JP2019151632A - Diarylethene compound, photochromic material, and display medium - Google Patents

Abstract

To provide a diarylethene compound that is colored by ultraviolet irradiation and allows favorable thermal bleaching of the coloring by heating.SOLUTION: The invention provides a diarylethene compound represented by general formula (1) in the figure.SELECTED DRAWING: None

Description

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

  The phenomenon of coloring by irradiation with ultraviolet light and the irradiation of visible light or returning to its original color is called photochromism, and a compound having such characteristics is called a photochromic compound. For example, a diarylethene compound is known as a photochromic compound. It is known that the diarylethene compound is thermally stable in both isomers before and after UV irradiation. It is also known that the physical properties of diarylethene compounds vary depending on the substituents. For example, a compound represented by the following formula (I) exhibits a thermally stable photochromism.

  On the other hand, for example, a compound represented by the following formula (II) is colored when irradiated with ultraviolet rays, and this colored state is stable even under visible light and has a characteristic that 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 returns to its original state 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 can be erased by heating, such as compound (III), is expected to be applied to a display medium, for example.

Patent No. 4025920 Japanese Patent No. 3964231

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

  As described above, a compound that can be colored by irradiation with ultraviolet rays and can be erased by heating, such as compound (III), is expected to be applied to a display medium, for example. For example, the colored photoisomer of compound (III) irradiated with ultraviolet rays is colorless when heated to a very high temperature of 160 ° C. with a half-life of 45 seconds (ie, compound (III)). Return to. In order to utilize the feature of coloring by ultraviolet irradiation and erasing of the coloring by heat, it is necessary to promote 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 that the coloring is favorably thermally faded by heating. Furthermore, 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 present inventor has intensively studied to solve the above problems. As a result, the present inventors have found that the diarylethene compound represented by the following general formula (1) is colored by ultraviolet irradiation, and that the color is thermally faded at a lower temperature or in 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 a branched or cyclic hydrocarbon group having 3 or more carbon atoms which may have a substituent. 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 is 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, or an electron pair when Y ² is N. X ¹ n and X ² n are each independently n electron-withdrawing groups bonded to the benzene ring, and n is an integer of 1 to 5.

  The present invention has been completed by further studies based on such knowledge.

［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, this invention provides the invention of the aspect hung up below.
Item 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 a branched or cyclic hydrocarbon group having 3 or more carbon atoms, which may have a substituent,
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 is 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 is an electron pair when Y ² is N;
X ¹ n and X ² n are each independently n electron-withdrawing groups bonded to the benzene ring, and n is an integer of 1 to 5. ]
Item 2. The ring A is a 5-membered ring structure;
Y ¹ and Y ² are each C;
R ¹ and R ² are each independently a branched or cyclic hydrocarbon group having 3 or more carbon atoms, which may have a substituent,
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 group containing a fluorine atom, a cyano group, or a formyl group.
Item 3. Item 3. The diarylethene compound according to Item 2, represented by the following general formula (1A).

[In the formula (1A), six Z's 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 represented by The same. ]
Item 4. Item 4. The diarylethene compound according to Item 3, represented by the following general formula (1B), (1C), (1D), or (1E).

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

[In 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 light and that is suitably thermally discolored by heating. Furthermore, according to the present invention, a photochromic material containing the diarylethene compound and a display medium containing the photochromic material can also be provided.

  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 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 discoloration by heating (formation of compound (1) by ring-opening reaction). ) Is reversible and can be repeated.

  In the general formula (1), ring A represents a 5-membered ring structure or a 6-membered ring structure. In terms of the three-dimensional structure, the 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 of being colored by irradiation with ultraviolet rays and being favorably thermally discolored by heating. Structure is mentioned.

As a preferable structure of the ring A, for example, a structure represented by the following general formula can be given.

