JPH0819341B2 - Metal chelate compound and optical recording medium using the compound - Google Patents

Description

Detailed Description of the Invention

[0001]

FIELD OF THE INVENTION 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, development of optical recording using a laser has been particularly promoted in order to enable high density information recording, storage and reproduction. An optical disc can be given as an example of the optical recording medium. In general, an optical disc has a thin recording layer provided on a circular substrate with a thickness of 1 μm.
By irradiating a laser beam focused to about m, high density information recording is performed. The recording is recorded on the recording layer at that location by absorption of the laser light energy applied.
This is done by producing thermal deformations such as decomposition, evaporation, and dissolution. The recorded information is reproduced by reading the difference in reflectance between the portion where the laser light is deformed and the portion where the laser light is not deformed. Therefore,
As the optical recording medium, it is necessary to efficiently absorb the energy of laser light, and a laser absorbing dye is used.

Various types of optical recording media are known as this type of optical recording medium. For example, JP-A-55-9703
Japanese Patent No. 3 discloses a substrate in which a single layer of a phthalocyanine dye is provided. However, phthalocyanine dyes have the problems of low sensitivity, high decomposition point and difficulty in vapor deposition, and also have the problem that they have extremely low solubility in organic solvents and cannot be used for coating by coating. ing.

Further, Japanese Patent Laid-Open Nos. 58-112790 and 5-5.
8-114989, 59-85791, 60-
Each of Japanese Patent No. 83236 discloses a recording layer provided with a cyanine dye. However, such dyes have the advantage that they have high solubility and can be coated by coating, but on the other hand, they have the problem of poor light resistance. Therefore, JP-A-59-55795 discloses them. It has been studied to add a quencher to this cyanine dye to improve the light resistance, but the level is still insufficient.

Regarding these problems, JP-A-62-30
JP-A 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
Since it has a short photosensitive wavelength and poor sensitivity, and further has poor storage stability under high temperature and high humidity, it has a problem as a recording medium.

[0006]

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

[0007]

The gist of the present invention is an azo metal chelate compound of an azo compound represented by the above general formula [I] and a metal, and an optical recording medium using the compound as a recording dye. To do. Hereinafter, the present invention will be described in detail.

In the above general formula [I], the substituent of ring B other than the --SR ¹ group is an alkyl group, an alkoxy group,
Halogen atom, nitro group, cyano group, alkylsulfonyl group, alkylcarbonyl group, trifluoromethyl group,
Examples thereof include trifluoromethoxy group, alkylthio group, and formyl group. In the general formula [I], —SO ₃
Examples of the substituent of the ring C other than the Y group include an alkyl group, an alkoxy group, a halogen atom and the like, and as R ² and R ³ , a hydrogen atom or an alkyl group having 1 to 20 carbon atoms, an aryl group, an alkenyl group, Or, it represents a cycloalkyl group, and these groups may be substituted.

The substituent of the alkyl group, aryl group, alkenyl group or cycloalkyl group represented by R ² and R ³ is, for example, an alkoxy group, an alkoxyalkoxy group, an alkoxyalkoxyalkoxy group, an allyloxy group, an aryl group or aryl. 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 to these, examples of the substituent of the aryl group and the cycloalkyl group include an alkyl group and a vinyl group.

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

[0011]

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[0012]

[Chemical 4]

[0013]

Embedded image

[0014]

[Chemical 6]

[0015]

[Chemical 7]

In the present invention, the metal forming the chelate compound with the azo compound is not particularly limited as long as it is a metal capable of forming the 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 Ni and C are particularly preferable.
o is preferred. General syntheses of azo metal chelate compounds of the present invention are described, for example, in Furukawa; Analytica Chi.
mica Acta 140 (1982) 281-28
It can be performed according to the description of 9.

That is, the general formula [III]

[0018]

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An amino compound represented by the formula (rings B, R ¹ and n are the same as defined above) is diazotized according to a conventional method to give the following general formula [IV]:

[0020]

[Chemical 9]

(Wherein, ring C, R ² , R ³ and Y are the same as defined above), the azo compound represented by the above general formula [I] is coupled with the substituted anilinesulfonic acid derivative represented by the formula. Then, the azo compound, the metal salt, water and / or dioxane, tetrahydrofuran, acetone,
The azo metal chelate compound of the present invention can be produced by reacting in an organic solvent such as ethanol or methanol.

