JPH08134063A - Perfluorocyclopentene derivative, photochromic material, optical recording medium and optical recording - Google Patents

Abstract

PURPOSE: To obtain a new perfluorocyclopentene derivative useful as an optical recording medium improved in regenerative cycle of recordings, having high degree of isomerization, high optical stability of isomerized molecules to a laser beam in time of read-out and a high threshold value. CONSTITUTION: This perfluorocyclopentene derivative is expressed by formula I, II or III [R1 is H or a lower alkyl; R2 is a lower alkyl; R is H, an alkyl, an alkoxy, cyano, etc.; (n), (k) and (m) are each 1-5], e.g. 1,2-bis[2,4-dimethyl-5-(4- N-phenylaminophenyl)thiophen-3-yl]perfluorocyclopentene, etc. The perfluorocyclopentene derivative is obtained by condensing a bisiodoarylthienylperfluorocyclopentene derivative with a specific amino compound in a usual method.

Description

Detailed Description of the Invention

[0001]

BACKGROUND OF THE INVENTION 1. Field of the Invention The present invention relates to a novel perfluorocyclopentene derivative, a photochromic material, and an optical recording medium using the same, and more particularly, it is useful as an optical recording medium in which the number of recording reproductions is remarkably improved. Perfluorocyclopentene derivative and photochromic material.

[0002]

2. Description of the Related Art Conventionally, a photochromic material that develops or erases color when irradiated with light has been widely used for various purposes such as an optical recording medium, an optical filter for sunglasses and the like, a masking material, a display material and the like.

As such a photochromic material,
Although various organic compounds are known, a typical example thereof is a spiropyran compound (for example, Japanese Patent Publication No. 4).
5-28892).

It is also known that a perfluorocyclopentene derivative is useful as a photochromic material. For example, Japanese Patent Application Laid-Open No. 3-261947 discloses the following formula (4).

[0005]

[Chemical 12]

In the formula, a photochromic material composed of a derivative in which Me is a methyl group (the same applies hereinafter) is described. The benzothiophene type perfluorocyclopentene derivative of the formula (4) is doped into a polymer or introduced into the main chain of the polymer and then cast on a film or laminated on a substrate to prepare a recording medium. This recording layer was irradiated with ultraviolet light to obtain the formula (5)

[0007]

[Chemical 13]

The recording material is converted into a ring-closed body, the recording is written, and then the recording is read using visible light.

[0009]

A photochromic material is an isomerization (ring closure, ring opening) of a molecular structure accompanied by irradiation of light.
However, when this is used as a recording material, the greatest problem is to have a high isomerization rate and to improve the number of recording reproductions.

However, most of the known photochromic materials as shown in the above formulas (4) and (5) tend not to have a threshold value in the photochemical reaction.

Therefore, even if a colored ring-closed body is formed by the actinic ray, it tends to be isomerized to the ring-opened body when the image is optically read, and the image disappears when read many times. The drawback is recognized.

Therefore, an object of the present invention is to use a diarylethene derivative as a photochromic memory medium, which has a high isomerization rate and a high photostability of isomerized molecules against laser light during reading of recording, that is, The purpose of the present invention is to provide a diarylethene derivative having a threshold value and enhance its practicality as an optical recording medium.

[0013]

According to the present invention, the following formula (1)

[0014]

Embedded image , The following formula (2)

[0015]

[Chemical 15] Or the following formula (3)

[0016]

Embedded image

In the formula, R ₁ is a hydrogen atom or a lower alkyl group, R ₂ is a lower alkyl group, R is a hydrogen atom, an alkyl group, an alkoxy group, a tertiary amino group or a cyano group, and n is Is a number from 1 to 5 and k is 1 to 5
Is provided and m is a number from 1 to 5, and a perfluorocyclopentene derivative represented by the following is provided.

According to the present invention, there is provided a photochromic material comprising a perfluorocyclopentene derivative represented by the above formula (1) or the above formula (2).

According to the present invention, a light containing a perfluorocyclopentene derivative represented by the above formula (1), the above formula (2) or the above formula (3) is provided on a substrate. A recording medium is provided.

