 22, 4364-4368Tetrahedron Lett. 2019, 60, 1715-1719J. Am. Chem. Soc. 2020, 142, 6538-6547

[0005] However, in order to melt the compounds described in Patent Documents 1 to 3 with light, ultraviolet light was required. The inventors recognized that ultraviolet light, due to its high energy, poses problems in terms of damage to materials and living organisms. Furthermore, they recognized that using ultraviolet light poses a problem in that the solar spectrum cannot be fully utilized effectively. Furthermore, the inventors' investigations revealed that azobenzene, which is widely used in photoresponsive compounds, has a problem in that the cis isomer, which corresponds to the state melted by light, is less stable, and therefore azobenzene reverts to a solid state when left at room temperature, even when left in the dark. For example, when azobenzene is used as an adhesive, it is difficult to maintain a molten and detachable state for a long period of time. Furthermore, when azobenzene is used as a photothermal storage material, it is difficult to maintain a state in which light energy is stored for a long period of time. Meanwhile, Non-Patent Documents 1 to 4 disclose halogen-substituted azobenzene derivatives. Furthermore, it has been shown that the compounds disclosed in Non-Patent Documents 1 to 4 can undergo photoisomerization between trans and cis isomers only when each compound is dissolved in a solvent to form a solution and when visible light is used, not ultraviolet light. However, the inventors have come to the realization that none of the compounds disclosed in Non-Patent Documents 1 to 4 have been melted by visible light.

[0006] As described above, conventional azobenzenes melt when irradiated with visible light, and it has been difficult to design the molecules to maintain the molten state (liquid phase) for a long period of time. Furthermore, molecular design that allows for adjustment of response characteristics to light wavelengths and photosensitivity has not been achieved due to the difficulty of molecular synthesis. As described above, the present inventors have realized that the challenge is to provide a compound that melts when irradiated with visible light.

[0007] The present invention provides an azobenzene derivative that melts when exposed to visible light, a method for producing the same, and a photothermal storage material, adhesive, optical element, and actuator material containing the azobenzene derivative.

[0008] The present invention provides the following inventions: [1] An azobenzene derivative represented by the following formula (1): (In formula (1), R １ represents an alkoxy group having 1 to 18 carbon atoms, and R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R ３ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; R ３ is R １ represents a functional group different from X １ ~X ４ each independently represents a halogen atom or an alkyl group having 1 to 2 carbon atoms; X １ ~X ４ [2] In the formula (1), one or more of R represents a halogen atom. ２ [3] The azobenzene derivative according to [1], wherein at least one of R １ represents an alkoxy group having 6 to 18 carbon atoms; X １ ~X ４ each independently represents a halogen atom; １ ~X ４ [4] The azobenzene derivative according to [1] or [2], wherein X represents a combination of two or more halogen atoms. １ ~X ４ [5] The azobenzene derivative according to any one of [1] to [3], wherein X is a combination of two or more halogen atoms selected from the group consisting of a fluorine atom, a chlorine atom, and a bromine atom. １ and X ２ are the same halogen atom, and X ３ and X ４ But, X １ and X ２ [6] The azobenzene derivative according to any one of [1] to [4], wherein X in the formula (1) is the same halogen atom as １ ~X ４ [7] The azobenzene derivative according to any one of [1] to [5], wherein R is a combination of a fluorine atom and a chlorine atom. ２are each independently a hydrogen atom or a methyl group. [8] The azobenzene derivative according to any one of [1] to [7], which is capable of undergoing a phase transition between a solid phase and a liquid phase upon irradiation with visible light. [9] The azobenzene derivative according to [8], which undergoes a phase transition from a solid phase to a liquid phase upon irradiation with visible light having a wavelength of 500 to 650 nm.

[10] The azobenzene derivative according to [8] or [9], which undergoes a phase transition from a liquid phase to a solid phase upon irradiation with visible light having a wavelength of 400 to 500 nm.

[11] A method for producing the azobenzene derivative according to any one of [1] to

[10] , comprising the steps of: step (A) of contacting at least one azobenzene derivative selected from the group consisting of azobenzene derivatives represented by the following formula (2-1), azobenzene derivatives represented by the following formula (2-2), and azobenzene derivatives represented by the following formula (2-3), with a halogenating agent in the presence of a palladium compound to obtain an azobenzene derivative represented by the following formula (3); and step (B) of deprotecting the acetoxy group of the azobenzene derivative represented by the following formula (3) obtained in step (A) to obtain the azobenzene derivative represented by the formula (1). (In formula (2-1), formula (2-2) and formula (2-3), R' １ represents an acetoxy group, and R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R ３ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; X １ ~X ４ each independently represents a halogen atom or an alkyl group having 1 to 2 carbon atoms. (In formula (3), R' １ represents an acetoxy group, and R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R ３ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; X １ ~X ４each independently represents a halogen atom or an alkyl group having 1 to 2 carbon atoms; X １ ~X ４

[12] In the formula (2-1), the formula (2-2), and the formula (2-3), one or more of X represents a halogen atom. １ ~X ４ each independently represents a halogen atom, １ ~X ４ each independently represents a halogen atom; １ ~X ４ represents a combination of two or more halogen atoms.

[13] A photothermal storage material containing the azobenzene derivative according to any one of [1] to

[10] .

[14] An adhesive containing the azobenzene derivative according to any one of [1] to

[10] .

[15] An optical element containing the azobenzene derivative according to any one of [1] to

[10] .

[16] An actuator material containing the azobenzene derivative according to any one of [1] to

[10] .

[0009] According to the present invention, it is possible to provide an azobenzene derivative that melts when exposed to visible light, a method for producing the same, and a photothermal storage material, adhesive, optical element, and actuator material containing the azobenzene derivative.

[0010] Observation results of crystalline phase-isotropic phase transition using a polarized optical microscope Observation results of crystalline phase-isotropic phase transition using a polarized optical microscope Observation results of crystalline phase-isotropic phase transition using a polarized optical microscope Observation results of crystalline phase-isotropic phase transition using a polarized optical microscope Observation results of sunlight irradiation experiment Observation results of crystalline phase-isotropic phase transition using a polarized optical microscope Observation results of crystalline phase-isotropic phase transition using a polarized optical microscope Observation results of crystalline phase-isotropic phase transition using a polarized optical microscope Observation results of crystalline phase-isotropic phase transition using a polarized optical microscope Observation results of the crystalline phase-isotropic phase transition using a polarizing optical microscope Observation results of the crystalline phase-isotropic phase transition using a polarizing optical microscope Observation results of the crystalline phase-isotropic phase transition using a polarizing optical microscope Observation results of the crystalline phase-isotropic phase transition using a polarizing optical microscope Observation results of the crystalline phase-isotropic phase transition using a polarizing optical microscope Observation results of the crystalline phase-isotropic phase transition using a polarizing optical microscope Observation results of the crystalline phase-isotropic phase transition using a polarizing optical microscope Observation results of the crystalline phase-isotropic phase transition using a polarizing optical microscope

[0011] The present invention will be described in detail below, but is not limited to the following description. The expressions "XX or more and YY or less" and "XX to YY" representing a numerical range mean a numerical range including the lower and upper limits, which are the endpoints, unless otherwise specified. When a numerical range is described in stages, the upper and lower limits of each numerical range can be combined arbitrarily. Furthermore, in this disclosure, visible light refers to light with a wavelength of 400 to 700 nm.

[0012] The azobenzene derivative is an azobenzene derivative represented by the following formula (1). (In formula (1), R １ represents an alkoxy group having 1 to 18 carbon atoms (preferably 3 to 18, more preferably 6 to 18, even more preferably 6 to 16, still more preferably 6 to 14, and particularly preferably 6 to 12), and R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms (preferably 1 to 2, preferably 3 to 4, more preferably 1), and R ３represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms (preferably 1 to 2, preferably 3 to 4, more preferably 1), or an alkoxy group having 1 to 4 carbon atoms (preferably 1 to 2, preferably 3 to 4, more preferably 1), and R ３ is R １ represents a functional group different from X １ ~X ４ each independently represents a halogen atom or an alkyl group having 1 to 2 carbon atoms; X １ ~X ４ At least one of the groups represents a halogen atom.)

[0013] When the azobenzene derivative has the structure represented by the above formula (1), it has the property of melting when irradiated with visible light, and can maintain the melted state for a long period of time. The mechanism by which this effect is achieved is not clear, but the present inventors speculate as follows. The azobenzene derivative having the structure represented by the above formula (1) has an alkoxy group R １ and a hydrogen atom, a relatively short-chain alkyl group, or R １ R is an alkoxy group different from ３ In this way, the azobenzene derivative has an asymmetric molecular structure, which makes it possible to control the strength of the interaction between molecules and the strength of packing in the crystalline state. １ is a relatively long-chain alkoxy group (e.g., having 6 to 18 carbon atoms), the strength of the interaction between molecules in the crystalline state and the strength of packing can be more easily controlled. Furthermore, the azobenzene derivative having the structure represented by the above formula (1) has one or more halogen atoms X in the molecule. １ ~X ４ When the azobenzene derivative has one or more halogen atoms, it becomes easier to control the electron density of the azobenzene derivative, the strength of the interaction between molecules in a crystalline state, and the strength of packing.

[0014] In the above formula (1), R １ ~R ３When is an alkyl group or an alkoxy group, the alkyl group and alkoxy group may be linear or branched, but preferably branched. By having a branch, the azobenzene derivative tends to have stronger asymmetry, making it easier to control the strength of the interaction between molecules and the packing strength in the crystalline state. Specifically, for example, alkyl groups such as an isopropyl group or an isobutyl group, or alkoxy groups such as an isopropoxy group or an isobutoxy group are preferred.

[0015] X １ ~X ４ each independently represents a halogen atom or an alkyl group having 1 to 2 carbon atoms; X １ ~X ４ In the above formula (1), one or more of X represents a halogen atom. １ ~X ４ The halogen atom represented by X is not particularly limited, and may be a fluorine atom, a chlorine atom, a bromine atom, an iodine atom, an astatine atom, or a tennessine atom. １ ~X ４ each independently represents a halogen atom; X １ ~X ４ It is preferable that X represents a combination of two or more halogen atoms. When the azobenzene derivative has two or more halogen atoms, the electron density of the azobenzene derivative, the strength of the interaction between molecules in a crystalline state, and the strength of packing can be more easily controlled. １ ~X ４ is preferably a combination of two or more halogen atoms selected from the group consisting of fluorine atoms, chlorine atoms, bromine atoms, and iodine atoms, more preferably a combination of two or more halogen atoms selected from the group consisting of fluorine atoms, chlorine atoms, and bromine atoms, and even more preferably a combination of fluorine atoms and chlorine atoms. １ ~X ４ is a combination of two or more halogen atoms, X １ ~X ４ is not particularly limited, but X １ and X ２ are the same halogen atoms, and X３ and X ４ But, X １ and X ２ It is more preferable that they are the same halogen atoms different from

[0016] It can be confirmed by NMR measurement described later that the azobenzene derivative has the structure represented by the above formula (1).

[0017] Examples of azobenzene derivatives having the structure represented by the above formula (1) include the following: 2,6-dichloro-4-octoxy-2',6'-difluoroazobenzene, 2,6-dichloro-3-methyl-4-octoxy-2',6'-difluoroazobenzene, 2,6-dichloro-3,5-dimethyl-4-octoxy-2',6'-difluoroazobenzene, 2,6-dichloro-2',6'-difluoro-4'-octoxyazobenzene, 2,6-dichloro-3-methyl-2',6'-difluoroazobenzene, 2,6-dichloro-4-hexoxy-2',6'-difluoroazobenzene, 2,6-dichloro-4-heptoxy-2',6'-difluoroazobenzene, 2,6-dibromo-4-octoxy-2',6'-difluoroazobenzene, 2,6-dibromo-4-octoxy-2',6'-difluoroazobenzene, 2,6-dibromo-4-octoxy-2',6'-dichloroazobenzene, 4-butoxy-2,6-dichloro-3,5-dimethyl-2 ',6'-difluoroazobenzene, 2,6-dichloro-3,5-dimethyl-4-pentoxy-2',6'-difluoroazobenzene, 2,6-dichloro-4-hexoxy-3,5-dimethyl-2',6'-difluoroazobenzene, 2,6-dichloro-3-methyl-2',6'-difluoro-4'-methoxyazobenzene, 2,6-dichloro-3-methyl-4'-ethoxy-2',6'-difluoroazo Benzene, 2,6-dichloro-3-methyl-2',6'-difluoro-4'-propoxyazobenzene, 2,6-dichloro-3-methyl-4'-butoxy-2',6'-difluoroazobenzene, 2,6-dichloro-3-methyl-2',6'-difluoro-4'-pentoxyazobenzene, 2-chloro-6-methyl-2'-chloro-4'-methoxy-6'-methyl-3'-isopropylazobenzene, and the like.

[0018] As described above, when an azobenzene derivative has the structure represented by the above formula (1), the azobenzene derivative has the property of melting when irradiated with visible light. That is, an azobenzene derivative having the structure represented by the above formula (1) can undergo a phase transition from a solid phase to a liquid phase when irradiated with visible light. This is because the azobenzene derivative undergoes a photoisomerization reaction upon irradiation with visible light, for example, photoisomerizing from a trans isomer to a cis isomer. Furthermore, an azobenzene derivative having the structure represented by the above formula (1) is a photosensitive azobenzene derivative. The azobenzene derivative having the structure represented by the above formula (1) preferably undergoes a phase transition from a solid phase to a liquid phase when irradiated with visible light having a wavelength of 500 to 650 nm (preferably 520 to 600 nm). The wavelength of this visible light is determined by the R in the above formula (1). １ ~R ３ and X １ ~X ４ The wavelength range used for the phase transition can be predicted from the absorption spectrum obtained by measuring the azobenzene derivative by ultraviolet-visible spectroscopy.

[0019] Furthermore, it is preferable that the azobenzene derivative having the structure represented by the above formula (1) can undergo a phase transition from a liquid phase to a solid phase upon irradiation with visible light. This is because the azobenzene derivative undergoes a photoisomerization reaction upon irradiation with visible light, for example, photoisomerizing from a cis form to a trans form. For example, it is preferable that the azobenzene derivative having the structure represented by the above formula (1) undergoes a phase transition from a liquid phase to a solid phase upon irradiation with visible light having a wavelength of 400 to 500 nm (preferably 420 to 480 nm). The wavelength of this visible light is determined by the R in the above formula (1). １ ~R ３ and X １ ~X ４ The wavelength range used for the phase transition can be predicted from the absorption spectrum obtained by measuring the azobenzene derivative by ultraviolet-visible spectroscopy.

