JP3175279B2 - Metal chelate compound and optical recording medium using the compound - Google Patents

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

The present invention relates to a novel azo metal chelate compound of an azo compound and a metal salt, and an optical recording medium using the compound.

[0002]

2. Description of the Related Art In recent years, optical recording using a laser has been particularly developed in order to enable high-density information storage and reproduction. An example of the optical recording medium is an optical disk. In general, an optical disc has a thin recording layer provided on a circular base, and
Irradiating a laser beam focused to about μm to perform high-density information recording. The recording is performed by causing thermal deformation such as decomposition, evaporation, or dissolution in the recording layer at that location due to absorption of the irradiated laser light energy. Reproduction of recorded information is performed by reading the difference in reflectance between a portion where deformation has occurred and a portion where no deformation has occurred due to laser light. Therefore, as the optical recording medium, it is necessary to efficiently absorb the energy of the laser light, and a laser absorbing dye is used.

As this type of optical recording medium, those having various configurations are known. For example, Japanese Patent Application Laid-Open No. 55-970
Japanese Patent Publication No. 33 discloses that a single layer of a phthalocyanine dye is provided on a substrate. However, phthalocyanine-based dyes have problems such as low sensitivity, high decomposition point, and difficulty in vapor deposition, and further, they have extremely low solubility in organic solvents and cannot be used for coating by application. ing.

Further, Japanese Patent Application Laid-Open Nos. 58-112790 and 5
Nos. 8-114989, 59-85791, 60-
JP-A-83236 discloses those in which a cyanine dye is provided in a recording layer. However, such dyes have high solubility and have the advantage of being capable of coating by application, but have the problem of poor light fastness. For this reason, JP-A-59-55795 discloses such a dye. It has been studied to improve the light fastness by adding a quencher to this cyanine dye, but it is still at an insufficient level.

Regarding these problems, Japanese Patent Application Laid-Open No. 62-30 / 1987
No. 090 discloses a complex of a monoazo compound and a metal as a medium having improved solubility in an organic solvent and light resistance. However, these compounds have a short photosensitive wavelength, are inferior in sensitivity, and have poor storage stability under high temperature and high humidity, and have a problem as a recording medium.

[0006]

SUMMARY OF THE INVENTION The present invention provides an azo dye suitable for spin coating, which is excellent in sensitivity, storage stability and weather resistance, as a recording dye which solves the above problems and an optical recording medium using the same. It is an object of the present invention to provide an azo metal chelate compound of a system compound and a metal and an optical recording medium using the compound.

[0007]

SUMMARY OF THE INVENTION The present invention provides an azo metal chelate compound of an azo compound represented by the following general formula [I] and a metal, and an optical recording medium using the compound as a recording dye. Is what you do.

[0008]

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Wherein A represents a residue which, together with the carbon and nitrogen atoms to which it is attached, forms a heterocycle, and X, together with the two carbon atoms to which it is attached, R ¹ represents an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkenyl group, or an optionally substituted cycloalkyl Represents a group, Y represents a hydrogen atom or a cation, and n is an integer of 1 to 3.) Hereinafter, the present invention will be described in detail.

Preferred azo compounds in the present invention include compounds represented by the following general formula [II].

[0011]

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(Wherein ring B may have a substituent. X represents a residue which forms an aromatic ring together with the two carbon atoms to which it is bonded, and R ¹ represents Represents an alkyl group which may be substituted, an aryl group which may be substituted, an alkenyl group which may be substituted or a cycloalkyl group which may be substituted, Y represents a hydrogen atom or a cation, and n represents It is an integer of 1 to 3.) More preferred azo compounds include the following general formula [III]:
The compound shown by these is mentioned.

[0013]

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(Wherein, rings B and C may each independently have a substituent. R ¹ is an optionally substituted alkyl group, an optionally substituted aryl group, Represents an optionally substituted alkenyl group or an optionally substituted cycloalkyl group, wherein R ³ and R ⁴ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, Represents an optionally substituted alkenyl group or an optionally substituted cycloalkyl group, Y represents a hydrogen atom or a cation, and n is an integer of 1 to 3.) Particularly preferred azo compounds are represented by the following general formula: The compound represented by [IV] is mentioned.

