JPH11130970A - Metal-containing azo compound and optical recording medium prepared by using same - Google Patents

Abstract

PROBLEM TO BE SOLVED: To provide a novel metal chelate compd. of a specific formula prepd. from an azo compd. and a metal salt and to provide an optical recording medium prepd. by using the same and excellent in recording and reading characteristics with a short-wavelength laser. SOLUTION: A metal chelate compd. of the formula formed from an azo compd. and a metal salt is provided. In the formula, R<1> is H or alkyl; B is an arom. residue; R<2> is alkyl; and X and Y are each cyano, alkyoxycarbonyl, monoalklaminocarbonyl, or dialkylaminocarbonyl. A salt of Ni, Co, or Cu, having an absorption spectrum with a pref. shape, is pref. as a metal salt for forming a chelate compd. with an azo compd. This chelate compd. is formed into a film on a substrate pref. by the spinner method to give an optical recording medium. Information is recorded by irradiating the recording medium with laser light to cause thermal deformation and can be read out by the difference in reflectance caused by the presence or absence of the thermal deformation. The medium responds well to laser light with a wavelength of 600-700 nm.

Description

DETAILED DESCRIPTION OF THE INVENTION

[0001]

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

[0002]

2. Description of the Related Art Metal chelates prepared by chelating an azo compound and a metal compound have been used for dyeing natural fibers such as wool and cotton and vinylon for a long time because of their good fastness. The phenomenon of discoloration that occurs when an azo compound and a metal are chelated is also used as a metal ion indicator.

In recent years, some of these dyes have been proposed as dyes for optical discs because of their high molecular extinction coefficient and high reflectance, and some of them have been put to practical use. Recently, semiconductor lasers having short oscillation wavelengths have been developed, and semiconductor lasers having shorter wavelengths than conventional 780 nm and 830 nm, for example, 650 nm and 635 nm are being mass-produced. In the field of optical recording, higher density recording / reproducing becomes possible, and therefore, development of a recording medium suitable for a short-wavelength semiconductor laser is required.

Conventionally proposed optical recording media include a magneto-optical recording medium, a phase-change recording medium, a chalcogen oxide optical recording medium, and an organic dye-based optical recording medium. Among these, the organic dye-based optical recording medium is considered to be significant in that it is inexpensive and the manufacturing process is simple. Further, as an organic dye-based optical recording medium, a type of a recordable compact disc (CD-R) in which a metal layer having high reflectivity is laminated on an organic dye layer is mass-produced.

Incidentally, an organic dye-based optical recording medium for recording a short-wavelength semiconductor laser uses a medium having a wavelength shorter than that of a laser used in CD-R, and the beam diameter of the laser is made smaller. Can increase the recording density, but the disk currently used as a CD-R has a problem that when used at wavelengths such as 680 nm, 650 nm, and 635 nm, the reflectivity is low and recording and reproduction are difficult. I have. Further, currently proposed ones have a problem that a recording portion is largely deformed due to decomposition of a dye at the time of recording, a problem that a modulation degree is small, and a problem that light resistance and durability are insufficient.

The present inventors have previously described Japanese Patent Application Laid-Open No. 3-268994.
In the publication, an optical recording medium using a metal chelate compound of a novel azo compound and a metal excellent in light resistance and durability was proposed, but as an optical recording medium having a metal reflection layer, a short wavelength semiconductor laser is used. The recording and reproduction characteristics were insufficient. Further, the present inventors have disclosed in Japanese Patent Application No.
187794 records with a short wavelength semiconductor laser,
Although an optical recording medium using a metal chelate compound of a reproducible azo dye and a metal was proposed, a recording medium using a metal chelate compound of the present invention further improved recording, reproduction characteristics, light resistance, and durability. Things.

[0007]

SUMMARY OF THE INVENTION The present invention provides a novel metal chelate compound of an azo compound and a metal, and a short-wavelength semiconductor using the metal chelate compound, which is suitable as an optical recording medium for solving the above problems. Laser recording,
It is an object of the present invention to provide an optical recording medium having excellent reproduction characteristics and excellent light resistance and durability.