In the above ring structure, the six groups Z are the same or different and each is a hydrogen atom or a fluorine atom, and preferably a fluorine atom from the viewpoint of repeated durability. The six groups Z are preferably all fluorine atoms or hydrogen atoms. In addition, the group R ^c , the group R ^d, and the group R ^e are each independently a phenyl group or an alkyl group which may have a substituent, and preferably a carbon which may have a substituent. Examples thereof include alkyl groups having 1 to 5 numbers. The substituents of the group R ^c , the group R ^d, and the group ^Re are not particularly limited, but preferably each independently include a cyano group, an alkyl group, an alkoxy group, a chloro group, a bromo group, and the like.

In the general formula (1), the group Y ¹ and the 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 a branched hydrocarbon group having 3 or more carbon atoms which may have a substituent, or a cyclic hydrocarbon group which may have a substituent. In the diarylethene compound having the structure represented by the general formula (1), the group R ¹ and the group R ² by ultraviolet irradiation are bonded by changing the number of carbons and the structure of the group R ¹ and the group 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 by ultraviolet irradiation and the reaction rate of thermal fading can be suitably adjusted. The group R ¹ and the group R ² may be different from each other, but are preferably the same. In the present invention, since the group R ¹ and the group R ² are each bonded to the thiophene skeleton via an oxygen atom, the ring-closure reaction by ultraviolet irradiation proceeds favorably and is colored, and visible light Ring-opening reaction due to irradiation is suppressed. That is, the diarylethene compound of the present invention is colored by ultraviolet irradiation, and the coloring is favorably thermally faded by heating, while fading by visible light irradiation is suitably suppressed.

The number of carbon atoms of the groups R ¹ and groups R ^2, preferably about 3 to 12, or more preferably about 3-6. Specific examples of the substituent that the group R ¹ and the group R ² may have include halogen atoms such as a chloro group and a bromo group.

Preferred examples of the group R ¹ and the group R ² from the viewpoint of being favorably colored by ultraviolet irradiation and favorably fading the color by heating at a lower temperature and in a shorter time include isopropyl group, isobutyl group, Examples include alkyl groups having a branched structure such as an isopentyl group; cyclic alkyl groups such as a cyclopentyl group, a substituted cyclopentyl group, a cyclohexyl group, and a substituted cyclohexyl group. Among these, a cyclohexyl group is particularly preferable.

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

In addition, the phenyl group, the alkyl group, and the alkoxy group of the group R ³ and the group R ⁴ may each have a substituent. The substituent is not particularly limited, and examples thereof include a cyano group, an alkyl group, an alkoxy group, a chloro group, and a bromo group.

In the general formula (1), the group X ¹ n and the group X ² n are each independently n electron-withdrawing groups bonded to the benzene ring, and n is an integer of 1 to 5. The group X ¹ and the 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 to 2. In the diarylethene compound of the present invention, the reaction rate by ultraviolet irradiation and the reaction rate of thermal fading can be adjusted by selecting the type of the group OR ¹ , the group OR ² , the group X ¹ , and the group X ² as described above. Further, it can be adjusted by the number of groups X ¹ and X ² and the bonding position on the benzene ring.

The group X ¹ n and the group X ² n are not particularly limited as long as each group has electron withdrawing properties. Examples of the electron withdrawing group include a chlorine atom, a bromine atom, a cyano group, a group containing a fluorine atom, a formyl group, an acetyl group, and a dicyanoethenyl group. Among these, a cyano group, a formyl group, or a group containing a fluorine atom is preferable. Examples of the group containing a fluorine atom include a fluorine atom and a fluorine-containing alkyl group. The fluorine-containing alkyl group is preferably a perfluoroalkyl group in which all hydrogen atoms of the alkyl group are substituted with fluorine atoms. Moreover, about 1-6 are preferable about carbon number of a fluorine-containing alkyl group. Specific examples of the fluorine-containing alkyl group include a trifluoromethyl group, a pentafluoroethyl group, and a trifluoroethyl group.