[0020] When an azobenzene derivative undergoes a phase transition from a solid phase to a liquid phase upon irradiation with visible light having a wavelength of 500 to 650 nm, and when the azobenzene derivative undergoes a phase transition from a liquid phase to a solid phase upon irradiation with visible light having a wavelength of 400 to 500 nm, photoisomerization from the trans isomer to the cis isomer and from the cis isomer to the trans isomer proceed simultaneously when the azobenzene derivative is irradiated with light having a wavelength of 400 to 650 nm. However, in this case, the phase transition of the azobenzene derivative can be controlled by adjusting the intensity distribution of the wavelength of 400 to 650 nm. For example, when the azobenzene derivative is irradiated with sunlight, which is light having a stronger intensity at wavelengths of 500 to 650 nm than at wavelengths of 400 to 500 nm, a phase transition from a solid phase to a liquid phase occurs. Conversely, by irradiating an azobenzene derivative with light whose intensity in the wavelength range of 400 to 500 nm is stronger than that in the wavelength range of 500 to 650 nm, a phase transition from a liquid phase to a solid phase can be caused.

[0021] The azobenzene derivative having the structure represented by the formula (1) is preferably capable of undergoing a phase transition between a solid phase and a liquid phase upon irradiation with visible light. That is, it is preferable that the azobenzene derivative undergoes a reversible phase change between the solid phase and the liquid phase upon irradiation with visible light. Such a property can contribute to energy and resource conservation in photothermal storage materials, adhesives, and the like containing the azobenzene derivative.

[0022] Here, "crystalline phase" refers to a solid state in which the molecules of the azobenzene derivative are regularly arranged, "liquid phase" refers to a fluid state in which the molecules of the azobenzene derivative are irregularly arranged, and "reversible" means that a substance that has once become liquid can be returned to its original solid state.

[0023] The azobenzene derivative having the structure represented by the above formula (1) can be incorporated into photosensitive materials, thin films, photoresist materials, printing plate materials, photothermal storage materials, adhesives, optical elements, or actuator materials that can be patterned by light irradiation, thereby utilizing the azobenzene derivative's property of melting under visible light. That is, the photothermal storage material is a photothermal storage material containing the azobenzene derivative of the present invention. The adhesive is an adhesive containing the azobenzene derivative of the present invention. The optical element is an optical element containing the azobenzene derivative of the present invention. Examples of optical elements include photocontrollable TFT elements and photocontrollable liquid crystal displays. Additionally, the actuator material is an actuator material containing the azobenzene derivative of the present invention.

[0024] The azobenzene derivative having the structure represented by the above formula (1) preferably has an isomerization reaction enthalpy (ΔHisom) measured by differential scanning calorimetry (DSC) of -70.0 to -30.0 J / g, more preferably -60.0 to -40.0 J / g. Furthermore, the crystallization enthalpy (ΔHcryst) measured by differential scanning calorimetry (DSC) is preferably -80.0 to -40.0 J / g, more preferably -70.0 to -50.0 J / g. Being within the above ranges allows for, for example, suitable heat storage and heat release in a photothermal storage material. ΔHisom and ΔHcryst are determined by R １ ~R ３ , X １ ~X ４ This can be adjusted by changing

[0025] The azobenzene derivative having the structure represented by the above formula (1) preferably has a lifespan at 30°C, calculated by the liquid phase stability calculation method described below, of 10.0 days or more, more preferably 31.0 days or more, even more preferably 40.0 days or more, and particularly preferably 50.0 days or more. The upper limit is not particularly limited, but may be 200.0 days or less, 150.0 days or less, or 120.0 days or less. Examples include 10.0 to 200.0 days, 31.0 to 200.0 days, 40.0 to 150.0 days, and 50.0 to 120.0 days. By being in the above range, for example, in a photothermal storage material, the stored state of light energy can be maintained for a long period of time. The lifespan at 30°C is R １ ~R ３ , X １ ~X ４ This can be adjusted by changing

[0026] Because the hardness, viscosity, and fluidity of the compound differ between the crystalline and liquid phases, the azobenzene derivative according to the present invention can be used to create materials whose hardness, viscosity, fluidity, and diffusion coefficient can be freely controlled by light. Because the refractive index of the compound differs between the crystalline and liquid phases, the azobenzene derivative according to the present invention can be used to create materials whose refractive index can be freely controlled by light. Because the birefringence of the compound differs between the crystalline and liquid phases, the azobenzene derivative according to the present invention can be used to create materials whose birefringence can be freely controlled by light. Because the scattering intensity of light differs between the crystalline and liquid phases, the azobenzene derivative according to the present invention can be used to create materials whose scattering intensity can be freely controlled by light. Furthermore, because the above-mentioned properties of the azobenzene derivative according to the present invention are changed using light, the properties can be changed at any location. That is, the hardness, viscosity, fluidity, diffusion coefficient, refractive index, birefringence, and scattering intensity can be patterned. Furthermore, by utilizing the difference in birefringence between the crystalline and liquid phases, a display element or a recording element can be created by combining it with a polarizing plate. That is, by sandwiching the azobenzene derivative according to the present invention between polarizing plates orthogonal to each other, it transmits light in a crystalline state having birefringence, but does not transmit light in a liquid state having no birefringence. By patterning this, a display or recording element can be created. Furthermore, by irradiating the azobenzene derivative according to the present invention with patterning light to pattern the crystalline phase and the liquid phase, the liquid phase can be removed by utilizing the difference in fluidity or diffusion coefficient, and a pattern can be created. This can be used to create a resist pattern.

[0027] A method for producing an azobenzene derivative having a structure represented by formula (1) above will be described. The method for producing an azobenzene derivative having a structure represented by formula (1) above is not particularly limited as long as it can produce an azobenzene derivative having the desired structure, but the following method is preferred. The following production method can be used to suitably produce an azobenzene derivative having a structure represented by formula (1) above. That is, the method for producing an azobenzene derivative preferably includes, in this order: step (A) of contacting at least one azobenzene derivative selected from the group consisting of azobenzene derivatives represented by formulas (2-1) below, (2-2) below, and (2-3) below with a halogenating agent in the presence of a palladium compound to obtain an azobenzene derivative represented by formula (3) below; and step (B) of deprotecting the acetoxy group of the azobenzene derivative represented by formula (3) obtained in step (A) to obtain the azobenzene derivative represented by formula (1). (In formula (2-1), formula (2-2) and formula (2-3), R' １ represents an acetoxy group, and R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms (preferably 1 to 2, preferably 3 to 4, more preferably 1), and R ３ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms (preferably 1 to 2, preferably 3 to 4, more preferably 1), or an alkoxy group having 1 to 4 carbon atoms (preferably 1 to 2, preferably 3 to 4, more preferably 1), and X １ ~X ４ each independently represents a halogen atom or an alkyl group having 1 to 2 carbon atoms. (In formula (3), R' １ represents an acetoxy group, and R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms (preferably 1 to 2, preferably 3 to 4, more preferably 1), and R ３represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms (preferably 1 to 2, preferably 3 to 4, more preferably 1), or an alkoxy group having 1 to 4 carbon atoms (preferably 1 to 2, preferably 3 to 4, more preferably 1), and X １ ~X ４ each independently represents a halogen atom or an alkyl group having 1 to 2 carbon atoms; X １ ~X ４ At least one of the groups represents a halogen atom.)

[0028] Step (A) will be described below. Step (A) is a step of contacting an azobenzene derivative intermediate represented by any of the above formulas (2-1) to (2-3) with a halogenating agent in the presence of a palladium compound to obtain an azobenzene derivative intermediate represented by the above formula (3). That is, step (A) is a step of halogenating an azobenzene derivative intermediate having an acetoxy group represented by any of the above formulas (2-1) to (2-3) to obtain an azobenzene derivative intermediate represented by the above formula (3). When the method for producing an azobenzene derivative includes step (A), the azobenzene derivative intermediate represented by the above formula (3) can be obtained. Here, in formulas (2-1), (2-2), and (2-3), X １ ~X ４ Preferably, each independently represents a halogen atom. １ ~X ４ each independently represents a halogen atom; １ ~X ４ It is preferred that represents a combination of two or more halogen atoms.

[0029] Palladium compounds are used as catalysts for halogenation reactions. The palladium compound is not particularly limited as long as it can be used as a catalyst for halogenation reactions, and examples thereof include palladium salts such as palladium chloride, palladium acetate, palladium trifluoroacetate, and palladium nitrate, complex compounds such as π-allylpalladium chloride dimer, palladium acetylacetonate, tris(dibenzylideneacetone)dipalladium, bis(dibenzylideneacetone)palladium, dichlorobis(acetonitrile)palladium, and dichlorobis(benzonitrile)palladium, and palladium having a tertiary phosphine as a ligand, such as dichlorobis(triphenylphosphine)palladium, tetrakis(triphenylphosphine)palladium(0), dichloro[1,1′-bis(diphenylphosphino)ferrocene]palladium, bis(tri-tert-butylphosphine)palladium, bis(tricyclohexylphosphine)palladium, and dichlorobis(tricyclohexylphosphine)palladium. Among these, tetrakis(triphenylphosphine)palladium(0) is preferred. Palladium compounds may be used alone or in combination. The amount of the palladium compound added is not particularly limited, but is preferably 0.1 to 5.0 mol, more preferably 0.5 to 4.0 mol, and particularly preferably 1.5 to 3.5 mol, relative to 100.0 mol of the azobenzene derivative represented by formulas (2-1) to (2-3).

[0030] The palladium compound may be prepared in the reaction system by adding a ligand such as a tertiary phosphine to a palladium salt or complex compound. Examples of tertiary phosphines that can be used in this case include triphenylphosphine, trimethylphosphine, tributylphosphine, tri(tert-butyl)phosphine, tricyclohexylphosphine, tert-butyldiphenylphosphine, 9,9-dimethyl-4,5-bis(diphenylphosphino)xanthene, 2-(diphenylphosphino)-2'-(N,N-dimethylamino)biphenyl, 2-(di-tert-butylphosphino)biphenyl, 2-(dicyclohexylphosphino)biphenyl, bis(diphenylphosphine), and the like. 1,2-bis(diphenylphosphino)methane, 1,2-bis(diphenylphosphino)ethane, 1,3-bis(diphenylphosphino)propane, 1,4-bis(diphenylphosphino)butane, 1,1'-bis(diphenylphosphino)ferrocene, tri(2-furyl)phosphine, tri(o-tolyl)phosphine, tris(2,5-xylyl)phosphine, (±)-2,2'-bis(diphenylphosphino)-1,1'-binaphthyl, 2-dicyclohexylphosphino-2',4',6'-triisopropylbiphenyl, and the like.

[0031] Examples of halogenating agents that can be used include chlorinating agents such as chlorine, N-chlorosuccinimide, N-chlorophthalimide, 1,3-dichloro-5,5-dimethylhydantoin (DCDMH), and trichloroisocyanuric acid; brominating agents such as bromine, N-bromosuccinimide, N-bromophthalimide, 1,3-dibromo-5,5-dimethylhydantoin, and tribromoisocyanuric acid; and iodinating agents such as iodine, N-iodosuccinimide, N-iodophthalimide, 1,3-diiodo-5,5-dimethylhydantoin, and triiodoisocyanuric acid. Among these, trichloroisocyanuric acid is preferred as the chlorinating agent, tribromoisocyanuric acid as the brominating agent, and triiodoisocyanuric acid as the iodinating agent. The halogenating agents may be used alone or in combination of two or more. The amount of the halogenating agent to be added is not particularly limited, but is preferably 50.0 to 250.0 mol, more preferably 50.0 to 200.0 mol, even more preferably 50.0 to 150.0 mol, particularly preferably 65.0 to 135.0 mol, and even more preferably 80.0 to 120.0 mol, relative to 100.0 mol of the azobenzene derivative represented by any of Formulas (2-1) to (2-3).

[0032] Other oxidizing agents can be used as needed. Examples of oxidizing agents include persulfuric acid and its salts, such as ammonium, sodium, potassium, cesium, and alkylammonium salts; inorganic peroxodisulfates; and peroxides such as benzoyl peroxide. Among these, potassium peroxodisulfate is preferred. Oxidizing agents may be used alone or in combination. The amount of oxidizing agent added is not particularly limited, but is preferably 70.0 to 170.0 mol, more preferably 85.0 to 155.0 mol, and particularly preferably 100.0 to 140.0 mol, relative to 100.0 mol of the azobenzene derivative represented by formulas (2-1) to (2-3).

[0033] The reaction solvent is not particularly limited, but examples thereof include carbon tetrachloride, 1,1,2,2-tetrachloroethane, 1,2-dichloroethane, 1,1,1-trichloroethane, 1,1,2-trichloroethane, chloroform, and chlorobenzene. Of these, 1,1,2,2-tetrachloroethane is preferred. The reaction solvent may be used alone or in combination. The amount of the reaction solvent added is not particularly limited, but is preferably an amount that results in a concentration of the azobenzene derivative represented by formulas (2-1) to (2-3) in the reaction solution of 0.1 to 2.0 mol / L, more preferably an amount that results in a concentration of 0.2 to 1.5 mol / L, and particularly preferably an amount that results in a concentration of 0.4 to 1.2 mol / L.

[0034] Other reaction conditions are not particularly limited, but the reaction temperature is preferably 90 to 130° C., more preferably 100 to 120° C. The reaction time is preferably 0.1 to 10.0 hours, more preferably 0.5 to 5.0 hours, and even more preferably 0.5 to 2.0 hours.

[0035] The azobenzene derivatives represented by the above formulas (2-1) to (2-3) can generally be synthesized by reductively dimerizing a nitro compound precursor. Alternatively, they can be synthesized by oxidatively dimerizing an amino compound precursor. Alternatively, they can be synthesized by a diazo coupling reaction between an amino compound precursor and a phenol derivative. Alternatively, they can be synthesized by a condensation reaction between a nitroso compound precursor and an amino compound.

[0036] Step (B) will be described below. Step (B) is a step of deprotecting the acetoxy group of the azobenzene derivative intermediate represented by formula (3) obtained in step (A) to obtain the azobenzene derivative represented by formula (1). The method for producing an azobenzene derivative includes step (B) as described above, thereby making it possible to obtain the azobenzene derivative represented by formula (1).

[0037] As long as the acetoxy group of the azobenzene derivative represented by formula (3) can be deprotected to obtain the azobenzene derivative represented by formula (1), the reaction conditions are not particularly limited. For example, to deprotect the acetoxy group, the acetoxy group can be hydrolyzed using an acid or a base. A base is preferred. Examples of bases that can be used include sodium hydride, sodium hydroxide, potassium hydroxide, and lithium hydroxide, with sodium hydride being preferred. Examples of acids that can be used include hydrogen chloride, sulfuric acid, acetic acid, and formic acid. The amount of acid or base added is not particularly limited, but is preferably 100.0 to 600.0 mol, more preferably 200.0 to 500.0 mol, and particularly preferably 350.0 to 450.0 mol, per 100.0 mol of the azobenzene derivative represented by formula (3). Water may be added for hydrolysis. The type of water is not particularly limited, and distilled water, for example, can be used. The amount of water added is preferably equal to the amount of the acid or base.

