JP2002145878A - Dithienylethene derivatives and light-controlled conjugated polymers - Google Patents

Abstract

(57) [Problem] To provide an organic photochromic material which is easy to mold and exhibits properties such as high responsiveness, sensitivity, thermal stability, and repeated durability. SOLUTION: The following general formula [1] (R is a hydrocarbon group which may have a substituent) and a polymer thereof.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a light control type conjugated polymer. More specifically, the invention of this application relates to a derivative having a dithienylethene moiety and a light control type conjugated polymer obtained by polymerizing the derivative.

[0002]

2. Description of the Related Art In recent years, with the spread of the Internet and portable telephones, in the field of electronics, materials capable of further high-speed transfer of information, high-density recording, and reduction in weight are required. Lighter than metal,
A conductive polymer material that can provide various properties by molecular design has attracted attention as such a material.
At present, various conductive polymer materials such as polyacetylene, polythiophene, polypyrrole, and polyparaphenylene have been put to practical use.

On the other hand, in the field of device science, the demand has shifted from so-called electronics to optoelectronic materials, and recently, research on photonics that enables the realization of next-generation ultra-high-speed, high-density recording molecular elements has been actively conducted. It has been done.

[0004] Above all, the color changes upon irradiation with light of a specific wavelength,
There is great expectation for photochromic materials that return to their original colors by light irradiation or heating after another discoloration, and many materials such as spirolans, spirooxazines, fulgides, and metacyclophane are being studied. In order to apply such a photochromic material as an image recording material or an optical storage material, it must have high-speed response, high sensitivity, thermal stability, repetition durability, etc., and no structural destruction during reading. Is required. However, organic compounds exhibiting photochromism, particularly polymer materials, which have been reported so far, have poor thermal stability, too large energy band between ON / OFF, poor responsiveness, and lack of repeated durability. There is a problem, and no satisfactory results have yet been obtained.

On the other hand, some inorganic compounds exhibiting photochromism have been put to practical use. However, since such inorganic compounds do not have a moldability per se, they have to be used for optical devices. Must be supported on a matrix material. That is, in order to use an inorganic photochromic material as an optical device, it is necessary to select a matrix to be supported. However, a polymer matrix having high moldability tends to decrease photochromic reactivity or cause a side reaction upon light irradiation, and it has been difficult to select a preferable polymer matrix. Further, although the crystal is preferable as a solid matrix, there is a problem that there is almost no photochromic material exhibiting photoresponsiveness in the crystal, and the formability of the matrix is not good.

Therefore, photochromic materials which are easy to mold and exhibit high responsiveness and repetitive durability have not been known.

The invention of this application has been made in view of the circumstances described above, and solves the problems of the prior art, is easy to mold, has high responsiveness, sensitivity, thermal stability, and repeatability. It is an object to provide an organic photochromic material exhibiting properties such as durability.

[0008]

SUMMARY OF THE INVENTION The invention of this application provides the following inventions to solve the problems of the prior art.

That is, first, the invention of this application is based on the following general formula [1]

[0010]

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[0011] The present invention provides a dithienylethene derivative represented by (R is a hydrocarbon group which may have a substituent).

Secondly, the invention of this application is a ring-closed form of the dithienylethene derivative, and has the following general formula [2]:

[0013]

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(R is a hydrocarbon group which may have a substituent).

Thirdly, the invention of this application provides a dithienylethene derivative wherein R is a formyl group in the first or second invention.

Fourth, the invention of this application relates to a polymer of the dithienylethene derivative of the first invention, and has the following general formula [3]:

[0017]

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(R ′ is a substituent of an aliphatic conjugated system or an aromatic conjugated system, and n is an integer of 10 to 1000 indicating the degree of polymerization).

Fifth, the invention of the present application provides a compound represented by the following general formula [4] as a ring-closure of the light control type conjugated polymer.

[0020]

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(R ′ is a substituent of an aliphatic conjugated system or an aromatic conjugated system, and n is an integer of 10 to 1000 indicating the degree of polymerization). .

The invention of this application is characterized in that, in the fourth or fifth invention, R ′ is represented by the following chemical formula [5]:

[0023]

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The present invention also provides a light control type conjugated polymer which is a conjugated substituent of any one of the above (a) to (d).