  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 being favorably thermally faded by heating at a lower temperature and in a shorter time. It is preferable.

In general formula (1A), six Z's 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 those described above. The same thing as what was illustrated by Formula (1) is mentioned.

  More specifically, the diarylethene compound of the present invention is preferably represented by the following general formula (1B), from the viewpoint of being colored by irradiation with ultraviolet light and suitably fading the coloration by heating at a lower temperature and in a shorter time. It is more preferable to have a structure represented by (1C), (1D) or (1E).

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

  Although it does not restrict | limit especially as a color (color before ring closure by ultraviolet irradiation) of the diarylethene compound of this invention, Preferably it is colorless and transparent.

In addition, the diarylethene compound of the present invention has absorption in the visible region after irradiation with ultraviolet light. For example, the ring-closed form of the diarylethene compound of the present invention (carbon atoms to which the groups R ¹ and R ² are bonded are bonded to each other). The 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 ring-closed body 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 and more preferably about 0.3 to 1 from the viewpoint of being rapidly colored by ultraviolet irradiation. In addition, the ring-opening reaction quantum yield of the ring-closed product 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. Can be mentioned. In addition, the ring-closing reaction quantum yield and the ring-opening reaction quantum yield mean the value measured by the method as described in an Example, respectively.

Moreover, the diarylethene compound of the present invention is colored by ultraviolet irradiation, and the coloring can be favorably thermally faded by heating. The activation energy E _a in the thermal discoloration reaction of the ring-closed product can be adjusted, for example, in the range of 100 to 120 kJmol ⁻¹ . The half-life t _1/2 of thermal fading can be appropriately adjusted according to the target thermal fading temperature and speed, but coloring by ultraviolet irradiation can be rapidly fading by heating at a lower temperature. From the viewpoint, the half-life t _1/2 of thermal fading at 150 ° C. is preferably about 10 to 60 seconds, more preferably about 10 to 40 seconds. The half-life t _{1 /} of thermal fading at 120 ° C. ₂ is preferably about 1 to 10 minutes, more preferably about 1 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 each mean a value measured by the method described in the examples. As described above, in the present invention, the reaction rate by ultraviolet irradiation and the reaction rate of thermal fading are specifically selected by selecting the type of the group OR ¹ , the group OR ² , the group X ¹ , and the group X ² , It is adjusted by the number of groups X ¹ and X ² and the bonding position 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) and the like).

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

  In the production of the diarylethene compounds of the present invention, the reaction conditions such as the starting materials, their use amounts and ratios, temperature, time, pressure, atmosphere, and solvent type and use amount depend on the structure of the diarylethene compounds to be produced. May be set as appropriate. Moreover, it is confirmed by a general organic analysis technique such as nuclear magnetic resonance spectroscopy (NMR) and mass spectrometry as shown in the examples that the prepared compound is the desired diarylethene compound (1). be able to.

In the diarylethene compound (1) of the present invention, for example, as represented by the following reaction formula, two carbon atoms to which the groups OR ¹ and OR ² are bonded are bonded to each other by irradiation with ultraviolet light. Is formed (ring closure) to give a discolored (colored) compound (2). As for this coloring, the diarylethene compound of the present invention can maintain the coloring in an environment where ultraviolet rays are not irradiated, and fading proceeds by heating. Further, the coloring is stable under visible light.

The reaction rate when the diarylethene compound of the present invention forms a ring structure upon irradiation with ultraviolet light to become the compound represented by the general formula (2) and the thermal fading reaction rate of the reverse reaction are 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 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 further the group X ¹ Depending on the number of n and group X ² n, the bonding position on the benzene ring, and the like, the reaction rate by ultraviolet irradiation and the reaction rate of thermal fading can be adjusted.

