JP3384087B2 - Photochromic optical recording material - Google Patents

Description

Detailed Description of the Invention

[0001]

TECHNICAL FIELD The present invention relates to an optical recording material having photochromic properties.

[0002]

2. Description of the Related Art A photochromic material is a material containing a molecule or a molecular assembly which reversibly produces two isomers having different states by the action of light. A variety of performances are required when using a photochromic material as an optical recording medium, one of which is a nondestructive read function.

[0003]

However, in the photochromic materials proposed hitherto, the photoreaction proceeds in proportion to the amount of absorbed light. Therefore, even if weak read light is used, the record disappears when read many times. Had.

In order to achieve non-destructive readout, it is only necessary to construct a system that does not photoreact when the amount of light is small and photoreacts only when the amount of light is large. One method is to synthesize a photochromic molecule that reacts with two photons. As such a two-photon photochromic reaction,
A naphthopyran derivative represented by the following structural formula [III] is known (M. Uchida, M. Irie J. Am. Chem. Soc., 115 (1993) 644
2). However, the absorption maximum of this molecule is at a wavelength of 396 nm in the ultraviolet region, and no remarkable color change is observed.

[0005]

[Chemical 3]

It is an object of the present invention to solve the above conventional problems and provide a photochromic optical recording material having an excellent nondestructive read function.

[0007]

A photochromic optical recording material according to claim 1 is a naphthopyran derivative having a main skeleton represented by the following general formula [I], which is at least a substituent of a naphthalene ring or a benzene ring. It is characterized by containing a naphthopyran derivative having one electron-withdrawing group.

[0008]

[Chemical 4]

The photochromic optical recording material of claim 2 is the same as the photochromic optical recording material of claim 1.
The naphthopyran derivative is represented by the following general formula [II], and
It is characterized by having at least one cyano group or nitro group as an electron-withdrawing group in a naphthalene ring or a benzene ring.

[0010]

[Chemical 5]

(Wherein R ¹ represents an alkyl group, an alkoxy group, a perfluoroalkyl group or a cyano group, and R 1
² , R ³ , R ⁴ , R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰
Alternatively, each R ¹¹ independently represents a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkylamino group, a dialkylamino group, a cyano group, a nitro group, an alkanoyloxy group or an alkyloxycarbonyl group. ) That is, the present inventors have realized a longer absorption wavelength for the naphthopyran derivative represented by the structural formula [III] described above in order to impart a sufficient color change to enable application to a recording material. In order to do so, the effect of introducing various substituents was examined as follows.

In the naphthopyran derivative represented by the above structural formula [III], the substituent may be an alkoxy group, a dialkylamino group, a halogen, a cyano group, a nitro group, or the like, and the introduction position thereof may be the following a to j. The position of.

[0013]

[Chemical 6]

The present inventors calculated using the ZINDO program what kind of substituent is introduced at what position is effective for lengthening the absorption wavelength. As a result, it was predicted that it would be effective to introduce an alkoxy group, a dialkylamino group, a halogen, a cyano group or a nitro group at the positions b and i in the above formula [IV]. In particular, it was predicted that it would be effective to introduce an electron-withdrawing group such as a cyano group or a nitro group into the naphthalene ring or the benzene ring. In fact, the naphthopyran derivative having a cyano group introduced at the position b or i has the above structural formula [II
I] compared to the naphthopyran derivative, the absorption wavelength is shifted to the long wavelength side of 40 nm or 15 nm, respectively,
It showed a two-photon photochromic reactivity. Therefore, a photochromic optical recording medium could be constructed by dispersing these molecules in a polymer medium.

As a result of repeating such studies, the present inventors have found that the naphthopyran derivative represented by the general formula [I] has at least one electron-withdrawing group on the naphthalene ring or benzene ring. The inventors have found that it is effective for increasing the absorption wavelength, and have completed the present invention.

The present invention will be described in detail below.

The naphthopyran derivative constituting the photochromic optical recording material of the present invention is represented by the above general formula [I] and has at least one electron-withdrawing group substituent in its naphthalene ring or benzene ring. And preferably has the cyano group or nitro group as the electron-withdrawing group represented by the general formula [II], and specifically, the naphthopyran derivative of the following (1) to (20) Is mentioned. In the following, Me represents a methyl group.