[0038] It is preferable to use an alkyl halide having 1 to 18 carbon atoms. The number of carbon atoms is more preferably 3 to 18, even more preferably 6 to 18, even more preferably 6 to 16, particularly preferably 6 to 14, and especially preferably 6 to 12. The alkyl halide is not particularly limited, but is preferably at least one selected from the group consisting of alkyl chloride, alkyl bromide, and alkyl iodide. More preferably, it is alkyl bromide. Examples of such alkyl halides include alkyl chlorides such as chloropropane, chlorobutane, chloropentane, chlorohexane, chloroheptane, chlorooctane, chlorononane, chlorodecane, chloroundecane, and chlorododecane; alkyl bromides such as bromopropane, bromobutane, bromopentane, bromohexane, bromoheptane, bromooctane, bromononane, bromodecane, bromoundecane, and bromododecane; and alkyl iodides such as iodopropane, iodobutane, iodopentane, iodohexane, iodoheptane, iodooctane, iodononane, iododecane, iodoundecane, and iodododecane. The amount of alkyl halide added is not particularly limited, but is preferably 100.0 to 300.0 mol, more preferably 150.0 to 250.0 mol, and particularly preferably 175.0 to 225.0 mol, per 100.0 mol of the azobenzene derivative represented by formula (3). A methylating agent such as methyl paratoluenesulfonate, or an ethylating agent such as ethyl paratoluenesulfonate, may also be used. The amount of the methylating agent or ethylating agent added may be the same as that of the alkyl halide.

[0039] It is preferable to use a crown ether as the catalyst. By using a crown ether, sodium can be trapped, thereby increasing the solubility of the intermediate salt. The crown ether is not particularly limited, but examples include 18-crown-6, 15-crown-5, and 12-crown-4, with 18-crown-6 being preferred. The amount of crown ether added is not particularly limited, but is preferably 0.1 to 5.0 mol, more preferably 0.5 to 4.0 mol, and particularly preferably 1.5 to 3.5 mol, relative to 100.0 mol of the azobenzene derivative represented by formula (3).

[0040] The reaction solvent is not particularly limited, but examples include 1,4-dioxane, tetrahydrofuran (THF), and N,N-dimethylformamide. Among these, tetrahydrofuran is preferred. The reaction solvent may be used alone or in combination of two or more. The amount of the reaction solvent added is not particularly limited, but is preferably an amount that results in a concentration of the azobenzene derivative represented by formula (3) in the reaction solution of 0.1 to 2.0 mol / L, more preferably an amount that results in a concentration of 0.1 to 1.0 mol / L, and particularly preferably an amount that results in a concentration of 0.1 to 0.5 mol / L.

[0041] Other reaction conditions are not particularly limited, but the reaction temperature is preferably 50 to 80°C, more preferably 60 to 70°C. A temperature at which the reaction solvent refluxes is particularly preferred. The reaction time is preferably 1.0 to 40.0 hours, more preferably 5.0 to 30.0 hours, and even more preferably 12.0 to 24.0 hours.

[0042] The present invention will be further described below based on examples, but the present invention is not limited to these representative examples.

[0043] <Synthesis and Characterization> The compounds shown below were synthesized and their thermal properties and photoresponsiveness were evaluated. An overview of the compounds examined is shown below.

[0044] <Reagents and equipment used in the experiments> (Reagents used in the experiments) Commercially available reagents and solvents were used as they were for synthesis and property evaluation. Silica gel 100 (manufactured by Kanto Chemical Co., Ltd.) was used for column chromatography. (NMR spectrum) NMR (nuclear magnetic resonance) spectra were measured using an NMR analyzer "Avance 400" (manufactured by Bruker).

[0045] (Analysis of Thermal Behavior of Synthesized Compounds) The thermal behavior of the synthesized compounds was analyzed in the dark using a differential scanning calorimeter (DSC) (DSC6100 manufactured by SII Nanotechnology Co., Ltd.). The phase transition temperatures of each compound are indicated by symbols. For example, "Cr 43 Iso, Iso 30 Cr" means that the crystal (Cr) melted at 43°C upon heating and changed to a liquid (Iso), and the liquid solidified at 30°C upon cooling. "Cr 43 Iso" means that the crystal (Cr) melted at 43°C upon heating and changed to a liquid (Iso). Note that X indicates an unidentified phase.

[0046] (Light Irradiation Experiments for Each Compound) Light irradiation experiments for each compound were conducted using samples prepared by sealing compound crystals in glass sandwich cells. Light irradiation was performed at room temperature under observation using a polarized optical microscope. The polarized optical microscope used was a "BX51" microscope (manufactured by Olympus Corporation). A high-pressure mercury lamp was used as the light source for light irradiation. Light was passed through a filter and irradiated at an arbitrary wavelength. When observing the sample using the polarized optical microscope with the polarizer and analyzer of the polarized microscope orthogonal to each other (crossed Nicols), if the bright field due to the birefringence of the crystal disappeared and a dark field appeared, it was determined that a phase transition from the crystalline phase to the isotropic phase had occurred. Conversely, if the dark field changed to a bright field, it was determined that a phase transition from the isotropic phase to the crystalline phase had occurred. In addition, the induction of a solid-to-liquid phase transition and a liquid-to-solid phase transition were determined visually.

[0047] (Liquid Phase Stability) The liquid phase stability was calculated as follows. The solid-to-liquid phase transition is induced by photoisomerization of the azobenzene derivative from the trans isomer to the cis isomer. On the other hand, the liquid-to-solid phase transition is induced by photoisomerization or thermal isomerization of the azobenzene derivative from the cis isomer to the trans isomer. Here, the liquid phase stability can be defined by the thermal stability of the cis isomer. That is, the liquid phase stability was calculated by determining the lifetime at 30°C from the rate constant of thermal isomerization of the cis isomer of the azobenzene derivative in the dark at 30°C. Here, the lifetime is defined as the reciprocal (1 / k) of the reaction rate constant (k) of the thermal isomerization reaction. The lifetime of the azobenzene derivative of the present application at 30°C is long and difficult to measure directly experimentally. Therefore, k at 30°C was calculated using measured values ​​at multiple temperatures in a high-temperature accelerated test and the Arrhenius equation. That is, the rate constant (k) of thermal isomerization was measured at different temperatures, and the horizontal axis was plotted with the reciprocal of absolute temperature (1 / T) and the vertical axis was plotted with the natural logarithm (ln k) of the reaction rate constant (k). Using this plot and the Arrhenius equation, k at 30°C was calculated. The Arrhenius equation is expressed by the following equation (4): ln k = A exp(-Ea / RT) (4) In equation (4), A is the frequency factor, Ea is the activation energy, R is the gas constant, and T is the absolute temperature.

[0048] The rate constant of thermal isomerization was measured as follows: A 1,1,2,2-tetrachloroethane (TCE) solution (5x10 －５ The sample (mol / L) was irradiated with 365 nm light for 10 minutes, and then held at a predetermined temperature using a UV-visible spectrophotometer "V-780" (JASCO Corporation) and the attached thermostatic cell holder "ETCR-762" (JASCO Corporation). The time change in the absorption spectrum of this sample was observed, and the rate constant (k) of thermal isomerization at a predetermined temperature was obtained.

[0049] Example 1-1 (Synthesis of Compound C2-A1-OAc (Intermediate 1-1)) 16 mL of distilled water and 4 mL of concentrated hydrochloric acid were added to 2,6-difluoroaniline (1.29 g, 10 mmol). A solution prepared by dissolving sodium nitrite (0.83 g, 12 mmol) in 5 mL of distilled water was added while stirring at 0°C. The resulting solution was then added to 20 mL of an aqueous solution of phenol (0.94 g, 10 mmol) and 4.7 g of sodium hydroxide, and the mixture was stirred for 15 minutes. The resulting solution was acidified with hydrochloric acid under cooling and then extracted with ethyl acetate. The organic layer was washed with saturated saline and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the resulting solid was diluted with 50 mL of dehydrated dichloromethane, followed by the addition of 12.1 g (12 mmol) of triethylamine (TEA). A mixture of 0.94 g (12 mmol) of acetyl chloride (AcCl) in 10 mL of dichloromethane (DCM) was added dropwise with stirring at 0°C under nitrogen. The resulting solution was allowed to stand for 1 hour and then extracted with water. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was purified by silica gel column chromatography to obtain Intermediate 1-1 shown below (orange solid, 1.33 g, yield: 48%).

[0050] Intermediate 1-1 １ The structure was determined by HNMR analysis. 1HNMR (400 MHz, CDCl3): 2.33 (s, 3H), 7.04 (t, J=8.5 Hz, 2H), 7.26 (dd, J1=8.7Hz, J2=1.9Hz, 2H), 7.28-7.35 (m, 1H), 7.97 (dd, J1=8.9Hz, J2=2.0Hz, 2H).

[0051] Example 1-2 (Synthesis of Compound C2-A1A-OAc (Intermediate 1-2)) 5 mL of 1,1,2,2-tetrachloroethane (TCE), trichloroisocyanuric acid (TCCA, 0.93 g, 4 mmol), potassium peroxodisulfate (1.3 g, 4.8 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.12 g, 0.1 mmol) were added to Compound C2-A1-OAc (Intermediate 1-1, 1.1 g, 4 mmol), and the mixture was stirred at 110°C for 2 hours. Thereafter, the mixture was filtered, and the solvent was distilled off from the filtrate under reduced pressure. The resulting solid was purified by silica gel column chromatography to obtain Intermediate 1-2 shown below (red solid, 1.1 g, yield: 80.4%).

[0052] Intermediate 1-2 １ The structure was determined by HNMR analysis. HNMR (400 MHz, CDCl): 2.29 (s, 3H), 7.00-7.11 (m, 1H), 7.07 (t, J=8.6 Hz, 2H), 7.27-7.47 (m, 1H).

[0053] Example 1-3 (Synthesis of Compound C2-A1A-OC8 (Azobenzene Derivative 1)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 160 mg, 4 mmol) were added to Compound C2-A1A-OAc (Intermediate 1-2, 0.34 g, 1 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 72 mg of distilled water was added dropwise to the reaction mixture, followed by stirring at room temperature for 1 hour. A catalytic amount (0.05 mmol) of crown ether 18-crown-6 and 1-bromooctane (0.38 g, 2 mmol) were added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 1 shown below (orange solid, 0.41 g, yield: 100%).

[0054] Azobenzene derivative 1 １ H NMR and １３The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.88-0.91 (m, 3H), 1.30-1.45 (m, 2H), 1.49-1.51 (m, 2H), 1.76-1.83 (m, 2H), 3.99 (t, J= 6.5 Hz, 2H), 7.23 (dd, J1= 4.8Hz, J2=2.1Hz, 2H), 7.90 (dd, J1= 6.9Hz, J2=1.5Hz 2H), 7.95 (dd, J1= 4.8Hz, J2=2.1Hz, 2H) 13CNMR (100 MHz, CDCl3): 14.12, 22.67, 25.90, 28.95, 29.22, 29.28, 31.81, 68.98, 76.72, 77.04, 77.24, 77.35, 77.52, 112.52, 112.55, 112.56, 112.71, 112.73, 112.76, 115 / 65, 129.06, 130.91, 131.01, 131.14, 131.24, 131.34, 141.64, 154.42, 154.46, 157.01, 157.05, 159.24

[0055] Example 1-4 (Thermal phase change of compound C2-A1A-OC8 (azobenzene derivative 1) by DSC measurement) A chloroform solution of compound C2-A1A-OC8 was irradiated with ultraviolet light (365 nm) for 15 minutes to induce trans-cis isomerization. The solvent was removed from the mixture under reduced pressure, and the isomer mixture was separated by silica gel column chromatography to obtain cis-type azobenzene derivative 1 and trans-type azobenzene derivative 1. The thermal phase transition temperatures of both isomers of compound C2-A1-OC8 were measured by a differential scanning calorimeter, and phase changes occurred at the following temperatures: Trans Cr 43 Iso, Iso 30 Cr Cis Cr 48 Iso

[0056] Example 1-5 (Measurement of isomerization reaction enthalpy and crystallization enthalpy of compound C2-A1A-OC8 (azobenzene derivative 1) by DSC measurement) The energy released in the thermally induced cis-trans isomerization (ΔHisom) of compound C2-A1A-OC8 and the subsequent recrystallization (ΔHcryst) of the trans compound C2-A1A-OC8 was measured by a differential scanning calorimeter, and the following results were obtained. ΔH isom = -56.1 J / g (-23.3 kJ / mol), ΔH cryst = -66.1 J / g (-27.4 kJ / mol)

[0057] Example 1-6 (Photoirradiation Experiment of Compound C2-A1A-OC8 (Azobenzene Derivative 1)) The phase transition from the crystalline phase to the isotropic phase of the compound C2-A1A-OC8 crystals at 23°C in a glass sandwich cell was observed using a polarizing optical microscope. The results are shown in Figure 1. In Figure 1, (a) is a polarizing optical microscope photograph showing the crystalline phase at 23°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 23°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 23°C. As is clear from Figure 1, irradiation with green light caused a phase transition from the crystalline phase to the isotropic phase, and a change from bright field to dark field was observed under crossed Nicols observation (see (b)). It was confirmed that the birefringence of the crystal disappeared upon irradiation with green light, and the crystal melted into a liquid. Furthermore, when the isotropic phase (liquid phase) was irradiated with blue light, crystalline birefringence appeared, confirming that a phase transition from the isotropic phase to the crystalline phase had occurred and crystals had been generated (see (c)).

[0058] Example 1-7 (Calculation of Liquid Phase Stability of Compound C2-A1A-OC8 (Azobenzene Derivative 1)) The rate constants (k) of thermal isomerization were measured at 50°C, 60°C, 70°C, 80°C, and 90°C, respectively, and from these values ​​and an Arrhenius plot, the lifetime at 30°C was calculated to be 60.0 days.

[0059] Example 2-1 (Synthesis of Compound C2-A4-OAc (Intermediate 2-1)) 16 mL of distilled water and 4 mL of concentrated hydrochloric acid were added to 2,6-difluoroaniline (1.29 g, 10 mmol). A solution prepared by dissolving sodium nitrite (0.83 g, 12 mmol) in 5 mL of distilled water was added while stirring at 0°C. The resulting solution was then added to 20 mL of an aqueous solution of o-cresol (1.08 g, 10 mmol) and 4.7 g of sodium hydroxide, and the mixture was stirred for 15 minutes. The resulting solution was acidified with hydrochloric acid under cooling and then extracted with ethyl acetate. The organic layer was washed with saturated saline and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the resulting solid was diluted with 50 mL of dehydrated dichloromethane, followed by the addition of 12.1 g (12 mmol) of triethylamine (TEA). While stirring under nitrogen at 0°C, a mixture of 0.94 g (12 mmol) of acetyl chloride (AcCl) dissolved in 10 mL of dichloromethane (DCM) was added dropwise. The resulting solution was allowed to stand for 1 hour and then extracted with water. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was purified by silica gel column chromatography to obtain Intermediate 2-1 shown below (orange solid, 2.47 g, yield: 85%).