[0025]

DETAILED DESCRIPTION OF THE PREFERRED EMBODIMENTS Hereinafter, embodiments of the present invention will be described in detail.

The dithienylethene derivative of the invention of the present application is firstly prepared by the following general formula [1]

[0027]

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Is a compound represented by the formula: In this compound, R is a hydrocarbon group which may have a substituent, and may be any of aliphatic, aromatic, saturated, unsaturated, chain, and cyclic. Specific examples include an alkyl group, a carboxyl group, a hydroxyl group, a carbonyl group, a formyl group, an amino group, a cyano group, a nitro group, a sulfonic acid group, and the like. Is preferably a formyl group (—CHO).

The dithienylethene derivative represented by the general formula [1] has two thiophenyl groups bonded to ethene at the 3-position. The dithienylethene derivative of the invention of the present application has a π-conjugated spread when it becomes a ring-closed body or a polymer, and has high conductivity and optical properties, as compared with those showing photochromism by bonding to ethene at the 2-position. Is preferred.

The compound represented by the general formula [1] of the invention of the present application undergoes a ring closure reaction upon irradiation with ultraviolet light, and as a ring-closed compound, a compound represented by the following general formula [2]

[0031]

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To give the compound of the formula In such a closed body, the conductivity is improved because the π conjugation is further expanded. In the compound of the general formula [2], R is as described above.

The ring closure reaction from compound [1] to compound [2] by irradiation with ultraviolet light as described above involves a change in color tone from colorless to blue in a solution. By irradiating the compound [2] with visible light, the color is faded and a ring-opened compound of the compound [1] is obtained again. Therefore, it can be said that the dithienylethene derivatives of the compounds [1] and [2] are both photochromic organic materials.

Compounds [1] and [2] as described above
The dithienylethene derivative of may be synthesized by any method. It can be obtained using various known chemical techniques. Of course, compound [2]
The compound [1] is not limited to those obtained by irradiation with ultraviolet light.

Further, according to the invention of the present application, the following general formula [3] obtained by polymerizing the compound of the general formula [1] as a monomer.

[0036]

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There is provided a compound of the formula: Such a polymer of the dithienylethene derivative may be polymerized by any method. For example, using a phosphonium salt obtained from a triarylphosphine and an alkyl halide, Dithienylethene derivatives
A method of performing polymerization by a ttig reaction is exemplified. Of course, the compound of the general formula [3] may be obtained by a polymerization reaction or a copolymerization reaction using another catalyst system or the like.

In the general formula [3], R 'may be any aliphatic or aromatic conjugated substituent, and is not particularly limited. Among various conjugated substituents, the following chemical formula [5]

[0039]

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Any of the conjugated substituents (a) to (d) represented by the following formula (1) can realize the spread of π conjugation, and is therefore preferable.

The compound [3] is further treated with the following general formula [4] by irradiation with ultraviolet rays.

[0042]

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The polymer is a closed-ring form of the thienylethene derivative shown in the above. The change from compound [3] to compound [4] due to ultraviolet irradiation is accompanied by a change in color tone from colorless to green in a solution or a thin film. At this time,
In the compound [4], R 'is as described above.

Of course, the compound [4] is the same as the compound [3]
The method is not limited to those obtained by ultraviolet irradiation, but may be obtained by other methods such as a method of polymerizing a dithienylethene derivative of the compound [2] as a monomer using various catalyst systems.

Further, when the compound [4] is irradiated with visible light, the green color is faded, and a ring-opened compound [3] is obtained. From such a reversible photoreaction, it can be said that the compounds [3] and [4] of the present invention are both photochromic polymer materials, that is, light control type conjugated polymers.

These light control type conjugated polymers are not only useful in that they have high conductivity and show clear photochromism, are soluble in a solvent, and can be formed into thin films by a casting method or the like. It can be said that it is more advantageous than the conventional photochromic material in that it can be made into any shape by the molding method of the above.

Hereinafter, embodiments will be described with reference to the accompanying drawings, and embodiments of the present invention will be described in more detail. Of course, the present invention is not limited to the following examples, and it goes without saying that various aspects are possible in detail.

[0048]

EXAMPLES Example 1 Monomer [1,2-bis (5'-formyl-2'-methylthien-3'-yl)
And photochromism of perfluorocyclopentene] SHKawai and JM Lehn, Chem. Eur. J., 5, 275 (19
Based on 95), compound (A) was synthesized according to the following reaction formula (I).