[0018]

[Chemical 7]

[0019]

[Chemical 8]

[0020]

[Chemical 9]

The photochromic optical recording material of the present invention having a recording layer containing such a naphthopyran derivative can be easily obtained according to a known method.

For example, the photochromic optical recording material of the present invention can be manufactured by forming a recording layer according to the following method (i) or (ii).

(I) A polyester resin, polystyrene resin, polyvinyl butyral resin, polyvinylidene chloride, polyvinyl chloride, polymethyl methacrylate, polyvinyl acetate, cellulose acetate, epoxy resin, or phenol, if necessary, with the naphthopyran derivative. With a binder such as resin, carbon tetrachloride, benzene, cyclohexane,
Methyl ethyl ketone, dispersed or dissolved in a solvent such as tetrachloroethane, coated on a suitable substrate, or by a known vapor deposition method or co-evaporation method with other compounds,
A recording layer is formed on the substrate by, for example, vapor deposition on a suitable substrate.

(Ii) The naphthopyran derivative is dissolved in the above-mentioned solvent and sealed in a glass cell or the like.

In the method (i), the substrate used may be either transparent or opaque to the light used. Examples of the material of the substrate material include supports for general recording materials such as glass, plastic, paper, plate-shaped or foil-shaped metal, and among these, plastic is preferable from various points. Examples of the plastic include acrylic resin, methacrylic resin, vinyl acetate resin, vinyl chloride resin, nitrocellulose, polyethylene resin, polypropylene resin, polycarbonate resin, polyimide resin, polysulfone resin and the like.

The film thickness of the recording layer formed on such a substrate is 100 Å to 100 μm, particularly 1000 Å to 10 μm.
Is preferred.

As the film forming method, a commonly used thin film forming method such as a vacuum vapor deposition method, a sputtering method, a doctor blade method, a casting method, a spinner method and a dipping method can be adopted.

When a binder is used for film formation,
It is desirable that the amount of the naphthopyran derivative according to the present invention is 5% or more by weight.

In the case of film formation by the spinner method, the number of revolutions is preferably 500 to 5000 rpm, and after spin coating, depending on the case, a treatment such as heating or exposure to solvent vapor may be performed.

When the recording layer is formed by a coating method such as a doctor blade method, a cast method, a spinner method, a dipping method, or a spinner method, a coating solvent is bromoform,
Boiling point of dibromoethane, ethyl cellosolve, xylene, chlorobenzene, cyclohexanone, etc.
Those of are preferably used.

In the present invention, a transition metal chelate compound (eg, acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-) is used as a singlet oxygen quencher in the recording layer in order to improve its stability and light resistance. (alpha-diketone etc.) or a tertiary amine compound may be contained.

The recording layer of the photochromic optical recording material of the present invention may be provided on both sides of the substrate or on only one side.

Recording on the photochromic optical recording material of the present invention obtained as described above is performed by irradiating the recording layer provided on both sides or one side of the substrate or the recording layer in the cell with light focused to about 1 to 10 μm. By. Then, the light-irradiated portion undergoes a color change due to absorption of light energy. The recorded information can be reproduced by reading the difference in reflectance or absorbance between the portion where the color change due to light has occurred and the portion where the color change due to light has not occurred.

[0034]

In the naphthalene ring or benzene ring of the naphthopyran derivative having the main skeleton represented by the general formula [I],
By introducing an electron-withdrawing group, in the naphthopyran derivative exhibiting a two-photon photochromic reactivity, the absorption wavelength is shifted to the longer wavelength side, and a naphthopyran derivative exhibiting a sufficient color change effective for a photochromic optical recording material can be obtained.

Therefore, a photochromic optical recording material exhibiting two-photon photochromic reactivity and capable of nondestructive readout is provided.

According to the photochromic optical recording material of the second aspect, a photochromic optical recording material having further excellent optical recording characteristics is provided.

[0037]

EXAMPLES Next, the present invention will be described more specifically with reference to Examples and Comparative Examples, but the present invention is not limited to these Examples unless it exceeds the gist.