[0015]

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(Wherein R ¹ represents an alkyl group which may be substituted, an aryl group which may be substituted, an alkenyl group which may be substituted or a cycloalkyl group which may be substituted; ⁴ and R ⁵ each independently represent an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 7 carbon atoms, and R ⁶ and R ⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms. X represents an alkoxy group having 1 to 6 carbon atoms or a halogen atom;
Represents a hydrogen atom or a cation, and n is an integer of 1 to 3. In the general formula [I], A is not particularly limited as long as it forms a heterocyclic ring together with the carbon atom and the nitrogen atom to which it is bonded. For example, in the general formula [1]

[0017]

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The following are mentioned as examples.

[0019]

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(In the formula, ring D may have a substituent. Examples of the substituent include an alkyl group, an alkoxy group, a halogen atom, an alkylsulfonyl group, an alkylcarbonyl group, a formyl group, a nitro group, and trifluoromethyl. Group, trifluoromethoxy group, cyano group, alkylthio group, etc., and Z ¹ represents a hydrogen atom, an alkyl group, a halogen atom, an aryl group, etc., and Z ² represents a hydrogen atom, a hydrogen alkyl group, etc.) In the general formula [I], X includes a group which forms an aromatic ring such as a benzene ring and a naphthalene ring together with two carbon atoms to which it is bonded.

In the general formula [II], the substituent of ring B is an alkyl group, an alkoxy group, a halogen atom, a nitro group, a cyano group, an alkylsulfonyl group, an alkylcarbonyl group, a trifluoromethyl group, a trifluoromethoxy group, Examples include an alkylthio group and a formyl group. In the general formula [III], examples of the substituent on the ring C include an alkyl group, an alkoxy group, and a halogen atom, and R ³ and R ⁴ represent a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, an aryl group, Represents an alkenyl group or a cycloalkyl group, and these groups may be substituted.

Examples of the substituent of the alkyl group, aryl group, alkenyl group or cycloalkyl group represented by R ³ and R ⁴ include, for example, alkoxy group, alkoxyalkoxy group, alkoxyalkoxyalkoxy group, allyloxy group, aryl group, aryl group Examples thereof include an oxy group, a cyano group, a nitro group, a hydroxy group, a tetrahydrofuryl group, an alkylsulfonylamino group, and a halogen atom. In addition, an alkyl group or a vinyl group is exemplified as a substituent of an aryl group or a cycloalkyl group.

In the present invention, specific examples of the azo compound forming a chelate compound with a metal include, for example, the following, which can be used alone or in combination of two or more.

[0024]

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[0025]

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[0026]

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[0027]

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[0028]

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[0029]

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[0030]

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In the present invention, the metal forming the chelate compound with the azo compound is not particularly limited as long as it is generally a metal capable of forming a chelate compound with the azo compound, but Ni, Co, Fe, Ru, Rh, Pd, O
Transition elements such as s, Ir, and Pt are preferable, and particularly, Ni,
Co is preferred.

The general synthesis of the azo metal chelate compounds of the present invention is described, for example, in Furukawa; Analytica Chim.
ica Acta 140 (1982) 281-289
Can be carried out according to the description of That is, the general formula [V]

[0033]

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(Wherein rings B, R ¹ and n are the same as defined above), are diazotized by a conventional method to give the following general formula [VI]

[0035]

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(Wherein, rings C, R ² , R ³ and Y are the same as defined above) to form an azo compound represented by the above general formula [III] by coupling with a substituted anilinesulfonic acid derivative represented by the following formula: Then, the azo compound and the metal salt are reacted with water and / or an organic solvent such as dioxane, tetrahydrofuran, acetone, ethanol, or methanol to produce the azo metal chelate compound of the present invention.

[0037] As the anion of the metal salt used in the preparation of the metal _{^{complexes, SCN -, SbF 6 -,}} Cl -, Br -,
_{^{F -, ClO 4 -, BF}} 4 -, PF 6 -, CH 3 COO
_{^{-, TiF 6 2-, SiF 6}} 2-, ZrF 6 2-,

[0038]

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[0039] such as monovalent or divalent anion include, in particular CH ₃ COO ^- are preferred. The optical recording medium of the present invention is basically composed of a substrate and a recording layer containing the metal chelate compound of the azo compound. Can be provided. Further, as a preferable layer structure, a recording medium is provided with a metal reflection layer such as gold or aluminum and a protective layer to provide a medium with high reflectivity, which can be a write-once CD medium.