[0049]

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The identification of the compound (A) was performed by the IR spectrum shown in FIG. 1 (A).

Next, the ultraviolet-visible absorption spectrum of this compound was measured, and it was confirmed that the compound had the maximum absorption wavelength (λmax) at 262 and 293 nm.

Further, 254 was added to a THF solution of the compound (A).
When irradiated with ultraviolet light of nm, the ring was closed to obtain a compound (A ′).

This compound (A ') had a λmax of 283 and 638 nm and exhibited a blue color. Further, when a THF solution of the compound (A ') was irradiated with visible light, the solution was discolored. Generation of compound (A) was confirmed from the ultraviolet-visible absorption spectrum.

FIG. 2 shows the ultraviolet-visible absorption spectra of the compounds (A) and (A ').

From this, reversible phorochromism represented by the following reaction formula (II) was confirmed.

[0056]

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Example 2 Synthesis of Light-Controlled Conjugated Polymer (1) Phenylenevinylene-Type Polymer: Compound (B) 1,4-dioxane (10 ml) was added to potassium carbonate (0.1 ml).
66 g, 0.48 mmol), formamide (0.4
g, 4.4 mmol), and p-xylylene-bis-
(Triphenylphosphonium bromide) (0.73 g,
0.93 mmol), and 30 minutes later, the monomer obtained in Example 1 (0.33 g, 0.77 mmol) was added. After refluxing at 70 ° C. for 24 hours to react, the obtained product was purified by washing with methanol.

The formation of the compound (B) was determined by the IR method shown in FIG.
It was confirmed by disappearance of the aldehyde peak in the spectrum.

[0059]

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(2) Vinylene type polymer: Compound (C) Zn (0.20 g, 3.1 mmol) was added to THF (5 ml).
l) was added thereto, and the mixture was kept at 0 ° C and stirred. TiCl4 (1m
1, 0.17 mmol), and after 30 minutes the monomer obtained in Example 1 (0.20 g, 0.47 m
mol) was dissolved in THF (10 ml) and slowly added dropwise. After refluxing at 60 ° C. for 24 hours to react, the product was purified by washing with methanol.

The formation of the compound (C) was determined by the IR method shown in FIG.
It was confirmed by disappearance of the aldehyde peak in the spectrum.

[0062]

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(3) Para-azomethine type polymer: Compound (D) LiCl (0.01 g, ca) was added to toluene (5 ml).
t. ) And p-phenylenediamine (0.05 g, 0.4
7 mmol) and stirred. The monomer (0.20 g, 0.47 mmol) obtained in Example 1 was dissolved in toluene (5 ml) and slowly added dropwise. 24 hours, 6
After refluxing at 0 ° C. and reacting, the product was purified by washing with methanol.

The production of the compound (D) was carried out according to the method shown in FIG.
Confirmed by a decrease in the aldehyde peak in the spectrum.

[0065]

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(4) Meta-azomethine type polymer: Compound (E) Toluene (10 ml) was mixed with LiCl (0.01 g, ca
t. ) And m-phenylenediamine (0.10 g, 0.9
4 mmol) and stirred. The monomer (0.40 g, 0.94 mmol) obtained in Example 1 was dissolved in toluene (5 ml) and slowly added dropwise. 24 hours, 6
After refluxing at 0 ° C. and reacting, the product was purified by washing with methanol.

The formation of the compound (E) was determined by the IR method shown in FIG.
Confirmed by a decrease in the aldehyde peak in the spectrum.

[0068]

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The degree of polymerization of the compounds (B) to (E) obtained by (1) to (4) was measured. Table 1 shows the yield and degree of polymerization of each polymer.

[0070]

[Table 1]

Example 3 Photochromism of Light-Controlled Conjugated Polymer The compounds (B) to (E) obtained in Example 2 were irradiated with ultraviolet rays, and the change in the ultraviolet-visible absorption spectrum of each polymer was measured. . The UV-visible absorption spectra are shown in FIGS.

Compounds (B) to (E) were closed by irradiation with ultraviolet rays to give compounds (B ') to (E').

It was confirmed that these compounds (B ′) to (E ′) were opened by irradiation with visible light and returned to (B) to (E) again. Thus, the photochromism of these compounds was shown.