[0060] Intermediate 2-1 １ The structure was determined by HNMR analysis. 1HNMR (400 MHz, CDCl3): 2.28 (s, 3H), 2.35 (s, 3H), 7.03 (t, J = 8.6 Hz, 2H), 7.27-7.34 (m, 1H), 7.80-7.83 (m, 2H).

[0061] Example 2-2 Synthesis of Compound C2-A4A-OAc (Intermediate 2-2) 5 mL of 1,1,2,2-tetrachloroethane (TCE), trichloroisocyanuric acid (TCCA, 0.70 g, 3 mmol), potassium peroxodisulfate (0.98 g, 3.6 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.90 g, 0.075 mmol) were added to Compound C2-A1-OAc (Intermediate 2-1, 0.87 g, 3 mmol), and the mixture was stirred at 110°C for 2 hours. The mixture was then filtered, and the solvent was distilled off from the filtrate under reduced pressure. The resulting solid was purified by silica gel column chromatography to obtain Intermediate 2-2 shown below (red solid, 0.97 g, yield: 89.9%).

[0062] Intermediate 2-2 １ The structure was determined by H NMR analysis. H NMR (400 MHz, CDCl): 2.21 (s, 3H), 2.35 (s, 3H), 7.04 (t, J= 8.6 Hz, 2H), 7.31 (s, 1H), 7.32-7.46 (m, 1H).

[0063] Example 2-3 (Synthesis of Compound C2-A4A-OC8 (Azobenzene Derivative 2)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 160 mg, 4 mmol) were added to Compound C2-A4A-OAc (Intermediate 1-2, 0.36 g, 1 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 72 mg of distilled water was added dropwise to the reaction mixture, followed by stirring at room temperature for 1 hour. A catalytic amount (0.05 mmol) of crown ether 18-crown-6 and 1-bromooctane (0.38 g, 2 mmol) were added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 2 shown below (orange solid, 0.34 g, yield: 79.5%).

[0064] Azobenzene derivative 2 １ H NMR and １３The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.88-0.91 (m, 3H), 1.30-1.56 (m, 10H), 1.80-1.87 (m, 2H), 4.00 (t, J= 7.8 Hz, 2H), 6.88 (s, 1H), 7.07 (t, J= 8.6 Hz, 2H) 7.31-7.41 (m, 1H) 13CNMR (100 MHz, CDCl3): 12.79, 1423, 22.68, 26.04, 29.24, 29.29, 31.82, 69.09, 115.58, 112.51, 112.53, 112.55, 112.70, 112.72, 112.74, 123.68, 125.83, 129.76, 130.92, 131.03, 131.13, 131.24, 141.97, 154.39, 154.44, 156.99, 157.03, 157.41

[0065] Example 2-4 (Thermal phase change of compound C2-A4A-OC8 (azobenzene derivative 2) by DSC measurement) A chloroform solution of compound C2-A4A-OC8 was irradiated with ultraviolet light (365 nm) for 15 minutes to induce trans-cis isomerization. The solvent was removed from the mixture under reduced pressure, and the isomer mixture was separated by silica gel column chromatography to obtain cis-azobenzene derivative 2 and trans-azobenzene derivative 2. The thermal phase transition temperatures of both isomers of compound C2-A4A-OC8 were measured by differential scanning calorimetry, and phase changes occurred at the following temperatures: Trans Cr1 58 X, X 60 Iso, Iso 42 X, X 39 Cr1 Cis Cr 61 Iso

[0066] Example 2-5 (Measurement of isomerization reaction enthalpy and crystallization enthalpy of compound C2-A4A-OC8 (azobenzene derivative 2) by DSC measurement) The energy released in the thermally induced cis-trans isomerization (ΔHisom) of compound C2-A4A-OC8 and the subsequent recrystallization (ΔHcryst) of the trans compound C2-A4A-OC8 was measured by a differential scanning calorimeter, and the following results were obtained. ΔH isom= -47.7 J / g (-20.5 kJ / mol), ΔH cryst = -59.8 J / g (-25.7 kJ / mol)

[0067] Example 2-6 (Photoirradiation Experiment of Compound C2-A4A-OC8 (Azobenzene Derivative 2)) The crystalline phase-isotropic phase transition of crystalline compound C2-A4A-OC8 in a glass sandwich cell at 23°C was observed using a polarizing optical microscope. The results are shown in Figure 2. In Figure 2, (a) is a polarizing optical microscope photograph showing the crystalline phase at 23°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 23°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 23°C. As is clear from Figure 2, irradiation with green light caused a phase transition from the crystalline phase to the isotropic phase, and a change from bright field to dark field was observed under crossed Nicols observation (see (b)). It was confirmed that irradiation with green light caused the crystalline birefringence to disappear, and the crystal melted into a liquid. Furthermore, irradiating the isotropic phase (liquid phase) with blue light revealed crystalline birefringence. This confirmed that a phase transition from an isotropic phase to a crystalline phase had occurred, resulting in the formation of crystals (see (c)).

[0068] Example 2-7 (Calculation of Liquid Phase Stability of Compound C2-A4A-OC8 (Azobenzene Derivative 2)) The rate constants (k) of thermal isomerization were measured at 50°C, 60°C, 70°C, and 90°C, respectively, and the lifetime at 30°C was calculated to be 70.5 days from these values ​​and an Arrhenius plot.

[0069] Example 3-1 Synthesis of Compound prec-A5-OAc (Intermediate 3-1) 1.67 g (10 mmol) of 2,6-dimethyl-4-nitrophenol was dissolved in 50 mL of dehydrated dichloromethane, and 12.1 g (12 mmol) of triethylamine was added. Under nitrogen at 0°C, a mixture of 0.94 g (12 mmol) of acetyl chloride (AcCl) dissolved in 5 mL of dichloromethane was added dropwise. The resulting solution was allowed to stand for 4 hours and then extracted with water. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. The solvent was removed under reduced pressure to obtain the following Intermediate 3-1 (white solid, 2.1 g, yield: 100%).

[0070] Intermediate 3-1 １ The structure was determined by HNMR analysis. HNMR (400 MHz, CDCl): 2.24 (s, 6H), 2.39 (s, 3H), 7.96 (s, 2H).

[0071] Example 3-2 Synthesis of Compound A5-OAc (Intermediate 3-2) To 2.1 g (10 mmol) of Intermediate 3-1, 50 mL of ethanol (EtOH) and a catalytic amount of 10% palladium(0) on carbon were added, and the atmosphere above the mixture was then evacuated and replaced with nitrogen, and then replaced with hydrogen again. After stirring at room temperature under a hydrogen atmosphere for 48 hours, the mixture was filtered using Celite. The solvent was evaporated from the filtrate under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain Intermediate 3-2 shown below (white solid, 1.5 g, yield: 84.1%).

[0072] Intermediate 3-2 １ The structure was determined by HNMR analysis. HNMR (400 MHz, CDCl): 2.05 (s, 6H), 2.29 (s, 3H), 3.47 (broad, 2H), 6.36 (s, 2H).

[0073] Example 3-3 (Synthesis of Compound C2-A5-OAc (Intermediate 3-3)) To a solution of 2,6-difluoroaniline (0.52 g, 4 mmol) in 10 mL of dichloromethane (DCM) was added a mixed solution of 12.3 g of potassium peroxysulfate (Oxone®, 20 mmol) and 20 mL of distilled water. After stirring for 2 hours, the organic layer was removed, washed with saturated brine, and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure to obtain 1,3-difluoro-2-nitrosobenzene as a gray powder, and then 5 mL of acetic acid and 0.72 g (4 mmol) of Intermediate 3-2 (Compound A5-OAc) were added. The mixture was stirred at room temperature for 24 hours, diluted with distilled water, and extracted with ethyl acetate. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was purified by silica gel column chromatography to obtain Intermediate 3-3 shown below (orange solid, 1.0 g, yield: 90%).

[0074] Intermediate 3-3 １ The structure was determined by HNMR analysis. HNMR (400 MHz, CDCl): 2.25 (s, 6H), 2.37 (s, 3H), 7.03 (t, J= 8.4 Hz, 2H), 7.26-7.33 (m, 1H), 7.68 (s, 2H).

[0075] Example 3-4 Synthesis of Compound C2-A5A-OAc (Intermediate 3-4) 5 mL of 1,1,2,2-tetrachloroethane (TCE), trichloroisocyanuric acid (TCCA, 0.47 g, 2 mmol), potassium peroxodisulfate (0.65 g, 2.4 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.06 g, 0.05 mmol) were added to Compound C2-A5-OAc (Intermediate 3-3, 0.61 g, 2 mmol), and the mixture was stirred at 110°C for 2 hours. The mixture was then filtered, and the solvent was distilled off from the filtrate under reduced pressure. The resulting solid was purified by silica gel column chromatography to obtain Intermediate 3-4 shown below (red solid, 0.68 g, yield: 90.1%).

[0076] Intermediate 3-4 １ The structure was determined by HNMR analysis. HNMR (400 MHz, CDCl): 2.25 (s, 6H), 2.39 (s, 3H), 7.09 (t, J= 8.6 Hz, 2H), 7.38-7.43 (m, 1H).

[0077] Example 3-5 (Synthesis of Compound C2-A5A-OC8 (Azobenzene Derivative 3)) 10 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 128 mg, 3.2 mmol) were added to Compound C2-A4A-OAc (Intermediate 3-4, 0.30 g, 0.8 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 58 mg of distilled water was added dropwise to the reaction mixture, followed by stirring at room temperature for 1 hour. A catalytic amount (0.04 mmol) of crown ether 18-crown-6 and 1-bromooctane (0.30 g, 1.6 mmol) were added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 3 shown below (orange solid, 0.24 g, yield: 66.9%).

[0078] Azobenzene derivative 3 １ H NMR and １３The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.88-0.92 (m, 3H), 1.31-1.36 (m, 8H), 1.49-1.51 (m, 2H), 1.78-1.85 (m, 2H) 2.36 (s, 6H), 3.73 (t, J= 6.6 Hz, 2H), 7.08 (t, J= 8.6 Hz, 2H), 7.36-7.41 (m, 1H) 13CNMR (100 MHz, CDCl3): 14.09, 14.48, 23.05, 26.48, 29.64, 29.87, 30.55, 32.22, 74.02, 112.93, 112.96, 112.97, 113.12, 113.14, 113.17, 124.61, 130.28, 131.24, 131.35, 131.92, 132.02, 132.13, 146.14, 154.85, 154.88, 156.54, 157.45, 157.49

[0079] Example 3-6 (Thermal phase change of compound C2-A5A-OC8 (azobenzene derivative 3) by DSC measurement) A chloroform solution of compound C2-A5A-OC8 was irradiated with ultraviolet light (365 nm) for 15 minutes to induce trans-cis isomerization. The solvent was removed from the mixture under reduced pressure, and the isomer mixture was separated by silica gel column chromatography to obtain cis-azobenzene derivative 3 and trans-azobenzene derivative 3. The thermal phase transition temperatures of both isomers of compound C2-A5A-OC8 were measured by a differential scanning calorimeter, and phase changes occurred at the following temperatures: Trans Cr 62 Iso, Iso 10 Cr Cis Cr 51 Iso

[0080] Example 3-7 (Measurement of isomerization reaction enthalpy and crystallization enthalpy of compound C2-A5A-OC8 (azobenzene derivative 3) by DSC measurement) The energy released in the thermally induced cis-trans isomerization (ΔHisom) of compound C2-A5A-OC8 and the subsequent recrystallization (ΔHcryst) of the trans compound C2-A5A-OC8 was measured by a differential scanning calorimeter, and the following results were obtained. ΔH isom= -51.0 J / g (-22.5 kJ / mol), ΔH cryst = -59.0 J / g (-26.1 kJ / mol)

[0081] Example 3-8 (Photoirradiation Experiment of Compound C2-A5A-OC8 (Azobenzene Derivative 3)) The crystalline phase-isotropic phase transition of crystalline compound C2-A5A-OC8 in a glass sandwich cell at 23°C was observed using a polarizing optical microscope. The results are shown in Figure 3. In Figure 3, (a) is a polarizing optical microscope photograph showing the crystalline phase at 23°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 23°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 23°C. As is clear from Figure 3, irradiation with green light caused a phase transition from the crystalline phase to the isotropic phase, and a change from bright field to dark field was observed under crossed Nicols observation (see (b)). It was confirmed that the birefringence of the crystal disappeared upon irradiation with green light, and the crystal melted into a liquid. Furthermore, when the isotropic phase (liquid phase) was irradiated with blue light, crystalline birefringence appeared, confirming that a phase transition from the isotropic phase to the crystalline phase had occurred and crystals had been generated (see (c)).

[0082] Example 3-9 (Calculation of Liquid Phase Stability of Compound C2-A5A-OC8 (Azobenzene Derivative 3)) The rate constants (k) of thermal isomerization were measured at 50°C, 60°C, 70°C, 80°C, and 90°C, respectively, and from these values ​​and an Arrhenius plot, the lifetime at 30°C was calculated to be 117.2 days.

[0083] Example 4-1 (Synthesis of Compound C3-A6-OAc (Intermediate 4-1)) To aniline (0.93 g, 10 mmol) were added 16 mL of distilled water and 4 mL of concentrated hydrochloric acid. While stirring at 0°C, a solution prepared by dissolving sodium nitrite (0.83 g, 12 mmol) in 5 mL of distilled water was added, and then 20 mL of an aqueous solution of 3,5-difluorophenol (1.3 g, 10 mmol) and 4.7 g of sodium hydroxide was added to the resulting solution, and the mixture was stirred for 15 minutes. Under cooling, the resulting solution was acidified with hydrochloric acid and then extracted with ethyl acetate. The organic layer was washed with saturated saline and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was diluted with 50 mL of dehydrated dichloromethane, and 12.1 g (12 mmol) of triethylamine (TEA) was added. While stirring under nitrogen at 0°C, a mixture of 0.94 g (12 mmol) of acetyl chloride (AcCl) dissolved in 10 mL of dichloromethane (DM) was added dropwise. The resulting solution was allowed to stand for 1 hour and then extracted with water. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was purified by silica gel column chromatography to obtain Intermediate 4-1 shown below (orange solid, 2.22 g, yield: 80.2%).

[0084] Intermediate 4-1 １ The structure was determined by HNMR analysis. HNMR (400 MHz, CDCl): 2.31 (s, 3H), 7.03 (d, J= 1.9 Hz, 2H), 7.51-7.53 (m, 3H), 7.91-7.93 (m, 2H).

[0085] Example 4-2 Synthesis of Compound C3-A6A-OAc (Intermediate 4-2) 5 mL of 1,1,2,2-tetrachloroethane (TCE), trichloroisocyanuric acid (TCCA, 1.16 g, 5 mmol), potassium peroxodisulfate (1.6 g, 6 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.15 g, 0.12 mmol) were added to Compound C2-A1-OAc (Intermediate 4-1, 1.38 g, 5 mmol), and the mixture was stirred at 110°C for 2 hours. The mixture was then filtered, and the solvent was distilled off from the filtrate under reduced pressure. The resulting solid was purified by silica gel column chromatography to obtain Intermediate 4-2 shown below (red solid, 2.2 g, yield: 100%).