[0008]

Means for Solving the Problems The present inventors have made intensive studies to achieve this object, and as a result, have reached the present invention. That is, the present invention provides a metal chelate compound obtained from an azo compound represented by the following general formula (1) and a metal salt, a method for producing the metal chelate compound, and an optical recording medium containing the metal chelate compound in a recording layer. I do.

[0009]

Embedded image

(Wherein R ¹ Represents a hydrogen atom or an alkyl group which may have a substituent, B represents a residue which forms an aromatic ring together with two carbon atoms to which it is bonded, and R ² represents Represents an alkyl group which may have a substituent, and X and Y each represent a cyano group, an alkyloxycarbonyl group which may have a substituent, and a monoalkylamino which may have a substituent Represents a carbonyl group or a dialkylaminocarbonyl group which may have a substituent. )

R ^{1 in} equation (1) Examples of a hydrogen atom, methyl group, ethyl group, n-propyl group, iso-propyl group, cyclopropyl group, n-butyl group, tert-butyl group, sec-butyl group, n-pentyl group, n-hexyl An alkyl group having 1 to 6 carbon atoms such as a group, a cyanoethyl group, a cyanomethyl group, a hydroxyethyl group, a hydroxypropyl group, a tetrahydrofurfuryl group, an allyl group, a trifluoromethyl group, a tetrafluoroethyl group, a pentafluoroethyl group, And a fluoroisopropyl group.

Further, R ^{2 in the} equation (1) Examples of methyl, ethyl, n-propyl, iso-propyl, cyclopropyl, n-butyl, tert-butyl, sec-butyl, n-pentyl, n-hexyl and the like An alkyl group having 1 to 6 carbon atoms, a cyanoethyl group, a cyanomethyl group, a hydroxyethyl group, a hydroxypropyl group, a tetrahydrofurfuryl group, an allyl group, a trifluoromethyl group, a tetrafluoroethyl group, a pentafluoroethyl group, and a hexafluoroisopropyl group And so on.

In the formula (1), the substituent of “alkyl which may have a substituent” of X and Y is the above R ² The same can be given. Examples of the residue B in the formula (1) include various condensed rings, each of which may have a substituent, such as a benzene ring, a naphthalene ring, a dihydroquinoline ring, and a benzomorpholine ring. One preferred embodiment of the compound of the present invention is a metal chelate compound of a monoazo compound represented by the following formula (2) and a metal.

[0014]