According to the present invention, the layer containing the perfluorocyclopentene derivative (ring-opened body) represented by the above formula (1) is further irradiated with an actinic ray, and the isomerized molecule represented by the above formula (2) ( (An image of a ring-closed compound) is formed, and then the image is oxidized to form an image of the compound (reduced compound) represented by the formula (3), and the isomerized molecule is stabilized against a reading light beam. There is provided an optical recording method characterized by the following:

In this optical recording method, the stabilized compound of formula (3) is reduced to a compound of formula (2) (closed ring), and then the compound of formula (1) is irradiated with visible light. The image can be erased by conversion.

[0022]

The compound of the present invention has a thiophene ring at the α-position (1-position) and β-position (2-position) of the perfluorocyclopentene derivative and an aryl-substituted aminoaryl group at the 5-position of the thiophene ring. This is a structural feature.
The compound of formula (1) is a ring-opened body, the compound of formula (2) is a ring-closed body, and the compound of formula (3) is an oxidized body of a ring-closed body.

According to the present invention, by changing the benzothiophene ring in the conventional perfluorocyclopentene derivative to a thiophene ring, the isomerization rate to a ring-closed compound can be markedly improved. Further, by introducing an arylaminoarylene chain at the 5-position of the thiophene ring,
When the ring-closed compound of formula (2) is oxidized, the oxidant of formula (3) in which the aminoarylene chain is converted into a quinoimine structure is easily produced.

In the quinoimine-type structure of the formula (3), the molar absorption coefficient (ε) is increased and the absorption maximum wavelength is on the long wavelength side as compared with the ring-closed body of the formula (2) because the conjugated chain is connected. The result that is convenient for reading the record is that the process moves to.

The ring-closure of the quinoimine structure of the formula (3) has no photochromic property and does not change to another structure upon optical reading of the record, which is extremely convenient for record keeping. In addition, the quinoimine structure of formula (3) is
Conversion to the aminoarylene structure of formula (2) by reduction,
Since the ring-closure of formula (2) has photochromic properties,
Erasure can be performed by irradiation with light rays.

In the present invention, the ring-opened product of the general formula (1) is generally a bright color such as yellow, and the ring-closed product (cyclohexadiene) of the general formula (2) is blue.
Further, since the reductant of formula (3) is green and has different hues from each other, and the reductant of formula (3) does not have photochromic properties, high contrast and high retention of recording can be obtained. To be

Since the perfluorocyclopentene derivative of the present invention has a large quantum yield in a ring-closed body, it can be used as a general photochromic material for color filters, sunglasses, etc., but is particularly useful as an optical recording medium. Is.

In FIG. 1 for explaining the operation as an optical recording medium, an optical recording medium 1 is a recording layer in which a perfluorocyclopentene derivative of the present invention is dissolved in a polymer on a substrate (transparent substrate) 2. It is made up of three. In this recording layer 3, the photochromic molecule is in the state of ring-opened body A (Formula 1) before writing.
When writing, light λ1 is emitted. As a result, the photochromic molecule becomes a ring-closed body B (Formula 2) in the bright part,
In the dark part, the photochromic molecule remains as the ring-opened body A. The written recording layer is oxidized. This allows
The ring-closed body B is converted to the oxidant C (formula 3) to give the ring-opened body A
Remains as is. At the time of reading, when the recording layer is irradiated with a light beam λ2, the photochromic molecule A described above is irradiated.
Since the light ray is transmitted in the portion of and the light ray is blocked in the portion of the photochromic molecule C, it can be reproduced as a light ray image (negative image). Since the recording layer once written has no sensitivity to light rays, it can be used for reproducing light ray images many times. The used recording layer can be erased by reducing the recording layer in the erasing step to oxidize the molecule C into the ring-closed body B and then irradiate it with the light beam λ2 to form the ring-opened body A.

[0029]

Preferred Embodiment of the Invention

[Perfluorocyclopentene Derivative] In the perfluorocyclopentene derivatives of the above general formulas (1), (2) and (3) of the present invention, a thiophene ring group, R ₁ may be a hydrogen atom or a lower alkyl group, wherein Examples of the alkyl group include methyl, ethyl, propyl and butyl groups (the same applies hereinafter). A methyl group is preferred. The group R _{2 on the} thiophene ring is the same lower alkyl group, and is preferably a sterically unhindered methyl group.