[0086] Intermediate 4-2 １ H NMR and １３ The structure was determined by CNMR analysis. 1H NMR (400 MHz, CDCl3): 2.33 (s, 3H), 6.95 (dd, J1 = 9.0 Hz, J2 = 2.9 Hz, 1H), 7.20 (t, J = 8.4 Hz, 1H), 7.40 (s, 1H), 7.42 (s, 1H).

[0087] Example 4-3 (Synthesis of Compound C3-A6A-OC8 (Azobenzene Derivative 4)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 160 mg, 4 mmol) were added to Compound C3-A6A-OAc (Intermediate 4-2, 0.34 g, 1 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 72 mg of distilled water was added dropwise to the reaction mixture, followed by stirring at room temperature for 1 hour. A catalytic amount (0.05 mmol) of crown ether 18-crown-6 and 1-bromooctane (0.38 g, 2 mmol) were added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 4 shown below (orange solid, 0.4 g, yield: 97.2%).

[0088] Azobenzene derivative 4 １ H NMR and１３ The structure was determined by CNMR. 1H NMR (400 MHz, CDCl3): 0.88-0.91 (m, 3H), 1.22-1.45 (m, 10H), 1.77-1.85 (m, 2H), 4.00-4.08 (m, 2H), 6.37 (dd, J1=12 Hz, J2=2.6 Hz, 1H), 6.60 (dd, J1=11.2 Hz, J2=2.9 Hz, 1H), 7.15-7.21 (m, 1H), 7.36-7.43 (m, 1H).

[0089] Example 4-4 (Thermal phase change of compound C3-A6A-OC8 (azobenzene derivative 4) by DSC measurement) The thermal phase transition temperatures of compound C3-A6A-OC8 were measured by a differential scanning calorimeter, and the phase changes were observed at the following temperatures: Cr 31 Iso, Iso -5 Cr

[0090] Example 4-5 (Photoirradiation Experiment of Compound C3-A6A-OC8 (Azobenzene Derivative 4)) The crystalline phase-isotropic phase transition of crystalline compound C3-A6A-OC8 in a glass sandwich cell at 29°C was observed using a polarizing optical microscope. The results are shown in Figure 4. In Figure 4, (a) is a polarizing optical microscope photograph showing the crystalline phase at 29°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 29°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 29°C. As is clear from Figure 4, irradiation with green light induced a limited phase transition from the crystalline phase to the isotropic phase, and a dark field was observed under crossed Nicols observation (see (b)). In other words, it was confirmed that irradiation with green light eliminated the birefringence of the crystals, causing the crystals to melt into a liquid. However, even when the isotropic phase was irradiated with blue light, no phase transition from the isotropic phase to the crystalline phase was induced (see (c)).

[0091] Example 5-1 (Synthesis of Compound C4-A6-OAc (Intermediate 5-1)) To m-toluidine (1.07 g, 10 mmol) were added 16 mL of distilled water and 4 mL of concentrated hydrochloric acid. While stirring at 0°C, a solution prepared by dissolving sodium nitrite (0.83 g, 12 mmol) in 5 mL of distilled water was added, and then 20 mL of an aqueous solution of 3,5-difluorophenol (1.3 g, 10 mmol) and 4.7 g of sodium hydroxide was added to the resulting solution, and the mixture was stirred for 15 minutes. The resulting solution was acidified with hydrochloric acid under cooling and then extracted with ethyl acetate. The organic layer was washed with saturated saline and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was diluted with 50 mL of dehydrated dichloromethane, and 12.1 g (12 mmol) of triethylamine (TEA) was added. While stirring under nitrogen at 0°C, a mixture of 0.94 g (12 mmol) of acetyl chloride (AcCl) dissolved in 10 mL of dichloromethane (DCM) was added dropwise. The resulting solution was allowed to stand for 1 hour and then extracted with water. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was purified by silica gel column chromatography to obtain Intermediate 5-1 shown below (orange solid, 2.22 g, yield: 75.5%).

[0092] Intermediate 5-1 １ The structure was determined by HNMR analysis. HNMR (400 MHz, CDCl): 2.31 (s, 3H), 2.45 (s, 3H), 6.88 (d, J = 10 Hz, 2H), 7.31 (dd, J = 7.3 Hz, J = 1.9 Hz, 1H), 7.40 (t, J = 7.6 Hz, 1H), 7.73 (s, 1H), 7.74 (s, 1H).

[0093] Example 5-2 (Synthesis of Compound C4-A6A-OAc (Intermediate 5-2)) 5 mL of 1,1,2,2-tetrachloroethane (TCE), trichloroisocyanuric acid (TCCA, 1.16 g, 5 mmol), potassium peroxodisulfate (1.6 g, 6 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.15 g, 0.12 mmol) were added to Compound C4-A6-OAc (Intermediate 5-1, 1.45 g, 5 mmol), and the mixture was stirred at 110°C for 2 hours. Thereafter, the mixture was filtered, and the solvent was distilled off from the filtrate under reduced pressure. The resulting solid was purified by silica gel column chromatography to obtain Intermediate 5-2 shown below (red solid, 1.16 g, yield: 64.6%).

[0094] Intermediate 5-2 １ The structure was determined by HNMR analysis. HNMR (400 MHz, CDCl): 2.33 (s, 3H), 2.41 (s, 3H), 6.88 (d, J= 10 Hz, 2H), 6.94 (dd, J= 9.3 Hz, J= 2.7 Hz, 1H), 7.14 (d, J= 8.24 Hz, 1H), 7.29 (d, J= 8.24 Hz, 1H).

[0095] Example 5-3 (Synthesis of Compound C4-A6A-OC8 (Azobenzene Derivative 5)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 160 mg, 4 mmol) were added to Compound C4-A6A-OAc (Intermediate 5-2, 0.36 g, 1 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 72 mg of distilled water was added dropwise to the reaction mixture, followed by stirring at room temperature for 1 hour. A catalytic amount (0.05 mmol) of crown ether 18-crown-6 and 1-bromooctane (0.38 g, 2 mmol) were then added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 5 shown below (orange solid, 0.4 g, yield: 91.6%).

[0096] Azobenzene derivative 5 １H NMR and １３ The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.88-0.91 (m, 3H), 1.22-1.46 (m, 10H), 2.41 (s, 3H), 1.78-1.85 (m, 2H), 4.01 (t, J= 6.5 Hz, 2H), 6.60 (dd, 13CNMR (100 MHz, CDCl3): 14.11, 20.01, 22.66, 25.88, 28.83, 29.20, 31.79, 69.28, 99.21, 99.23, 99.44, 99.47, 123.01, 124.75, 124.85, 124.95, 126.88, 128.15, 128.56, 129.58, 136.42, 149.24, 156.41, 156.49, 159.02, 159.09

[0097] Example 5-4 (Thermal Phase Change of Compound C4-A6A-OC8 (Azobenzene Derivative 5) by DSC Measurement) A chloroform solution of Compound C4-A6A-OC8 was irradiated with ultraviolet light (365 nm) for 15 minutes to induce trans-cis isomerization. The solvent was removed from the mixture under reduced pressure, and the isomer mixture was separated by silica gel column chromatography to obtain cis-azobenzene derivative 5 and trans-azobenzene derivative 5. The thermal phase transition temperatures of Compound C4-A6A-OC8 were measured using a differential scanning calorimeter, and phase changes occurred at the following temperatures: Trans Cr 51 Iso, Iso 21 Cr Cis-azobenzene derivative 5 did not exhibit a crystallization peak when cooled to -50°C by DSC.

[0098] Example 5-5 (Measurement of isomerization reaction enthalpy and crystallization enthalpy of compound C4-A6A-OC8 (azobenzene derivative 5) by DSC measurement) The energy released in the thermally induced cis-trans isomerization (ΔHisom) of compound C4-A6A-OC8 and the subsequent recrystallization (ΔHcryst) of the trans compound C4-A6A-OC8 was measured by a differential scanning calorimeter, and the following results were obtained. ΔH isom = -56.7 J / g (-24.3 kJ / mol), ΔH cryst = -57.5 J / g (-24.7 kJ / mol)

[0099] Example 5-6 (Photoirradiation Experiment of Compound C4-A6A-OC8 (Azobenzene Derivative 5)) The crystalline phase-isotropic phase transition of crystalline compound C4-A6A-OC8 in a glass sandwich cell at 23°C was observed using a polarizing optical microscope. The results are shown in Figure 5. In Figure 5, (a) is a polarizing optical microscope photograph showing the crystalline phase at 23°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 23°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 23°C. As is clear from Figure 5, irradiation with green light caused a phase transition from the crystalline phase to the isotropic phase, and a change from bright field to dark field was observed under crossed Nicols observation (see (b)). It was confirmed that irradiation with green light eliminated the crystalline birefringence and caused the crystal to melt into a liquid. Furthermore, irradiating the isotropic phase (liquid phase) with blue light revealed crystalline birefringence. This confirmed that a phase transition from an isotropic phase to a crystalline phase had occurred, resulting in the formation of crystals (see (c)).

[0100] Examples 5-7 (Sunlight Irradiation Experiment of Compound C4-A6A-OC8 (Azobenzene Derivative 5)) The crystalline-isotropic phase transition of crystalline compound C4-A6A-OC8 was observed in a glass sandwich cell exposed to sunlight at 23°C. The results are shown in Figure 6. In Figure 6, (a) shows the state before exposure, and (b) shows the state after several hours of exposure to sunlight. (c) shows the temperature of the glass substrate surface recorded during exposure. The left diagram in (c) shows the time of sunrise, the center diagram shows the time of solar noon, and the right diagram shows the time of sunset. As is clear from Figure 6, a phase transition from a crystalline phase to an isotropic phase was induced by sunlight irradiation even in an experiment conducted at a temperature significantly lower than the phase transition temperature from a crystalline phase to an isotropic phase.

[0101] Example 5-8 (Calculation of Liquid Phase Stability of Compound C4-A6A-OC8 (Azobenzene Derivative 5)) The rate constants (k) of thermal isomerization were measured at 40°C, 50°C, 60°C, 70°C, 80°C, and 90°C, respectively, and from these values ​​and an Arrhenius plot, the lifetime at 30°C was calculated to be 43.0 days.

[0102] Example 6-1 (Synthesis of Compound C2-A5A-OC4 (Azobenzene Derivative 9)) 5 mL of tetrahydrofuran (THF), sodium ethoxide (34 mg, 0.5 mmol), and a catalytic amount (0.01 mmol) of crown ether 18-crown-6 were added to Compound C2-A5A-OAc (Intermediate 3-4, 75 mg, 0.2 mmol), and the mixture was stirred at room temperature for 2 hours. Next, 1-bromobutane (68 mg, 0.5 mmol) was added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 9 shown below (orange solid, 51 mg, yield: 65.3%).

[0103] Azobenzene derivative 9 １ H NMR and １３The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.99-1.02 (m, 3H), 1.42-1.84 (m, 4H), 2.36 (s, 6H), 3.73-3.86 (m, 2H), 7.08 (t, J= 8.6 Hz, 2H), 7.36-7.43 (m, 1H) 13CNMR (100 MHz, CDCl3): 14.07, 15.84, 19.70, 69.56, 73.72, 112.92, 112.95, 113.13, 113.16, 124.59, 124.61, 130.27, 130.32, 131.26, 131.36, 131.91, 132.00, 132.10, 146.15, 146.18, 154.56, 154.90, 156.46, 156.54, 157.45, 157.50

[0104] Example 6-2 (Thermal phase change of compound C2-A5A-OC4 (azobenzene derivative 9) by DSC measurement) The thermal phase transition temperatures of the trans isomer of compound C2-A5A-OC4 were measured by a differential scanning calorimeter, and the phase changes were observed at the following temperatures: Cr 76 Iso, Iso 54 Cr

[0105] (Photoirradiation Experiment of Compound C2-A5A-OC4 (Azobenzene Derivative 9)) The crystalline phase-isotropic phase transition of crystalline compound C2-A5A-OC4 in a glass sandwich cell at 30°C was observed using a polarizing optical microscope. The results are shown in Figure 9. In Figure 9, (a) is a polarizing optical microscope photograph showing the crystalline phase at 30°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 30°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 30°C. As is clear from Figure 9, irradiation with green light caused a phase transition from the crystalline phase to the isotropic phase, and a change from bright field to dark field was observed under crossed Nicols observation (see (b)). It was confirmed that irradiation with green light caused the crystalline birefringence to disappear, and the crystal melted into a liquid. Furthermore, irradiating the isotropic phase (liquid phase) with blue light caused crystalline birefringence to appear. This confirmed that a phase transition from an isotropic phase to a crystalline phase had occurred, resulting in the formation of crystals (see (c)).

[0106] Example 7-1 (Synthesis of Compound C2-A5A-OC5 (Azobenzene Derivative 10)) 5 mL of tetrahydrofuran (THF), sodium ethoxide (34 mg, 0.5 mmol), and a catalytic amount (0.01 mmol) of crown ether 18-crown-6 were added to Compound C2-A5A-OAc (Intermediate 3-4, 75 mg, 0.2 mmol), and the mixture was stirred at room temperature for 2 hours. Next, 1-bromopentane (76 mg, 0.5 mmol) was added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 10 shown below (orange solid, 72 mg, yield: 88.6%).

[0107] Azobenzene derivative 10 １ H NMR and １３The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.94-0.98 (m, 3H), 1.38-1.52 (m, 4H), 1.80-1.87 (m, 2H) 2.36 (s, 6H), 3.74 (t, J= 6.6 Hz, 2H), 7.09 (t, J= 8.7 Hz, 2H), 7.38-7.42 (m, 1H) 13CNMR (100 MHz, CDCl3): 14.07, 14.37, 22.95, 28.60, 30.21, 74.01, 112.92, 112.95, 113.16, 124.60, 131.97, 146.15, 156.53

[0108] Example 7-2 (Thermal phase change of compound C2-A5A-OC5 (azobenzene derivative 10) measured by DSC) The thermal phase transition temperatures of the trans isomer of compound C2-A5A-OC5 were measured by a differential scanning calorimeter, and the phase changes were observed at the following temperatures: Cr 76 Iso, Iso 35 Cr

[0109] Example 7-3 (Photoirradiation Experiment of Compound C2-A5A-OC5 (Azobenzene Derivative 10)) The crystalline phase-isotropic phase transition of crystalline compound C2-A5A-OC5 in a glass sandwich cell at 30°C was observed using a polarizing optical microscope. The results are shown in Figure 10. In Figure 10, (a) is a polarizing optical microscope photograph showing the crystalline phase at 30°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 30°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 30°C. As is clear from Figure 10, irradiation with green light caused a phase transition from the crystalline phase to the isotropic phase, and a change from bright field to dark field was observed under crossed Nicols observation (see (b)). It was confirmed that the birefringence of the crystal disappeared upon irradiation with green light, and the crystal melted into a liquid. Furthermore, when the isotropic phase (liquid phase) was irradiated with blue light, crystalline birefringence appeared, confirming that a phase transition from the isotropic phase to the crystalline phase had occurred and crystals had been generated (see (c)).