Embedded image

(Wherein ring D is an alkyl group having 1 to 6 carbon atoms,
C1-C6 alkoxy group, halogen atom, nitro
Group, cyano group, alkylsulfonyl group having 1 to 6 carbon atoms,
An alkoxycarbonyl group having 2 to 7 carbon atoms and thiocyan
May have a plurality of substituents selected from
K, R^Five , R⁶ Are each independently a hydrogen atom; methyl
Group, ethyl group, n-propyl group, isopropyl group, n-
Butyl group, tert-butyl group, sec-butyl group, n
-Having 1 to 20 carbon atoms such as a pentyl group and an n-hexyl group;
Alkyl, phenyl, tolyl, naphthyl, etc.
Aryl group having 6 to 20 carbon atoms, vinyl group, 1-propene
Group, isopropenyl group, 2-butenyl group, butadienyl
Alkenyl having 2 to 10 carbon atoms, such as
A cyclopropyl group, a cyclobutyl group,
Clopentyl, cyclohexyl, cyclooctyl
And a cycloalkyl group having 3 to 10 carbon atoms. Pertain
Alkyl group having 1 to 20 carbon atoms, ant having 6 to 20 carbon atoms
Alkenyl group having 2 to 10 carbon atoms and 3 carbon atoms
A cycloalkyl group of 10 to 10 is a methoxy group, an ethoxy group,
n-propoxy group, isopropoxy group, n-butoxy
Group, tert-butoxy group, sec-butoxy group, n-
Pentyloxy group, n-octyloxy group, n-decyl
An alkoxy group having 1 to 10 carbon atoms such as an oxy group; methoxy
Ethoxy, ethoxymethoxy, propoxymethoxy
Group, methoxypropoxy group, ethoxypropoxy group,
2 carbon atoms such as toxicbutoxy and ethoxybutoxy
To 12 alkoxyalkoxy groups;
Toxic group, methoxymethoxyethoxy group, ethoxymeth
Xymethoxy group, methoxyethoxyethoxy group, ethoxy
Alcohols having 3 to 15 carbon atoms such as ethoxyethoxy groups
Xyalkoxyalkoxy group; allyloxy group; phenyl
Number of carbons such as phenyl, tolyl, xylyl, and naphthyl
6 to 12 aryl groups; phenyloxy group, tolyloxy
Carbon such as silyl, xylyloxy and naphthyloxy
Aryloxy group of the formulas 6 to 12; cyano group; nitro
Group, hydroxyl group, tetrahydrofuryl group; methyls
Ruphonylamino group, ethylsulfonylamino group, n-propyl
Ropylaminosulfonyl group, isopropylsulfonylua
Mino group, n-butylaminosulfonylamino group, ter
t-butylsulfonylamino group, sec-butylsulfo
Nilamino group, n-pentylaminosulfonylamino
Group, n-hexylsulfonylamino group, etc.
6 alkylsulfonylamino group; fluorine atom, chlorine atom
Halogen atom such as bromine atom and bromine atom; methoxycarbonyl
Group, ethoxycarbonyl group, n-propoxycarbonyl
Group, isopropoxycarbonyl group, n-butoxycarbo
Nil group, tert-butoxycarbonyl group, sec-butyl
Toxylcarbonyl group, n-pentyloxycarbonyl
Group, n-hexyloxycarbonyl group, etc.
7 alkoxycarbonyl group; methylcarbonyloxy
Group, ethylcarbonyloxy group, n-propyl carbonyl
Loxy group, isopropylcarbonyloxy group, n-butyl
Tylcarbonyloxy group, tert-butylcarbonyl
Oxy group, sec-butylcarbonyloxy group, n-pe
Nthyloxycarbonyloxy group, n-hexylcarbo
C2-C7 alkyl carbonyl, such as a niloxy group,
Roxy group; methoxycarbonyloxy group, ethoxyca
Rubonyloxy group, n-propoxycarbonyloxy
Group, isopropoxycarbonyloxy group, n-butoxy
Carbonyloxy group, tert-butoxycarbonyl
Xy group, sec-butoxycarbonyloxy group, n-pe
Nthyloxycarbonyloxy group, n-hexylcarbo
An alkoxycarbo having 2 to 7 carbon atoms such as a niloxy group,
It may be substituted with a nyloxy group. X¹ , Y¹ Haso
A cyano group, each of which may have a substituent;
10 alkyloxycarbonyl groups, having a substituent
Monoalkylaminocarbon having 1 to 10 carbon atoms
2 to 20 carbon atoms which may have a substituent or a substituent
Represents a dialkylaminocarbonyl group. )
Examples of the alkyl which may have^Three , R
^Four The same as in the case of

Further, as one embodiment of a preferred compound of the present invention, an azo chelate compound of an azo compound and a metal, which is a compound represented by the following general formula (3), can be mentioned.

[0017]

Embedded image

(Wherein R ⁷ , R ⁸ , R ⁹ Each R ¹⁰ is independently methyl, ethyl, n- propyl group, an i- propyl, X ² , Y ² Each represents a cyano group; a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an i-propoxycarbonyl group or the like, a linear or branched alkoxycarbonyl group having 1 to 3 carbon atoms; a methylaminocarbonyl group, an ethylamino group; A linear or branched carbon atom having 1 carbon atom such as a carbonyl group, an n-propylaminocarbonyl group, an i-propylaminocarbonyl group, etc.
To 3 monoalkylaminocarbonyl groups; dimethylaminocarbonyl group, methylethylaminocarbonyl group, diethylaminocarbonyl group, ethyl-n-propylaminocarbonyl group, di-n-propylaminocarbonyl group, di-i-propylaminocarbonyl group And other linear or branched dialkylaminocarbonyl groups. In the present invention, preferred specific examples of the metal chelate compound of an azo compound and a metal include the following.

