JP7364202B2 - diarylethene compound - Google Patents

Description

The present invention relates to novel diarylethene compounds. Furthermore, the present invention relates to a photochromic material containing the diarylethene compound, an optical functional element, and a temperature sensor containing the photochromic material.

Advances in freezing and refrigeration technology have made it possible to maintain the quality and safety of foods, medicines, and other goods for long periods of time. Furthermore, with the development and spread of low-temperature transportation technology, a variety of frozen and refrigerated foods are becoming available on the market. For this reason, temperature control of goods during distribution and storage processes is important. For example, if the item is food, if the temperature cannot be maintained at a predetermined level due to an unexpected event such as a power outage, bacteria will breed in the food, causing spoilage and deterioration. Furthermore, as goods are now being distributed internationally, temperature control (safety) of goods during transport by ship under the equator has become an issue in the food logistics industry.

It may be difficult to easily determine just by looking at the article whether the article has been exposed to conditions at or above the control temperature even once. For this reason, attempts have been made to manage the temperature of individual articles, such as low-temperature-preserved foods, by attaching temperature indicators, temperature-sensitive coloring materials, and the like to individual articles. Temperature indicators and temperature-sensitive coloring materials change color when the product is exposed to conditions above the control temperature, and it is desirable that the color change is maintained for a long period of time, that is, the color change is irreversible. .

Various materials and applied technologies have been proposed as temperature indicators and temperature-sensitive coloring materials. For example, Patent Document 1 proposes a temperature history indicator that irreversibly changes color (also referred to as "coloring" or "coloring") at low temperatures and includes a coloring agent layer, a temperature measuring agent layer, and a coloring agent layer. For example, in Patent Document 2, a heat-sensitive recording layer containing a dye precursor as a main component, a color developer that reacts with the dye precursor when heated to form a colored body, a pigment, and a binder is provided on a support. A temperature-indicating label has been proposed in which a permeable layer as a main component, a microcapsule-containing layer containing a temperature-sensitive substance with a melting point of 0° C. or higher, and a protective layer are sequentially laminated.

However, since the temperature history indicators and temperature labels described in Patent Documents 1 and 2 use temperature measuring agents and temperature-sensitive substances that have a specific melting point, the temperature history indicators and temperature labels described in Patent Documents 1 and 2 use temperature measuring agents and temperature sensitive substances, so that after manufacturing the temperature history indicators and temperature labels, It is necessary to maintain the temperature below a specified level during transportation and storage up to the point in time. Also, because the material is irreversible, once it discolors, it can no longer be used. For this reason, it is desirable that these materials include a switch-on mechanism to enable the temperature change mechanism.

As a material (temperature history display material) equipped with such a switch-on mechanism, there is a material using a photochromic compound (photochromic material) which is colored by ultraviolet light irradiation and whose temperature history starts. For example, Patent Document 3 discloses a photochromic material that senses temperature with 10 times the sensitivity of conventional materials and irreversibly erases color depending on the colored state. However, in order to make a photochromic material exhibit such a function, a strong acid such as trifluoromethanesulfonic acid is required. Further, in order to express a predetermined function in a solid state, it is necessary to add acid uniformly, and this addition of acid poses a big problem in the manufacturing process.

Moreover, the present inventor has discovered that the compound described in Non-Patent Document 1 reversibly changes color due to temperature change or irradiation with ultraviolet light or visible light. However, when using this compound as a temperature sensor by irradiating it with ultraviolet light with the compound exposed on the surface of the article, the color produced by the ultraviolet light irradiation does not change under the storage environment of the article. , disappears when exposed to visible light or when the temperature rises. Therefore, there is a problem that the compound cannot be used in an environment where visible light is irradiated.

Furthermore, the present inventors have discovered a compound that, after being colored by irradiation with ultraviolet light, the colored state is extremely stable under visible light, and further disappears irreversibly by heating (Patent Document 4). However, in the compound described in Patent Document 4, the maximum half-life of the colored compound is about 30 hours at 30°C, and if a temperature change occurs at a temperature lower than room temperature, for example, Coloring does not disappear. Therefore, it is difficult to use this compound as a temperature sensor at low temperatures, such as room temperature or lower. In addition, the compound of Non-Patent Document 1 also has the problem that it is difficult to use at low temperatures, in addition to the above-mentioned problem, because the coloring hardly disappears when the temperature changes at a temperature lower than room temperature. have.

Japanese Patent Application Publication No. 10-287863 Japanese Patent Application Publication No. 2004-184920 International publication WO2007/105699 Japanese Patent Application Publication No. 2014-15552

Seiya Kobatake, Hiroyuki Imagawa, Hidenori Nakatani, and Seiichiro Nakashima, “New J. Chem., 2009, 33, 1362-1367”

As mentioned above, conventional photochromic materials, which are used as temperature history display materials, have the problem of slightly discoloring (also called "fading") even under visible light, so further stability under visible light is required. There is a problem with this. In addition, the present inventor has proposed a compound described in Patent Document 4 as a photochromic material that solves such problems, but in this compound, for example, temperature changes occur at a temperature lower than room temperature. In some cases, the coloring hardly disappears, making it difficult to use it as a temperature sensor at low temperatures. Furthermore, it is desired to develop a compound that does not require the addition of an acid to exhibit its function.

Under these circumstances, the present invention does not require additional components such as acids to produce the coloring phenomenon, has a switching function (coloring by ultraviolet light irradiation), has excellent stability of the colored state under visible light, and The main object of the present invention is to provide a diarylethene compound that can suitably exhibit the function of decoloring that cannot be reproduced by increasing the temperature in a low-temperature environment (for example, below room temperature). Furthermore, another object of the present invention is to provide a photochromic material containing the diarylethene compound, an optical functional element, a temperature sensor, etc. containing the photochromic material.

The present inventor conducted extensive studies to solve the above problems. As a result, the diarylethene compound represented by the following general formula (1) does not require additional components such as acids to develop a coloring phenomenon, has a switching function (coloring by ultraviolet light irradiation), and has a visible light under colored state. It has been found that it has excellent stability at low temperatures, and also preferably exhibits the function of decoloring, which cannot be reproduced by increasing the temperature in a low-temperature environment (for example, below room temperature).

In formula (1), ring A represents a 5-membered ring structure or a 6-membered ring structure, X is S, NR ⁷ , or O, R ⁷ is a hydrogen atom or an alkyl group, and Y ¹ and Y ² are each independently C or N, the three R ^1s are each independently an alkyl group or an aromatic group, and the three R ² are each independently an alkyl group or an aromatic group. group, and R ³ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded with R ⁴ to form a ring structure when Y ¹ is C, When Y ¹ is N, it is an electron pair, and when Y ² is C, R ⁵ is a hydrogen atom, phenyl group, alkyl group, alkoxy group, or cyano group, or mutually with R ⁶ . When Y ² is N, it is an electron pair, and R ⁴ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or R ³ and They are bonded to each other to form a ring structure, and R ⁶ is bonded to a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or to R ⁵ to form a ring structure.