The anions of the metal salt used in the production of the metal chelate compound include SCN ⁻ , SbF ₆ ⁻ and C.
l ⁻ , Br ⁻ , F ⁻ , ClO ₄ ⁻ , BF ₄ ⁻ , P
_{^{F 6 -, CH 3 COO -}} , TiF 6 2 -, Si
_{^{F 6 2 -, ZrF 6 2}} -, Ph-SO 3 -, CH 3 -P
Examples thereof include monovalent or divalent anions such as h-SO ₃ ⁻ and B ⁻ − (Ph) ₄ , and CH ₃ COO ⁻ is particularly preferable (in the above formula, Ph represents a benzene ring). The optical recording medium of the present invention basically comprises a substrate and a recording layer containing a metal chelate compound of the azo compound, but an undercoat layer is further provided on the substrate if necessary. be able to. In addition, as a preferable layer structure, a metal reflective layer such as gold or aluminum and a protective layer are provided on the recording layer to form a medium having a high reflectance, and a recordable CD medium can be used.

The substrate in the present invention is preferably transparent to the laser light used, and examples thereof include supports for common recording materials such as glass and plastic, or plastic is preferable from various points. Examples of 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 these, high productivity and cost From the viewpoint of moisture absorption resistance, an injection molded polycarbonate resin substrate is particularly preferable.

The recording layer containing a complex of an azo compound and a metal in the optical recording medium of the present invention has a film thickness of 100Å.
It is 5 μm, preferably 700 Å to 3 μm. As a film forming method, it is possible to form a film by 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. Is preferred.

If desired, a binder can be used. Known binders such as polyvinyl alcohol, polyvinylpyrrolidone, ketone resins, nitrocellulose, cellulose acetate, polyvinyl butyral, and polycarbonate are used as the binder. In the case of film formation by the spinner method, the rotation speed is preferably 500 to 5000 rpm, and after spin coating, treatment such as heating or applying to solvent vapor may be performed depending on the case.

To improve the stability and light resistance of the recording layer, a transition metal chelate compound (eg, 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 in combination, if necessary. The other pigment may be a different type of compound of the same family,
Other types of dyes such as triarylmethane dyes, azo dyes, cyanine dyes, squarylium dyes, and Ni-indoaniline dyes may be used.

As a coating solvent for forming the recording layer by a coating method such as a doctor blade method, a casting method, a spinner method, a dipping method, or a spinner method, tetrafluoropropanol, octafluoropentanol, tetrachloroethane, bromoform, Dibromoethane, diacetone alcohol, ethyl cellosolve, xylene, 3-hydroxy-3-methyl-2-butanone, chlorobenzene,
Boiling point of cyclohexanone, methyl lactate, etc. 120-160
Those of ℃ are preferably used.

Among these, for the injection-molded polycarbonate resin substrate excellent in high productivity, cost and moisture absorption resistance, diacetone alcohol, 3-hydroxy-, etc. are particularly suitable as a solvent which can be suitably used without leaving the substrate. Three
A ketone alcohol solvent such as methyl-2-butanone;
Cellosolve solvents such as methyl cellosolve and ethyl cellosolve; perfluoroalkyl alcohol solvents such as tetrafluoropropanol and octafluoropentanol; hydroxy ester 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 or one side of the substrate. Recording on the optical recording medium obtained as described above is performed by irradiating a recording layer provided on both sides or one side of the substrate with a laser beam focused to about 1 μm, preferably a semiconductor laser beam. In the portion irradiated with laser light, thermal deformation of the recording layer such as decomposition, evaporation, and melting occurs due to absorption of laser light energy.

The recorded information is reproduced by reading the difference in reflectance between the portion where thermal deformation has occurred and the portion where thermal deformation has not occurred, using laser light. The laser light 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, but in particular, light weight, easy handling,
A semiconductor laser is preferable in terms of compactness and the like.

[0031]

EXAMPLES The present invention will be specifically described below with reference to examples, but the examples do not limit the present invention. Example 1 (a) Production example

[0032]

[Chemical 10]

4.63 g of p-aminophenyltrifluoromethyl sulfide represented by the above structural formula (1) and 7.61 g of ammonium thiocyanate were added to 62.5 ml of acetic acid,
It was dissolved in a mixed solution of 3.1 ml of water, and a solution of 5.0 g of bromine in 12.5 ml of acetic acid was added dropwise at 10 ° C. After stirring for 2 hours, it was left overnight. Heat to 70 ° C. and stir for 4 hours. The mixture was filtered while hot, the filtrate was poured into 250 ml of hot water, and the precipitated crystals were filtered off. Sodium carbonate was added to the filtrate to adjust the pH to 6, and the precipitated crystals were filtered and washed with water,
When dried, 5.21 g of pale yellow crystals of the compound represented by the following structural formula (2) were obtained (MASS spectrum M
⁺ = 250).

