JP7337364B2 - Diarylethene compound, photochromic material, and display medium - Google Patents

Description

Application of Article 30, paragraph 2 of the Patent Act (1) Publication: Abstracts of the 61st Symposium on Radiation Chemistry, published by the Japan Society of Radiation Chemistry, pp. 185-186 Publication date: September 25, 2018 (2) ▼Publication: Proceedings of the 8th CSJ Chemistry Festa 2018 Published by The Chemical Society of Japan, P3-094 Publication date: September 26, 2018 ▼Meeting name: The 61st Radiation Chemistry Symposium Venue: Osaka City University (Sugimoto Campus) Academic Information Center 10F (3-3-138 Sugimoto, Sumiyoshi-ku, Osaka) Dates: September 26, 2018-September 28, 2018 ▲4▼Meeting Name: No. 8th CSJ Chemistry Festa 2018 Venue: Tower Hall Funabashi (4-1-1 Funabori, Edogawa-ku, Tokyo) Dates: October 23, 2018 to October 25, 2018

The present invention relates to novel diarylethene compounds. Furthermore, the present invention relates to a photochromic material containing the diarylethene compound and a display medium containing the photochromic material.

Photochromism is a phenomenon in which a material is colored by irradiation with ultraviolet light and the coloration is restored by irradiation with visible light or heat, and a compound having such a property is called a photochromic compound. Diarylethene compounds, for example, are known as photochromic compounds. It is known that both isomers of diarylethene compounds are thermally stable before and after ultraviolet irradiation. It is also known that diarylethene compounds change their physical properties depending on their substituents. For example, compounds represented by the following formula (I) exhibit thermally stable photochromism.

On the other hand, for example, the compound represented by the following formula (II) is characterized in that it is colored when irradiated with ultraviolet rays, this colored state is stable even under visible light, and the coloring hardly returns. This is described in Patent Document 1 and Non-Patent Document 1.

Furthermore, the compound represented by the following formula (III) is colored when irradiated with ultraviolet rays, and this colored state is stable even under visible light, but the colored state is restored when heated to a high temperature. have. This is described in Patent Document 2 and Non-Patent Document 2.

A compound that can be colored by irradiation with ultraviolet rays and erased by heating, such as compound (III), is expected to be applied to, for example, display media.

Patent No. 4025920 Patent No. 3964231

K. Shibata, S.; Kobatake, M.; Irie, Chem. Lett. , 618 (2001) K. Morimitsu, K.; Shibata, S.; Kobatake, M.; Irie, J. Org. Chem. , 67, 4574-4578 (2002)

As described above, compounds such as compound (III) that can be colored by irradiation with ultraviolet rays and erased by heating are expected to be applied to display media, for example. For example, when compound (III) is irradiated with UV light, the colored photoisomer turns into a colorless state (i.e., compound (III)) with a half-life of 45 seconds when heated to a very high temperature of 160°C. back to In order to utilize the characteristics of coloring by ultraviolet irradiation and erasing of the coloring by heat for use in display media, it is necessary to accelerate the thermal fading reaction.

Under such circumstances, the main object of the present invention is to provide a diarylethene compound that is colored by irradiation with ultraviolet rays and whose coloration is favorably thermally faded by heating. Another object of the present invention is to provide a photochromic material containing the diarylethene compound and a display medium containing the photochromic material.

The inventor of the present invention has made intensive studies to solve the above problems. As a result, the inventors have found that the diarylethene compound represented by the following general formula (1) is colored by ultraviolet irradiation, and that the coloration is thermally faded by heating at a lower temperature or for a shorter time.

In general formula (1), ring A represents a 5-membered ring structure or a 6-membered ring structure. Y ¹ and Y ² are each independently C or N; R ¹ and R ² are each independently an optionally substituted branched or cyclic hydrocarbon group having 3 or more carbon atoms. R ³ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group when Y ¹ is C, and an electron pair when Y ¹ is N; R ⁴ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group when Y ² is C, and an electron pair when Y ² is N. X ¹ n and X ² n are each independently n electron-withdrawing groups bonded to a benzene ring, where n is an integer of 1-5.

The present invention has been completed through further studies based on such findings.

［式（１）中、環Ａは、５員環構造または６員環構造を示しており、
Ｙ¹及びＹ²は、それぞれ独立に、ＣまたはＮであり、
Ｒ¹及びＲ²は、それぞれ独立に、置換基を有していてもよい炭素数３以上の分岐または環状炭化水素基であり、
Ｒ³は、Ｙ¹がＣである場合には、水素原子、フェニル基、アルキル基、アルコキシ基、またはシアノ基であり、Ｙ¹がＮである場合には、電子対であり、
Ｒ⁴は、Ｙ²がＣである場合には、水素原子、フェニル基、アルキル基、アルコキシ基、またはシアノ基であり、Ｙ²がＮである場合には、電子対であり、
Ｘ¹ｎ及びＸ²ｎは、それぞれ独立に、ベンゼン環に結合したｎ個の電子求引性基であり、ｎは、１～５の整数である。］
項２． 前記環Ａが、５員環構造であり、
前記Ｙ¹及びＹ²が、それぞれ、Ｃであり、
Ｒ¹及びＲ²は、それぞれ独立に、置換基を有していてもよい炭素数３以上の分岐または環状炭化水素基であり、
前記Ｒ³及びＲ⁴は、それぞれ独立に、水素原子、フェニル基、または炭素数が１～５のアルキル基であり、
Ｘ¹ｎ及びＸ²ｎは、フッ素原子を含んでいる基、シアノ基、またはホルミル基である、項１に記載のジアリールエテン化合物。
項３． 下記一般式（１Ａ）で表される、項２に記載のジアリールエテン化合物。