The present invention was completed through 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、
Ｘは、Ｓ、ＮＲ⁷、またはＯであり、Ｒ⁷は、水素原子またはアルキル基であり、
Ｙ¹及びＹ²は、それぞれ独立に、ＣまたはＮであり、
３つのＲ¹は、それぞれ独立に、アルキル基または芳香族基であり、
３つのＲ²は、それぞれ独立に、アルキル基または芳香族基であり、
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、あるいはＲ⁴と互いに結合して環構造を形成しており、Ｙ¹がＮである場合には、電子対であり、
Ｒ⁵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、あるいはＲ⁶と互いに結合して環構造を形成しており、Ｙ²がＮである場合には、電子対であり、
Ｒ⁴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、あるいはＲ³と互いに結合して環構造を形成しており、
Ｒ⁶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、あるいはＲ⁵と互いに結合して環構造を形成している。］
項２． 前記環Ａが、５員環構造であり、
前記Ｘは、Ｓであり、
前記Ｙ¹及びＹ²が、それぞれ、Ｃ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のアルキル基であるか、前記Ｒ³とＲ⁴とが互いに結合して６員環構造を形成しており、
前記Ｒ⁵及びＲ⁶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のアルキル基であるか、前記Ｒ⁵とＲ⁶とが互いに結合して６員環構造を形成している、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、Ｒ⁵、及びＲ⁶は、それぞれ、項２と同じである。］
項４． 下記一般式（１Ｂ）で表される、項３に記載のジアリールエテン化合物。

［式（１Ｂ）中、Ｚ、Ｒ¹、Ｒ²、Ｒ³、及びＲ⁵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。

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、光機能素子。
項８． 項６に記載のフォトクロミック材料を含む、温度センサー。That is, the present invention provides the inventions of the following aspects.
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,
X is S, NR ⁷ or O, R ⁷ is a hydrogen atom or an alkyl group,
Y ¹ and Y ² are each independently C or N,
The three R ¹ are each independently an alkyl group or an aromatic group,
The three R ² are each independently an alkyl group or an aromatic group,
When Y ¹ is C, R ³ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded with R ⁴ to form a ring structure, and Y ¹ is N If , it is an electron pair,
When Y ² is C, R ⁵ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded with R ⁶ to form a ring structure, and Y ² is N If , it is an electron pair,
R ⁴ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded with R ³ to form a ring structure,
R ⁶ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded to R ⁵ to form a ring structure. ]
Item 2. The ring A is a 5-membered ring structure,
Said X is S,
Said Y ¹ and Y ² are each C,
The above R ³ and R ⁴ are each independently a hydrogen atom, a phenyl group, or an alkyl group having 1 to 5 carbon atoms, or the above R ³ and R ⁴ are bonded to each other to form a 6-membered ring structure. and
The above R ⁵ and R ⁶ are each independently a hydrogen atom, a phenyl group, or an alkyl group having 1 to 5 carbon atoms, or the above R ⁵ and R ⁶ are bonded to each other to form a 6-membered ring structure. Item 1. The diarylethene compound according to Item 1.
Item 3. The diarylethene compound according to item 2, which is represented by the following general formula (1A).

[In formula (1A), each of the six Z's is independently a hydrogen atom or a fluorine atom, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are each the same as in Item 2. It is. ]
Item 4. Item 3. The diarylethene compound according to item 3, which is represented by the following general formula (1B).

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

Item 6. Item 5. A photochromic material comprising the diarylethene compound according to any one of Items 1 to 5.
Section 7. Item 6. An optical functional element comprising the photochromic material according to item 6.
Section 8. A temperature sensor comprising the photochromic material according to item 6.

According to the present invention, an additional component such as an acid is not required for the expression of the coloring phenomenon, and the switching function (coloring by ultraviolet light irradiation), excellent stability of the colored state under visible light, and furthermore, It is possible to provide a novel diarylethene compound that suitably exhibits the function of non-reproducible discoloration due to temperature rise (for example, below room temperature, further below 0°C, below -20°C, below -30°C, etc.) . Further, according to the present invention, it is possible to provide a photochromic material containing the diarylethene compound, an optical functional element containing the photochromic material, a temperature sensor, and the like.

FIG. 2 is a conceptual diagram of a temperature management identification label having an optical switching function. 2 is a graph showing the relationship between the degree of discoloration (A/A ₀ ) and time (minutes) when the n-hexane solution of the diarylethene compound of Example 1 is colored by irradiating it with ultraviolet light and left at various temperatures. . 2 is a graph showing the relationship between the degree of discoloration (A/A ₀ ) and time (minutes) when the n-hexane solution of the diarylethene compound of Example 2 is colored by irradiating it with ultraviolet light and left at various temperatures. . The relationship between the degree of discoloration (A/A ₀ ) and time (dashed line) when the n-hexane solution of the diarylethene compound of Example 1 was colored by irradiating it with ultraviolet light and left for 10 hours at a temperature of -40 ° C. The relationship between the degree of discoloration (A/A ₀ ) and time (solid line) when left at a temperature of -40°C for 2 hours, then left at a temperature of -20°C for 1 hour, and further left at a temperature of -40°C for 7 hours. This is a graph showing. Relationship between degree of discoloration (A/A ₀ ) and time (dashed line) when the n-hexane solution of the diarylethene compound of Example 2 was colored by irradiating it with ultraviolet light and left for 10 hours at a temperature of -50°C Relationship between degree of discoloration (A/A ₀ ) and time when left at -50°C for 2 hours, then left at -40°C for 1 hour, and further left at -50°C for 7 hours (upper solid line) , and the relationship between the degree of discoloration (A/A ₀ ) and time when left at a temperature of -50°C for 2 hours, then left at a temperature of -30°C for 1 hour, and then left at a temperature of -50°C for 7 hours (see below). This is a graph showing the solid line on the side. The n-hexane solution of the diarylethene compound of Comparative Example 6 was irradiated with ultraviolet light to be colored, and the relationship between the degree of discoloration (A/A ₀ ) and time (dashed line) and temperature when left for 10 hours at a temperature of 10 ° C. It is a graph showing the relationship between the degree of discoloration (A/A ₀ ) and time (solid line) when left at 10°C for 2 hours, then left at 30°C for 1 hour, and further left at 10°C for 7 hours. . The relationship between the degree of discoloration (A/A ₀ ) and time (dashed line) when the n-hexane solution of the diarylethene compound of Comparative Example 9 was colored by irradiating it with ultraviolet light and left for 10 hours at a temperature of -10 ° C. The relationship between the degree of discoloration (A/A ₀ ) and time (solid line) is shown when the sample was left at a temperature of -10°C for 2 hours, then left at a temperature of 10°C for 1 hour, and then left at a temperature of -10°C for another 7 hours. It is a graph.