[0019]

Embedded image

[0020]

Embedded image

[0021]

Embedded image

[0022]

Embedded image

[0023]

Embedded image

[0024]

Embedded image

In the present invention, various metal salts that form a complex can be used as the metal salt that forms a chelate compound with the azo compound. However, Ni is preferred because of its good absorption spectrum shape. , Co or C
are preferable, and the solubility and light resistance in various solvents,
From the viewpoint of durability, Ni salt is particularly preferable. For example, the metal chelate compound (2) of the present invention has the general formula (4)

[0026]

Embedded image

(Wherein R ³ , X ¹ , Y ¹ Is the general formula (2)
Is diazotized by a known method, and

[0028]

Embedded image

(Wherein R ⁴ , R ⁵ , R ⁶ , D are the same as those of the general formula (2)).
It is obtained by adding a methanol solution or an aqueous solution of a metal compound in an organic solvent such as tetrahydrofuran or acetone.

The optical recording medium for short-wavelength recording of the present invention basically comprises a substrate and a recording layer containing a metal chelate compound of the azo compound and a metal.
Further, an undercoat layer can be provided on the substrate as needed. As an example of a preferred layer configuration, gold,
A high-reflectance medium provided with a metal reflective layer such as silver or aluminum and a protective layer may be used. The substrate is preferably transparent to a laser beam to be used, and glass and various plastics are used. Examples of the plastic include an acrylic resin, a methacrylic resin, a polycarbonate resin, a vinyl chloride resin, a vinyl acetate resin, a polyester resin, a polyethylene resin, a polypropylene resin, a polyimide resin, a polystyrene resin, and an epoxy resin. Injection molded polycarbonate resin substrates are particularly preferred from the viewpoint of moisture absorption resistance.

The method for forming a recording film of the recording layer containing a metal chelate compound of an azo compound and a metal in the optical recording medium of the present invention includes a vacuum deposition method, a sputtering method, a doctor blade method, a casting method, and a spinner. The film can be formed by a generally used thin film forming method such as a immersion method or an immersion method, but the spinner method is preferable in terms of mass productivity and cost. 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 the 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 in combination as needed.
As the other dye, another kind of the same type of compound may be used, or a triarylmethane dye, an azo dye, a cyanine dye, a squarylium dye, a metal-containing indoaniline dye, a phthalocyanine dye, or the like. May be.

The coating solvent for forming the recording layer by a coating method such as a doctor blade method, a casting method, a spinner method, an immersion method, especially a spinner method is not particularly limited as long as it does not attack the substrate. For example, ketone alcohol solvents such as diacetone alcohol and 3-hydroxy-3-methyl-2-butanone, cellosolve solvents such as methyl cellosolve and ethyl cellosolve, hydrocarbon solvents such as n-hexane and n-octane, cyclohexane Hydrocarbon solvents such as methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, n-butylcyclohexane, t-butylcyclohexane and cyclooctane, ether solvents such as diisopropyl ether and dibutyl ether, tetrafluoropropanol, octafluoropentanol, hexa Perfluoroalkyl alcohol solvents such as fluorobutanol; and hydroxyester solvents such as methyl lactate, ethyl 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. Further, two media having a recording layer provided on a substrate may be bonded. The protective layer may be any layer that can protect the recording layer and the reflective layer, and is formed of, for example, an ultraviolet curable resin. If necessary, a print receiving layer can be provided on the protective layer.