  Moreover, the reaction rate by ultraviolet irradiation and the reaction rate of thermal fading can be adjusted by using a plurality of types of the diarylethene compound of the present invention. For example, the temperature and speed of thermal fading can be adjusted by using a mixture of a plurality of types of diarylethene compounds having different thermal fading reaction rates.

  As described above, the diarylethene compound of the present invention can be colored by irradiation with ultraviolet rays, and the coloring can be faded at a suitable heating temperature and time. For example, the diarylethene compound can be suitably used as a photochromic material used for a display medium or the like. can do.

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

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

  The display medium of the present invention can have, for example, a configuration in which a photochromic material is dispersed in a resin. It does not restrict | limit especially as content of the photochromic material in a display medium, For example, about 1-20 mass% is mentioned. Moreover, it does not restrict | limit especially as resin, A thermoplastic resin, a thermosetting resin, etc. can be used. Specific examples of the resin include polyolefin, acrylic resin, vinyl chloride resin, urethane resin, and styrene resin. There may be one kind of resin in the display medium, or two or more kinds.

  The diarylethene compound of the present invention can be used not only for display media but also for a wide range of uses such as printing on textile products, cosmetics, playground equipment, printing ink, decorative materials, toys, information recording materials, display materials, etc. it can.

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

( ¹ HNMR)
Intermediate compounds and diarylethene compounds were identified using a nuclear magnetic resonance spectrometer (manufactured by Bruker BioSpin KK, model: AV-300N). Deuterated chloroform was used as a solvent, and tetramethylsilane was used as a reference substance.

(Mass spectrometry)
Intermediate compounds and diarylethene compounds 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 with high resolution.

Example 1
The compound represented by the 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 [document description: K. et al. Morimitsu, K.M. Shibata, S .; Kobatake, M.M. Irie, J. et al. 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. 1.6 M n-butyllithium hexane solution 2.5 mL (4.0 mmol) was slowly added dropwise and stirred for 1 hour. Tributyl borate 1.5 mL (5.6 mmol) was slowly added dropwise and stirred for 1 hour. The reaction was stopped by adding water, transferred to a 200 mL eggplant type flask, p-iodobenzotrifluoride 0.98 g (3.62 mmol), Pd (PPh ₃ ) ₄ 80 mg, 20 wt% aqueous sodium carbonate solution 6 mL. And refluxed at 80 ° C. for 5 hours. Neutralized with dilute hydrochloric acid and extracted with ether. Salting out was carried out with a saturated aqueous sodium chloride solution and dried over magnesium sulfate. After that, 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%
¹ H NMR (300 MHz, CDCl ₃ , 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 C ₁₇ H ₁₆ BrF ₃ OS · 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 10 mL was added and cooled to -78 ° C. 1.6 M (1.9 mmol) of 1.6 M n-butyllithium hexane solution was slowly added dropwise and stirred for 1.5 hours. Octafluorocyclopentene 0.1 mL (0.75 mmol) was slowly added and stirred for 3 hours. The reaction was stopped by adding water and extracted with ether. Salting out was carried out with a saturated aqueous sodium chloride solution and dried over magnesium sulfate. Thereafter, silica gel column chromatography using hexane: ethyl acetate = 9: 1 as a developing solvent is performed, and further purified by HPLC (hexane: ethyl acetate = 95: 5) to obtain a compound represented by the following formula (1a). Obtained.
Yield 200 mg, Yield 16%
¹ H NMR (300 MHz, CDCl ₃ , 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 C ₃₉ H ₃₂ F ₁₂ O ₂ S ₂ ⁺ = 8244.1647.