[0034]

[Chemical 11]

2- obtained by the above structural formula (2)
2.50 g of amino-6-trifluoromethylthiobenzothiazole was dissolved in 17.8 g of phosphoric acid and 0.99 g of sulfuric acid, 6.3 ml of acetic acid and 0.85 g of sodium nitrate were added, and then sulfuric acid was added at 0 to 5 ° C. to 2. 43 g was added dropwise, and 0 to -5
Diazotization was carried out at 44 ° C. with 3.47 g of 44% nitrosylsulfuric acid, and the resulting diazo solution was added to 150 ml of methanol to give 2-dipropylaminoanisole-4-sulfonic acid 3.73.
g, 0.4 g of urea, and 4.0 g of sodium acetate were added dropwise to the solution at a temperature of 0 to 5 ° C. while using an alkaline compound such as an aqueous ammonium solution while maintaining pH 4 to 6. After stirring for 2 hours, it was left overnight. The precipitated crystals were separated by filtration and dried to obtain 4.92 g of dark brown crystals represented by the following structural formula (3). The λ _max (in methanol) of this compound was 561 nm.

[0036]

[Chemical 12]

4.06 g of the azo compound represented by the structural formula (3) obtained above was added to 300 ml of methanol.
Was dissolved in 30 ml of a solution of 2.21 g of nickel acetate in 30 ml of methanol at 15 to 18 ° C., and the mixture was stirred at room temperature for 5 hours. The precipitated crystals were separated by filtration, washed with methanol and dried to obtain 2.66 g of dark brown crystal nickel chelate compound. The λ _max (in chloroform) of this compound was 688 nm (ε = 1.40 × 10 ⁵ ) (FIG. 1). The melting point was higher than 250 ° C. The infrared absorption spectrum of this compound is shown in FIG. (B) Recording medium example 0.15 g of the nickel chelate compound of the azo compound obtained in the above Production Example (a) was added with octafluoropentanol 7.5.
g and filtered through a 0.22 μm filter to obtain a solution. Add 5 ml of this solution to a depth of 700Å and a width of 0.7μ
It was dropped on an injection-molded polycarbonate resin substrate (diameter: 5 inches) with a groove of m and was applied at a rotation speed of 500 rpm by a spinner method. After application, 1 at 60 ℃
Dry for 0 minutes. The maximum absorption wavelength of the coating film was 713 nm. The absorption spectrum of the coating film is shown in FIG.

Next, a gold film having a film thickness of 2000 Å was formed on the coated film by a sputtering method to form a reflective layer. Further, an ultraviolet curable resin was spin-coated on this reflective layer, and this 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, a semiconductor laser beam having a central wavelength of 780 nm was used for recording power 6.6.
Irradiation at mW and EFM signal recorded. Next, when this recording portion was reproduced with a CD player having a semiconductor laser with a central wavelength of 780 nm, a good reproduced signal was obtained.

This disc has light resistance (xenon fade meter acceleration test; 60 hours) and storage stability (70
As a result of conducting a test at 85 ° C., 85% RH for 500 hours, deterioration of sensitivity and reproduction signal was not seen as compared with the initial stage, and it was extremely excellent as an optical recording medium. Comparative Example 1 The following structural formula (4)

[0040]

[Chemical 13] The nickel chelate compound obtained from the azo compound represented by and the nickel acetate was applied in the same manner as in Example 1, a reflective layer and a protective layer were attached, and a disc was prepared, and sensitivity and reflectance were evaluated and compared. The sensitivity was inferior to that of the optical recording medium of Example 1 of the invention (sensitivity 7.5).
mW).

Example 2 (a) Production Example 4-aminophenylpentafluoroethyl sulfide represented by the following structural formula (5) synthesized according to the method described in Japanese Patent Application No. 4-268857.

[0042]

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24.3 g, ammonium thiocyanate 3
0.5 g was dissolved in a mixed solution of 240 ml of acetic acid and 13 ml of water, and a solution of 20.0 g of bromine in 50 ml of acetic acid was added dropwise at 10 ° C. After stirring for 4 hours, heat to 70 ° C for 3
Stirred for hours. The mixture was filtered while hot, the filtrate was poured into 900 ml of hot water, the precipitated crystals were filtered, washed with water and dried to give yellow crystals of a compound represented by the following structural formula (6): 22.0
g was obtained (yield 73.3%, MASS spectrum
M ⁺ = 250).