[0110] Example 8-1 (Synthesis of Compound C2-A5A-OC6 (Azobenzene Derivative 11)) 5 mL of tetrahydrofuran (THF), sodium ethoxide (34 mg, 0.5 mmol), and a catalytic amount (0.10 mmol) of crown ether 18-crown-6 were added to Compound C2-A5A-OAc (Intermediate 3-4, 75 mg, 0.2 mmol), and the mixture was stirred at room temperature for 2 hours. Next, 1-bromohexane (82 mg, 0.5 mmol) was added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 11 shown below (orange solid, 77 mg, yield: 92.3%).

[0111] Azobenzene derivative 11 １ H NMR and １３ The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.91-0.94 (m, 3H), 1.33-1.52 (m, 6H), 1.79-1.86 (m, 2H) 2.36 (s, 6H), 3.74 (t, J= 6.6 Hz, 2H), 7.08 (t, J= 8.6 Hz, 2H), 7.36-7.42 (m, 1H) 13CNMR (100 MHz, CDCl3): 14.08, 14.40, 22.98, 26.12, 30.51, 32.08, 74.02, 112.92, 112.95, 113.11, 113.16, 124.61, 130.26, 131.89, 131.99, 132.09, 146.15, 154.86, 154.89, 156.55, 157.45, 157.49

[0112] (Thermal Phase Change of Compound C2-A5A-OC6 (Azobenzene Derivative 11) by DSC Measurement) The thermal phase transition temperatures of the trans isomer of Compound C2-A5A-OC6 were measured by a differential scanning calorimeter, and the phase changes were observed at the following temperatures: Cr 59 Iso, Iso 34 Cr

[0113] (Photoirradiation Experiment of Compound C2-A5A-OC6 (Azobenzene Derivative 11)) The crystalline phase-isotropic phase transition of crystalline compound C2-A5A-OC6 in a glass sandwich cell at 30°C was observed using a polarizing optical microscope. The results are shown in Figure 11. In Figure 11, (a) is a polarizing optical microscope photograph showing the crystalline phase at 30°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 30°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 30°C. As is clear from Figure 11, a phase transition from the crystalline phase to the isotropic phase occurred upon irradiation with green light, and a change from bright field to dark field was observed under crossed Nicols observation (see (b)). It was confirmed that the crystalline birefringence disappeared upon irradiation with green light, and the crystal melted into a liquid. Furthermore, crystalline birefringence appeared when the isotropic phase (liquid phase) was irradiated with blue light. This confirmed that a phase transition from an isotropic phase to a crystalline phase had occurred, resulting in the formation of crystals (see (c)).

[0114] Example 9-1 Synthesis of Compound C2-A5A-OC7 (Azobenzene Derivative 12) 5 mL of tetrahydrofuran (THF), sodium ethoxide (34 mg, 0.5 mmol), and a catalytic amount (0.01 mmol) of crown ether 18-crown-6 were added to Compound C2-A5A-OAc (Intermediate 3-4, 75 mg, 0.2 mmol), and the mixture was stirred at room temperature for 2 hours. Next, 1-bromoheptane (90 mg, 0.5 mmol) was added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 12 shown below (orange solid, 59 mg, yield: 68.2%).

[0115] Azobenzene derivative 12 １ H NMR and １３The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.89-0.92 (m, 3H), 1.25-1.56 (m, 8H), 1.76-1.85 (m, 2H) 2.35 (s, 6H), 3.73 (t, J= 6.6 Hz, 2H), 7.08 (t, J= 8.6 Hz, 2H), 7.37-7.41 (m, 1H) 13CNMR (100 MHz, CDCl3): 12.68, 13.04, 21.59, 24.99, 28.15, 29.14, 30.74, 72.62, 111.52, 111.55, 111.71, 111.76, 123.20, 128.86, 130.58, 130.68, 132.09, 144.75, 153.46, 155.14, 156.06, 156.10

[0116] Example 9-2 (Thermal phase change of compound C2-A5A-OC7 (azobenzene derivative 12) measured by DSC) The thermal phase transition temperatures of the trans isomer of compound C2-A5A-OC7 were measured by a differential scanning calorimeter, and the phase changes were observed at the following temperatures: Cr 62 Iso, Iso 20 Cr

[0117] Example 9-3 (Photoirradiation Experiment of Compound C2-A5A-OC7 (Azobenzene Derivative 12)) The crystalline phase-isotropic phase transition of crystalline compound C2-A5A-OC7 in a glass sandwich cell at 30°C was observed using a polarizing optical microscope. The results are shown in Figure 12. In Figure 12, (a) is a polarizing optical microscope photograph showing the crystalline phase at 30°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 30°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 30°C. As is clear from Figure 12, irradiation with green light caused a phase transition from the crystalline phase to the isotropic phase, and a change from bright field to dark field was observed under crossed Nicols observation (see (b)). It was confirmed that the birefringence of the crystal disappeared upon irradiation with green light, and the crystal melted into a liquid. Furthermore, when the isotropic phase (liquid phase) was irradiated with blue light, crystalline birefringence appeared, confirming that a phase transition from the isotropic phase to the crystalline phase had occurred and crystals had been generated (see (c)).

[0118] Example 10-1 (Synthesis of Compound C4-A6A-OC1 (Azobenzene Derivative 13)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 2 mmol) were added to Compound C4-A6A-OAc (Intermediate 5-2, 0.36 g, 0.5 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 36 mg of distilled water was added dropwise to the reaction mixture, followed by stirring at room temperature for 1 hour. Subsequently, a catalytic amount (0.02 mmol) of crown ether 18-crown-6 and methyl paratoluenesulfonate (TsOMe, 0.38 g, 2 mmol) were added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 13 shown below (orange solid, 0.15 g, yield: 90.5%).

[0119] Azobenzene derivative 13 １ H NMR and １３The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 2.39 (s, 3H), 3.85 (s, 3H), 6.60 (dd, J1= 11.1 Hz, J2=2.84Hz, 2H), 7.10 (dd, J1= 8.24 Hz, J2=0.68Hz, 1H), 7.27 (d, J= 8.3 Hz, 1H) 13CNMR (100 MHz, CDCl3): 20.31, 56.59, 99.21, 99.24, 99.45, 99.48, 123.36, 127.26, 128.55, 130.04, 136.85, 149.58, 156.74, 156.81, 159.35, 159.42, 163.29, 163.43, 163.57

[0120] Example 10-2 (Thermal phase change of compound C4-A6A-OC1 (azobenzene derivative 13) measured by DSC) The thermal phase transition temperatures of the trans isomer of compound C4-A6A-OC1 were measured by a differential scanning calorimeter, and the phase changes were observed at the following temperatures: Cr 67 Iso, Iso 33 Cr

[0121] Example 10-3 (Photoirradiation Experiment of Compound C4-A6A-OC1 (Azobenzene Derivative 13)) The crystalline phase-isotropic phase transition of crystalline compound C4-A6A-OC1 in a glass sandwich cell at 30°C was observed using a polarizing optical microscope. The results are shown in Figure 13. In Figure 13, (a) is a polarizing optical microscope photograph showing the crystalline phase at 30°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 30°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 30°C. As is clear from Figure 13, irradiation with green light caused a phase transition from the crystalline phase to the isotropic phase, and a change from bright field to dark field was observed under crossed Nicols observation (see (b)). It was confirmed that the birefringence of the crystal disappeared upon irradiation with green light, and the crystal melted into a liquid. Furthermore, when the isotropic phase (liquid phase) was irradiated with blue light, crystalline birefringence appeared, confirming that a phase transition from the isotropic phase to the crystalline phase had occurred and crystals had been generated (see (c)).

[0122] Example 11-1 (Synthesis of Compound C4-A6A-OC2 (Azobenzene Derivative 14)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 160 mg, 4 mmol) were added to Compound C4-A6A-OAc (Intermediate 5-2, 0.72 g, 1 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 72 mg of distilled water was added dropwise to the reaction mixture, followed by stirring at room temperature for 1 hour. Subsequently, catalytic amounts (0.05 mmol) of crown ether 18-crown-6 and ethyl paratoluenesulfonate (TsOEt, 0.80 g, 4 mmol) were added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was removed from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 14 shown below (orange solid, 0.24 g, yield: 70.1%).

[0123] Azobenzene derivative 14 １ H NMR and １３ The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 1.42-1.46 (m, 3H), 2.39 (s, 3H), 4.05-4.11 (m, 2H), 6.60 (dd, J1= 11.1 Hz, J2=2.84 Hz, 2H), 7.11 (d, J= 8.24 Hz, 1H), 7.28 (d, J= 8.24 Hz, 1H) 13CNMR (100 MHz, CDCl3): 14.78, 20.32, 65.21, 99.56, 99.60, 99.80, 99.84, 123.40, 125.31, 127.28, 128.53, 129.97, 136.81, 149.63, 156.77, 156.84, 159.38, 159.45, 162.69, 162.83, 162.97

[0124] Example 11-2 (Thermal phase change of compound C4-A6A-OC2 (azobenzene derivative 14) by DSC measurement) When the thermal phase transition temperature of the trans isomer of compound C4-A6A-OC2 was measured by a differential scanning calorimeter, the phase change occurred at the following temperature. Note that the compound was cooled to -50°C at a cooling rate of 2°C / min, but no signal due to crystallization during cooling was observed. Cr 65 Iso

[0125] Example 11-3 (Photoirradiation Experiment of Compound C4-A6A-OC2 (Azobenzene Derivative 14)) The crystalline-isotropic phase transition of crystalline compound C4-A6A-OC2 in a glass sandwich cell at 30°C was observed using a polarizing optical microscope. The results are shown in Figure 14. In Figure 14, (a) is a polarizing optical microscope photograph showing the crystalline phase at 30°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 30°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 30°C. As is clear from Figure 14, irradiation with green light caused a phase transition from the crystalline phase to the isotropic phase, and a change from bright field to dark field was observed under crossed Nicols observation (see (b)). It was confirmed that the birefringence of the crystal disappeared upon irradiation with green light, and the crystal melted into a liquid. Furthermore, when the isotropic phase (liquid phase) was irradiated with blue light, crystalline birefringence appeared, confirming that a phase transition from the isotropic phase to the crystalline phase had occurred and crystals had been generated (see (c)).

[0126] Example 12-1 (Synthesis of Compound C4-A6A-OC3 (Azobenzene Derivative 15)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 128 mg, 3.2 mmol) were added to Compound C4-A6A-OAc (Intermediate 5-2, 0.58 g, 0.8 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 58 mg of distilled water was added dropwise to the reaction mixture, followed by stirring at room temperature for 1 hour. A catalytic amount (0.04 mmol) of crown ether 18-crown-6 and 1-bromopropane (0.39 g, 3.2 mmol) were then added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was removed from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 15 shown below (orange solid, 0.23 g, yield: 79.7%).

[0127] Azobenzene derivative 15 １ H NMR and １３ The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 1.03-1.07 (m, 3H), 1.80-1.89 (m, 2H), 2.40 (s, 3H), 3.98 (t, J= 6.4 Hz, 2H) 6.60 (dd, J1= 11.2 Hz, J2=2.92 Hz, 2H), 7.11 (d, J= 8.24 Hz, 1H), 7.27 (d, J= 8.28 Hz, 1H) 13CNMR (100 MHz, CDCl3): 10.71, 20.34, 22.61, 71.10, 99.59, 99.62, 99.82, 99.86, 123.41, 125.29, 127.28, 128.53, 129.56, 149.65, 156.79, 156.86, 159.39, 159.46, 163.03, 163.18

[0128] Example 12-2 (Thermal phase change of compound C4-A6A-OC3 (azobenzene derivative 15) by DSC measurement) When the thermal phase transition temperature of the trans isomer of compound C4-A6A-OC3 was measured by a differential scanning calorimeter, the phase change occurred at the following temperature. Note that the compound was cooled to -50°C at a cooling rate of 2°C / min, but no signal due to crystallization during cooling was observed. Cr 61 Iso

[0129] Example 12-3 (Photoirradiation Experiment of Compound C4-A6A-OC3 (Azobenzene Derivative 15)) The crystalline-isotropic phase transition of crystalline compound C4-A6A-OC3 in a glass sandwich cell at 30°C was observed using a polarizing optical microscope. The results are shown in Figure 15. In Figure 15, (a) is a polarizing optical microscope photograph showing the crystalline phase at 30°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 30°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 30°C. As is clear from Figure 15, irradiation with green light induced a phase transition from the crystalline phase to the isotropic phase, and a dark field was observed in crossed Nicols observation (see (b)). Furthermore, when the isotropic phase was irradiated with blue light, a phase transition from the isotropic phase to the crystalline phase was induced, and crystals were formed (see (c)).

[0130] Example 13-1 (Synthesis of Compound C4-A6A-OC4 (Azobenzene Derivative 16)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 128 mg, 3.2 mmol) were added to Compound C4-A6A-OAc (Intermediate 5-2, 0.58 g, 0.8 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 58 mg of distilled water was added dropwise to the reaction mixture, which was then stirred at room temperature for 1 hour. A catalytic amount (0.04 mmol) of crown ether 18-crown-6 and 1-bromobutane (0.44 g, 3.2 mmol) were then added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was removed from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 16 shown below (orange solid, 0.14 g, yield: 47.6%).

[0131] Azobenzene derivative 16 １ H NMR and １３ The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.97-1.01 (m, 3H), 1.45-1.5 (m, 2H), 1.77-1.83 (m, 2H), 2.40 (s, 3H), 4.02 (t, J= 6.5 Hz, 2H), 6.60 (dd, J1= 11.1 Hz, J2=2.96 Hz, 2H), 7.11 (d, J= 8.24 Hz, 1H), 7.27 (d, J= 8.24 Hz, 1H) 13CNMR (100 MHz, CDCl3): 14.09, 19.47, 20.22, 20.34, 31.23, 69.35, 99.58, 99.61, 99.82, 99.85, 127.28, 128.53, 129.95, 130.02, 136.80, 149.65, 159.79, 156.86, 159.39, 159.46, 162.91, 163.05

[0132] Example 13-2 (Thermal phase change of compound C4-A6A-OC4 (azobenzene derivative 16) by DSC measurement) When the thermal phase transition temperature of the trans isomer of compound C4-A6A-OC4 was measured by a differential scanning calorimeter, the phase change occurred at the following temperature. Note that the compound was cooled to -50°C at a cooling rate of 2°C / min, but no signal due to crystallization during cooling was observed. Cr 47 Iso

[0133] Example 13-3 (Photoirradiation Experiment of Compound C4-A6A-OC4 (Azobenzene Derivative 16)) The crystalline-isotropic phase transition of crystalline compound C4-A6A-OC4 in a glass sandwich cell at 30°C was observed using a polarizing optical microscope. The results are shown in Figure 16. In Figure 16, (a) is a polarizing optical microscope photograph showing the crystalline phase at 30°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 30°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 30°C. As is clear from Figure 16, irradiation with green light induced a phase transition from the crystalline phase to the isotropic phase, and a dark field was observed in crossed Nicols observation (see (b)). Furthermore, when the isotropic phase was irradiated with blue light, a phase transition from the isotropic phase to the crystalline phase was induced, and crystals were formed (see (c)).