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

Here, ring A represents a 5-membered ring structure or a 6-membered ring structure. The diarylethene compound of the present invention has the following functions: coloration by ultraviolet light irradiation, excellent stability of the colored state under visible light, and non-reproducible decolorization by temperature rise in low-temperature environments (for example, below room temperature). , is strongly influenced by the reactivity between the sites where the groups SiR ¹ ₃ and SiR ² ₃ are bonded, while the structure of ring A is not so influenced. Therefore, in terms of steric structure, ring A may have either a 5-membered ring structure or a 6-membered ring structure, but preferably a 5-membered ring structure.

Further, in formula (1), the group X is S (sulfur atom), NR ⁷ , or O (oxygen atom). In the group NR ⁷ , the group R ⁷ is a hydrogen atom or an alkyl group. Among these, S is preferred as the group X.

Further, the group Y ¹ and the group Y ² are each independently C (carbon atom) or N (nitrogen atom), preferably C.

From the viewpoint of effectively exhibiting the functions of coloring by ultraviolet light irradiation, excellent stability of the colored state under visible light, and non-renewable decolorization by temperature rise in low-temperature environments (for example, below room temperature). The three R ¹ 's of the group SiR ¹ ₃ are each independently preferably an alkyl group or an aromatic group, more preferably an alkyl group having 1 to 5 carbon atoms or a phenyl group. From the same point of view, each of the three R ² of the group SiR ² ₃ is preferably an alkyl group or an aromatic group, more preferably an alkyl group having 1 to 5 carbon atoms or a phenyl group. . Specific examples of the group SiR ¹ ₃ and the group SiR ² ₃ include, independently, the group Si(CH ₃ ) ₃ , the group Si(CH ₂ CH ₃ ) ₃ , the group Si(CH(CH ₃ ) ₂ ) ₃ , the group Examples include SiC(CH ₃ ) ₃ (CH ₃ )(CH ₃ ), and the group SiC(CH ₃ ) ₃ (Ph) (Ph).

When the group Y ¹ is C, the group R ³ is bonded to a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or to the group R ⁴ to form a ring structure. Further, when the group Y ¹ is N, R ³ is an electron pair. In the group R ³ , the group Y ¹ is C and is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

When the group Y ² is C, the group R ⁵ is bonded to a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or to the group R ⁶ to form a ring structure. Further, when the group Y ² is N, R ⁵ is an electron pair. In the group R ⁵ , the group Y ² is C and is preferably a hydrogen atom or an alkyl group, more preferably a hydrogen atom or an alkyl group having 1 to 3 carbon atoms.

Note that the phenyl group, alkyl group, and alkoxy group of the group R ³ and the group R ⁵ 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, a bromo group, and the like.

The group R ⁴ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded with R ³ to form a ring structure, and is preferably a hydrogen atom, a phenyl group, or a group having 1 carbon number. ~5 alkyl groups are mentioned. The group R ⁶ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded with R ⁵ to form a ring structure, and is preferably a hydrogen atom, a phenyl group, or a group having 1 carbon number. ~5 alkyl groups are mentioned. Among these, it is particularly preferable that the group R ⁴ and the group R ⁶ are each a phenyl group. Note that the phenyl group, alkyl group, and alkoxy group of the group R ⁴ and the group R ⁶ 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, a bromo group, and the like.

A preferable structure of ring A includes, for example, a structure represented by the following general formula.

In these structures, the six groups Z are the same or different and each is a hydrogen atom or a fluorine atom, and is preferably a fluorine atom because of its excellent stability under visible light. It is preferable that all six groups Z are fluorine atoms or hydrogen atoms. Further, as the group R ^c , the group R ^d and the group R ^e , each independently includes a phenyl group and an alkyl group which may have a substituent, and preferably a carbon group which may have a substituent. Examples include alkyl groups having 1 to 5 atoms. 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.

From the viewpoint of effectively exhibiting the functions of coloring by ultraviolet light irradiation, excellent stability of the colored state under visible light, and non-renewable decolorization by temperature rise in low-temperature environments (for example, below room temperature). In the general formula (1), the group X is preferably S (sulfur atom). From the same viewpoint, it is preferable that the group Y ¹ and the group Y ² are each C (carbon atom). Further, the group R ³ and the group R ⁴ are each independently a hydrogen atom, a phenyl group, or an alkyl group having 1 to 5 carbon atoms, or the group R ³ and the group R ⁴ are bonded to each other to form a 6-membered Preferably, it forms a ring structure. Further, the group R ⁵ and the group R ⁶ are each independently a hydrogen atom, a phenyl group, or an alkyl group having 1 to 5 carbon atoms, or the group R ⁵ and the group R ⁶ are bonded to each other to form a 6-membered Preferably, it forms a ring structure. It is preferable that the group R ³ and the group R ⁴ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Moreover, it is particularly preferable that the group R ⁴ and the group R ⁶ are each a phenyl group.

The 6-membered ring structure in which the group R ³ and the group R ⁴ are bonded to each other, and the 6-membered ring structure in which the group R ⁵ and the group R ⁶ are bonded to each other are not particularly limited, but from the viewpoint of effectively exhibiting the above functions. is preferably a benzene ring skeleton.

From the viewpoint of effectively exhibiting the functions of coloring by ultraviolet light irradiation, excellent stability of the colored state under visible light, and non-renewable decolorization by temperature rise in low-temperature environments (for example, below room temperature). The diarylethene compound of the present invention preferably has a structure represented by the following general formula (1A).

In general formula (1A), the six groups Z are each independently a hydrogen atom or a fluorine atom. Further, as for the group R ¹ , the group R ² , the group R ³ , the group R ⁴ , the group R ⁵ , and the group R ⁶ , the same ones as exemplified in the above-mentioned general formula (1) can be mentioned. In general formula (1A), it is preferable that the group R ³ and the group R ⁵ are each independently a hydrogen atom or an alkyl group having 1 to 5 carbon atoms. Preferably, the group R ⁴ and the group R ⁵ are each a phenyl group. Further, the group R ³ and the group R ⁴ may be bonded to each other to form a benzene ring. Similarly, the group R ⁵ and the group R ⁶ may be bonded to each other to form a benzene ring. In general formula (1A), it is particularly preferable that all six Z atoms are fluorine atoms because of excellent stability under visible light.

More specifically, from the viewpoint of effectively exhibiting the above functions, the diarylethene compound of the present invention preferably has a structure represented by the following general formula (1B).