The recording on the optical recording medium obtained as described above is performed by irradiating a laser beam to a recording layer provided on both sides or one side of the substrate. Thermal deformation of the recording layer, such as decomposition, heat generation, 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. Various types of lasers can be used.
A semiconductor laser having a wavelength of 0 to 700 nm is preferable, and a semiconductor laser is preferable in terms of lightness, ease of handling, compactness, cost, and the like. Further, the novel metal chelate compound of the present invention is a very useful compound that can be used for uses other than optical recording media, such as coloring various materials such as plastic and paper, coloring various fibers, and coloring optical filters.

[0036]

BEST MODE FOR CARRYING OUT THE INVENTION

 Example 1 (a) Production example

[0037]

Embedded image

The 2-amino- represented by the above structural formula (6)
4.65 g of 4,5-dicyanoimidazole was added to 200 m of water.
l, dissolved in 33.5 ml of 35% hydrochloric acid, and 12.5 ml of an aqueous solution of 3.8 g of sodium nitrite was added dropwise at 0 to 5 ° C.
Diazotized. The obtained diazo liquid was treated with 200 m of methanol.
1-liter contains 3-N, N-diethyl-methylsulfonamitoaniline 14.54 g, urea 2.0 g, sodium acetate 20
g was added dropwise to the solution in which g was dissolved at 0 to 5 ° C., and the mixture was stirred for 3 hours and left overnight. The precipitated crystals were separated by filtration and dried to obtain 12.8 g of red crystals represented by the following structural formula (7).

[0039]

Embedded image

3.86 g of the azo compound represented by the structural formula (7) obtained as described above and 1.5 g of sodium bicarbonate were dissolved in 75 ml of DMF, and ethyl iodide was dissolved in 75 ml of DMF.
After adding 3 g dropwise, the mixture was heated to 70 ° C. After stirring at 70 ° C. for 3 hours, the mixture was allowed to cool, 50 ml of water was added thereto, and the precipitated crystals were collected by filtration, dried and dried to give red crystals of the following structural formula (8).
34 g were obtained.

[0041]

Embedded image

2.0 g of the azo compound represented by the structural formula (8) obtained above was dissolved in 300 ml of THF, and a solution of 0.75 g of nickel acetate tetrahydrate in 10 ml of methanol was added at room temperature. Stir at room temperature for 2 hours, add water 3
00 ml was added. The precipitated crystals were separated by filtration, washed with water, and dried to obtain 1.5 g of a nickel chelate compound as green-brown crystals. The λ _max (in chloroform) of this compound was 574 nm (ε = 9.2 × 10 ⁴ ).

(B) Example of recording medium The nickel chelate compound obtained as described above was dissolved in octafluoropentanol to make up to 1.2% by weight. This was ultrasonically dispersed at 50 ° C. for 30 minutes.
The solution is filtered through a 2 μm filter, and the liquid is rotated at 800 r.
It was spin coated on a 0.6 mm thick polycarbonate substrate at pm. Note that the groove width of this substrate is 0.35 μm,
(Track pitch 0.8 μm) The groove depth is 140 nm. Next, after drying this coating film at 80 ° C. open,
An Au film having a thickness of 100 nm was formed on the coating film by a sputtering method to form a reflective layer. Further, an ultraviolet-curable resin was spin-coated on this reflective layer at 3 μm, and this was irradiated with ultraviolet rays to be cured to obtain a recording medium. Further, a hot-melt adhesive was applied, and the recording media obtained in the same manner were adhered to each other to produce a recording medium. Λ of coating film
_max was 590 nm. The thickness of the recording layer is about 110 n
m.

(C) Optical Recording Method A 635 nm semiconductor laser (NA = 0.6) is used to input an EFM signal for quadruple-speed recording of a CD-R at a linear velocity of 2.6 m / s and a reproducing power of 0.7 mW. The recording power was 5.8 mW, the I _top reflectance was 65%, and the modulation factor was 60.
% Good recording characteristics were obtained.