The terminal group R is a hydrogen atom, an alkyl group, an alkoxy group, a tertiary amino group or a cyano group, and examples of the alkoxy group include lower alkoxy groups such as methoxy, ethoxy, propoxy and butoxy groups. Examples of the primary amino group include di-substituted amino groups, for example, amino groups di-substituted with methyl, ethyl, propyl, butyl groups and the like.

The repeating numbers n and m of the p-phenylene group are numbers from 1 to 5, and p-phenylene group, 4,4'-biphenylene group and the like correspond to this. k is a number from 1 to 5.

Examples of suitable compounds are:
1,2-bis [2,4-dimethyl-5- (4-N-phenylaminophenyl) thiophen-3-yl] perfluorocyclopentene. 1,2-bis [2,4-dimethyl-5- (4'-N-phenylaminobiphenyl-4) thiophen-3-yl] perfluorocyclopentene.
1,2-bis [2,4-dimethyl-5- (4- (p-methoxyphenylamino) phenyl-1) thiophene-3
-Yl] perfluorocyclopentene. 1,2-bis [2,4-dimethyl-5- (4- (p-cyanophenylamino) phenyl-1) thiophen-3-yl] perfluorocyclopentene.

[Synthesis Method] The perfluorocyclopentene derivative of the present invention has the following formula (6):

[0034]

[Chemical 17]

A bisiodoaryl thienyl perfluorocyclopentene derivative represented by the following formula (7)

[0036]

Embedded image

It is synthesized by condensing the amino compound represented by and a method known per se.

The bisiodoaryl thienyl perfluorocyclopentene derivative of the above formula (6) is synthesized as follows. That is, the following formula (8)

[0039]

[Chemical 19]

As shown in the reaction scheme of, a derivative having a lower alkyl group at the 2-position of a thiophene is represented by the formula (9)
The thienyl zinc chloride derivative shown in
By reacting with a 4-halobenzene derivative shown in
1-) as a 2-lower alkyl-5-arylthiophene derivative represented by the formula (12) as a 2-lower alkyl-3-halo-5-phenylthiophene derivative, which is reacted with perfluorocyclopentene to obtain the compound represented by the formula (13) ) Bis (arylthienyl) perfluorocyclopentene derivative). It is obtained by introducing iodine at the p-position of the aryl group of this derivative.

[Use] The perfluorocyclopentene derivative of the present invention is useful as a photochromic material, especially as an optical recording medium. That is, the perfluorocyclopentene derivative is dissolved in a polymer and the composition is formed into a film or formed into an appropriate shape and used as a photochromic material.

In order to dissolve the perfluorocyclopentene derivative in the polymer, a solution of the perfluorocyclopentene derivative is dissolved in a preformed polymer solution, and the solution is used for film formation or molding by means such as casting. You can Alternatively, as another method, a perfluorocyclopentene derivative is dissolved in a polymerization-curable monomer or prepolymer, and this is film-formed or molded by means such as casting, and then polymerized and cured.

As the polymer, a resin having excellent optical characteristics is used, and for example, a styrene polymer, an acrylic polymer, a styrene-acrylic copolymer or a carbonate polymer is used.

Examples of the polymerization-curable monomer include ethyl acrylate, methyl methacrylate, 2-ethylhexyl acrylate, mono- or di-ethyl maleate, vinyl acetate, vinyl propionate, acrylamide, methacrylamide, maleimide, Acrolein, methacrolein, vinyl methyl ketone, vinyl butyl ketone, acrylonitrile, methacrylonitrile, γ-hydroxymethacrylate propyl, β-hydroxyacrylate ethyl, vinyl methyl ether, vinyl ethyl ether, allyl ethyl ether, glycidyl acrylate, glycidyl methacrylate. , Glycidyl vinyl ether, styrene, etc., as well as multi-sensitive monomers such as polyalkylene polyol (meth) acrylic acid ester, bisdiethylene glycol carbon DOO, divinylbenzene and the like,
Used in combination with a radical initiator.

There is no problem even if a reaction such as grafting occurs between the perfluorocyclopentene derivative of the present invention and the polymer during this polymerization.