[0134] Example 14-1 (Synthesis of Compound C4-A6A-OC5 (Azobenzene Derivative 17)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 80 mg, 2 mmol) were added to Compound C4-A6A-OAc (Intermediate 5-2, 0.36 g, 0.5 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 36 mg of distilled water was added dropwise to the reaction mixture, which was then stirred at room temperature for 1 hour. Subsequently, a catalytic amount (0.02 mmol) of crown ether 18-crown-6 and 1-bromopentane (0.27 g, 2 mmol) were added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 17 shown below (orange solid, 0.19 g, yield: 100.0%).

[0135] Azobenzene derivative 17 １ H NMR and １３The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.92-0.96 (m, 3H), 1.36-1.47 (m, 4H), 1.78-1.84 (m, 2H), 2.40 (s, 3H), 4.01 (t, J= 6.5 Hz, 2H), 6.59 (dd, J1= 11.2 Hz, J2=2.92 Hz, 2H), 7.11 (d, J= 8.24 Hz, 1H), 7.27 (d, J= 8.24 Hz, 1H) 13CNMR (100 MHz, CDCl3): 14.33, 20.32, 22.74, 28.39, 28.91, 69.65, 99.5781, 99.61, 99.81, 99.84, 123.41, 125.28, 127.28, 128.53, 129.95, 149.64, 156.79, 156.86, 159.06, 159.39, 159.46, 162.90, 163.04, 163.18

[0136] Example 14-2 (Thermal phase change of compound C4-A6A-OC5 (azobenzene derivative 17) measured by DSC) When the thermal phase transition temperature of the trans isomer of compound C4-A6A-OC5 was measured by a differential scanning calorimeter, a phase change occurred at the following temperature. Note that the compound was cooled to -50°C at a cooling rate of 2°C / min, but no signal due to crystallization during cooling was observed. Cr 50 Iso Example 14-3 (Photoirradiation experiment of compound C4-A6A-OC5 (azobenzene derivative 17)) The crystalline-isotropic phase transition of crystalline compound C4-A6A-OC5 was observed in a glass sandwich cell at 30°C using a polarizing optical microscope. The results are shown in Figure 17. 17, (a) is a polarized optical microscope photograph showing the crystalline phase at 30°C, (b) is a polarized optical microscope photograph showing the state after irradiation with green light (540 nm) at 30°C, and (c) is a polarized optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 30°C. As is clear from FIG. 17, a phase transition from the crystalline phase to the isotropic phase was induced by irradiation with green light, and a dark field was observed in crossed Nicols observation (see (b)). Furthermore, when the isotropic phase was irradiated with blue light, a phase transition from the isotropic phase to the crystalline phase was induced, and crystals were generated (see (c)).

[0137] Example 15-1 (Synthesis of Compound C5-B2-OAc (Intermediate 18-1)) 16 mL of distilled water and 4 mL of concentrated hydrochloric acid were added to o-toluidine (1.07 g, 10 mmol) to obtain a mixture. A solution prepared by dissolving sodium nitrite (0.83 g, 12 mmol) in 5 mL of distilled water was added to the mixture with stirring at 0°C. The resulting solution was then added to 20 mL of an aqueous solution of thymol (1.5 g, 10 mmol) and sodium hydroxide (4.7 g), and the resulting mixture was stirred for 15 minutes. The resulting solution was acidified with hydrochloric acid under cooling and extracted with ethyl acetate. The organic layer was washed with brine and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the resulting solid was diluted with 50 mL of dehydrated dichloromethane (DCM), followed by the addition of 12.1 g (12 mmol) of triethylamine (TEA). A mixture of 0.94 g (12 mmol) of acetyl chloride (AcCl) (10 mL) in dichloromethane was added dropwise with stirring at 0°C under nitrogen. The resulting solution was allowed to stand for 1 hour and then extracted with water. The organic layer was washed with brine and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was purified by silica gel column chromatography to give Intermediate 18-1 (orange solid, 2.18 g, yield: 70.2%) shown below.

[0138] Intermediate 18-1 １ The structure was determined by HNMR analysis. 1HNMR (400 MHz, CDCl3): 1.23 (s, 3H), 1.25 (s, 3H), 2.35 (s, 3H), 2.68 (s, 3H), 2.73 (s, 3H), 2.96-3.06 (m, 1H), 6.99 (s, 1H), 7.23-7.35 (m, 3H), 7.59 (d, J= 7.7 Hz, 1H), 7.62 (s, 1H).

[0139] Example 15-2 (Synthesis of Compound C5-B2A-OAc (Intermediate 18-2)) 5 mL of 1,1,2,2-tetrachloroethane (PCE), trichloroisocyanuric acid (TCCA, 0.46 g, 2 mmol), potassium peroxodisulfate (0.6 g, 2.4 mmol), and tetrakis(triphenylphosphine)palladium(0) (Pd(PPh ３ ) ４ Compound C5-B2-OAc (Intermediate 18-1, 0.62 g, 2 mmol) was added, and the mixture was stirred at 110°C for 2 hours. The mixture was then filtered, and the solvent was removed from the filtrate under reduced pressure. The resulting solid was purified by silica gel column chromatography to obtain Intermediate 18-2 shown below (red solid, 0.43 g, yield: 62.4%).

[0140] Intermediate 18-2 １ The structure was determined by HNMR analysis. 1HNMR (400 MHz, CDCl3): 1.24 (s, 3H), 1.26 (s, 3H), 2.31 (s, 3H), 2.37 (s, 3H), 2.65 (s, 3H), 2.99-3.06 (m, 1H), 7.02 (s, 1H), 7.14-7.19 (m, 2H), 7.35-7.37 (m, 1H), 7.67 (s, 1H).

[0141] Example 15-3 (Synthesis of Compound C5-B2A-OMe (Azobenzene Derivative 18)) 5 mL of tetrahydrofuran (THF), sodium ethoxide (68 mg, 1.0 mmol), and a catalytic amount (0.03 mmol) of crown ether 18-crown-6 were added to Compound C5-B2A-OAc (Intermediate 18-3, 190 mg, 0.5 mmol). The mixture was then stirred at room temperature for 2 hours. Next, methyl paratoluenesulfonate (TsOMe, 0.19 g, 1.0 mmol) was added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was removed from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 18 shown below (orange solid, 55 mg, yield: 31.7%).

[0142] Azobenzene derivative 18 １ H NMR and １３ The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 1.23 (s, 3H), 1.25 (s, 3H), 2.32 (s, 3H), 2.68 (s, 3H), 3.24-3.31 (m, 1H), 3.91 (s, 3H), 6.78 (s, 1H), 7.12 (t, J= 7.6 Hz, 1H), 7.15-7.17 (m, 1H), 7.32-7.35 (m, 1H), 7.69 (s, 1H) 13CNMR (100 MHz, CDCl3): 17.96, 19.35, 22.89, 27.33, 55.97, 112.46, 114.05, 128.04, 128.47, 130.19, 131.61, 135.99, 139.00, 160.52

[0143] Example 15-4 (Thermal phase change of compound C5-B2A-OMe (azobenzene derivative 18) measured by DSC) The thermal phase transition temperature of the trans isomer of compound C5-B2A-OMe was measured by a differential scanning calorimeter, and the phase change occurred at the following temperature. The compound was cooled to -50°C at a cooling rate of 2°C / min, but no signal due to crystallization during cooling was observed. Cr 74 Iso

[0144] Example 15-5 (Photoirradiation Experiment of Compound C5-B2A-OMe (Azobenzene Derivative 18)) The crystalline-isotropic phase transition of crystalline compound C5-B2A-OMe in a glass sandwich cell at 23°C was observed using a polarizing optical microscope. The results are shown in Figure 18. In Figure 18, (a) is a polarizing optical microscope photograph showing the crystalline phase at 30°C, (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 30°C, and (c) is a polarizing optical microscope photograph showing the state after irradiation with green light and then irradiation with blue light (450 nm) at 30°C. As is clear from Figure 18, irradiation with green light induced a phase transition from the crystalline phase to the isotropic phase, and a dark field was observed in crossed Nicols observation (see (b)). Furthermore, when the isotropic phase was irradiated with blue light, a phase transition from the isotropic phase to the crystalline phase was induced, and crystals were formed (see (c)).

[0145] Reference Example 1-1 (Synthesis of Compound C3-A1-OAc (Intermediate 6-1)) To aniline (1.86 g, 20 mmol) were added 24 mL of distilled water and 6 mL of concentrated hydrochloric acid. A solution prepared by dissolving sodium nitrite (1.66 g, 24 mmol) in 10 mL of distilled water was added with stirring at 0°C, and the resulting solution was then added to 30 mL of an aqueous solution of phenol (1.88 g, 20 mmol) and sodium hydroxide (7.05 g), followed by stirring for 15 minutes. The resulting solution was acidified with hydrochloric acid under cooling and then extracted with ethyl acetate. The organic layer was washed with saturated saline and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the resulting solid was diluted with 50 mL of dehydrated dichloromethane, followed by the addition of 24.2 g (24 mmol) of triethylamine (TEA). While stirring under nitrogen at 0°C, a mixture of 1.88 g (24 mmol) of acetyl chloride (AcCl) dissolved in 10 mL of dichloromethane (DCM) was added dropwise. The resulting solution was allowed to stand for 1 hour and then extracted with water. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was purified by silica gel column chromatography to obtain Intermediate 6-1 shown below (orange solid, 4.6 g, yield: 80.2%).

[0146] Intermediate 6-1 １The structure was determined by HNMR analysis. 1HNMR (400 MHz, CDCl3): 2.29 (s, 3H), 7.23 (dd, J1 = 4.8 Hz, J2 = 2.1 Hz, 2H), 7.42-7.51 (m, 3H), 7.90 (dd, J1 = 6.9 Hz, J2 = 2.1 Hz, 2H), 7.95 (dd, J1 = 4.8 Hz, J2 = 2.1 Hz, 2H).

[0147] Reference Example 1-2 (Synthesis of Compound C3-A1A-OAc (Intermediate 6-2)) 5 mL of 1,1,2,2-tetrachloroethane (TCE), trichloroisocyanuric acid (TCCA, 0.70 g, 3 mmol), potassium peroxodisulfate (0.48 g, 1.8 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.48 g) were added to Compound C3-A1-OAc (Intermediate 6-1, 0.36 g, 1.5 mmol), and the mixture was stirred at 110°C for 2 hours. Thereafter, the mixture was filtered, and the solvent was distilled off from the filtrate under reduced pressure. The resulting solid was purified by silica gel column chromatography to obtain Intermediate 6-2 shown below (red solid, 0.52 g, yield: 91.8%). Intermediate 6-2 １ The structure was determined by HNMR analysis. HNMR (400 MHz, CDCl): 2.34 (s, 3H), 7.23-7.29 (m, 3H), 7.44 (s, 1H), 7.46 (s, 1H).

[0148] Reference Example 1-3 (Synthesis of Compound C3-A1A-OC8 (Azobenzene Derivative 6)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 192 mg, 4.8 mmol) were added to Compound C3-A1A-OAc (Intermediate 6-2, 0.45 g, 1.2 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 86 mg of distilled water was added dropwise to the reaction mixture, followed by stirring at room temperature for 1 hour. A catalytic amount (0.06 mmol) of crown ether 18-crown-6 and 1-bromooctane (0.46 g, 2.4 mmol) were added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 6 shown below (orange solid, 0.53 g, yield: 98.6%).

[0149] Azobenzene derivative 6 １ H NMR and １３ The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.88-0.91 (m, 3H), 1.29-1.45 (m, 10H), 1.76-1.83 (m, 2H), 4.00 (t, J= 6.5 Hz, 2H), 7.00 (s, 2H), 7.21 (t, J= 8.4 Hz, 1H), 7.42 (d, J= 8.0 Hz, 1H) 13CNMR (100 MHz, CDCl3): 14.14, 22.69, 25.90, 28.93, 29.23, 29.28, 31.82, 69.05, 115.90, 126.92, 128.94, 129.23, 130.11, 140.31, 148.33, 159.76

[0150] Reference Example 1-4 Thermal Phase Change of Compound C3-A1A-OC8 (Azobenzene Derivative 6) by DSC Measurement The thermal phase transition temperatures of compound C3-A1A-OC8 were measured by a differential scanning calorimeter, and the phase changes were observed at the following temperatures: Cr 44 Iso, Iso 5 Cr

[0151] Reference Example 1-5 (Light Irradiation Experiment of Compound C3-A1A-OC8 (Azobenzene Derivative 6)) The crystalline phase-isotropic phase transition of crystalline compound C3-A1A-OC8 in a glass sandwich cell at 29°C was observed using a polarizing optical microscope. The results are shown in Figure 7. In Figure 7, (a) is a polarizing optical microscope photograph showing the crystalline phase at 29°C, and (b) is a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 29°C. As is clear from Figure 7, irradiation with green light caused a phase transition from the crystalline phase to the isotropic phase, and a dark field was observed under crossed Nicols observation (see (b)). In other words, it was confirmed that irradiation with green light eliminated the birefringence of the crystals, causing them to melt from the crystal to a liquid. However, irradiating the isotropic phase with blue light did not induce a phase transition from the isotropic phase to the crystalline phase (see (c)).

[0152] Reference Example 1-6 (Calculation of Liquid Phase Stability of Compound C3-A1A-OC8 (Azobenzene Derivative 6)) The rate constants (k) of thermal isomerization at 50°C, 60°C, 70°C, 80°C, and 90°C were measured, and from these values ​​and an Arrhenius plot, the lifetime at 30°C was calculated to be 5.8 days.

[0153] Comparative Example 1-1 (Synthesis of Compound C2-A6-OAc (Intermediate 7-1)) 16 mL of distilled water and 4 mL of concentrated hydrochloric acid were added to 2,6-difluoroaniline (1.29 g, 10 mmol). A solution prepared by dissolving sodium nitrite (0.83 g, 12 mmol) in 5 mL of distilled water was added while stirring at 0°C. Then, 20 mL of an aqueous solution of 3,5-difluorophenol (1.3 g, 10 mmol) and 4.7 g of sodium hydroxide was added to the resulting solution, and the mixture was stirred for 15 minutes. The resulting solution was acidified with hydrochloric acid under cooling and then extracted with ethyl acetate. The organic layer was washed with saturated saline and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the resulting solid was diluted with 50 mL of dehydrated dichloromethane, followed by the addition of 12.1 g (12 mmol) of triethylamine (TEA). While stirring under nitrogen at 0°C, a mixture of 0.94 g (12 mmol) of acetyl chloride (AcCl) dissolved in 10 mL of dichloromethane (DCM) was added dropwise. The resulting solution was allowed to stand for 1 hour and then extracted with water. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was purified by silica gel column chromatography to obtain Intermediate 7-1 shown below (orange solid, 2.9 g, yield: 92%).