The substrate in the present invention is preferably transparent to the laser beam to be used, and may be a support of a general recording material such as glass or plastic, or plastic is suitable from various points. Plastics include acrylic resin, methacrylic resin, vinyl acetate resin, vinyl chloride resin, nitrocellulose, polyethylene resin, polypropylene resin, polycarbonate resin, polyimide resin, epoxy resin, polysulfone resin, etc. Among them, high productivity and cost Injection molded polycarbonate resin substrates are particularly preferred from the viewpoint of moisture absorption resistance.

The recording layer containing a complex of an azo compound and a metal in the optical recording medium of the present invention has a thickness of 100 to 100 μm.
5 μm, preferably 700 ° to 3 μm. The film can be formed by a generally used thin film forming method such as a vacuum evaporation method, a sputtering method, a doctor blade method, a casting method, a spinner method, and an immersion method, but from the viewpoint of mass productivity and cost, the spinner method is used. Is preferred.

Further, a binder can be used if necessary. Known binders such as polyvinyl alcohol, polyvinyl pyrrolidone, ketone resin, nitrocellulose, cellulose acetate, polyvinyl butyral, and polycarbonate are used as the binder. In the case of film formation by a spinner method, the number of rotations is preferably 500 to 5000 rpm, and after spin coating, depending on the case, treatment such as heating or exposure to solvent vapor may be performed.

In order to improve the stability and light resistance of the recording layer, a transition metal chelate compound (for example, acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-α-diketone, etc.) is used as a singlet oxygen quencher. ) May be contained. Further, other dyes can be used together if necessary. The other dye may be another kind of the same series of compounds,
Other types of dyes such as a triarylmethane dye, an azo dye, a cyanine dye, a squarylium dye, and a Ni-indoaniline dye may be used.

When the recording layer is formed by a coating method such as a doctor blade method, a casting method, a spinner method, and a dipping method, particularly a spinner method, the coating solvent may be tetrafluoropropanol, octafluoropentanol, tetrachloroethane, bromoform, Dibromoethane, diacetone alcohol, ethyl cellosolve, xylene, 3-hydroxy-3-methyl-2-butanone, chlorobenzene,
Boiling point of cyclohexanone, methyl lactate, etc. 120 to 160
° C is preferably used.

Among these, for an injection-molded polycarbonate resin substrate which is excellent in high productivity, cost and moisture absorption resistance, diacetone alcohol, 3-hydroxy-, and the like can be preferably used without damaging the substrate. 3
Ketone alcohol solvents such as -methyl-2-butanone;
Cellosolve solvents such as methyl cellosolve and ethyl cellosolve; perfluoroalkyl alcohol solvents such as tetrafluoropropanol and octafluoropentanol; and hydroxyester solvents such as methyl lactate and methyl isobutyrate.

The recording layer of the optical recording medium of the present invention may be provided on both sides of the substrate, or may be provided on one side. Recording on the optical recording medium obtained as described above is performed by irradiating a laser beam, preferably a semiconductor laser beam, focused to about 1 μm on a recording layer provided on both sides or one side of the substrate. Thermal deformation of the recording layer such as decomposition, evaporation, and melting occurs due to absorption of laser light energy in the portion irradiated with the laser light.

Reproduction of recorded information is performed by reading the difference in reflectance between a portion where thermal deformation has occurred and a portion where thermal deformation has not occurred using a laser beam. The laser beam used for the optical recording medium of the present invention is N ₂ , He-
Cd, Ar, He-Ne, ruby, semiconductor, dye laser, and the like can be mentioned, and a semiconductor laser is particularly preferable in terms of lightness, ease of handling, compactness, and the like.