(Example 2)
The 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 [document description: K. et al. Morimitsu, K.M. Shibata, S .; Kobatake, M.M. Irie, J. et al. 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. 1.6 M n-butyllithium hexane solution 8.0 mL (13 mmol) 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. The reaction was stopped by adding water, transferred to a 500 mL eggplant-shaped flask, and added with p-bromobenzonitrile 2.2 g (12 mmol), Pd (PPh ₃ ) ₄ 200 mg, 20 wt% aqueous sodium carbonate solution 20 mL. , And refluxed at 80 ° C. for 6 hours. Neutralized with dilute hydrochloric acid and extracted with ether. Salting out was carried out with a saturated aqueous sodium chloride solution and dried over magnesium sulfate. After that, 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, 40% yield
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. 1.6 M n-butyllithium hexane solution 2.2 mL (3.5 mmol) was slowly added dropwise, octafluorocyclopentene 0.20 mL (1.5 mmol) was slowly added, and the mixture was stirred for 4 hours. The reaction was stopped by adding water and extracted with ether. Salting out was carried out with a saturated aqueous sodium chloride solution and dried over magnesium sulfate. The product 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)
The 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. Argon-substituted 200 mL four-necked flask was charged with 3,5-dibromo-2-cyclohexyloxythiophene [document description: K. et al. Morimitsu, K.M. Shibata, S .; Kobatake, M.M. Irie, J. et al. 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. 1.6 M n-butyllithium hexane solution 2.8 mL (4.5 mmol) was slowly added dropwise and stirred for 1 hour. Tolubutyl borate 1.2 mL (4.5 mmol) was slowly added dropwise and stirred for 1 hour. The reaction was stopped by adding water, and after returning to room temperature, 0.67 g (3.6 mmol) of p-bromobenzaldehyde, 80 mg of Pd (PPh ₃ ) ₄ , 6.5 mL of a 20 wt% aqueous sodium carbonate solution was added. Then, the set temperature of the oil bath was set to 80 ° C. and refluxed for 7 hours. After returning to room temperature, the mixture 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, removed by filtration, and concentrated. After that, 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, J 1 = 8.4} Hz, J 2 = 1.8 Hz, 2H), 7.85 (dt, J 1 = 8.4 Hz, J 2 = 1.8 Hz, 2H), 9.98 (s, 1H). MS m / z = 365.0204 (MH ^<+> ), Calcd. for C ₁₇ H ₁₇ BrO ₂ S · 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, the oil bath was set at 160 ° C., and refluxed for 2 hours. After returning to room temperature, the mixture was extracted with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, removed by filtration, and concentrated. Then, it isolate _| separated by the silica gel column chromatography ( _Rf = 0.4) which used hexane: ethyl acetate = 9: 1 for the developing solvent, and refine _| 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 C ₁₉ H ₂₁ BrO ₃ S · H ⁺ = 409.0468.

Next, 1.3 g (3.1) of 2- (4- (4-bromo-5-cyclohexyloxythiophen-2-yl) phenyl) -1,3-dioxane was added to a 50 mL three-neck flask purged with argon. mmol) was added, dissolved in 20 mL of anhydrous tetrahydrofuran, and cooled to -80 ° C. 1.6 mL of 1.6 M n-butyllithium hexane solution was slowly added (3.5 mmol) and stirred for 1 hour. Octafluorocyclopentene 0.20 mL (1.5 mmol) was slowly added and stirred for 4 hours. The reaction was stopped by adding a small amount of water, and the temperature was returned to room temperature, followed by extraction with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, removed by filtration, 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 diluted 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 solution of sodium chloride, dried by adding magnesium sulfate, filtered to remove the magnesium sulfate, and concentrated. After that, 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 C ₃₉ H ₃₄ F ₆ O ₄ S ₂ .H ⁺ = 745.1876.