[0044]

[Chemical 15]

2-obtained by the above structural formula (6)
Amino-6- (pentafluoroethylthio) benzothiazole 15.0 g acetic acid / propionic acid solution (acetic acid 6
3.0 ml / propionic acid 63.0 ml) to phosphoric acid 8
It was added to 9.0 g and sulfuric acid 4.95 g. After adding 4.25 g of sodium nitrate, 12.2 g of sulfuric acid was added dropwise at 0 to 5 ° C., and 17.4 g of 44% nitrosyl sulfuric acid was added at 0 to −5 ° C., followed by stirring for 1 hour to diazotize. The obtained diazo solution was added to 750 ml of methanol to prepare 2-di (n-propyl).
Aminoanisole-4-sulfonic acid (18.7 g), urea (2.0 g), and sodium acetate (20.0 g) were dissolved in the solution at a temperature of 0 to 5 ° C while using an alkaline compound such as an aqueous ammonium solution to maintain pH 4 to 6. , Dripped. Two
After stirring for an hour, it was left overnight. The precipitated crystals were separated by filtration, dried, and dark brown crystals 20.3 represented by the following structural formula (7).
g (yield 67.9%, MASS spectrum M ⁺
= 598). Λ _max (in methanol) of this compound is 5
It was 62 nm. This compound was nickel chelated. An infrared absorption spectrum of this nickel chelate compound (FIG. 4) and a visible absorption spectrum in chloroform (FIG. 5) are shown.

[0046]

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(B) Recording Medium Example 0.21 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. Add 5 ml of this solution to a depth of 700Å and a width of 0.7μ.
It was dropped on an injection-molded polycarbonate resin substrate (diameter: 5 inches) with a groove of m and was applied at a rotation speed of 500 rpm by a spinner method. After application, 1 at 60 ℃
Dry for 0 minutes. The maximum absorption wavelength of the coating film was 709 nm. FIG. 6 shows the absorption spectrum of the coating film.

Next, a gold film having a film thickness of 2000 Å was formed on the coating film by a sputtering method to form a reflection layer. Further, an ultraviolet curable resin was spin-coated on this reflective layer, and this 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 6.9 with semiconductor laser light having a central wavelength of 780 nm.
Irradiation at mW and EFM signal recorded. Next, when this recording portion was reproduced with a CD player having a semiconductor laser with a central wavelength of 780 nm, a good reproduced signal was obtained.

This disc was tested for light resistance (xenon fade meter acceleration test; 60 hours) and storage stability (70
As a result of conducting a test at 85 ° C., 85% RH for 500 hours, deterioration of sensitivity and reproduction signal was not seen as compared with the initial stage, and it was extremely excellent as an optical recording medium. Example 3 (a) Preparation Example Acetic acid / propionic acid solution of 2.1 g of 2-amino-6- (pentafluoroethylthio) benzothiazole represented by the structural formula (6) (acetic acid 8.8 ml / propionic acid 8. 8 ml) was added to 12.5 g of phosphoric acid and 0.69 g of sulfuric acid. After adding 0.60 g of sodium nitrate, 0-5 ° C
Then, 1.70 g of sulfuric acid was added dropwise, and 2.49 g of 44% nitrosyl sulfuric acid was added dropwise at 0 to -5 ° C, followed by stirring for 1 hour to diazotize. The diazo solution obtained was added to 105 ml of methanol to obtain 2
-Di (n-butyl) aminophenetol-4-sulfonic acid 3.0 g, urea 0.28 g, sodium acetate 2.8 g
Was added dropwise at a temperature of 0 to 5 ° C. to an alkaline compound such as an aqueous ammonium solution while maintaining pH 4 to 6. After stirring for 3 hours, it was left overnight. The precipitated crystals were separated by filtration, washed by suspension with water and toluene, and dried to obtain 3.19 g of dark brown crystals represented by the following structural formula (8) (yield 71.1%). The λ _max (in methanol) of this compound was 568 nm.

[0050]

[Chemical 17]

3.0 g of the azo compound represented by the structural formula (8) obtained above was dissolved in 300 ml of methanol, and a solution of 1.40 g of nickel acetate in 20 ml of methanol was added at 20 to 22 ° C. Stir for 5 hours. The precipitated crystals were separated by filtration, washed with methanol, and dried to give 1.96 g of a dark brown crystalline nickel chelate compound.
I got Λ _max (in chloroform) of this compound is 69
It was 1 nm. The melting point was higher than 250 ° C.
The infrared absorption spectrum and the visible absorption spectrum of the obtained compound are shown in FIG. 7 and FIG. 8, respectively. (B) Recording medium example 0.21 g of the nickel chelate compound of the azo compound obtained in the above Production Example (a) was added with octafluoropentanol 7.5.
g and filtered through a 0.22 μm filter to obtain a solution. Add 5 ml of this solution to a depth of 700Å and a width of 0.7μ.
It was dropped on an injection-molded polycarbonate resin substrate (diameter: 5 inches) with a groove of m and was applied at a rotation speed of 500 rpm by a spinner method. After application, 1 at 60 ℃
Dry for 0 minutes. The maximum absorption wavelength of the coating film was 708 nm. The absorption spectrum of the coating film is shown in FIG.