The perfluorocyclopentene derivative of the present invention can be used alone as a photochromic material, or can be used as a photochromic material in combination with other photochromic materials. In the latter case, the color tone at the time of color development is desired. There is an advantage that the color tone can be adjusted.

When used as an optical recording material, the perfluorocyclopentene derivative-dissolved polymer can be used alone, but in general, the perfluorocyclopentene derivative-dissolved polymer composition is applied to the surface of a plastic film such as biaxially oriented PET. It is preferable to use a coated layer as the recording layer. Paper or metal foil may be used as the substrate for applications where light transmittance is not required.

Ultraviolet rays having a wavelength of 253.7 nm or 184.9 nm are advantageous as the ultraviolet rays for coloring the perfluorocyclopentene derivative of the present invention, while HeN is used as a laser beam as a heat source for writing.
gas laser such as e, CO2, Ar ion, excimer,
Solid-state lasers such as alexandrite, YAG, ruby and glass are used.

On the other hand, as the oxidizing agent for converting the ring-closed compound of the formula (2) into the quinoimine structure of the formula (3), an oxidizing agent known per se, for example, an alkaline agent such as proton sponge is used. Further, as the reducing agent for converting the quinoimine structure of the formula (3) into the ring-closed body of the formula (2), a reducing agent known per se, for example, an acid agent such as trifluoroacetic acid and the like are used.

[0050]

The invention is explained in more detail in the following examples.

Synthesis Example 1 Synthesis of 2,4-dimethylthiophene 9.82 ml (0.1 mo) in a 500 ml four-necked flask.
l) 3-methylthiophene 1 and 50 ml of dry ether
Then, 18.1 ml (0.12 mol) of tetramethylethylenediamine was added. Next, 75.0 ml
(0.12 mol) of n-BuLi / hexane solution was slowly added dropwise using an addition funnel under ice cooling. Under ice cooling 1
The mixture was stirred for 1 hour and further at room temperature for 1 hour. After ice-cooling again, 7.5 ml (0.12 mol) of methyl iodide / dry ether (20 ml) was slowly added dropwise from the dropping funnel. After stirring overnight, pour into 100 ml of ice water and separate the organic layer,
It was extracted with ether. The organic layers were combined, washed with dilute hydrochloric acid, then washed with water and dried over anhydrous magnesium sulfate, and the solvent was distilled off. The obtained liquid was distilled under reduced pressure to obtain a colorless liquid of formula (14).

[0052]

Embedded image

There was obtained 2,4-dimethylthiophene. Yield 9.74 g Yield 87.1%

2,4-dimethyl-3-phenylthiophene
Synthesis of 2,4-dimethylthiophene 3.36 g (0.03 m
ol) / dry diethyl ether 30ml 4.84ml
(0.033 mol) tetramethylethylenediamine
Was added to 22.5 ml (0.036 mol) of n-Bu.
The Li / hexane solution was added dropwise at room temperature using a dropping funnel.
Was. After dropping, stir for 2 hours and dissolve the precipitate with a small amount of THF.
I let you. 36.0 ml (0.036 mol) Zn
Cl₂/ Diethyl ether (1.0M) is added dropwise at room temperature
And dried at room temperature for 3 hours. Prepare this solution in a separate container.
0.33g (3 x 10^-Fourmol) of Pd (PPh
₃) _Four, Iodobenzene 4.4 g (0.028 mo
l), 20 ml of dry THF was added dropwise at room temperature. After dropping
After stirring at 50 ° C. for 3 hours, the mixture was stirred overnight. Organic layer with water added
Is extracted with diethyl ether, washed with dilute hydrochloric acid water,
After drying and evaporating the solvent, column chromatography was performed.
Purified by formula (15)

[0055]

[Chemical 21]

There was obtained 2,4-dimethyl-3-phenylthiophene. Yield 5.16g Yield 92.9%

Synthesis of 3-iodo-2,4-dimethyl-5-phenylthiophene 2,4-dimethyl-3-phenylthiophene 3.76
g (0.02 mol), carbon tetrachloride 35 ml, acetic acid 35
What melt | dissolved 0.81 g of iodic acid in 10 ml of water was added to ml at room temperature, and it heated at 60-65 degreeC. I
₂ 2.54 g (0.01 mol) was added and refluxed for 4 hours. Water was added, the mixture was extracted with chloroform, washed with water and washed with sodium hydrogen carbonate, dried and the solvent was distilled off. Purified by column chromatography, the formula (16)