Example 4
The compound represented by formula (1d) was synthesized by the following method. First, according to the following procedure, 3,5-dibromo-2-cyclohexyloxythiophene [document description: K. Morimitsu, K.M. Shibata, S .; Kobatake, M.M. Irie, J. et al. 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. 1.6 M of n-butyllithium hexane solution 2.4 mL (3.8 mmol) 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. Water was added to stop the reaction, and the temperature was returned to normal temperature. Then, 3,5-bis (trifluoromethyl) iodobenzene 1.2 g (3.4 mmol), Pd (PPh ₃ ) ₄ 80 mg, 20 wt% sodium carbonate 6.0 mL of an aqueous solution was added to set the temperature of the oil bath to 80 ° C. and refluxed for 7 hours. After returning to room temperature, the mixture 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, removed by filtration, and concentrated. Then, it isolate _| separated by the silica gel column chromatography ( _Rf = 0.3) which used hexane for the developing solvent, and refine _| purified by HPLC (developing solvent: hexane).
Yield 1.1 g, 66% yield
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 C ₁₈ H ₁₅ BrF ₆ OS ⁺ = 471.9926.

To a three-necked flask purged with argon, 0.72 g (1.5 mmol) of 3-bromo-2-cyclohexyloxy-5- (3,5-bis (trifluoromethyl)) phenylthiophene was added, and anhydrous tetrahydrofuran 10 Dissolved in mL and cooled to -80 ° C. A 1.6 M n-butyllithium hexane solution 1.2 mL (1.9 mmol) was slowly added, and the mixture was stirred for 30 minutes. 0.10 mL (0.75 mmol) of octafluorocyclopentene was slowly added and stirred for 4 hours. The reaction was stopped by adding a small amount of water, and the temperature was returned to room temperature, followed by extraction with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, removed by filtration, and concentrated. After that, 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 C ₄₁ H ₃₀ F ₁₈ O ₂ S ₂ ⁺ = 960.1394.

(Reference Example 2)
The compound represented by Formula (3) was synthesized by the following method. First, according to the following procedure, 3,5-dibromo-2-cyclohexyloxythiophene [document description: K. Morimitsu, K.M. Shibata, S .; Kobatake, M.M. Irie, J. et al. 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 M (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 tolbutyl borate was slowly added dropwise and stirred overnight. The reaction was stopped by adding water, and after returning to room temperature, p-iodoanisole 0.64 g (2.7 mmol), Pd (PPh ₃ ) ₄ 70 mg, 20 wt% sodium carbonate aqueous solution 5.0 mL was added. Then, the set temperature of the oil bath was set to 80 ° C. and refluxed for 7 hours. After returning to room temperature, the mixture 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, removed by filtration, and concentrated. Thereafter, the resultant 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, J 1 = 9.5 Hz, J 2 = 2.5 Hz, 2H), 7.39 (dt, J 1 = 9.5 Hz, J ₂ = 2.5 Hz, 2H).
MS m / z = 366.0284 (M ^<+> ). Calcd. for C ₁₇ H ₁₉ BrO ₂ S ⁺ = 366.0284.

To a three-necked flask purged with argon, 0.55 g (1.5 mmol) of 3-bromo-2-cyclohexyloxy-5- (4-methoxyphenyl) thiophene was added, dissolved in 10 mL of anhydrous tetrahydrofuran, and -80 ° C. Until cooled. A 1.6 M n-butyllithium hexane solution 1.2 mL (1.9 mmol) was slowly added and stirred for 1 hour. 0.10 mL (0.75 mmol) of octafluorocyclopentene was slowly added and stirred for 4 hours. The reaction was stopped by adding a small amount of water, and the temperature was returned to room temperature, followed by extraction with diethyl ether. The organic layer was washed with a saturated aqueous sodium chloride solution, dried by adding magnesium sulfate, removed by filtration, and concentrated. After that, 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, J ₁ = 9.3 Hz, J ₂ = 2.5 Hz, 4H), 7.0 (s, 2H), 7.4 (dt, J ₁ = 9.3 Hz, J ₂ = 2. 5 Hz, 4H).
MS m / z = 748.2109 (M ^<+> ), Calcd. for C ₃₉ H ₃₈ F ₆ O ₄ S ₂ ⁺ = 748.2110.