[0048]

The present invention will be described in detail with reference to the following Examples, which should not be construed as limiting the present invention. Example 1 (a) Production example

[0049]

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22.67 g of methyl p-aminobenzoate represented by the above structural formula (1) and 45.66 g of ammonium thiocyanate were added to 375 ml of acetic acid and 18.8 m of water.
10.0 ml of a mixed solution at 10 ° C.
Of acetic acid in 75 ml was added dropwise. After stirring for 2 hours, it was left overnight. Heated to 70 ° C. and stirred for 11 hours. The mixture was filtered while hot, the filtrate was poured into 500 ml of hot water, and the precipitated crystals were removed by filtration. Sodium carbonate was added to the filtrate, and pH = 5
The precipitated crystals were filtered, washed with water, and dried to give pale yellow crystals of the compound represented by the following structural formula (2).
5.09 g were obtained. MASS spectrum M ⁺ = 20
8

[0051]

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The obtained 2- represented by the above-mentioned structural formula (2)
Amino-6-carbomethoxybenzothiazole 4.16
g was dissolved in 35.6 g of phosphoric acid and 1.98 g of sulfuric acid, and 12.6 ml of acetic acid and 1.70 g of sodium nitrate were added. Then, 4.86 g of sulfuric acid was added dropwise at 0 to 5 ° C., and 0 to −5 ° C. Diazotization was performed using 6.93 g of 44% nitrosylsulfuric acid, and the resulting diazo solution was dissolved in 300 ml of methanol, 8.04 g of 2-dipropylaminoanisole-4-sulfonic acid, 0.8 g of urea, and 8.0 g of sodium acetate. The solution was added dropwise at a temperature of 0 to 5 ° C. using an alkaline compound such as an aqueous ammonium solution while maintaining the pH at 4 to 6. After stirring for 4 hours, the mixture was left overnight. The precipitated crystals were separated by filtration and dried to obtain 7.66 g of dark brown crystals represented by the following structural formula (3).

[0053]

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2.03 g of the azo compound represented by the structural formula (3) obtained as described above was added to 200 ml of methanol.
In nickel, 0.60 g of nickel acetate in 5 ml of methanol
After adding the solution, the mixture was stirred at room temperature for 4 hours. The precipitated crystals were separated by filtration, washed with methanol, and dried to obtain 1.55 g of a nickel chelate compound as dark brown crystals.
The λ _max (in chloroform) of this compound is 690 nm
(Ε = 1.34 × 10 ⁵ ) (FIG. 1). Also, the melting point was higher than 250 ° C. FIG. 2 shows the infrared absorption spectrum of this compound.

(B) Example of recording medium 0.15 g of the nickel chelate compound of the azo compound obtained in the above Production Example (a) was added to octafluoropentanol 7.5.
g, and filtered through a 0.22 μm filter to obtain a solution. 5 ml of this solution is 700Å in depth and 0.7μ in width
m was dropped on an injection-molded polycarbonate resin substrate (5 inches in diameter) with a groove (groove) of m, and was applied by a spinner method at a rotation speed of 500 rpm. After application, at 60 ° C 1
Dry for 0 minutes. The maximum absorption wavelength of the coating film was 714 nm.

FIG. 3 shows the absorption spectrum of the coating film. Next, an Au film having a thickness of 200 Å was formed on this coating film by a sputtering method to form a reflection layer. Furthermore,
Spin coating of UV curable resin on this reflective layer,
This was irradiated with ultraviolet rays and cured to form a protective layer having a thickness of 10 μm.

(C) Optical Recording Method While rotating the recording medium at 1.4 m / s, the recording power was 7.3 with a semiconductor laser beam having a center wavelength of 780 nm.
Irradiation at mW and EFM signals were recorded. Next, when the recorded portion was reproduced by a CD player having a semiconductor laser having a center wavelength of 780 nm, a good reproduced signal was obtained. This disc has light resistance (xenon fademeter accelerated test; 60 hours) and storage stability (70 ° C, 85% R
H: 500 hours) As a result of the test, no deterioration in sensitivity and reproduction signal was observed as compared with the initial stage, and the optical recording medium was extremely excellent.

Comparative Example 1 The following structural formula (4)

[0059]

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A nickel chelate compound obtained from the azo compound represented by the above structural formula (4) and nickel acetate was applied in the same manner as in Example 1, a reflective layer and a protective layer were provided, and a disk was prepared. As a result, the sensitivity was inferior to that of the optical recording medium of Example 1 of the present invention (sensitivity: 7.5 mW).

Example 2 (a) Production Example Instead of the methyl p-aminobenzoate used in Example 1, the following structural formula (5)

[0062]

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By using the same method as in Example 1 except for using 24.78 g of ethyl p-aminobenzoate represented by the following formula, 33.28 g of a benzothiazole derivative represented by the following structural formula (6) was obtained. Was.