Example 1 [Synthesis of naphthopyran derivative] A naphthopyran derivative (1-13) having a cyano group at the b-position represented by the above general formula [IV] was synthesized according to the following synthetic route.

[0039]

[Chemical 10]

[0040]

[Chemical 11]

Of 2-methylbenzothiophene (1-2)
Synthesis Benzothiophene (1-1) 5 g (3.73 × 10 ^-2 m
ol) was placed in a flask, the atmosphere was replaced with nitrogen, and the residue was dissolved in 25 ml of anhydrous tetrahydrofuran. Methanol-
28 ml of 1.6N n-butyllithium hexane solution was cooled with stirring in a dry ice bath to -60 ° C.
(4.47 × 10 ^-2 mol) was added dropwise over 30 minutes.

After the dropping, the mixture was stirred at -60 ° C for 1 hour and then at room temperature for 1 hour. During this period, the solution changed from cloudy to yellow cloudy. After cooling to 0 ° C. again, 3.48 ml (5.59 × 10 ^-2 mol) of methyl iodide was added dropwise over 15 minutes while keeping the temperature constant. After becoming cloudy, it became cloudy at room temperature and was stirred as it was overnight. After the solvent was distilled off, water was added, the mixture was extracted with ether, washed with water and dried over magnesium sulfate, and the ether was distilled off to obtain a yellow transparent liquid. This was developed with hexane using a silica gel column and separated, and the first effluent was fractionated to obtain 5.2 g of needle-like colorless transparent crystals of 2-methylbenzothiophene (1-2) (yield. : 94%).

3-iodo-2-methylbenzothiophene
Synthesis of (1-3) 2-methylbenzothiophene (1-2) 3 g (2.02
X10 ^-2 mol) is dissolved in 10 ml of benzene, and 65
After heating to ° C, 4.82 g (2.23 x mercuric oxide)
10 ^-2 mol) and 5.65 g of iodine (2.23 x 10 ^-2)
and mol) were alternately added little by little over 50 minutes, and the mixture was stirred for 1 hour at 65 ° C. as it was.

Mercury oxide was removed by filtration, and benzene was distilled off from the filtrate. This was developed with hexane using a silica gel column and separated, and the first effluent was recrystallized with hexane to give 3-iodo-2 as plate-like colorless transparent crystals.
-Methylbenzothiophene (1-3) 5.45g was obtained (yield: 98%).

[0045]2,4-dibromo-1-naphthylamine
Synthesis of (1-5) 1-naphthylamine (1-4) 10 g (6.99 × 10
^-2mol) of acetic acid 100 ml and propionic acid 50 ml
Dissolve in a mixed solvent, cool to 0-5 ° C in an ice bath, and
Element 13.4 g (8.39 × 10)^-2mol) dissolved vinegar
100 ml of acid was added dropwise over 1 hour. During this time, a white precipitate
It has started to precipitate. After the dropping, add 100 ml of acetic acid.
Then, heat in an oil bath and stir at 60 ° C for 15 minutes.
It was After standing to cool, the precipitate deposited by filtration is removed and the filtrate
Add 1% aqueous NaOH to make it alkaline and
Extracted with form, dried over magnesium sulfate,
Holm was distilled off. Using a silica gel column,
Develop with chloroform and separate, collect first effluent
Needle-shaped brown crystals 2,4-dibromo-1-naphthylami
12.6 g of benzene (1-5) was obtained (yield: 60%).

[0046]4-bromonaphtho [1,2-d] [1,
Synthesis of 2,3] oxadiazole (1-6) 2,4-dibromo-1-naphthylamine (1-5) 12
g (3.99 × 10^-2mol) acetic acid 200 ml, pro
Dissolve 25 ml of pionic acid in a mixed solvent, and use an ice bath for 8 to 1
After cooling to 0 ° C., 3.3 g of sodium nitrite (4.7
9 x 10^-2mol) little by little, and leave it for 30 minutes.
Stir at 8-10 ° C. 10% NaOH aqueous solution in the reaction solution
Add liquid to make it alkaline and extract with chloroform,
Dry over magnesium sulfate and evaporate chloroform.
It was This was washed with chloroform using a silica gel column.
After developing and separating, the main product with an Rf value of 0.2 was
Eluate and evaporate the solvent to remove yellow crystals of 4-bromonaphthalene.
[1,2-d] [1,2,3] oxadiazole (1
-6) 7.35 g was obtained (yield: 74%).