［式（１Ａ）中、６つのＺは、それぞれ独立に、水素原子またはフッ素原子であり、Ｒ¹、Ｒ²、Ｒ³、Ｒ⁴、Ｘ¹ｎ及びＸ²ｎは、それぞれ、項２と同じである。］
項４． 下記一般式（１Ｂ）、（１Ｃ）、（１Ｄ）または（１Ｅ）で表される、項３に記載のジアリールエテン化合物。

［式（１Ｂ）～（１Ｅ）中、６つのＺ、Ｒ¹、Ｒ²、Ｒ³、及びＲ⁴は、それぞれ、項３と同じである。］
項５． 下記式で表される、ジアリールエテン化合物。

［前記各一般式において、Ｒ¹及びＲ²は、それぞれシクロヘキシル基である。］
項６． 項１～５のいずれかに記載のジアリールエテン化合物を含む、フォトクロミック材料。
項７． 項６に記載のフォトクロミック材料を含む、表示媒体。 That is, the present invention provides inventions in the following aspects.
Section 1. A diarylethene compound represented by the following general formula (1).

[In formula (1), ring A represents a 5-membered ring structure or a 6-membered ring structure,
Y ¹ and Y ² are each independently C or N;
R ¹ and R ² are each independently an optionally substituted branched or cyclic hydrocarbon group having 3 or more carbon atoms,
^R is a hydrogen atom, a phenyl group, an alkyl group, ^an alkoxy group, or a cyano group when Y is C; an electron pair when ^Y is N;
^R is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group when Y ^is C; an electron pair when ^Y is N;
X ¹ n and X ² n are each independently n electron-withdrawing groups bonded to a benzene ring, where n is an integer of 1-5. ]
Section 2. The ring A is a 5-membered ring structure,
each of Y ¹ and Y ² is C;
R ¹ and R ² are each independently an optionally substituted branched or cyclic hydrocarbon group having 3 or more carbon atoms,
R ³ and R ⁴ are each independently a hydrogen atom, a phenyl group, or an alkyl group having 1 to 5 carbon atoms,
Item 2. The diarylethene compound according to Item 1, wherein X ¹ n and X ² n are a fluorine atom-containing group, a cyano group, or a formyl group.
Item 3. 3. The diarylethene compound according to item 2, represented by the following general formula (1A).

[In formula (1A), six Zs are each independently a hydrogen atom or a fluorine atom, and R ¹ , R ² , R ³ , R ⁴ , X ¹ n and X ² n are each independently are the same. ]
Section 4. Item 3. The diarylethene compound according to item 3, represented by the following general formula (1B), (1C), (1D) or (1E).

[In formulas (1B) to (1E), six Z, R ¹ , R ² , R ³ and R ⁴ are each the same as in item 3. ]
Item 5. A diarylethene compound represented by the following formula.

[In each of the above general formulas, R ¹ and R ² are each a cyclohexyl group. ]
Item 6. Item 6. A photochromic material comprising the diarylethene compound according to any one of Items 1 to 5.
Item 7. Item 7. A display medium comprising the photochromic material according to item 6.

According to the present invention, it is possible to provide a diarylethene compound that is colored by irradiation with ultraviolet rays, and whose coloration is favorably thermally faded by heating. Furthermore, according to the present invention, it is also possible to provide a photochromic material containing the diarylethene compound and a display medium containing the photochromic material.

The diarylethene compound of the present invention has a chemical structure represented by the following general formula (1).

As will be described later, the color of the diarylethene compound (the color of the ring-opened product before ring closure by ultraviolet irradiation) is not particularly limited, but it is usually colorless and transparent. Further, as shown in the following formula, the diarylethene compound (1) of the present invention is colored by ultraviolet irradiation (formation of compound (2) by ring-closing reaction) and faded by heating (formation of compound (1) by ring-opening reaction). ) is reversible and can be repeated.

In general formula (1), ring A represents a 5-membered ring structure or a 6-membered ring structure. Structurally, ring A may be either a 5-membered ring structure or a 6-membered ring structure, but is preferably a 5-membered ring from the viewpoint that it is colored by ultraviolet irradiation and that the coloration is favorably thermally faded by heating. structure.

Preferred structures of ring A include, for example, structures represented by the following general formulas.

In the above ring structure, the six groups Z are the same or different and each is a hydrogen atom or a fluorine atom, preferably a fluorine atom from the viewpoint of repeated durability. All six groups Z are preferably fluorine atoms or hydrogen atoms. Further, the group R ^c , the group R ^d and the group R ^e each independently include an optionally substituted phenyl group and an alkyl group, preferably an optionally substituted carbon Alkyl groups having a number of 1 to 5 are included. The substituents of the group R ^c , the group R ^d and the group R ^e are not particularly limited, but each independently preferably includes a cyano group, an alkyl group, an alkoxy group, a chloro group, a bromo group and the like.

In general formula (1), group Y ¹ and group Y ² are each independently C (carbon atom) or N (nitrogen atom), preferably C.

The group R ¹ and the group R ² are each independently an optionally substituted branched hydrocarbon group having 3 or more carbon atoms or an optionally substituted cyclic hydrocarbon group. In the diarylethene compound having the structure represented by the general formula (1), the groups R ¹ and R ² are bonded by ultraviolet irradiation by changing the carbon number and structure of the groups R ¹ and R ² . The ring-closing reaction rate between carbon atoms and the ring-opening reaction rate by heating can be adjusted. Therefore, the reaction rate of ultraviolet irradiation and the reaction rate of thermal fading can be adjusted appropriately. The groups R ¹ and R ² may be different, but are preferably the same. In addition, in the present invention, the groups R ¹ and R ² are each bonded to the thiophene skeleton via an oxygen atom, so that the ring closure reaction by ultraviolet irradiation proceeds favorably, resulting in coloration and visible light. The ring-opening reaction upon irradiation is suppressed. That is, the diarylethene compound of the present invention is colored by ultraviolet irradiation, and the coloration is favorably thermally faded by heating, while discoloration by visible light irradiation is favorably suppressed.