[0064]

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The 2-amino- represented by the structural formula (6)
Except that 4.45 g of 6-carbethoxybenzothiazole was used, it was prepared in the same manner as in Example 1 to obtain crystals of the azo compound represented by the following structural formula (7) 6.3.
0 g was obtained.

[0066]

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Produced in the same manner as in Example 1 except that 2.08 g of the azo compound represented by the structural formula (7) was used, and a dark brown crystal 1.4 of a nickel chelate compound was obtained.
7 g were obtained. Absorption spectrum of a chloroform solution of this compound _{λ max 608nm (ε = 1.35 ×} 10 5)
Met.

(B) Example of recording medium 0.15 g of the nickel chelate compound of the azo compound obtained in the above-mentioned Production Example (a) was added to octafluoropentanol 7.5.
g, and filtered through a 0.22 μm filter to obtain a solution. 5 ml of this solution is 700Å in depth and 0.7μ in width
m was dropped on an injection-molded polycarbonate resin substrate (5 inches in diameter) with a groove (groove) of m, and was applied by a spinner method at a rotation speed of 500 rpm. After application, at 60 ° C 1
Dry for 0 minutes. The maximum absorption wavelength of the coating film was 713 nm.

Next, a 200-Å-thick Au film was formed on this coating film by a sputtering method to form a reflection layer. Further, an ultraviolet-curable resin was spin-coated on the reflective layer, and was irradiated with ultraviolet rays to be cured to form a protective layer having a thickness of 10 μm.

(C) Optical Recording Method While rotating the recording medium at 1.4 m / s, the recording power was 7.4 with a semiconductor laser beam having a center wavelength of 780 nm.
Irradiation at mW and EFM signals were recorded. Next, when the recorded portion was reproduced by a CD player having a semiconductor laser having a center wavelength of 780 nm, a good reproduced signal was obtained. This disc has light resistance (xenon fademeter accelerated test; 60 hours) and storage stability (70 ° C, 85% R
H: 500 hours) As a result of the test, no deterioration in sensitivity and reproduction signal was observed as compared with the initial stage, and the optical recording medium was extremely excellent.

Example 3 A solution obtained by using the compound shown in Table 1 instead of the compound used in Example 1 was applied on a substrate.
An optical recording medium having the maximum absorption wavelength of the coating film shown in Table 1 was obtained. When the recording medium thus obtained was written using a semiconductor laser as a light source, the recording medium was excellent in sensitivity, light resistance and storage stability.

[0072]

[Table 1]

[0073]

The metal chelate compound of the azo compound of the present invention has high solubility in an organic solvent, can be coated by coating, and has good sensitivity and light resistance.
An optical recording medium having excellent storage stability and using the metal chelate compound is extremely useful industrially.

[Brief description of the drawings]

FIG. 1 is a view showing a visible absorption spectrum of a nickel chelate compound obtained in Example 1 of the present invention in a chloroform solution.

FIG. 2 is a diagram showing an infrared absorption spectrum of a nickel chelate compound obtained in Example 1 of the present invention.

FIG. 3 is a view showing a visible absorption spectrum of a thin film coated with a nickel chelate compound obtained in Example 1 of the present invention.

FIG. 4 is a view showing an infrared absorption spectrum of a nickel chelate compound obtained in Example 2 of the present invention.

────────────────────────────────────────────────── ─── Continued on the front page (51) Int.Cl. ⁷ Identification symbol FI G11C 13/04 B41M 5/26 Y (72) Inventor Satoru Imamura 1000 Kamoshida-cho, Midori-ku, Yokohama-shi, Kanagawa Prefecture Mitsubishi Chemical Corporation (56) References JP-A-62-20090 (JP, A) JP-A-4-141489 (JP, A) WO 91/18057 (WO, A1) Chemical Abstracts, 95: 143427 (1981) (58) ) Field surveyed (Int. Cl. ⁷ , DB name) C09B 29/09 C09B 29/045 CA (STN) REGISTRY (STN)

Claims (11)