<Evaluation of photoreactivity>
Compounds (1a), (1b), (1c), (1d) and (3) were each dissolved in a solvent (concentration: about 10 ⁻⁵ mol / L), and an ultraviolet-visible absorption spectrum in the solution was measured. The maximum absorption wavelength and molar extinction coefficient of the ring-opened product were determined. As the solvent, hexane was used for the compounds (1a), (1d) and (3), and dichloromethane was used for the compounds (1b) and (1c). The closed ring of each compound was colored by irradiation with ultraviolet light, and then the closed ring was fractionated by HPLC, the ultraviolet-visible absorption spectrum in the solution was measured, and the maximum absorption wavelength and molar extinction coefficient were determined. The quantum yield of the ring-closing reaction is obtained by extracting light of 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-closed body. Was determined by determining the relative reaction rate and comparing with the quantum yield of existing compounds. The quantum yield of the ring-opening reaction is determined by extracting light corresponding to the absorption maximum wavelength λ _max of the closed ring from a 300 W xenon light source using a cut filter and a monochromator, and applying it to the solution of each compound in the quartz cell. Irradiation was performed to determine the rate of reduction of the ring closure and was compared with the quantum yield of existing compounds. The results are shown in Table 1. For the compound (III) described in Patent Document 1, the data described in “K. Morimitsu et al., J. Org. Chem., 67, 4574-4578 (2002)” is also shown in Table 1. It was written together.

<Evaluation of thermal fading and determination of half-life t1 _{/ 2} >
Compounds (1a), (1b), (1c), (1d) and (3) were dissolved in toluene, put in an optical cell, and degassed and sealed. Irradiated with ultraviolet light, colored to produce a closed ring. The absorbance at the absorption maximum wavelength in the colored state was measured, the optical cell was placed in a thermostatic chamber, the optical cell was taken out after a predetermined time, and the absorbance at the absorption maximum 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. Then, the cell was allowed to stand, and the thermal fading reaction at each temperature was traced by plotting the change in absorbance at the absorption maximum wavelength of the ring-closed body against time. Assuming that the thermal fading reaction is a primary reaction in the obtained data, and plotting the natural logarithm ln (Abs / Abs ₀ ) of the absorbance Abs at a certain time divided by the initial absorbance Abs ₀ against time, The decay was linear and the thermal fading reaction was found to be a primary reaction. The reaction rate constant k (s ⁻¹ ) at each temperature is calculated from the slope of this linear reaction line, and the reaction rate constant is plotted against the temperature (1 / T) (Arrhenius plot). The activation energy E _a and frequency factor A in the thermal fading reaction are determined from the slope and intercept. Using the obtained E _a and A, temperature 150 ℃, 120 ℃, and the reaction rate constant k at 30 ° C. respectively calculated, t _1/2 = ln2 / k using the formula t _1/2 (0.99 ° C.), t _1/2 (120 ° C.), and t _1/2 (30 ° C.). The results are shown in Table 2. For the compound (III) described in Patent Document 1, the data described in "K. Morimitsu et al., J. Org. Chem., 67, 4574-4578 (2002)." It was 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 a branched or cyclic hydrocarbon group having 3 or more carbon atoms, which may have a substituent,
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 is 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 is an electron pair when Y ² is N;
X ¹ n and X ² n are each independently n electron-withdrawing groups bonded to the benzene ring, and n is an integer of 1 to 5. ] The ring A is a 5-membered ring structure;
Y ¹ and Y ² are each C;
R ¹ and R ² are each independently a branched or cyclic hydrocarbon group having 3 or more carbon atoms, which may have a substituent,
R ³ and R ⁴ are each independently a hydrogen atom, a phenyl group, or an alkyl group having 1 to 5 carbon atoms,
The diarylethene compound according to claim 1, wherein X ¹ n and X ² n are a group containing a fluorine atom, a cyano group, or a formyl group. The diarylethene compound of Claim 2 represented by the following general formula (1A).

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

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

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