In general formula (1B), the six groups Z, group R ¹ , group R ² , and group R ³ are the same as those exemplified in general formula (1) above, and general formula (1A) The same ones as exemplified above are preferred. Among these, in particular, all six Z are fluorine atoms or hydrogen atoms, the groups R ³ and R ⁵ are independently hydrogen atoms or methyl groups, and the groups SiR ¹ ₃ and SiR ² ₃ are each independently , the group Si(CH ₃ ) ₃ , the group Si(CH ₂ CH ₃ ) ₃ , the group Si(CH(CH ₃ ) ₂ ) ₃ , the group SiC(CH ₃ ) ₃ (CH ₃ )(CH ₃ ), or the group SiC (CH ₃ ) ₃ (Ph) (Ph) is preferred. In general formula (1B), it is particularly preferable that all six Z atoms are fluorine atoms because of excellent stability under visible light.

Among the diarylethene compounds represented by the general formula (1), those having the structure represented by the following formula are particularly preferred from the viewpoint of effectively exhibiting the above functions.

The method for producing the diarylethene compound represented by general formula (1) is not particularly limited, and any known production method can be employed. For example, first, a precursor (1') of the diarylethene compound represented by the general formula (1) is produced in the same manner as the production method described in Non-Patent Document 1. Next, the compound represented by general formula (1) can be produced by oxidizing S (sulfur atom) in the five-membered ring skeleton (thiophene) and converting it into a group SO ₂ (sulfonyl group). can.

The method of oxidizing S in the five-membered ring skeleton of the diarylethene compound precursor (1') to convert it into a group _SO2 is not particularly limited, and for example, the diarylethene compound precursor (1') may be Examples include a method of oxidizing with a peracid such as m-chloroperbenzoic acid.

In the production of the diarylethene compound of the present invention, reaction conditions such as starting materials, their usage amounts and proportions, temperature, time, pressure, atmosphere, and solvent type and usage amount vary depending on the structure of the diarylethene compound to be produced. You can set it as appropriate. In addition, it is confirmed that the produced compound is the desired diarylethene compound (1) 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 of the present invention, for example, as represented by the following formula, two thiophene rings to which SiR ¹ ₃ and SiR ² ₃ are bonded form a ring (ring closure) by irradiation with ultraviolet light. and color it (switching function). This coloring is stable under visible light and below a predetermined temperature (Δ), but is decomposed into by-products when exposed (heated) to conditions above this predetermined temperature (Δ). Because of this, the color disappears (fading). This decolored (bleached) state is stable under ultraviolet light or visible light, and the change from coloring to decoloring is irreversible.

After the diarylethene compound of the present invention forms a ring structure by ultraviolet light irradiation and becomes a compound represented by the above general formula (2), the temperature at which it decomposes into by-products is _set ^to It is influenced by the type of group SiR ² ₃ . For example, the larger the groups R ¹ and R ² of the SiR ¹ ₃ and SiR ² ₃ groups, the more the compound represented by the general formula (2) becomes thermally unstable and is decomposed at lower temperatures and extinguished. color. That is, in the diarylethene compound of the present invention, the coloring can be erased at a desired temperature by adjusting the types of the groups R ¹ and R ² of the SiR ¹ ₃ and SiR ² ₃ groups.

In this way, when the diarylethene compound of the present invention is used in a temperature sensor, the operating temperature (functional temperature) can be changed. Since the diarylethene compound of the present invention has the performance of P-type photochromism that can set a desired operating temperature, the present invention can provide a photochromic material containing the diarylethene compound.

The operating temperature range of the diarylethene compound of the present invention is not particularly limited, but preferably includes room temperature (25°C) or lower, more preferably 0°C or lower, and still more preferably about -30°C to -10°C. That is, the diarylethene compound of the present invention can be colored by irradiation with ultraviolet light and then decolored by raising the temperature in this temperature range.

By disposing the diarylethene compound of the present invention on the surface of an article, it can be suitably used as a temperature sensor or the like. The method for disposing the diarylethene compound on the surface of the article is not particularly limited, and, for example, a coating film of the diarylethene compound may be formed on a base material. Note that the base material is not particularly limited, and examples thereof include paper, cloth, plastic, metal, metal oxide, and the like.

Further, according to the present invention, it is possible to provide an optical functional element containing the above photochromic material. For example, as shown in FIG. 1, temperature increases can be easily managed by combining temperature sensors that can sense various temperatures, selected from temperature sensors containing the diarylethene compound of the present invention and known temperature sensors. Figure 1 shows a temperature sensor unit in which three temperature sensors each sensing different temperatures are installed on a board.From the state before switching (left figure), each temperature sensor is colored by irradiation with ultraviolet light. Temperature control begins (center image), and some temperature sensors turn off due to heating, allowing you to see the temperature progress (history) at a glance (right image).

Furthermore, the diarylethene compound of the present invention can be used in many applications other than temperature sensors. Examples include application examples described in Japanese Patent No. 3964231, ie, optical switching elements, optical memory elements, optical recording media, and the like. When used in an optical switching element, for example, a thin film is formed using the photochromic material containing the diarylethene compound of the present invention, and the optical switching element is manufactured using this thin film. By utilizing the large refractive index change of the photochromic material, it is possible to miniaturize the device, which is preferable.

Further, when used in an optical memory element, for example, a thin film is formed using a photochromic material containing the diarylethene compound of the present invention, and the optical memory element is produced using this as a recording layer. Photon mode recording on the recording layer is preferable because it enables a significant improvement in recording density, and by utilizing multiphoton absorption reactions, three-dimensional recording is also possible, which allows for an improvement in recording capacity. This is even more preferable.

The above thin film can be formed on a substrate by appropriately selecting and setting the materials and conditions to be combined depending on the use (purpose). The substrate may be transparent or opaque to the light used, and is appropriately selected from those commonly used in the art. Specific materials for the substrate include, for example, glass, plastic, paper, and metals such as plate-shaped or foil-shaped aluminum, and among these, plastic is preferable from various points of view. Examples of the plastic include acrylic resin, methacrylic resin, vinyl acetate resin, vinyl chloride resin, nitrocellulose, polyethylene resin, polypropylene resin, polycarbonate resin, polyimide resin, and polysulfone resin.

More specifically, the thin film is prepared by dissolving the diarylethene compound of the present invention in an appropriate solvent together with a binder resin if necessary, and applying the diarylethene compound of the present invention onto a substrate by a known method such as a doctor blade method, a casting method, a spinner method, or a dipping method. It can be formed by coating and drying as appropriate. The film thickness is usually 2 nm to 50 μm, preferably 10 nm to 30 μm.

Examples of the binder resin include (meth)acrylic resins such as phenol resin, polycarbonate resin, polystyrene resin, and methyl poly(meth)acrylate. It is most preferable not to use a binder resin because it generally causes a decrease in the concentration of the diarylethene structure, but when used, it should be used in an amount equal to or less than the same amount as the diarylethene compound of the present invention, more preferably less than half the amount by weight. be. Examples of the solvent include hexane, toluene, xylene, chlorobenzene, methyl ethyl ketone, and ethyl acetate.