The number of carbon atoms in the groups R ¹ and R ² is preferably about 3-12, more preferably about 3-6. Specific examples of substituents that the groups R ¹ and R ² may have include halogen atoms such as chloro and bromo groups.

Preferred specific examples of the groups R ¹ and R 2 are isopropyl group, isobutyl group, and R ² from the viewpoint of being suitably colored by ultraviolet irradiation and being suitably thermally faded by heating at a lower temperature for a shorter time. An alkyl group having a branched structure such as an isopentyl group; and a cyclic alkyl group such as a cyclopentyl group, a substituted cyclopentyl group, a cyclohexyl group, and a substituted cyclohexyl group. Among these, a cyclohexyl group is particularly preferred.

The group R ³ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group when Y ¹ is C and an electron pair when Y ¹ is N. The group R ³ is such that the group Y ¹ is C
and is preferably a hydrogen atom, a phenyl group, or an alkyl group, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

The group R ⁴ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group when Y ² is C and an electron pair when Y ² is N. In the group R ⁴ , the group Y ² is C, and is preferably a hydrogen atom, a phenyl group, or an alkyl group, preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

The phenyl group, alkyl group and alkoxy group of the groups R ³ and R ⁴ may each have a substituent. Examples of the substituent include, but are not particularly limited to, a cyano group, an alkyl group, an alkoxy group, a chloro group, and a bromo group.

In general formula (1), the groups X ¹ n and X ² n are each independently n electron-withdrawing groups bonded to a benzene ring, where n is an integer of 1-5. Group X ¹ and group X ² may be the same or different. Also when n is 2 or more, the n groups X ¹ and the n groups X ² may be the same or different. n is preferably an integer of 1-2. In the diarylethene compound of the present invention, the reaction rate due to ultraviolet irradiation and the reaction rate of thermal fading can be adjusted by selecting the types of the groups OR ¹ , OR ² , X ¹ and X ² as described above. Furthermore, it can also be adjusted by the number of groups X ¹ and X ² and the bonding positions on the benzene ring.

The groups X ¹ n and X ² n are not particularly limited as long as they are electron-withdrawing groups. Electron-withdrawing groups include, for example, chlorine atoms, bromine atoms, cyano groups, groups containing fluorine atoms, formyl groups, acetyl groups, and dicyanoethenyl groups. Among these, a cyano group, a formyl group, or a group containing a fluorine atom is preferable. A fluorine atom, a fluorine-containing alkyl group, etc. are mentioned as a group containing a fluorine atom. As the fluorine-containing alkyl group, a perfluoroalkyl group in which all hydrogen atoms of an alkyl group are substituted with fluorine atoms is preferable. Also, the number of carbon atoms in the fluorine-containing alkyl group is preferably about 1 to 6. Specific examples of fluorine-containing alkyl groups include trifluoromethyl, pentafluoroethyl and trifluoroethyl groups.

The diarylethene compound of the present invention preferably has a structure represented by the following general formula (1A) from the viewpoint of being colored by ultraviolet irradiation and suitably thermally fading the coloration by heating at a lower temperature for a short time. preferably.

In general formula (1A), six Zs are each independently a hydrogen atom or a fluorine atom, and R ¹ , R ² , R ³ , R ⁴ , X ¹ⁿ and X ²ⁿ are each the above-described general Examples are the same as those exemplified in formula (1).

More specifically, the diarylethene compound of the present invention is colored by ultraviolet irradiation, and from the viewpoint of suitably thermally fading the coloration by heating at a lower temperature for a short time, the diarylethene compound of the present invention preferably has the following general formula (1B), More preferably, it has a structure represented by (1C), (1D) or (1E).

In general formulas (1B), (1C), (1D) and (1E), the six Zs, R ¹ , R ² , R ³ and R ⁴ are respectively exemplified in general formula (1) above. The same is mentioned.

Although the color of the diarylethene compound of the present invention (the color before ring closure by ultraviolet irradiation) is not particularly limited, it is preferably colorless and transparent.

In addition, the diarylethene compound of ^{the present} invention has absorption in the visible region after being irradiated with ultraviolet rays. 6-membered ring structure) has a maximum absorption wavelength λ _max in the range of 400 to 700 nm. Further, the molar extinction coefficient ε of the closed-ring form satisfies ε>10000 M ⁻¹ cm ⁻¹ . Furthermore, the ring closure reaction quantum yield of the diarylethene compound of the present invention is preferably about 0.1 to 1, more preferably about 0.3 to 1, from the viewpoint of rapid coloration by ultraviolet irradiation. Further, the ring-opening reaction quantum yield of the closed-ring form of the diarylethene compound of the present invention is preferably 10 ⁻³ or less, more preferably 5×10 ⁻⁴ or less, because it is necessary to keep it stable under visible light. mentioned. The ring-closing reaction quantum yield and the ring-opening reaction quantum yield respectively mean values measured by the method described in Examples.