[0154] Intermediate 7-1 １ The structure was determined by HNMR analysis. 1HNMR (400 MHz, CDCl3): 2.32 (s, 3H), 6.92 (d, J = 9.4 Hz, 2H), 7.05 (t, J = 8.6 Hz, 2H), 7.33-7.40 (m, 1H).

[0155] Comparative Example 1-2 (Compound C2-A6A-OC8 (Azobenzene Derivative 7)) 5 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 160 mg, 4 mmol) were added to Compound C2-A6A-OAc (Intermediate 7-1, 0.31 g, 1 mmol), and the mixture was stirred at room temperature. A mixture of 5 mL of THF and 72 mg of distilled water was added dropwise to the reaction mixture, followed by stirring at room temperature for 1 hour. A catalytic amount (0.05 mmol) of crown ether 18-crown-6 and 1-bromooctane (0.38 g, 2 mmol) were added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 7 shown below (orange solid, 0.36 g, yield: 93.1%).

[0156] Azobenzene derivative 7 １ H NMR and １３ The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.88-0.91 (m, 3H), 1.30-1.45 (m, 10H), 1.77-1.83 (m, 2H), 3.99-4.03 (m, 2H), 6.36 (dd, J1=12Hz, J2=2.6 Hz, 1H), 6.58 (d, J1=11.2 Hz, 1H), 7.01-7.07 (m, 2H), 7.28-7.34 (m, 1H) 13CNMR (100 MHz, CDCl3): 14.29, 22.85, 26.06, 29.02, 29.39, 29.45, 69.41, 99.32, 99.36, 99.56, 99.59, 125.94, 126.04, 126.13, 130.39, 130.49, 130.59, 132.24, 132.34, 132.44, 154.37, 154.41, 156.36, 156.43, 158.96, 159.03

[0157] Comparative Example 1-3 (Thermal Phase Change of Compound C2-A6A-OC8 (Azobenzene Derivative 7) by DSC Measurement) When the thermal phase transition temperatures of Compound C2-A6A-OC8 were measured by a differential scanning calorimeter, the phase changes were observed at the following temperatures: Cr 45 Iso, Iso 22 Cr

[0158] Comparative Example 1-4 (Light Irradiation Experiment of Compound C2-A6A-OC8 (Azobenzene Derivative 7)) The crystalline phase-isotropic phase transition of crystalline compound C2-A6A-OC8 in a glass sandwich cell at 29°C was observed using a polarizing optical microscope. The results are shown in Figure 8. In Figure 8, (a) shows a polarizing optical microscope photograph showing the crystalline phase at 29°C, and (b) shows a polarizing optical microscope photograph showing the state after irradiation with green light (540 nm) at 29°C. As is clear from Figure 8, the phase transition from the crystalline phase to the isotropic phase did not occur upon irradiation with green light. In other words, the azobenzene derivative did not undergo a phase transition from a solid phase to a liquid phase upon irradiation with green light.

[0159] Comparative Example 1-5 (Calculation of Liquid Phase Stability of Compound C2-A6A-OC8 (Azobenzene Derivative 7)) The rate constants (k) of thermal isomerization were measured at 60°C, 75°C, 85°C, and 90°C, respectively, and from these values ​​and an Arrhenius plot, the lifetime at 30°C was calculated to be 30.2 days.

[0160] Comparative Example 2-1 (Synthesis of Compound A1-B9-diOAc (Intermediate 8-1)) 16 mL of distilled water and 4 mL of concentrated hydrochloric acid were added to 4-aminophenol (1.09 g, 10 mmol). A solution prepared by dissolving sodium nitrite (0.83 g, 12 mmol) in 5 mL of distilled water was added while stirring at 0°C. To the resulting solution, 20 mL of an aqueous solution of o-cresol (1.08 g, 10 mmol) and 4.7 g of sodium hydroxide was added, and the mixture was stirred for 15 minutes. The resulting solution was acidified with hydrochloric acid under cooling and then extracted with ethyl acetate. The organic layer was washed with saturated saline and dried over anhydrous magnesium sulfate. The solvent was evaporated under reduced pressure, and the resulting solid was diluted with 50 mL of dehydrated dichloromethane, followed by the addition of 24.2 g (24 mmol) of triethylamine (TEA). A mixture of 1.88 g (24 mmol) of acetyl chloride (AcCl) in 10 mL of dichloromethane (DCM) was added dropwise under nitrogen at 0°C while stirring. The resulting solution was allowed to stand for 1 hour and then extracted with water. The organic layer was washed with saturated brine and dried over anhydrous magnesium sulfate. After evaporating the solvent under reduced pressure, the resulting solid was purified by silica gel column chromatography to obtain Intermediate 8-1 shown below (orange solid, 0.45 g, yield: 14.4%).

[0161] Intermediate 8-1 １ The structure was determined by HNMR analysis. 1HNMR (400 MHz, CDCl3): 2.28 (s, 3H), 2.33 (s, 3H), 2.35 (s, 3H), 7.17 (d, J = 8.4 Hz, 1H), 7.24 (d, J = 8.8 Hz, 2H), 7.77-7.81 (m, 2H), 7.94 (d, J = 8.8 Hz, 2H).

[0162] Comparative Example 2-2 (Synthesis of Compound A1-B9A-diOAc (Intermediate 8-2)) 5 mL of 1,1,2,2-tetrachloroethane (TCE), trichloroisocyanuric acid (TCCA, 0.94 g, 4 mmol), potassium peroxodisulfate (1.3 g, 4.8 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.24 g, 0.2 mmol) were added to Compound A1-B9-diOH (Intermediate 8-1, 0.62 g, 2 mmol), and the mixture was stirred at 110° C. for 2 hours. Thereafter, the mixture was filtered, and the solvent was distilled off from the filtrate under reduced pressure. The resulting solid was purified by silica gel column chromatography to obtain Intermediate 8-2 shown below (red solid, 0.42 g, yield: 48.6%).

[0163] Intermediate 8-2 １ The structure was determined by HNMR analysis. HNMR (400 MHz, CDCl): 2.28 (s, 3H), 2.33 (s, 3H), 2.37 (s, 3H), 7.21 (s, 1H), 7.28 (s, 2H).

[0164] Comparative Example 2-3 (Synthesis of Compound A1-B9A-diOC8 (Azobenzene Derivative 8)) 10 mL of tetrahydrofuran (THF) and sodium hydride (60% in paraffin, 160 mg, 4 mmol) were added to Compound A1-B9A-diOAc (Intermediate 8-2, 0.18 g, 0.5 mmol), and the mixture was stirred at room temperature. After stirring for 1 hour, a catalytic amount (0.025 mmol) of crown ether 18-crown-6 and 1-bromooctane (0.38 g, 2 mmol) were added to the reaction mixture, and the mixture was stirred at 66°C for 22 hours. The solvent was distilled off from the mixture under reduced pressure, and the resulting solid was purified by silica gel column chromatography to obtain the azobenzene derivative 8 shown below (orange solid, 0.25 g, yield: 84.4%).

[0165] Azobenzene derivative 8 １ H NMR and １３The structure was determined by CNMR analysis. 1HNMR (400 MHz, CDCl3): 0.88-0.91 (m, 6H), 1.30-1.51 (m, 20H), 1.78-1.87 (m, 2H), 2.33 (s, 3H), 3.98 (m, 4H), 6.89 (s, 1H), 6.98 (s, 2H) 13CNMR (100 MHz, CDCl3): 12.85, 14.12, 22.67, 25.90, 26.04, 28.95, 29.04, 29.21, 29.23, 29.27, 31.81, 68.96, 69.09, 111.73, 115.74, 123.93, 125.84, 129.31, 130.17, 140.95, 141.26, 157.37, 159.11

[0166] Comparative Example 2-4 (Thermal Phase Change of Compound A1-B9A-diOC8 (Azobenzene Derivative 8) by DSC Measurement) When the thermal phase transition temperatures of Compound A1-B9A-diOC8 were measured by a differential scanning calorimeter, the phase changes were observed at the following temperatures: Cr 91 Iso, Iso 85 Cr

[0167] Comparative Example 2-5 (Light Irradiation Experiment of Compound A1-B9A-diOC8 (Azobenzene Derivative 8)) The crystalline phase-isotropic phase transition of the crystals of Compound A1-B9A-diOC8 was observed using a polarizing optical microscope at 29°C in a glass sandwich cell. The results are shown in Figure 9. In Figure 9, (a) is a polarizing optical microscope photograph showing the crystalline phase at 29°C, and (b) is a polarizing optical microscope photograph showing the state of the sample irradiated with green light (540 nm) at 29°C. As is clear from Figure 9, the phase transition from the crystalline phase to the isotropic phase did not occur upon irradiation with green light. In other words, the azobenzene derivative did not undergo a phase transition from a solid phase to a liquid phase upon irradiation with green light.

[0168] Comparative Example 2-6 (Calculation of Liquid Phase Stability of Compound A1-B9A-diOC8 (Azobenzene Derivative 8)) The rate constants (k) of thermal isomerization were measured at 40°C, 45°C, 50°C, and 55°C, respectively, and the lifetime at 30°C was calculated to be 4.8 days from these values ​​and an Arrhenius plot.

[0169] Comparative Example 3-1 (Chlorination reaction of compound C2-A1-OH) 5 mL of 1,1,2,2-tetrachloroethane (TCE), trichloroisocyanuric acid (TCCA, 0.23 g, 1 mmol), potassium peroxodisulfate (0.33 g, 1.2 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.03 g, 0.025 mmol) were added to compound C2-A1-OH (0.23 g, 1 mmol), and the mixture was stirred at 110° C. for 2 hours. However, the target compound was not obtained (the starting material was decomposed).

[0170] Comparative Example 3-2 (Chlorination reaction of compound C2-A1-OTIPS) 5 mL of 1,1,2,2-tetrachloroethane (TCE), trichloroisocyanuric acid (TCCA, 0.23 g, 1 mmol), potassium peroxodisulfate (0.33 g, 1.2 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.03 g, 0.025 mmol) were added to compound C2-A1-OTIPS (0.39 g, 1 mmol), and the mixture was stirred at 110° C. for 2 hours. However, the target compound was not obtained (several decomposition products were obtained).

[0171] Comparative Example 3-3 (Chlorination reaction of compound C2-A1-OC8) 5 mL of 1,1,2,2-tetrachloroethane (TCE), trichloroisocyanuric acid (TCCA, 0.23 g, 1 mmol), potassium peroxodisulfate (0.33 g, 1.2 mmol), and tetrakis(triphenylphosphine)palladium(0) (0.03 g, 0.025 mmol) were added to compound C2-A1-OC8 (0.35 g, 1 mmol), and the mixture was stirred at 110° C. for 2 hours. However, the target compound was not obtained (several decomposition products were obtained).

Claims

1. An azobenzene derivative represented by the following formula (1): (In formula (1), R １ represents an alkoxy group having 1 to 18 carbon atoms; R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R ３ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; R ３ is R １ represents a functional group different from X １ ~X ４ each independently represents a halogen atom or an alkyl group having 1 to 2 carbon atoms; X １ ~X ４ At least one of the groups represents a halogen atom.

2. In the formula (1), R ２ 2. The azobenzene derivative according to claim 1, wherein one or more of the following is a branched alkyl group having 3 to 4 carbon atoms:

3. In the formula (1), R １ represents an alkoxy group having 6 to 18 carbon atoms; １ ~X ４ each independently represents a halogen atom; X １ ~X ４ The azobenzene derivative according to claim 1 , wherein represents a combination of two or more halogen atoms.

4. In the formula (1), X １ ~X ４ The azobenzene derivative according to claim 1, wherein is a combination of two or more halogen atoms selected from the group consisting of a fluorine atom, a chlorine atom and a bromine atom.

5. In the formula (1), X １ and X ２ are the same halogen atom, and X ３ and X ４ But, X １ and X ２ The azobenzene derivative according to claim 1 , wherein each of the halogen atoms is different from and is the same.

6. In the formula (1), X １ ~X ４ The azobenzene derivative according to claim 1 , wherein is a combination of a fluorine atom and a chlorine atom.

7. In the formula (1), R ２ The azobenzene derivative according to claim 1 , wherein each of the is independently a hydrogen atom or a methyl group.

8. 2. The azobenzene derivative according to claim 1, which is capable of undergoing a phase transition between a solid phase and a liquid phase upon irradiation with visible light.

9. 9. The azobenzene derivative according to claim 8, which undergoes a phase transition from a solid phase to a liquid phase upon irradiation with visible light having a wavelength of 500 to 650 nm.

10. 9. The azobenzene derivative according to claim 8, which undergoes a phase transition from a liquid phase to a solid phase upon irradiation with visible light having a wavelength of 400 to 500 nm.

11. A method for producing the azobenzene derivative according to any one of claims 1 to 10, comprising the steps of: A step (A) of contacting at least one azobenzene derivative selected from the group consisting of an azobenzene derivative represented by the following formula (2-1), an azobenzene derivative represented by the following formula (2-2), and an azobenzene derivative represented by the following formula (2-3) with a halogenating agent in the presence of a palladium compound to obtain an azobenzene derivative represented by the following formula (3); and a step (B) of deprotecting an acetoxy group of the azobenzene derivative represented by the following formula (3) obtained in the step (A) to obtain the azobenzene derivative represented by the formula (1), in this order. (In the formulas (2-1), (2-2) and (2-3), R' １ represents an acetoxy group, R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R ３ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; X １ ~X ４ each independently represents a halogen atom or an alkyl group having 1 to 2 carbon atoms. (In formula (3), R' １ represents an acetoxy group, R ２ each independently represents a hydrogen atom or an alkyl group having 1 to 4 carbon atoms; R ３ represents a hydrogen atom, an alkyl group having 1 to 4 carbon atoms, or an alkoxy group having 1 to 4 carbon atoms; X １ ~X ４ each independently represents a halogen atom or an alkyl group having 1 to 2 carbon atoms; X １ ~X ４ At least one of the groups represents a halogen atom.

12. In the formula (2-1), formula (2-2) and formula (2-3), X １ ~X ４ each independently represents a halogen atom; In the formula (3), X １ ~X ４ each independently represents a halogen atom; X １ ~X ４ The method for producing an azobenzene derivative according to claim 11, wherein represents a combination of two or more halogen atoms.

13. A photothermal storage material comprising the azobenzene derivative according to any one of claims 1 to 10.

14. An adhesive comprising the azobenzene derivative according to any one of claims 1 to 10.

15. An optical element comprising the azobenzene derivative according to any one of claims 1 to 10.

16. An actuator material comprising the azobenzene derivative according to any one of claims 1 to 10.

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