Of 4-bromo-2-naphthol (1-7)
Synthetic 4-bromonaphtho [1,2-d] [1,2,3] oxadiazole (1-6) 6.95 g (2.79 × 10 ^-2 m
ol) is suspended in 150 ml of ethanol and the mixture is cooled to 0 ° C in an ice bath.
Cooled to 320mg sodium borohydride
(8.37 × 10 ^-2 mol) was added little by little, and the mixture was stirred as it was for 3 hours at 0 ° C. After distilling off the ethanol,
Add 100 ml of 5% HCl aqueous solution, and add 10%
Aqueous NaOH was added to make it alkaline and the neutral product was extracted with dichloromethane. An aqueous HCl solution was added to the alkaline aqueous phase to make it acidic, the mixture was extracted with dichloromethane, dried over magnesium sulfate, and the dichloromethane was distilled off. This was developed with chloroform using a silica gel column and separated, the main product with an Rf value of 0.1 was eluted with chloroform, the solvent was distilled off, and dark brown crystals 4-
4.85 g of bromo-2-naphthol (1-7) was obtained (yield: 78%).

4-bromo-2-methoxynaphthalene (1
Synthesis of 4--8) 5.0 g of 4-bromo-2-naphthol (1-7) (2.
(11 × 10 ⁻² mol) was placed in a flask, the atmosphere was replaced with nitrogen, and the residue was dissolved in 35 ml of anhydrous dimethylformamide.
600 mg of sodium hydride (2.5 × 10 ^-2 m
ol) was added and the mixture was stirred at room temperature for 15 minutes. To this product, 1.9 ml (2.5 × 10 ^-2 mol) of methyl iodide was added, and the mixture was stirred at room temperature for 1 hour. Water was added, the mixture was extracted with chloroform, washed with water, dried over magnesium sulfate, and the chloroform was distilled off. This was developed with hexane using a silica gel column and separated to give an Rf value of 0.2.
The main product of was eluted with hexane and the solvent was distilled off to give a yellow transparent liquid 4-bromo-2-methoxynaphthalene (1-
8) 4.65 g was obtained (yield: 93%).

4-Bromo-2-methoxy-1-naphthoa
Synthesis of aldehyde (1-9) 4-bromo-2-methoxynaphthalene (1-8) 3.0
g (1.27 × 10 ^-2 mol) was placed in a flask, the atmosphere was replaced with nitrogen, and then 2.23 g of N-methylformanilide was added.
(1.65 × 10 ^-2 mol) and phosphorus oxychloride 2.53
g (1.65 × 10 ^-2 mol) was added, the mixture was heated in an oil bath, and the mixture was stirred for 3 hours at 100 ° C. as it was. Water was added, the mixture was extracted with chloroform, washed with water, dried over magnesium sulfate, and the chloroform was distilled off. This was developed with chloroform using a silica gel column and separated, and the main product having an Rf value of 0.8 was eluted with chloroform,
The solvent was distilled off to give brown crystals 4-bromo-2-methoxy-
1.69 g of 1-naphthaldehyde (1-9) was obtained (yield: quantitative (100%)).

4-Bromo-2-hydroxy-1-naphtho
Synthesis of aldehyde (1-10) 4-bromo-2-methoxy-1-naphthaldehyde (1
-9) 500 mg (1.89 mmol) was placed in a flask and, after purging with nitrogen, dissolved in a mixed solvent of 25 ml of hexane and 25 ml of chloroform. Boron tribromide 61
5 mg (2.46 mmol) was added, and the mixture was heated in an oil bath and stirred as it was for 3 hours at 70 ° C. After the solvent was distilled off, 20 ml of 10% NaOH aqueous solution was added, and further,
Aqueous HCl was added to acidify and extracted with ether,
After washing with water, it was dried over magnesium sulfate and the ether was distilled off. This was developed with chloroform using a silica gel column and separated, the main product having an Rf value of 0.9 was eluted with chloroform, the solvent was distilled off, and yellow crystals of 4-bromo-2-hydroxy-1-naphtho were obtained. Aldehyde (1-10)
400 mg was obtained (yield: 85%).