In addition, the diarylethene compound of the present invention can be colored by ultraviolet irradiation, and the coloration can be favorably thermally faded by heating. The activation energy E _a in the thermal bleaching reaction of the closed-ring form can be adjusted, for example, in the range of 100 to 120 kJmol ⁻¹ . In addition, the half-life t _1/2 of heat fading can be appropriately adjusted according to the desired temperature and rate of heat fading. From the point of view, the half-life t _1/2 of heat fading at 150° C. is preferably about 10 seconds to 60 seconds, more preferably about 10 seconds to 40 seconds _{. 2} is preferably about 1 minute to 10 minutes, more preferably about 1 minute to 8 minutes. From the viewpoint of maintaining thermal stability at room temperature, the half-life t _1/2 of thermal fading at 30° C. is preferably 30 days or longer, more preferably 50 days or longer. The activation energy E _a and the half-life t _1/2 in the thermal fading reaction are values measured by the method described in Examples. As described above, in the present invention, the adjustment of the reaction rate due to ultraviolet irradiation and the reaction rate of thermal fading is specifically performed by selecting the types of the groups OR ¹ , OR ² , X ¹ and X ² , and furthermore It is adjusted by the number of groups X ¹ and X ² and the bonding positions on the benzene ring.

Specific examples of the diarylethene compound of the present invention include compounds represented by the following formulas (1a) to (1d) (hereinafter referred to as compounds (1a) to (1d), etc.).

The method for producing the diarylethene compound represented by the general formula (1) is not particularly limited, and a known production method can be employed. For example, it can be produced according to the method described in the Examples.

In the production of the diarylethene compound of the present invention, the reaction conditions such as the starting materials, the amounts and ratios thereof used, temperature, time, pressure, atmosphere, and the type and amount of solvent used depend on the structure of the diarylethene compound to be produced. can be set as appropriate. Further, whether the produced compound is the desired diarylethene compound (1) is confirmed by general organic analysis techniques such as nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry, as shown in Examples. be able to.

In the diarylethene compound (1) of the present invention, for example, as represented by the following reaction formula, the two carbon atoms to which the groups OR ¹ and OR ² are bonded are bonded to form a ring by irradiation with ultraviolet light. is formed (ring closed) to give a discolored (colored) compound (2). Regarding this coloring, the diarylethene compound of the present invention can retain the coloring in an environment where it is not irradiated with ultraviolet rays, and fading progresses with heating. Moreover, the coloring is stable under visible light.

The reaction rate when the diarylethene compound of the present invention forms a ring structure and becomes the compound represented by the above general formula (2) by ultraviolet light irradiation, and the thermal fading reaction rate of the reverse reaction thereof are determined based on the structure of the diarylethene compound. can be adjusted by That is, in the diarylethene compound of the present invention, in the skeleton of the above general formula (1), selection of the types of groups X ¹ n, X ² n, Y ¹ , Y ² , R ¹ to R ⁴ , and group X ¹ The reaction rate of ultraviolet irradiation and the reaction rate of thermal fading can be adjusted by adjusting the number of n and groups X ² n, the bonding positions on the benzene ring, and the like.

Moreover, by using a plurality of types of the diarylethene compound of the present invention, it is possible to adjust the reaction rate of ultraviolet irradiation and the reaction rate of thermal fading. For example, by mixing and using a plurality of types of diarylethene compounds having different thermal fading reaction rates, the temperature and rate of thermal fading can be adjusted.

As described above, the diarylethene compound of the present invention can be colored by ultraviolet irradiation, and the coloring can be faded at a suitable heating temperature and time. can do.

The photochromic material of the present invention may contain one type of the diarylethene compound of the present invention alone, or may contain two or more types. Moreover, the photochromic material of the present invention may contain a photochromic compound different from the diarylethene compound of the present invention (for example, compounds described in Patent Documents 1 and 2 and Non-Patent Documents 1 and 2).

The display medium of the present invention contains the photochromic material of the present invention, and can exhibit, for example, the property of being colored by irradiation with ultraviolet rays and fading under suitable heating conditions.

The display medium of the present invention can have, for example, a structure in which a photochromic material is dispersed in a resin. The content of the photochromic material in the display medium is not particularly limited, and is, for example, about 1 to 20 mass %. Also, the resin is not particularly limited, and a thermoplastic resin, a thermosetting resin, or the like can be used. Specific examples of resins include polyolefins, acrylic resins, vinyl chloride resins, urethane resins, and styrene resins. The number of resins in the display medium may be one, or two or more.

In addition, the diarylethene compound of the present invention can be used not only for display media but also for a wide range of applications such as printing on textile products, cosmetics, playground equipment, printing inks, decorative materials, toys, information recording materials, and display materials. can.

The present invention will be described in more detail in the following examples, but the invention is not limited thereto. For identification of the diarylethene compound, the following ¹ HNMR and mass spectrometry were used.

( ¹ H NMR)
The intermediate compound and the diarylethene compound were identified using a nuclear magnetic resonance spectrometer (manufactured by Bruker BioSpin K.K., model: AV-300N). Deuterated chloroform was used as a solvent, and tetramethylsilane was used as a reference substance.

(mass spectrometry)
An intermediate compound and a diarylethene compound were identified using a mass spectrometer (manufactured by Bruker, model: FT-ICR/solariX). It was ionized by matrix-assisted laser desorption ionization (MALDI) and measured at high resolution.