[0058]

[Chemical formula 22]

3-iodo-2,4-dimethyl-5-phenylthiophene was obtained. Yield 5.08g Yield 80.9%

Synthesis of 1,2-bis (2,4-dimethyl-5-phenylthiophen-3-yl) perfluorocyclopentene 1.83 g (5.83 mmol) 3-iodo-2,4-dimethyl-5-phenylthiophene , THF 20ml
Was cooled to -78 ° C, to which 5.3 ml (8.75 mm
Ol) n-BuLi / hexane solution was added dropwise using a dropping funnel and stirred for 1 hour. 0.37 ml (2.92
(mmol) of perfluorocyclopentene was added in 3 portions and the mixture was stirred overnight. Water was added, the mixture was extracted with diethyl ether, washed with hydrochloric acid and water, dried over anhydrous magnesium sulfate, the solvent was evaporated, and the residue was purified by column chromatography to obtain the compound represented by the formula (17).

[0061]

[Chemical formula 23]

1,2-bis (2,4-dimethyl-5-)
Phenylthiophen-3-yl) perfluorocyclopentene was obtained. Yield 0.792g Yield 51%

1,2-bis (2,4-dimethyl-5-
Synthesis of (4-iodophenyl) thiophen-3-yl) perfluorocyclopentene 1,2-bis (2,4-dimethyl-5-phenylthiophen-3-yl) perfluorocyclopentene 0.7
6 g (1.38 mmol), 20 ml of carbon tetrachloride and 20 ml of acetic acid were added with 0.25 g of iodic acid at room temperature at 10.0.
What was melt | dissolved in ml was added and it heated at 60-65 degreeC.
To this, 0.50 g (0.7 mmol) of I ₂ was added and refluxed for 4 hours. Water was added, the mixture was extracted with chloroform, washed with water and washed with sodium hydrogen carbonate, dried and the solvent was distilled off. Purified by column chromatography to obtain formula (18)

[0064]

[Chemical formula 24]

1,2-bis (2,4-dimethyl-5-)
(4-Iodophenyl) thiophen-3-yl) perfluorocyclopentene was obtained. Yield 1.25g Yield 68.5%

1,2-bis (2,4-dimethyl-5-
Synthesis of (4-phenylaminophenyl) thiophen-3-yl) perfluorocyclopentene In a 100 ml three neck flask 1,2-bis (2,4-
Dimethyl-5- (4-iodophenyl) -3-yl) perfluorocyclopentene 0.10 g (0.13 mm)
ol), 18-crown-6 ether 6.7 mg
(0.25 mmol), 0.14 g of anhydrous potassium carbonate
(1 mmol), copper powder 0.032 g (0.5 mmo
l) and aniline (0.02 g, 2 mmol) were added, and the atmosphere was replaced with nitrogen. Further, 10 ml of o-dichlorobenzene was added, and the mixture was stirred at 160-170 ° C for 15 hours. The reaction solution was filtered, and o-dichlorobenzene was distilled off under reduced pressure, followed by purification by column chromatography to obtain the compound of formula (19).

[0067]

[Chemical 25]

1,2-bis (2,4-dimethyl-5-)
(4-Phenylaminophenyl) thiophen-3-yl) perfluorocyclopentene was obtained. Yield 3.0 mg (3.1%) 270 MHz ¹ H NMR (CDCl ₃ ) δ = 2.08 (s, 6H, Ar—CH ₃ ) 2.33 (s, 6H, Ar—CH ₃ ) 5.77 ( s, 2H, -NH-) 6.93-7.31 (m, 18H, Aromatic-
Proton) Elemental analysis cal. C: 67.96 H: 4.42
N: 3.87 fon. C: 67.95 H: 4.41 N: 3.85 m. p. 89.6 ° C