(57) [Claims] An azo metal chelate compound of an azo compound represented by the general formula [I] and a metal. Embedded image Wherein A represents a residue which, together with the carbon and nitrogen atoms to which it is attached, forms a heterocycle, and X, which, together with the two carbon atoms to which it is attached, is aromatic. And R ¹ represents an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkenyl group or an optionally substituted cycloalkyl group. , Y represents a hydrogen atom or a cation, and n is an integer of 1 to 3.) 2. The azo metal chelate compound according to claim 1, wherein the azo compound is a compound represented by the following general formula [II]. Embedded image (Wherein ring B may have a substituent; X represents a residue that forms an aromatic ring together with the two carbon atoms to which it is attached, and R ¹ is substituted Represents an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkenyl group or an optionally substituted cycloalkyl group, Y represents a hydrogen atom or a cation, and n represents 1-3 Is an integer.) 3. The azo metal chelate compound according to claim 1, wherein the azo compound is a compound represented by the following general formula [III]. Embedded image (Wherein, rings B and C may each independently have a substituent. R ¹ may be an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted Represents an alkenyl group or an optionally substituted cycloalkyl group, wherein R ² and R ³ each independently represent a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, Represents an optionally substituted alkenyl group or an optionally substituted cycloalkyl group; Y represents a hydrogen atom or a cation;
It is an integer of 3. ) 4. The azo metal chelate compound according to claim 1, wherein the azo compound is a compound represented by the following general formula [IV]. Embedded image (In the formula, R ¹ may be substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkenyl or optionally substituted cycloalkyl group, R ⁴ and R ⁵ each independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 7 carbon atoms, and R ⁶ and R ⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, Represents an alkoxy group of 1 to 6 or a halogen atom, X represents a hydrogen atom or a cation, and n is an integer of 1 to 3.) 5. An optical recording medium provided with a recording layer on which information can be written and / or read by a laser on a substrate, wherein the recording layer comprises an azo compound represented by the following general formula [I], a metal An optical recording medium comprising an azo metal chelate compound of the formula (1). Embedded image (Where A represents a residue which, together with the carbon and nitrogen atoms to which it is attached, forms a polycyclic ring, and X, together with the two carbon atoms to which it is attached, Represents an aromatic residue; R ¹ represents an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkenyl group or an optionally substituted cycloalkyl group; Y represents a hydrogen atom or a cation, and n is an integer of 1 to 3.) 6. The optical recording medium according to claim 5, wherein the azo compound is a compound represented by the following general formula [II]. Embedded image (Wherein ring B may have a substituent; X represents a residue that forms an aromatic ring together with the two carbon atoms to which it is attached, and R ¹ is substituted Represents an optionally substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkenyl group or an optionally substituted cycloalkyl group, Y represents a hydrogen atom or a cation, and n represents 1-3 Is an integer.) 7. The optical recording medium according to claim 5, wherein the azo compound is a compound represented by the following general formula [III]. Embedded image (Wherein, rings B and C may each independently have a substituent. R ¹ may be an optionally substituted alkyl group, an optionally substituted aryl group, or an optionally substituted Represents an alkenyl group or an optionally substituted cycloalkyl group, wherein R ³ and R ⁴ are each independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group, Represents an optionally substituted alkenyl group or an optionally substituted cycloalkyl group; Y represents a hydrogen atom or a cation;
It is an integer of 3. ) 8. The optical recording medium according to claim 5, wherein the azo compound is a compound represented by the following general formula [IV]. Embedded image (In the formula, R ¹ may be substituted alkyl group, an optionally substituted aryl group, an optionally substituted alkenyl or optionally substituted cycloalkyl group, R ⁴ and R ⁵ each independently represents an alkyl group having 1 to 6 carbon atoms or an alkoxyalkyl group having 2 to 7 carbon atoms, and R ⁶ and R ⁷ each independently represent a hydrogen atom, an alkyl group having 1 to 6 carbon atoms, Represents an alkoxy group of 1 to 6 or a halogen atom, X represents a hydrogen atom or a cation, and n is an integer of 1 to 3.) 9. The optical recording medium according to any one of claims 5 to 8 metal is characterized by a transition element. 10. The optical recording medium of <br/> according to any one of claims 5 to 9, wherein providing the reflective layer and the protective layer of metal on the recording layer. 11. The method according to claim 1, wherein the metal is a transition element.
An azo metal chelate according to any one of claims 1 to 4.
Compound.