(Example 1)
A compound represented by formula (1a) was synthesized by the following method. First, 3-bromo-2-cyclohexyloxy-5-(4-trifluoromethyl)phenylthiophene was synthesized by the following procedure. 3,5-Dibromo-2-cyclohexyloxythiophene [reference: K.K. Morimitsu, K.; Shibata, S.; Kobatake, M.; Irie, J. Org. Chem. , 67, 4574-4578 (2002)] 1.23 g (3.62 mmol) was added, 60 mL of anhydrous tetrahydrofuran was added, and the mixture was cooled to -78°C. 2.5 mL (4.0 mmol) of 1.6 M n-butyllithium hexane solution was slowly added dropwise and stirred for 1 hour. 1.5 mL (5.6 mmol) of tributyl borate was slowly added dropwise and stirred for 1 hour. Water was added to stop the reaction, transferred to a 200 mL eggplant-shaped flask, p-iodobenzotrifluoride 0.98 g (3.62 mmol), Pd(PPh₃)_Four 80 mg and 6 mL of a 20 wt % sodium carbonate aqueous solution were added, and the mixture was refluxed at 80° C. for 5 hours. Neutralized with dilute hydrochloric acid and extracted with ether. It was salted out with a saturated aqueous sodium chloride solution and dried with magnesium sulfate. Thereafter, it was isolated by silica gel column chromatography using hexane as a developing solvent, and purified by recrystallization using hexane.
Yield 0.82 g, Yield 56%
¹H NMR (300 MHz, CDCl₃, TMS) δ = 1.3-2.1 (m, 10H), 4.1-4.2 (m, 1H), 7.07 (s, 1H), 7.5-7.7 (m, 4H). HRMS (MALDI) m/z = 405.0130 (MH⁺), Calcd. for C₁₇H.₁₆BrF₃OS-H⁺ = 405.0130.

Next, 0.61 g (1.5 mmol) of 3-bromo-2-cyclohexyloxy-5-(4-trifluoromethyl)phenylthiophene was placed in a 50 mL three-necked flask purged with argon, and anhydrous tetrahydrofuran was added. mL was added and cooled to -78°C. 1.2 mL (1.9 mmol) of 1.6 M n-butyllithium hexane solution was slowly added dropwise and stirred for 1.5 hours. 0.1 mL (0.75 mmol) of octafluorocyclopentene was slowly added and stirred for 3 hours. Water was added to stop the reaction, and the mixture was extracted with ether. It was salted out with a saturated aqueous sodium chloride solution and dried with magnesium sulfate. Thereafter, silica gel column chromatography using hexane:ethyl acetate = 9:1 as a developing solvent was performed, and further purification was performed by HPLC (hexane:ethyl acetate = 95:5) to obtain a compound represented by the following formula (1a). Obtained.
Yield 200 mg, Yield 16%
¹H NMR (300 MHz, CDCl₃, TMS) δ = 1.1-1.8 (m, 10H), 4.0-4.1 (m, 2H), 7.25 (s, 2H), 7.5-7.7 (m, 8H). HRMS (MALDI) m/z = 824.1644 (M⁺), Calcd. for C₃₉H.₃₂F.₁₂O.₂S.₂ ⁺ = 824.1647.

(Example 2)
A compound represented by formula (1b) was synthesized by the following method. First, 3-bromo-2-cyclohexyloxy-5-(4-cyanophenyl)thiophene was synthesized by the following procedure. 3,5-dibromo-2-cyclohexyloxythiophene [reference: K.K. Morimitsu, K.; Shibata, S.; Kobatake, M.; Irie, J. Org. Chem. , 67, 4574-4578 (2002)] 4.0 g (12 mmol) was added, 200 mL of anhydrous tetrahydrofuran was added, and the mixture was cooled to -78°C. 8.0 mL (13 mmol) of 1.6 M n-butyllithium hexane solution was slowly added dropwise and stirred for 1 hour. 3.5 mL (13 mmol) of tributyl borate was slowly added dropwise and stirred for 1 hour. Water was added to stop the reaction, transferred to a 500 mL eggplant-shaped flask, and 2.2 g (12 mmol) of p-bromobenzonitrile, 200 mg of Pd(PPh ₃ ) ₄ and 20 mL of 20 wt% sodium carbonate aqueous solution were added. , and refluxed at 80° C. for 6 hours. Neutralized with dilute hydrochloric acid and extracted with ether. It was salted out with a saturated aqueous sodium chloride solution and dried with magnesium sulfate. Thereafter, it was isolated by silica gel column chromatography using hexane:ethyl acetate=8:2 as a developing solvent, and further purified by recycle HPLC.
Yield 1.7 g, Yield 40%
¹ H NMR (300 MHz, CDCl ₃ , TMS) δ = 1.3-2.1 (m, 10H), 4.1-4.2 (m, 1H), 7.11 (s, 1H),
7.5-7.7 (m, 4H).

Next, 1.2 g (3.3 mmol) of 3-bromo-2-cyclohexyloxy-5-(4-cyanophenyl)thiophene was placed in a 50 mL three-necked flask purged with argon, and 20 mL of anhydrous tetrahydrofuran was added. In addition, it was cooled to -78°C. 2.2 mL (3.5 mmol) of 1.6 M n-butyllithium hexane solution was slowly added dropwise, 0.20 mL (1.5 mmol) of octafluorocyclopentene was slowly added, and the mixture was stirred for 4 hours. Water was added to stop the reaction, and the mixture was extracted with ether. It was salted out with a saturated aqueous sodium chloride solution and dried with magnesium sulfate. It was isolated by silica gel column chromatography using hexane:ethyl acetate = 8:2 as a developing solvent, and further purified by recrystallization to obtain a compound represented by the following formula (1b).
Yield 72 mg, Yield 5.9%
¹ H NMR (300 MHz, CDCl ₃ , TMS) δ = 1.1-1.8 (m, 10H), 4.0-4.1 (m, 2H), 7.30 (s, 2H),
7.5-7.7 (m, 8H).