The content of the diarylethene compound (1) of the present invention in the thin film is not particularly limited, but may be appropriately set in consideration of its use, absorbance, luminescence intensity, etc. When the thin film is a recording layer of an optical recording medium, it may be provided not only on one side of the substrate but also on both sides. Further, a protective film may be provided on the recording layer for the purpose of improving weather resistance.

The present invention will be explained in more detail in the following examples, but the present invention is not limited thereto. Note that the following ¹ H NMR and mass spectrometry were used to identify the diarylethene compound.

( ^1H NMR, ^13C NMR)
The intermediate compound and 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 (TMS) was used as a reference substance.

(Mass spectrometry)
The mass spectrometer was manufactured by Bruker BioSpin K.K., model: FT-ICR/solariX (MALDI) or manufactured by JEOL Ltd., model: JMS-700/700S (FAB). Intermediate compounds and diarylethene compounds were identified. Ionization was performed using 3-nitrobenzyl alcohol as a matrix.

(Example 1)
A diarylethene compound represented by the following chemical formula was synthesized by the method described in Non-Patent Document 1.

Next, S in one of the thiophene skeletons of the compound was oxidized to a sulfonyl group under the following conditions to synthesize the diarylethene compound of Example 1 represented by the following general formula. First, a diarylethene compound (75 mg, 0.12 mmol) represented by the above chemical formula was placed in a flask, and dichloromethane (3 mL) was added to dissolve it. Next, m-chloroperbenzoic acid (m-CPBA) (70 mg, 0.29 mmol) was added into the flask and stirred overnight. Next, an aqueous sodium bicarbonate solution was added to neutralize the mixture, extraction and salting out were performed with dichloromethane, and the mixture was further dried over magnesium sulfate, filtered, and the solvent was distilled off. Next, it was purified by silica gel chromatography (developing solution: n-hexane: ethyl acetate = 85:15), and further purified by HPLC (developing solvent: n-hexane: ethyl acetate = 95:5). A diarylethene compound represented by the following formula was isolated with a yield of 9.4 mg and a yield of 12%.

¹ H NMR (300 MHz, CDCl ₃ , TMS) of the compound obtained in Example 1: δ = 0.25 (s, 9H), 0.34 (s, 9H), 6.72 (s, 1H), 7.2-7.2 (m, 11H).

(Example 2)
A diarylethene compound represented by the following formula was synthesized by the following procedure.

Synthesis of 3-bromo-2-triethylsilyl-5-phenylthiophene (compound (22))

2.8 mL (20 mmol) of diisopropylamine was placed in a four-necked flask under an argon atmosphere and dissolved in 100 mL of anhydrous THF. ? At 30° C., 9.8 mL (16 mmol) of a 1.6 M n-BuLi hexane solution was slowly added dropwise and stirred for 1 hour. ? A solution of 3.0 g (13 mmol) of compound (21) dissolved in anhydrous THF was added dropwise at 78 °C, and the mixture was stirred for 2 hours, followed by slow dropwise addition of a solution of 2.7 mL (16 mmol) of chlorotriethylsilane dissolved in anhydrous THF. The mixture was stirred for 30 minutes. The mixture was returned to room temperature, stirred overnight, quenched with water, THF was distilled off, extracted with ether, salted out, dried over magnesium sulfate, filtered, and the solvent was distilled off. It was purified by silica gel column chromatography (n-hexane, R _f =0.75).
Yield: 4.1g, yield: 93%
^1H NMR (300MHz, CDCl ₃ , TMS): δ = 0.92-1.05 (m, 15H, CH ₂ CH ₃ ), 7.30-7.40 (m, 4H, Aromatic), 7.55 -7.59 (m, 2H, Aromatic). ^13C NMR (75MHz, _CDCl3 ) δ=3.91, 7.55, 117.96, 125.83, 128.23, 128.41, 129.08, 131.56, 133.35, 149.63 ．． HR-MS (MALDI) m/z = 352.0311 (M ⁺ ). Calcd for C ₁₆ H ₂₁ BrSSi ⁺ =352.0311.

Synthesis of 1-(2-triethylsilyl-5-phenyl-3-thienyl)heptafluorocyclopentene (compound (23))

3.4 g (9.6 mmol) of compound (22) was placed in a four-necked flask under an argon atmosphere and dissolved in 30 mL of anhydrous ether. At -78°C, 6.6 mL (11 mmol) of a 1.6 M n-BuLi hexane solution was slowly added dropwise and stirred for 1.5 hours, and then a solution of 1.9 mL (14 mmol) of octafluorocyclopentene dissolved in anhydrous ether was added dropwise at once. The mixture was stirred for 2 hours. The temperature was returned to room temperature, quenched with water, neutralized, extracted with ether, salted out, dried over magnesium sulfate, filtered, and the solvent was distilled off. It was purified by silica gel column chromatography (n-hexane) (R _f =0.75).
Yield 3.0g, yield 67%
^1H NMR (300MHz, _CDCl3 , TMS): δ=0.82 (q, J=7.6Hz, 6H, _CH2 ), 0.98 (t, J=7.6Hz, 9H, _CH3 ), 7.30-7.43 (m, 4H, Aromatic), 7.61-7.63 (m, 2H, Aromatic). ^13C NMR (75MHz, _CDCl3 ) δ=4.09, 7.25, 125.05, 126.22, 128.49, 128.68, 129.19, 133.15, 140.56, 150.91 ．． HR-MS (MALDI) m/z = 466.1018 (M ⁺ ). Calcd for C ₂₁ H ₂₁ F ₇ SSi ⁺ =466.1016.

Synthesis of 1,2-bis(2-triethylsilyl-5-phenyl-3-thienyl)perfluorocyclopentene (compound (24))

980 mg (2.8 mmol) of compound (22) was placed in a four-necked flask under an argon atmosphere, and dissolved in 10 mL of anhydrous ether. At -78°C, 1.9 mL (3.1 mmol) of a 1.6 M n-BuLi hexane solution was slowly added dropwise and stirred for 2 hours, followed by 1.3 g (2.8 mmol) of compound (23).
A solution dissolved in anhydrous ether was slowly added dropwise and stirred for 2 hours. After returning to room temperature and stirring overnight, the mixture was quenched with water, neutralized, extracted with ether, salted out, dried over magnesium sulfate, filtered, and the solvent was distilled off. It was purified by silica gel column chromatography (n-hexane, R _f =0.50). Thereafter, it was purified by recrystallization.
Yield 380 mg, yield 19%
^1H NMR (300MHz, _CDCl3 , TMS): δ=0.53 (q, J=7.8Hz, 12H, _CH2 ), 0.82 (t, J=7.8Hz, 18H, _CH3 ), 7.29-7.43 (m, 8H, Aromatic), 7.56-7.59 (m, 4H, Aromatic). ^13C NMR (75MHz, _CDCl3 ) δ=3.85, 7.35, 126.16, 126.89, 128.30, 129.15, 133.42, 134.03, 139.53, 150.20 ．． HR-MS (MALDI) m/z = 720.2168 (M+). Calcd for C ₃₇ H ₄₂ F ₆ S ₂ Si ₂ ⁺ =720.2165.