Synthesis Example 2 Synthesis of 1,2-bis (2,4-dimethyl-5- (4- (4-cyanophenyl) aminophenyl) thiophen-3-yl) perfluorocyclopentene 1 in a 100 ml three-necked flask. , 2-bis (2,4-
Dimethyl-5- (4-iodophenyl) thiophene-3
-Yl) perfluorocyclopentene 39 0.10 g
(0.13 mmol), 18-crown-6 ether 6.7 mg (0.25 mmol), anhydrous potassium carbonate 0.14 g (1 mmol), copper powder 0.032 g (0.5).
mmol), p-aminobenzonitrile 0.02 g
(2 mmol) was added and the atmosphere was replaced with nitrogen. Further, 10 ml of o-dichlorobenzene was added, and the mixture was stirred at 160-170 ° C for 15 hours. The reaction solution is filtered, and o-dichlorobenzene is distilled off under reduced pressure, followed by purification by column chromatography to obtain the compound of the formula (20).

[0070]

[Chemical formula 26]

1,2-bis (2,4-dimethyl-5-)
(4- (4-Cyanophenyl) aminophenyl) thiophen-3-yl) perfluorocyclopentene was obtained. Yield 11.3 mg (5.8%) 270 MHz ¹ H NMR (CDCl ₃ ) δ = 2.18 (s, 6H, Ar-CH ₃ ) 2.23 (s, 6H, Ar-CH ₃ ) 5.57 ( s, 2H, -NH-) 6.91-7.36 (m, 16H, Aromatic-
Proton) Elemental analysis cal. C: 66.67 H: 3.88
N: 7.24 fon. C: 66.68 H: 3.88 N: 7.25 m.p. p. 85.7 ° C

Example 1 1,2-bis (2,4-dimethyl-5-) of the above formula (1)
A toluene solution of (4-phenylaminophenyl) thiophen-3-yl) perfluorocyclopentene (hereinafter referred to as compound 1) was irradiated with ultraviolet light to obtain a compound of formula (21).

[0073]

[Chemical 27]

It is a closed ring. The ring-closure solution was blue.

By adding proton sponge = 1.8 bis (N, N-dimethylamine) naphthalene (several mg) to this solution, the formula (22) was obtained.

[0076]

[Chemical 28]

The quinoimine structure of was obtained, and the solution turned green. The absorption spectrum did not change even when the green solution was irradiated with light having a wavelength of 600 nm or more, and the solution was a green solution.

Comparative Example 1 Similarly, a toluene solution of the derivative of formula (4) (compound 2) is irradiated with ultraviolet light to obtain a ring-closed body of formula (5). The ring-closure solution was blue. Even if proton sponge (several mg) was added to this blue solution, the solution remained a blue solution. Further, by irradiating this solution with light having a wavelength of 500 nm or more, the blue ring-closed body solution was changed to the original colorless ring-opened body solution.

The changes in absorption spectra of Compound 1 and Compound 2 are shown in FIGS.

Example 2 Compound 1 was dissolved in toluene and the concentration in polymethylmethacrylate was 0.3 per unit of polymethylmethacrylate.
A recording film was obtained by dissolving the solution in a molar ratio of 10%, coating the solution on a substrate having electrodes so that the film thickness after drying was 100 μm, and drying.

Ultraviolet light was radiated to the recording film to write a clear blue record. A uniform voltage was applied to this recording film by using the electrode as an anode to change the blue recording portion to the green recording portion. The recording film having the green recording portion was irradiated with Ar-ion laser light to read out the recording. This green recording portion was remarkably stable to laser light.

[0082]

EFFECTS OF THE INVENTION According to the present invention, a chemistry in which a perfluorocyclopentene derivative has a thiophene ring at the α-position (1-position) and β-position (2-position) and an arylaminoarylene chain at the 5-position of the thiophene ring. It has structural features.

By changing the benzothiophene ring in the conventional perfluorocyclopentene derivative to a thiophene ring, not only the isomerization ratio to the ring-closed compound of the formula (2) is improved, but also the arylaminoarylene at the 5-position of the thiophene ring. When the ring-closed compound of formula (2) is oxidized by introducing a chain, the oxidized form of formula (3), which is converted into an arylquinoimine structure, is easily produced.