(Example 3)
A compound represented by formula (1c) was synthesized by the following method. First, 3-bromo-2-cyclohexyloxy-5-(4-formylphenyl)thiophene was synthesized by the following procedure. 3,5-Dibromo-2-cyclohexyloxythiophene [reference: K.K. Morimitsu, K.; Shibata, S.; Kobatake, M.; Irie, J. Org. Chem. , 67, 4574-4578 (2002)] 1.4 g (4.0 mmol) was added, dissolved in 60 mL of anhydrous tetrahydrofuran, and cooled to -80°C. 2.8 mL (4.5 mmol) of 1.6 M n-butyllithium hexane solution was slowly added dropwise and stirred for 1 hour. 1.2 mL (4.5 mmol) of tolubutyl borate was slowly added dropwise, and the mixture was stirred for 1 hour. After adding water to stop the reaction and returning to room temperature, 0.67 g (3.6 mmol) of p-bromobenzaldehyde, 80 mg of Pd(PPh ₃ ) ₄ and 6.5 mL of 20 wt% sodium carbonate aqueous solution were added. , the set temperature of the oil bath was set to 80° C., and the mixture was refluxed for 7 hours. After returning to normal temperature, it was neutralized with dilute hydrochloric acid and extracted with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, filtered to remove magnesium sulfate, and concentrated. Thereafter, it was isolated by silica gel column chromatography (R _f = 0.4) using hexane:ethyl acetate = 9:1 as a developing solvent, and purified by recrystallization using acetone and hexane.
Yield 0.72 g, Yield 49%
¹ H NMR (300 MHz, CDCl ₃ , TMS): δ = 1.3-2.1 (m, 10H), 4.1-4.2 (m, 1H), 7.15 (s, 1H), 7.60 (dt, _J1 = 8.4 Hz, _J2 = 1.8 Hz, 2H), 7.85 (dt, _J1 = 8.4 Hz, _J2 = 1.8 Hz, 2H), 9.98 (s, 1H). MS m/z = 365.0204 (MH ⁺ ), Calcd. _{for C17H17BrO2S.H} ⁺ ₌ 365.0205.

3-bromo-2-cyclohexyloxy-5-(4-formylphenyl)thiophene 0.90 g (2.5 mmol), p-toluenesulfonic acid 4.7 mg (0.025 mmol), ethylene glycol 1.4 mL (25 mmol) was dissolved in 30 mL of toluene, a Dean-Stark condenser was attached, an oil bath was set at 160° C., and reflux was performed for 2 hours. After returning to room temperature, extraction was performed with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, filtered to remove magnesium sulfate, and concentrated. Then, it was separated by silica gel column chromatography (R _f = 0.4) using hexane:ethyl acetate = 9:1 as a developing solvent, and purified by recrystallization using acetone and hexane.
Yield 0.85 g, Yield 84%
¹ H NMR (300 MHz, CDCl ₃ , TMS): δ = 1.6-1.8 (m, 10H), 4.0-4.2 (m, 5H), 5.8 (s, 1H), 7.0 (s, 1H), 7.4-7.5 (m, 4H).
MS m/z = 409.0466 _{( MH} ^<+ >), Calcd for _{C19H21BrO3S.H} <^+> = 409.0468.

Next, 2-(4-(4-bromo-5-cyclohexyloxythiophen-2-yl)phenyl)-1,3-dioxane 1.3 g (3.1 mmol) was added, dissolved in 20 mL of anhydrous tetrahydrofuran, and cooled to -80°C. 2.2 mL (3.5 mmol) of 1.6 M n-butyllithium hexane solution was slowly added and stirred for 1 hour. 0.20 mL (1.5 mmol) of octafluorocyclopentene was slowly added and stirred for 4 hours. A small amount of water was added to stop the reaction, the temperature was returned to normal temperature, and the mixture was extracted with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, filtered to remove magnesium sulfate, and concentrated. Then, it was isolated by silica gel column chromatography (R _f =0.4) using hexane:ethyl acetate=8:2 as a developing solvent. Acetone and a small amount of dilute hydrochloric acid were added thereto, and the mixture was stirred at 50° C. for 30 minutes. After extraction with diethyl ether, the organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, filtered to remove magnesium sulfate, and concentrated. Thereafter, it was isolated by silica gel column chromatography (R _f = 0.2) using hexane:ethyl acetate = 8:2 as a developing solvent, and purified by recrystallization using acetone and hexane.
Yield: 0.64 g, Yield: 57%
¹ H NMR (300 MHz, CDCl ₃ , TMS): δ = 1.1-1.8 (m, 20H), 4.1 (m, 2H), 7.35 (s, 2H), 7.62 ( d, J = 8.3 Hz, 4H), 7.87 (d, J = 8.3 Hz, 4H), 9.99 (s, 2H)
MS m/z = 745.1873 (MH ⁺ ), Calcd. _{for C39H34F6O4S2.H + =} ^745.1876 _.