Synthesis of 1-(2-triethylsilyl-5-phenyl-1,1-dioxide-3-thienyl)-2-(2-triethylsilyl-5-phenyl-3-thienyl) perfluorocyclopentene (compound (25))

350 mg (0.49 mmol) of compound (24) was placed in a flask and dissolved in 3.0 mL of dichloromethane. After sufficient exposure to visible light, 300 mg (1.2 mmol) of m-CPBA (70 wt%) was added and stirred overnight. The mixture was neutralized, extracted with dichloromethane, salted out, dried over magnesium sulfate, filtered, and the solvent was distilled off. It was purified by silica gel column chromatography (n-hexane:ethyl acetate = 9:1, R _f =0.35). Thereafter, it was purified by HPLC (n-hexane:ethyl acetate=98:2).
Yield 170mg, yield 48%
^1H NMR (300MHz, CDCl ₃ , TMS): δ = 0.67-0.98 (m, 30H, CH ₂ CH ₃ ), 6.76 (s, 1H, Aromatic), 7.31-7.41 (m, 4H, Aromatic), 7.44-7.46 (m, 3H, Aromatic), 7.53-7.57 (m, 2H, Aromatic), 7.70-7.73 (m, 2H, Aromatic). ^13C NMR (75MHz, _CDCl3 ) δ=2.77, 4.58, 7.08, 7.39, 121.65, 126.28, 126.58, 126.64, 127.07, 128.64 , 129.23, 129.46, 131.10, 132.37, 132.88, 137.09, 140.24, 145.12, 147.40, 151.09. HR-MS (MALDI) m/z = 752.2065 (M ⁺ ). Calcd for C ₃₇ H ₄₂ F ₆ O ₂ S ₂ Si ₂ ⁺ =752.2063.

(Comparative example 1-9)
Diarylethene compounds of Comparative Examples 1-9 having the structures shown in Table 1 below were synthesized by the method described in Patent Document 4.

¹ H NMR (300 MHz, CDCl ₃ , TMS) of the compound obtained in Comparative Example 1: δ = 1.13 (d, J = 7.1 Hz, 6H, CH ₃ ), 1.25 (d, J = 6 .8Hz, 6H, CH ₃ ), 2.72-2.95 (m, 2H, CH), 6.79 (s, 1H, Aromatic), 7.15 (s, 1H, Aromatic), 7.30- 7.47 (m, 6H, Aromatic), 7.53-7.57 (m, 2H, Aromatic), 7.65-7.71 (m, 2H, Aromatic). HR-MS (FAB) m/z=609.1332 ([M+H] ⁺ ). Calcd for C ₃₁ H ₂₇ F ₆ O ₂ S ₂ =609.1357 (M+H).

¹ H NMR (300 MHz, CDCl ₃ , TMS) of the compound obtained in Comparative Example 2: δ = 0.88-1.89 (m, 20 H, CH ₂ ), 2.31-2.51 (m, 2 H , CH), 6.85 (s, 1H, Aromatic), 7.19 (t, J=1.3Hz, 1H, Aromatic), 7.29-7.49 (m, 4H, Aromatic), 7.53 -7.57 (m, 2H, Aromatic), 7.68-7.72 (m, 2H, Aromatic). HR-MS (FAB) m/z=689.1984 ([M+H] ⁺ ). Calcd for C ₃₇ H ₃₅ F ₆ O ₂ S ₂ =689.1983.

¹ H NMR (300 MHz, CDCl ₃ , TMS) of the compound obtained in Comparative Example 3: δ = 0.67-1.28 (m, 12H, CH ₃ ), 1.45-1.88 (m, 4H , CH ₂ ), 2.39-2.60 (m, 2H, CH), 6.86-6.89 (m, 1H, Aromatic), 7.18 (s, 1H, Aromatic), 7.30- 7.49 (m, 6H, Aromatic), 7.55-7.60 (m, 2H, Aromatic), 7.69-7.73 (m, 2H, Aromatic). HR-MS (FAB) m/z=637.1678 ([M+H] ⁺ ). Calcd for C ₃₃ H ₃₁ F ₆ O ₂ S ₂ =637.1670.

¹ H NMR (300 MHz, CDCl ₃ , TMS) of the compound obtained in Comparative Example 4: δ = 0.68-1.54 (m, 20H, alkyl), 2.50-2.68 (m, 2H, CH), 7.86-7.88 (m, 1H, Aromatic), 7.16-7.18 (m, 1H, Aromatic), 7.30-7.48 (m, 6H, Aromatic), 7. 55-7.58 (m, 2H, Aromatic), 7.68-7.74 (m, 2H, Aromatic). HR-MS (FAB) m/z=665.1990 ([M+H] ⁺ ). Calcd for C ₃₅ H ₃₅ F ₆ O ₂ S ₂ =665.1983.

¹ H NMR (300 MHz, CDCl ₃ , TMS) of the compound obtained in Comparative Example 5: δ = 0.64-0.75 (m, 12H, CH ₃ ), 1.01-1.74 (m, 12H , CH ₂ ), 2.24-2.47 (m, 2H, CH), 6.93 (s, 1H, Aromatic), 7.21 (t, J=1.5Hz, 1H, Aromatic), 7. 29-7.51 (m, 6H, Aromatic), 7.55-7.59 (m, 2H, Aromatic), 7.71-7.77 (m, 2H, Aromatic).

¹ H NMR (300 MHz, CDCl ₃ , TMS) of the compound obtained in Comparative Example 6: δ = 0.63-1.61 (m, 28H), 2.34-2.56 (m, 2H, CH) , 6.91 (s, 1H, Aromatic), 7.2-7.5 (m, 7H, Aromatic), 7.5-7.6 (m, 2H, Aromatic), 7.7-7.8 ( m, 2H, Aromatic). HR-MS (FAB) m/z = 720.2524 (M ⁺ ). Calcd for C ₃₉ H ₄₂ F ₆ O ₂ S ₂ =720.2530.