Next, a gold film having a film thickness of 2000 Å was formed on this coating film by a sputtering method to form a reflection layer. Further, an ultraviolet curable resin was spin-coated on this reflective layer, and this 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 6.8 with semiconductor laser light having a central wavelength of 780 nm.
Irradiation at mW and EFM signal recorded. Next, when this recording portion was reproduced with a CD player having a semiconductor laser with a central wavelength of 780 nm, a good reproduced signal was obtained.

This disc was tested for light resistance (xenon fade meter acceleration test; 60 hours) and storage stability (70
As a result of conducting a test at 85 ° C., 85% RH for 500 hours, deterioration of sensitivity and reproduction signal was not seen as compared with the initial stage, and it was extremely excellent as an optical recording medium. Example 4 An optical recording having the maximum absorption wavelength of the coating film shown in Table 1 was prepared by coating the solution obtained by using the compounds shown in Table 1 instead of the compound used in Example 1 on a substrate. The media was manufactured.

When writing was performed on the obtained optical recording medium using a semiconductor laser as a light source, the recording sensitivity was good, and the light resistance and the storage stability were excellent.

[0055]

[Table 1]

[0072]

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

[Brief description of drawings]

FIG. 1 is a diagram showing a visible region 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 the nickel chelate compound obtained in Example 1 of the present invention.

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

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

FIG. 5 is a diagram showing a visible region absorption spectrum of a nickel chelate compound obtained in Example 2 of the present invention in a chloroform solution.

FIG. 6 is a diagram showing a visible region absorption spectrum of a coated film of a nickel chelate compound obtained in Example 2 of the present invention.

FIG. 7 is a diagram showing an infrared absorption spectrum of a nickel chelate compound obtained in Example 3 of the present invention.

FIG. 8 is a diagram showing a visible region absorption spectrum of a nickel chelate compound obtained in Example 3 of the present invention in a chloroform solution.

FIG. 9 is a diagram showing a visible region absorption spectrum of a coated film of a nickel chelate compound obtained in Example 3 of the present invention.

─────────────────────────────────────────────────── ─── Continuation of the front page (51) Int.Cl. ⁶ Identification code Internal reference number FI Technical display location C07D 285/08 G03C 1/735 G11B 7/24 516 7215-5D (72) Inventor Takako Tsukahara Kanagawa Prefecture Sanryo Kasei Co., Ltd., Research Institute, Sanyo Kasei Co., Ltd. 1000, Kamoshida-cho, Midori-ku, Yokohama (72) Inventor Satoru Imamura 1000, Kamoshita-cho, Sanroku Kasei Co., Ltd., Midori-ku, Yokohama-shi, Kanagawa (56) Reference International Publication 91 / 18057 (WO, A)

Claims (6)

[Claims] 1. An azo metal chelate compound of an azo compound represented by the general formula [I] and a metal. Embedded image (In the formula, the ring B may have a substituent other than the —SR ¹ group. The ring C may have a substituent other than the —SO ₃ Y group. R ¹ is at least one hydrogen atom. Represents an alkyl group having 1 to 6 carbon atoms substituted with a fluorine atom, R ²
And R ³ are each independently a hydrogen atom, an optionally substituted alkyl group, an optionally substituted aryl group,
It 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. ) 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 (In the formula, R ¹ represents an alkyl group having 1 to 6 carbon atoms in which at least one hydrogen atom is replaced by a fluorine atom,
R 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,
R ⁶ and R ⁷ are each independently a hydrogen atom and a carbon number of 1 to
6 represents an alkyl group having 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, or a cation, and n is an integer of 1 to 3. ) 3. An optical recording medium in which a recording layer capable of writing and / or reading information by a laser is provided on a substrate, the recording layer comprising an azo compound represented by the general formula [I] and a metal. An optical recording medium containing the azo metal chelate compound of. 4. An optical recording medium in which a recording layer capable of writing and / or reading information by a laser is provided on a substrate, wherein the recording layer comprises an azo compound represented by the general formula [II] and a metal. An optical recording medium containing the azo metal chelate compound of. 5. The optical recording medium according to claim 3, wherein the metal is a transition element. 6. The optical recording medium according to claim 3, wherein a metal reflection layer and a protective layer are provided on the recording layer.