(Example 4)
A compound represented by formula (1d) was synthesized by the following method. First, according to the following procedure, 3,5-dibromo-2-cyclohexyloxythiophene was added to an argon-substituted four-necked flask [reference: K.K. Morimitsu, K.; Shibata, S.; Kobatake, M.; Irie, J. Org. Chem. , 67, 4574-4578 (2002)] 1.2 g (3.4 mmol) was added, dissolved in 60 mL of anhydrous tetrahydrofuran, and cooled to -80°C. 2.4 mL (3.8 mmol) of 1.6 M n-butyllithium hexane solution was slowly added dropwise and stirred for 1 hour. Next, 1.1 mL (4.1 mmol) of tributyl borate was slowly added dropwise and stirred for 1 hour. After adding water to stop the reaction and returning to room temperature, 1.2 g (3.4 mmol) of 3,5-bis(trifluoromethyl)iodobenzene, 80 mg of Pd(PPh ₃ ) ₄ and 20 wt% sodium carbonate. 6.0 mL of the aqueous solution was added, the set temperature of the oil bath was set to 80° C., and the mixture was refluxed for 7 hours. After returning to normal temperature, it was neutralized with dilute hydrochloric acid and extracted with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, filtered to remove magnesium sulfate, and concentrated. Then, it was separated by silica gel column chromatography (R _f = 0.3) using hexane as a developing solvent, and purified by HPLC (developing solvent: hexane).
Yield 1.1 g, Yield 66%
¹ H-NMR (300 MHz, CDCl ₃ , TMS): δ = 1.3-2.1 (m, 2H), 4.1-4.3 (m, 1H), 7.14 (s, 1H) , 7.72 (s, 1H), 7.84 (s, 2H).
_MS m/z = 471.9927 (M ⁺ ₎ , Calcd for _C18H15BrF6OS ⁺ = 471.9926.

0.72 g (1.5 mmol) of 3-bromo-2-cyclohexyloxy-5-(3,5-bis(trifluoromethyl))phenylthiophene was added to a three-necked flask purged with argon, and anhydrous tetrahydrofuran was added. mL and cooled to -80°C. 1.2 mL (1.9 mmol) of 1.6 M n-butyllithium hexane solution was slowly added and stirred for 30 minutes. 0.10 mL (0.75 mmol) of octafluorocyclopentene was slowly added and stirred for 4 hours. A small amount of water was added to stop the reaction, the temperature was returned to normal temperature, and the mixture was extracted with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, filtered to remove magnesium sulfate, and concentrated. Thereafter, it was isolated by silica gel column chromatography (R _f = 0.4) using hexane as a developing solvent, and further purified by recrystallization using hexane.
Yield 0.17 g, Yield 22%
¹ H-NMR (300 MHz, CDCl ₃ , TMS): δ = 1.1-1.8 (m, 20H), 4.0-4.2 (m, 2H), 7.27 (s, 2H) , 7.73 (s, 2H), 7.83 (s, 4H).
MS m/z = 960.1396 (M ⁺ ), Calcd. _{for C41H30F18O2S2 + =} ^960.1394 _.

(Reference example 2)
A compound represented by formula (3) was synthesized by the following method. First, according to the following procedure, 3,5-dibromo-2-cyclohexyloxythiophene was added to an argon-substituted four-necked flask [reference: K.K. Morimitsu, K.; Shibata, S.; Kobatake, M.; Irie, J. Org. Chem. , 67, 4574-4578 (2002)] 1.0 g (3.0 mmol) was added, dissolved in 50 mL of anhydrous tetrahydrofuran, and cooled to -80°C. 2.1 mL (3.4 mmol) of 1.6 M n-butyllithium hexane solution was slowly added dropwise and stirred for 1 hour. Next, 1.0 mL (3.7 mmol) of tolubutyl borate was slowly added dropwise and stirred overnight. After adding water to stop the reaction and returning the temperature to room temperature, 0.64 g (2.7 mmol) of p-iodoanisole, 70 mg of Pd(PPh ₃ ) ₄ and 5.0 mL of a 20 wt% sodium carbonate aqueous solution were added. , the set temperature of the oil bath was set to 80° C., and the mixture was refluxed for 7 hours. After returning to normal temperature, it was neutralized with dilute hydrochloric acid and extracted with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, filtered to remove magnesium sulfate, and concentrated. Then, it was separated by silica gel column chromatography (R _f =0.6) using hexane:ethyl acetate=8:2 as a developing solvent, and further purified by recycle HPLC.
Yield: 0.70 g, Yield: 64%
¹ H-NMR (300 MHz, CDCl ₃ , TMS): δ = 1.3-2.1 (m, 10H), 3.82 (s, 3H), 4.1-4.2 (m, 1H) , 6.83 (s, 1H), 6.89 (dt, _J1 = 9.5 Hz, _J2 = 2.5 Hz, 2H), 7.39 (dt, _J1 = 9.5 Hz, J ₂ = 2.5Hz, 2H).
MS m/z = 366.0284 (M ⁺ ). Calcd. for _C17H19BrO2S ⁺ ₌ 366.0284 _.

0.55 g (1.5 mmol) of 3-bromo-2-cyclohexyloxy-5-(4-methoxyphenyl)thiophene was added to a three-necked flask purged with argon, dissolved in 10 mL of anhydrous tetrahydrofuran, and heated to -80°C. cooled to 1.2 mL (1.9 mmol) of 1.6 M n-butyllithium hexane solution was slowly added and stirred for 1 hour. 0.10 mL (0.75 mmol) of octafluorocyclopentene was slowly added and stirred for 4 hours. A small amount of water was added to stop the reaction, the temperature was returned to normal temperature, and the mixture was extracted with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, filtered to remove magnesium sulfate, and concentrated. Thereafter, it was isolated by silica gel column chromatography (R _f = 0.4) using hexane:ethyl acetate = 9:1 as a developing solvent, and purified by recrystallization using acetone and hexane.
Yield 78 mg, Yield 14%
¹ H-NMR (300 MHz, CDCl ₃ , TMS): δ = 1.1-1.8 (m, 20H), 3.8 (s, 6H), 4.0 (m, 2H), 6.9 (dt, _J1 = 9.3 Hz, _J2 = 2.5 Hz, 4H), 7.0 (s, 2H), 7.4 (dt, _J1 = 9.3 Hz, _J2 = 2.5 Hz) 5Hz, 4H).
MS m/z = 748.2109 (M ⁺ ), Calcd. _{for C39H38F6O4S2 + = 748.2110} ^.