Synthesis of Compound (1-11) 3-Iodo-2-methylbenzothiophene (1-3)
1.0 g (3.64 mmol) was placed in a flask, the atmosphere was replaced with nitrogen, and then the residue was dissolved in 20 ml of anhydrous tetrahydrofuran. This was cooled to −60 ° C. in a methanol-dry ice bath, and 2.3 ml (3.64 mmol) of 1.6N n-butyllithium hexane solution was added dropwise over 10 minutes while stirring.

After the dropping, the mixture was stirred at -60 ° C for 1 hour. During this time, the solution changed from a cloudy color to a yellow cloudy color. afterwards,
10 ml of anhydrous tetrahydrofuran in which 500 mg (1.99 mmol) of compound (1-10) was dissolved was added dropwise over 30 minutes, and the mixture was stirred overnight as it was.

After distilling off the solvent, water and dilute hydrochloric acid were added, the mixture was extracted with ether, washed with water, and dried over magnesium sulfate.
The ether was distilled off. This was separated and developed with chloroform using a silica gel column, the main product having an Rf value of 0.5 was eluted with chloroform, and the solvent was distilled off to obtain 240 mg of a yellow crystalline compound (1-11) ( Yield: 30
%). At this time, the compound (1-12) was also produced as a by-product.

Synthesis of Compound (1-12) Compound (1-11) 200 mg (5.0 × 10 ^-4 mo)
1) was dissolved in 30 ml of benzene, 500 mg of magnesium sulfate and a trace amount (catalytic amount) of p-toluenesulfonic acid were added, and the mixture was stirred at 65 ° C. for 30 minutes. By filtration
Magnesium sulfate and p-toluenesulfonic acid are removed,
After the solvent was distilled off, this was developed with hexane using a silica gel column and separated, and the first outflow was separated to obtain 120 mg of a yellow crystalline compound (1-12) (yield: 62%).

Synthesis of Compound (1-13) Compound (1-12) 200 mg (5.2 × 10 ^-4 mo)
l) was dissolved in 30 ml of dimethylformamide, 56 mg (6.2 × 10 ⁻⁴ mol) of copper cyanide was added, and 1)
The mixture was stirred at 40 ° C for 6 hours.

To the reaction solution was added 100 ml of water containing 10 ml of ethylenediamine, extracted with benzene, washed with water and dried with magnesium sulfate to distill off benzene. This was developed with hexane using a silica gel column and separated, and the first effluent was collected to give a yellow crystalline compound (1
-13) 20 mg was obtained (yield: 13%).

[Preparation of Recording Material] Compound (1-13) 1
0 mg and 1 g of polystyrene were dissolved in toluene to prepare a polymer film by a casting method. The absorption spectrum of this product is shown by the solid line in FIG. When this polymer film was irradiated with light having a wavelength of 425 nm, the absorption spectrum gradually decreased as shown by the broken line in FIG. Then, it was confirmed that when irradiated with light having a wavelength of 305 nm again, the spectrum of the solid line was restored, and photochromic reactivity was exhibited.

Example 2 [Synthesis of naphthopyran derivative] A naphthopyran derivative (2-7) having a cyano group at the i-position represented by the above general formula [IV] was synthesized according to the following synthetic route.

[0059]

[Chemical 12]

3-bromo-6-cyano-2-methylben
Synthesis of zothiophene (2-5 ) 500 mg of 6-cyano-2-methylbenzothiophene (2-3) obtained by the above-mentioned reaction route by a known method
(2.9 mmol) was dissolved in 40 ml of chloroform, 20 ml of chloroform in which 300 mg (1.9 mmol) of bromine was dissolved was added dropwise over 30 minutes, and the mixture was stirred at room temperature for 4 hours. An aqueous sodium thiosulfate solution was added, the mixture was extracted with chloroform, washed with water, dried over magnesium sulfate, and chloroform was distilled off. This was developed with hexane using a silica gel column and separated, and the first effluent was separated to give a white crystalline compound (2-5) 720 m.
g was obtained (yield: 99%).