[0074]

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Further, in all of the polymers, an isosbestic point accompanying isomerization was observed, and it was confirmed that one-to-one isomerization occurred. In particular, in the case of compound (E), the ring opening
It was shown to progress by 0%, and a reversible photoreaction was confirmed. <Example 4> Electric conductivity of conjugated polymer Further, compounds (B) to (D) and (B ') to
(D ′) was measured for electric conductivity. Table 2 shows the electric conductivity of each polymer.

[0076]

[Table 2]

In any polymer, 10 ^-10 to 1
A high electrical conductivity of 0 ^-5 S / cm was obtained. Also,
It was confirmed that higher electrical conductivity was obtained with the ring-closed body than with the ring-opened body.

From this, it was suggested that the π-conjugated system was expanded in the closed ring form. Example 5 Fluorescence Spectrum of Light Controlled Conjugated Polymer The fluorescence spectra of Compounds (B), (B ′), (C), and (C ′) were measured and are shown in FIGS. 6 and 7.

In each of the compounds, a difference in fluorescence intensity was observed between the ring-opened compound and the closed-ring compound. In addition, it was shown that the fluorescence intensity of the closed form was about three times higher than that of the open form.

[0080]

As described above in detail, according to the present invention, a photoresponsive conjugated polymer is provided, and a polymer material capable of controlling conductivity and light emission characteristics by optical switching is provided. Such a polymer material has high moldability and is a very useful material in the field of photoelectronics.

[Brief description of the drawings]

FIG. 1 is a diagram showing infrared absorption spectra of compounds (A), (B), (C), (D) and (E) synthesized in Examples of the present invention. (A) a monomer;
(B) phenylene vinylene polymer; (C) vinylene polymer; (D) para-azomethine polymer; (E) meta-azomethine polymer

FIG. 2 is a view showing an ultraviolet-visible absorption spectrum of a compound (B) synthesized in an example of the present invention before and after ultraviolet irradiation. (A) ring-opened form; (b) ring-closed form (after UV irradiation)

FIG. 3 is a view showing an ultraviolet-visible absorption spectrum of a compound (C) synthesized in an example of the present invention before and after ultraviolet irradiation. (A) ring-opened form; (b) ring-closed form (after UV irradiation)

FIG. 4 is a diagram showing an ultraviolet-visible absorption spectrum of compound (D) synthesized in Examples of the present invention before and after ultraviolet irradiation. (A) ring-opened form; (b) ring-closed form (after UV irradiation)

FIG. 5 is a view showing an ultraviolet-visible absorption spectrum of compound (E) synthesized in an example of the present invention before and after ultraviolet irradiation. (A) ring-opened form; (b) ring-closed form (after UV irradiation)

FIG. 6 is a fluorescence spectrum of compound (B) synthesized in Examples of the present invention before and after ultraviolet irradiation.
(A) ring-opened form; (b) ring-closed form (after UV irradiation)

FIG. 7 shows fluorescence spectra of compound (C) synthesized in Examples of the present invention before and after ultraviolet irradiation.
(A) ring-opened form; (b) ring-closed form (after UV irradiation)

Claims (6)

[Claims] [Claim 1] The following general formula [1] (R is a hydrocarbon group which may have a substituent), wherein the dithienylethene derivative is represented by the formula: 2. A ring-closed form of the dithienylethene derivative of claim 1, which is represented by the following general formula [2]: (R is a hydrocarbon group which may have a substituent). 3. The dithienylethene derivative according to claim 1, wherein R is a formyl group. 4. A polymer of the dithienylethene derivative according to claim 1, which is represented by the following general formula [3]: (R ′ is a substituent of an aliphatic conjugated system or an aromatic conjugated system, and n is an integer of 10 to 1000 indicating the degree of polymerization). 5. A closed ring of the light control type conjugated polymer according to claim 4, which is represented by the following general formula [4]: (R ′ is a substituent of an aliphatic conjugate system or an aromatic conjugate system, and n is an integer of 10 to 1000 indicating the degree of polymerization.)
A light control type conjugated polymer represented by the formula: 6. R ′ is a compound represented by the following chemical formula [5]: 6. The light control type conjugated polymer according to claim 4, which is a conjugated substituent represented by any one of (a) to (d).