The ring-closed product of the arylquinoimine structure of the formula (3) has no photochromic property and does not change to another structure upon optical reading of recording, which is extremely convenient for record retention. Further, in the quinoimine-type structure of the formula (3), the molar absorption coefficient (ε) is increased and the maximum absorption wavelength is shifted to the long wavelength side due to the connection of the conjugated chains, as compared with the closed ring of the formula (2). It is possible to obtain an advantageous result in reading the record that the transfer is performed. Furthermore, the phenylaminoquinomethane structure of the formula (3) is converted into the phenyliminomethylidenephenyl structure of the formula (2) by oxidation, and the ring-closed body of the formula (2) has photochromic properties, and therefore is erased by irradiation with light. It can be carried out.

The ring-opened compound of the general formula (1) is generally a bright color such as yellow, the ring-closed compound (cyclohexadiene) of the general formula (2) is green, and the reductant of the formula (3) is Since they are blue and have different hues from each other, and the reductant of formula (3) does not have photochromic properties, high contrast and stable record retention of the recording medium can be obtained.

[Brief description of drawings]

FIG. 1 is an explanatory diagram for explaining an operation as an optical recording medium.

FIG. 2 is an absorption spectrum of a compound of formula (1) according to the present invention.

FIG. 3 is an absorption spectrum of a conventional compound of formula (4).

[Explanation of symbols]

 1 Optical Recording Medium 2 Base (Transparent Base) 3 Recording Layer A Ring-Opened Body B Ring-Closed Body C Reductant

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location G11B 7/00 K 9464-5D 7/24 516 7215-5D

Claims (8)

[Claims] 1. The following formula (1): , The following formula (2) Or the following formula (3) In the formula, R ₁ is a hydrogen atom or a lower alkyl group, and R 1
₂ is a lower alkyl group, R is a hydrogen atom, an alkyl group, an alkoxy group, a tertiary amino group or a cyano group, n is a number from 1 to 5, k is a number from 1 to 5, and m is Is a number from 1 to 5, and is a perfluorocyclopentene derivative represented by. 2. R ₁ and R ₂ are methyl groups.
The perfluorocyclopentene derivative described. 3. In the formula (1), (2) or (3), each of R ₁ and R ₂ is a methyl group, R is a hydrogen atom, and each of n, k and m is 1. The perfluorocyclopentene derivative according to claim 1. 4. In the above formula (1), (2) or (3), each of R ₁ and R ₂ is a methyl group, R is a cyano group, and each of n, k and m is 1. The perfluorocyclopentene derivative according to claim 1. 5. The following formula (1): Or the following formula (2) In the formula, R ₁ is a hydrogen atom or a lower alkyl group, and R 1
₂ is a lower alkyl group, R is a hydrogen atom, an alkyl group, an alkoxy group, a tertiary amino group or a cyano group, n is a number of 1 to 5, k is a number of 1 to 5, and m is Is a perfluorocyclopentene derivative represented by the following formula: 1. A photochromic material. 6. The following formula (1): , The following formula (2): Or the following formula (3) In the formula, R ₁ is a hydrogen atom or a lower alkyl group, and R 1
₂ is a lower alkyl group, R is a hydrogen atom, an alkyl group, an alkoxy group, a tertiary amino group or a cyano group, n is a number of 1 to 5, k is a number of 1 to 5, and m is Is a number from 1 to 5, and a layer containing a perfluorocyclopentene derivative represented by is provided on a substrate. 7. The following formula (1): In the formula, R ₁ is a hydrogen atom or a lower alkyl group, and R 1
₂ is a lower alkyl group, R is a hydrogen atom, an alkyl group, an alkoxy group, a tertiary amino group or a cyano group, n is a number of 1 to 5, k is a number of 1 to 5, and m is Is a number from 1 to 5, and the layer containing the perfluorocyclopentene derivative represented by is irradiated with an actinic ray to obtain a compound represented by the following formula (2): To form an image consisting of isomerized molecules of An optical recording method comprising the step of converting an image of a compound consisting of ## STR3 ## to stabilize the isomerized molecule against a reading light beam. 8. A stabilized isomerized molecule of formula (3) is reduced to a compound of formula (2) and then converted to a compound of formula (1) by irradiating the compound of formula (2) with visible light. The optical recording method according to claim 7, wherein the image is erased by this.