Synthesis of Compound (2-6) 700 mg (2.77 mmol) of 3-bromo-6-cyano-2-methylbenzothiophene (2-5) was placed in a flask and the atmosphere was replaced with nitrogen.
It was dissolved in 1. This in methanol-liquid nitrogen bath-
2.1 ml (3.32 mmol) of 1.6 N n-butyllithium hexane solution was cooled to 100 ° C. and stirred.
Was added dropwise over 10 minutes.

After the dropping, the mixture was stirred at -100 ° C for 2 hours. During this time, the solution changed from cloudy to dark brown. afterwards,
2-hydroxy-1-naphthaldehyde 500 mg
10 ml of anhydrous tetrahydrofuran in which (2.91 mmol) was dissolved was added dropwise over 30 minutes, and the temperature was kept at -100 ° C.
Stir for hours.

After distilling off the solvent, water and dilute hydrochloric acid were added, the mixture was extracted with ether, washed with water and dried over magnesium sulfate.
The ether was distilled off. This was developed with chloroform using a silica gel column and separated, the main product having an Rf value of 0.5 was eluted with chloroform, and the solvent was distilled off to obtain 600 mg of a yellow crystalline compound (2-6) ( Yield: 63%).
At this time, the compound (2-7) was also produced as a by-product.

Synthesis of compound (2-7) 600 mg (1.7 mmol) of compound (2-6) was dissolved in 30 ml of benzene to obtain 500 m of magnesium sulfate.
g, p-toluenesulfonic acid (trace amount) was added,
The mixture was stirred at 65 ° C for 30 minutes. Magnesium sulfate and p-toluenesulfonic acid were removed by filtration, the solvent was distilled off, and this was developed with hexane using a silica gel column for separation, and the first effluent was separated to give a yellow crystalline compound (2
-7) 320 mg was obtained (yield: 62%).

[Preparation of Recording Material] Compound (2-7) 10
mg and polystyrene 1g were melt | dissolved in toluene, and the polymer film was created by the casting method. The absorption spectrum of this product is shown by the solid line in FIG. When this polymer film was irradiated with light having a wavelength of 405 nm, the absorption spectrum changed as shown by the broken line in FIG. Then, it was confirmed that when irradiated with light having a wavelength of 305 nm again, the spectrum of the solid line was restored, and photochromic reactivity was exhibited.

[0066]

As described in detail above, according to the photochromic optical recording material of the present invention, a photochromic optical recording material capable of nondestructive read is provided. That is, according to the photochromic optical recording material of the present invention, if weak reading light is used for reading, it is possible to read without destroying the recording, and it is possible to erase the recording by increasing the light amount. Is.

According to the photochromic optical recording material of the second aspect, a photochromic optical recording material having further excellent optical recording characteristics is provided.

[Brief description of drawings]

FIG. 1 is an absorption spectrum diagram of a recording material prepared in Example 1.

FIG. 2 is an absorption spectrum diagram of the recording material prepared in Example 2.

Claims (2)

(57) [Claims] 1. A naphthopyran derivative having a main skeleton represented by the following general formula [I], which contains a naphthopyran derivative having at least one electron-withdrawing group as a substituent of a naphthalene ring or a benzene ring. A photochromic optical recording material characterized by the above. [Chemical 1] 2. The photochromic optical recording material according to claim 1, wherein the naphthopyran derivative is represented by the following general formula [II] and has at least one cyano group or nitro group as an electron-withdrawing group on the naphthalene ring or benzene ring. A photochromic optical recording material having: [Chemical 2] (In the formula, R ¹ represents an alkyl group, an alkoxy group, a perfluoroalkyl group or a cyano group, and R ² , R ³ , R ⁴ ,
R ⁵ , R ⁶ , R ⁷ , R ⁸ , R ⁹ , R ¹⁰ or R ¹¹ are each independently a hydrogen atom, a halogen atom, an alkyl group, an alkoxy group, an alkylamino group, a dialkylamino group, a cyano group, a nitro group. Represents an alkanoyloxy group or an alkyloxycarbonyl group. )