¹ H NMR (300 MHz, CDCl ₃ , TMS) of the compound obtained in Comparative Example 7: δ = 1.03-1.53 (m, 12H, CH ₃ ), 1.86-2.16 (m, 6H , CH ₃ ), 2.73-3.04 (m, 2H, CH), 7.35-7.52 (m, 10H, Aromatic). HR-MS (FAB) m/z=637.1672 ([M+H] ⁺ ). Calcd for C ₃₃ H ₃₁ F ₆ O ₂ S ₂ =637.1670.

¹ H NMR (300 MHz, CDCl ₃ , TMS) of the compound obtained in Comparative Example 8: δ = 0.44-0.93 (m, 12H, CH ₃ ), 1.13-1.83 (m, 12H , CH ₂ ), 2.14 (d, J=4.8Hz, 3H, CH ₃ ), 2.23 (d, J=5.5Hz, 3H, CH ₃ ), 2.26-2.35 (m , 1H, CH), 2.43-2.49 (m, 1H, CH), 7.34-7.61 (m, 10H, Aromatic).

¹ H NMR (300 MHz, CDCl ₃ , TMS) of the compound obtained in Comparative Example 9: δ = 0.63-0.90 (m, 12H, CH ₃ ), 1.14-1.74 (m, 16H , CH ₂ ), 2.14 (d, J=4.9Hz, 3H, CH ₃ ), 2.23 (d, J=5.3Hz, 3H, CH ₃ ), 2.36-2.46 (m , 1H, CH), 2.50-2.59 (m, 1H, CH), 7.32-7.58 (m, 10H, Aromatic). HR-MS (FAB) m/z = 748.2833 (M ⁺ ). Calcd for C ₄₁ H ₄₆ F ₆ O ₂ S ₂ =748.2843.

Test Example 1: Stability Evaluation under Visible Light 5 mg of each diarylethene compound obtained in Examples 1 and 2 and Comparative Examples 1-9 was dissolved in 10 mL of toluene together with 50 mg of polystyrene. Each of the obtained solutions was transferred to a Petri dish, immersed in filter paper, and dried at room temperature (25° C.) for 2 hours. This was left for one day at room temperature and under visible light. As a result, there was no change in the coating film portion of the filter paper for any of the diarylethene compounds obtained in Examples 1 and 2 and Comparative Examples 1-9.

Next, this filter paper was placed at a low temperature of -10°C, and the coated part of the filter paper was exposed to ultraviolet light (wavelength 365 nm) for 10 seconds using an ultraviolet light lamp (manufactured by As One Corporation, model: SLUV-4). When irradiated, all filter papers were colored purple. Next, when these filter papers were placed under the visible light of a fluorescent lamp (ultraviolet light cut) and left as they were at -10°C, no discoloration was observed within 1 hour for the filter paper of Comparative Example 1-9. On the other hand, in the filter papers of Examples 1 and 2, the color faded at almost the same rate as the thermal fading when no visible light was irradiated. From this result, stability at low temperatures and under visible light was confirmed for all of the diarylethene compounds obtained in Examples 1 and 2 and Comparative Examples 1-9.

Test Example 2: Measurement of 1-hour and 0.5-hour half-life temperatures For each diarylethene compound obtained in Examples 1 and 2 and Comparative Examples 1-9, 10-hour, 1-hour, and 0.5-hour half-life temperatures were measured and the possibility of application to temperature sensors was investigated. A n-hexane solution (Examples 1, 2) or a toluene solution (Comparative Example 1-9) of each diarylethene compound was placed in a quartz cell at -10°C to 80°C, sealed, and exposed to ultraviolet light (wavelength 365 nm). was irradiated to confirm its coloration. Note that the concentration of each diarylethene compound is approximately 10 ⁻⁵ mol/L. Leave the cell at that temperature, observe the color change in the cell over time, measure the absorption spectrum using an absorption photometer (manufactured by JASCO Corporation, model: V-560), and measure the absorption spectrum at each temperature. Rate constants were determined. Based on the rate constant, the temperature dependence of the rate constant was determined by Arrhenius plotting, and the 10-hour half-life temperature, 1-hour half-life temperature, and 0.5-hour half-life temperature were determined.

As is clear from the results shown in Table 1, the diarylethene compound of Example 1 has a 10-hour half-life temperature of -36°C, a 1-hour half-life temperature of -21°C, and a 0.5-hour half-life temperature of -16°C. Both have low temperatures, and it can be seen that they can be suitably used as temperature sensors for articles that require temperature control at low temperatures, for example, 0° C. or lower. Further, the diarylethene compound of Example 2 has a 10-hour half-life temperature of -47°C, a 1-hour half-life temperature of -35°C, and a 0.5-hour half-life temperature of -32°C, all of which are low temperatures, such as 0. It can be seen that the present invention can be suitably used as a temperature sensor for articles that require temperature control at low temperatures below .degree. C., further below -20.degree. C. or -30.degree. On the other hand, the diarylethene compounds of Comparative Examples 1 to 9 all have 1-hour and 0.5-hour half-life temperatures exceeding 0°C, and are used as temperature sensors for articles that require temperature control at low temperatures below 0°C. It turns out that it is difficult to do so.

Test example 3: Evaluation 1 of temperature and degree of fading
At temperatures of -20°C, -15°C, -10°C, -5°C, 0°C, 5°C, and 10°C, an n-hexane solution (concentration: about 10 ^-5 mol/L) was placed in a quartz cell, sealed, and colored by irradiation with ultraviolet light (wavelength: 365 nm). Next, the cells were left at each temperature to observe changes in color over time, and absorption spectra were measured using an absorption photometer (manufactured by JASCO Corporation, model: V-560). FIG. 2 shows a graph showing the relationship between the degree of fading (A/A ₀ ) and time (minutes).

From the results shown in FIG. 2, it can be seen that the diarylethene compound obtained in Example 1 fades slowly at a temperature of about -10° C., but significantly fades even after about 10 minutes at 0° C., for example. This result also shows that the diarylethene compound obtained in Example 1 can be suitably used as a temperature sensor for products that require temperature control at low temperatures of 0° C. or lower.

In addition, an n-hexane solution (concentration: about 10 ^-5 mol/L) of the diarylethene compound obtained in Example 2 was added at temperatures of -40°C, -30°C, -20°C, and -10°C. After placing it in a quartz cell and sealing it, it was colored by irradiating it with ultraviolet light (wavelength 365 nm). Next, the cells were left at each temperature to observe changes in color over time, and absorption spectra were measured using an absorption photometer (manufactured by JASCO Corporation, model: V-560). FIG. 3 shows a graph showing the relationship between the degree of color fading (A/A ₀ ) and time (minutes).

From the results shown in Figure 3, the diarylethene compound obtained in Example 2 shows gradual discoloration at temperatures of about -40°C or -30°C, but significant discoloration at -20°C for about 5 minutes, for example. I know that. This result also indicates that the diarylethene compound obtained in Example 2 can be suitably used as a temperature sensor for products that require temperature control at low temperatures below 0°C, further below -20°C or -30°C. I understand.