<Evaluation of photoreactivity>
Compounds (1a), (1b), (1c), (1d) and (3) are each dissolved in a solvent (concentration: about 10 ^-5 mol/L), and the UV-visible absorption spectrum in the solution is measured. and determined the maximum absorption wavelength and molar extinction coefficient of the open-ring form. As a solvent, hexane was used for compounds (1a), (1d) and (3), and dichloromethane was used for compounds (1b) and (1c). The closed-ring form of each compound was colored by irradiation with ultraviolet light, separated by HPLC, and the ultraviolet-visible absorption spectrum in the solution was measured to determine the maximum absorption wavelength and molar extinction coefficient. The ring-closing reaction quantum yield was measured by extracting light at 313 nm from a 200 W mercury-xenon light source with a cut filter and a monochromator, irradiating the solution of each compound in a quartz cell, and monitoring the reacted ring-closing isomers. The relative reaction rates were determined by , and compared with the quantum yields of existing compounds. The ring-opening reaction quantum yield was measured by using a cut filter and a monochromator from a 300 W xenon light source, extracting light corresponding to the absorption maximum wavelength λ _max of the closed ring, and adding it to the solution of each compound in a quartz cell. It was determined by irradiation, determination of the reduction rate of the closed-ring form, and comparison with the quantum yield of existing compounds. Table 1 shows the results. Regarding the compound (III) described in Patent Document 1, the data described in "K. Morimitsu et al., J. Org. Chem., 67, 4574-4578 (2002)." written together.

<Evaluation of thermal fading and determination of half-life t _1/2 >
Compounds (1a), (1b), (1c), (1d) and (3) were each dissolved in toluene, placed in an optical cell, and degassed and sealed. It was irradiated with ultraviolet light to color and produce a closed-ring form. The absorbance at the maximum absorption wavelength in the colored state was measured, the optical cell was placed in a constant temperature bath, the optical cell was taken out after the lapse of a predetermined time, and the absorbance at the maximum absorption wavelength in the colored state was measured. It was cooled to a constant temperature using a cryostat, and then irradiated with ultraviolet light in the cooled state to produce a closed-ring form. Then, the cell was allowed to stand, and the thermal fading reaction at each temperature was tracked by plotting the change in absorbance at the absorption maximum wavelength of the closed-ring form against time. Assuming that the thermal bleaching reaction is a first-order reaction for the obtained data, plotting the natural logarithm ln (Abs/Abs ₀ ) of the value obtained by dividing the absorbance Abs at a certain time by the initial absorbance Abs ₀ against time, The decay becomes linear, indicating that the thermal bleaching reaction is first order reaction. The reaction rate constant k (s ⁻¹ ) at each temperature is calculated from the slope of the straight line of this first-order reaction, and the reaction rate constant is plotted against the temperature (1/T) (Arrhenius plot) to obtain a straight line. Activation energy E _a and frequency factor A in the thermal bleaching reaction are obtained from the slope and the intercept. Using the obtained E _a and A, the reaction rate constant k at temperatures of 150° C., 120° C., and 30° C. was calculated, respectively, and t _1/2 ( ₁₅₀ °C), t _1/2 (120 °C), and t _1/2 (30 °C) were determined respectively. Table 2 shows the results. Regarding the compound (III) described in Patent Document 1, the data described in "K. Morimitsu et al., J. Org. Chem., 67, 4574-4578 (2002)." written together.

Claims (7)

A diarylethene compound represented by the following general formula (1).

[In formula (1), ring A represents a 5-membered ring structure or a 6-membered ring structure,
Y ¹ and Y ² are each independently C or N;
R ¹ and R ² are each independently an optionally substituted branched or cyclic hydrocarbon group having 3 or more carbon atoms,
^R is a hydrogen atom, a phenyl group, an alkyl group, ^an alkoxy group, or a cyano group when Y is C; an electron pair when ^Y is N;
^R is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group when Y ^is C; an electron pair when ^Y is N;
X ¹ n and X ² n are each independently n electron-withdrawing groups bonded to a benzene ring, the electron-withdrawing groups being fluorine atoms and fluorine-containing alkyl having 1 to 6 carbon atoms; group, cyano group, or formyl group, and n is an integer of 1-5. ] The ring A is a 5-membered ring structure,
each of Y ¹ and Y ² is C;
R ¹ and R ² are each independently an optionally substituted branched or cyclic hydrocarbon group having 3 or more carbon atoms,
R ³ and R ⁴ are each independently a hydrogen atom, a phenyl group, or an alkyl group having 1 to 5 carbon atoms,
2. The diarylethene compound according to claim 1, wherein X ¹ n and X ² n are a fluorine atom, a fluorine-containing alkyl group having 1 to 6 carbon atoms , a cyano group, or a formyl group. 3. The diarylethene compound according to claim 2, represented by the following general formula (1A).

[In formula (1A), six Zs are each independently a hydrogen atom or a fluorine atom, and R ¹
, R ² , R ³ , R ⁴ , X ¹ n and X ² n are the same as in claim 2, respectively. ] 4. The diarylethene compound according to claim 3, represented by the following general formula (1B), (1C), (1D) or (1E).

[In formulas (1B) to (1E), six Z, R ¹ , R ² , R ³ and R ⁴ are the same as in claim 3, respectively. ] A diarylethene compound represented by the following formula.

[In each of the above general formulas, R ¹ and R ² are each a cyclohexyl group. ] A photochromic material comprising the diarylethene compound according to any one of claims 1 to 5. A display medium comprising the photochromic material of claim 6 .