Test example 4: Evaluation of temperature and degree of fading 2
At -40°C, a solution of the diarylethene compound obtained in Example 1 in n-hexane (concentration: approximately 10 ^-5 mol/L) was placed in a quartz cell, sealed, and then irradiated with ultraviolet light (wavelength 365 nm). and colored it. Next, one sample was left at -40°C for 10 hours, and the color change in the cell was observed over time. The absorption spectrum was measured using the same, and the relationship between the degree of discoloration (A/A ₀ ) and time (dashed line in FIG. 4) when left at a temperature of -40° C. for 10 hours was measured. Regarding the other colored sample, the degree of color fading (A/A ₀ ) and time (solid line in Figure 4) was measured.

From the results shown in FIG. 4, when the diarylethene compound of Example 1 colored with ultraviolet light was left at -40°C for 10 hours, the color gradually faded, but for 1 hour out of the 10 hours - When placed in an environment of 20° C., the color fades significantly, and since the color fading is irreversible, it can be seen that a temporary rise in temperature can be detected by the color fading (discoloration) of the diarylethene compound.

Further, at -50°C, the n-hexane solution (concentration: about 10 ^-5 mol/L) of the diarylethene compound obtained in Example 2 was placed in a quartz cell, sealed, and exposed to ultraviolet light (wavelength 365 nm). was colored by irradiation. Next, one sample was left at -50°C for 10 hours, and the color change in the cell was observed over time. The absorption spectrum was measured using the same, and the relationship between the degree of discoloration (A/A ₀ ) and time (dashed line in FIG. 5) when left at -50° C. for 10 hours was measured. Regarding the other colored sample, the degree of discoloration (A/A ₀ ) and time (upper solid line in Figure 5) was measured. In addition, for yet another colored sample, the degree of discoloration ( The relationship between A/A ₀ ) and time (lower solid line in FIG. 5) was measured.

From the results shown in FIG. 5, when the diarylethene compound of Example 1 colored with ultraviolet light was left at -50°C for 10 hours, the color gradually faded, but for 1 hour out of the 10 hours - If left in an environment of 40°C, the color will fade slightly, and if left in an environment of -30°C for 1 hour, the color will fade significantly.Also, as this fading is irreversible, the temperature will temporarily change. It can be seen that the increase can be detected by the fading (discoloration) of the diarylethene compound.

On the other hand, at 10°C, an n-hexane solution (concentration: about 10 ^-5 mol/L) of the diarylethene compound obtained in Comparative Example 6 was placed in a quartz cell, sealed, and exposed to ultraviolet light (wavelength 365 nm). It was colored by irradiation. Next, one sample was left at 10°C for 10 hours, and the color change in the cell was observed over time using an absorption photometer (manufactured by JASCO Corporation, model: V-560). Then, the absorption spectrum was measured, and the relationship between the degree of discoloration (A/A ₀ ) and time (dashed line in FIG. 6) when the sample was left at a temperature of 10° C. for 10 hours was measured. Regarding the other colored sample, the degree of discoloration (A/A ₀ ) is calculated by leaving it at 10°C for 2 hours, then leaving it at 30°C for 1 hour, and then leaving it at 10°C for 7 hours. The time relationship (solid line in Figure 6) was measured.

From the results shown in Figure 6, when the diarylethene compound of Comparative Example 6 colored with ultraviolet light was left at 10°C for 10 hours, the color gradually faded, and for 1 hour out of the 10 hours, the diarylethene compound of Comparative Example 6 was kept at 30°C. When the diarylethene compound was placed at a temperature of I know that I can't do it.

Further, at -10°C, the n-hexane solution (concentration: about 10 ^-5 mol/L) of the diarylethene compound obtained in Comparative Example 9 was placed in a quartz cell, sealed, and exposed to ultraviolet light (wavelength 365 nm). was colored by irradiation. Next, one sample was left at -10°C for 10 hours, and the color change in the cell was observed over time. The absorption spectrum was measured using the same, and the relationship between the degree of discoloration (A/A ₀ ) and time (dashed line in FIG. 7) when left at a temperature of 10° C. for 10 hours was measured. For the other colored sample, the degree of discoloration (A/A ₀ ) and time (solid line in Figure 7) were measured.

From the results shown in Figure 7, when the diarylethene compound of Comparative Example 7 colored with ultraviolet light was left at -10°C for 10 hours, the color faded relatively quickly, and for 1 hour out of the 10 hours, the diarylethene compound of Comparative Example 7 was kept at -10°C. When the diarylethene was placed at a temperature of It can be seen that it is not suitable for understanding by color fading (discoloration) of compounds.

Claims (8)

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,
X is S, NR ⁷ or O, R ⁷ is a hydrogen atom or an alkyl group,
Y ¹ and Y ² are each independently C or N,
The three R ¹ are each independently an alkyl group or an aromatic group,
The three R ² are each independently an alkyl group or an aromatic group,
When Y ¹ is C, R ³ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded with R ⁴ to form a ring structure, and Y ¹ is N If , it is an electron pair,
When Y ² is C, R ⁵ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded with R ⁶ to form a ring structure, and Y ² is N If , it is an electron pair,
R ⁴ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded with R ³ to form a ring structure,
R ⁶ is a hydrogen atom, a phenyl group, an alkyl group, an alkoxy group, or a cyano group, or is bonded to R ⁵ to form a ring structure. ] The ring A is a 5-membered ring structure,
Said X is S,
Said Y ¹ and Y ² are each C,
The above R ³ and R ⁴ are each independently a hydrogen atom, a phenyl group, or an alkyl group having 1 to 5 carbon atoms, or the above R ³ and R ⁴ are bonded to each other to form a 6-membered ring structure. and
The above R ⁵ and R ⁶ are each independently a hydrogen atom, a phenyl group, or an alkyl group having 1 to 5 carbon atoms, or the above R ⁵ and R ⁶ are bonded to each other to form a 6-membered ring structure. The diarylethene compound according to claim 1, wherein the diarylethene compound is The diarylethene compound according to claim 2, which is represented by the following general formula (1A).

[In formula (1A), the six Z's are each independently a hydrogen atom or a fluorine atom, and R ¹ , R ² , R ³ , R ⁴ , R ⁵ , and R ⁶ are each independently a hydrogen atom or a fluorine atom; It's the same. ] The diarylethene compound according to claim 3, which is represented by the following general formula (1B).

[In formula (1B), Z, R ¹ , R ² , R ³ and R ⁵ are each the same as in claim 3. ] A diarylethene compound represented by the following formula.

A photochromic material comprising the diarylethene compound according to any one of claims 1 to 5. An optical functional element comprising the photochromic material according to claim 6. A temperature sensor comprising the photochromic material according to claim 6.

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