Example 2 (a) Production Example In place of 2.00 g of 2-amino-4,5-diaminoimidazole [structural formula (6)] used in Example 1, the compound is represented by the following structural formula (9). amino

[0046]

Embedded image

In the same manner as in Example 1 except that the amino compound represented by the following formula was used, the following structural formula (10)

[0048]

Embedded image

Was obtained. 1.8 g of the azo compound represented by the structural formula (10) obtained as described above and 0.41 g of anhydrous sodium acetate are mixed with tetrahydrofuran (THF) 80
The solution was dissolved in water and 40 ml of water, and a solution of 0.75 g of nickel acetate tetrahydrate in 10 ml of methanol was added at room temperature. The mixture was stirred at room temperature for 2 hours, and 40 ml of water was added. The precipitated crystals were collected by filtration, washed with water, and dried to obtain 0.9 g of a green-brown crystalline nickel chelate compound. Λ of this compound
_max (in chloroform) is 575 nm (ε = 8.5 × 1
It was 0 ^4).

(B) Example of recording medium A recording medium was prepared in the same manner as in Example 1 using the nickel chelate compound obtained as described above. Λ of coating film
_max was 576 nm. The thickness of the recording layer was almost the same as in Example 1. (C) Optical recording method Recording was performed under the same conditions as in Example 1;
At 1 mW, the I _top reflectance was 50%, and good recording characteristics with a modulation factor of 55% were obtained.

Examples 3 to 9 Examples 3 to 9 were carried out in the same manner as Examples 1 and 2. Table 1 shows the solutions λ _max (in chloroform) of the nickel chelate compounds of Examples 1 to 9 and the coating films λ _max . Example 1
1 and 2 show the absorption spectrum in chloroform and the absorption spectrum of the coating film, respectively.

[0052]

[Table 1]

[0053]

[Table 2]

[0054]

The metal chelate compound of the present invention with an azo compound and a metal has absorption in the range of 500 to 700 nm, and has good light resistance, storage stability and heat resistance. Thus, it is very useful as an absorbing material for an optical recording medium. Examples of uses other than the optical recording medium include various optical filters and plastic colorants. The optical recording medium comprising the metal chelate compound of an azo compound and a metal of the present invention has excellent recording / reproducing characteristics with respect to a laser beam of 600 to 700 nm, and is capable of high reflectance and high density recording. Also, it has excellent light resistance and durability.

[Brief description of the drawings]

FIG. 1 is an absorption spectrum of a metal chelate compound of Example 1 in a chloroform solution.

FIG. 2 is an absorption spectrum of a metal chelate compound of Example 1 in a coating film.

Claims (7)

[Claims] 1. An azo metal chelate compound of an azo compound represented by the following general formula (1) and a metal. Embedded image (Where R ¹ Represents a hydrogen atom or an alkyl group which may have a substituent, B represents a residue which forms an aromatic ring together with two carbon atoms to which it is bonded, and R ² represents Represents an alkyl group which may have a substituent, and X and
Y represents a cyano group, an alkyloxycarbonyl group which may have a substituent, a monoalkylaminocarbonyl group which may have a substituent or a dialkylaminocarbonyl group which may have a substituent, respectively. . ) 2. An azo chelate compound of an azo compound and a metal, wherein the azo compound in the metal chelate compound according to claim 1 is a compound represented by the following general formula (2). Embedded image (Where R ³ , R ⁴ Represents an alkyl group having 1 to 10 carbon atoms which may have a substituent, and D represents 1 carbon atom.
1 selected from an alkyl group having 1 to 6 carbon atoms, an alkoxy group having 1 to 6 carbon atoms, a halogen atom, a nitro group, a cyano group, an alkylsulfonyl group having 1 to 6 carbon atoms, an alkoxycarbonyl group having 2 to 7 carbon atoms, and a thiocyanate group R ⁵ may have the substituent described above. , R ⁶ Each independently has a hydrogen atom, an alkyl group having 1 to 20 carbon atoms which may have a substituent, an aryl group having 6 to 20 carbon atoms which may have a substituent, Good carbon number 2 to 10
X ¹ represents an alkenyl group or a cycloalkyl group having 3 to 10 carbon atoms which may have a substituent; , Y ¹ Represents a cyano group and a carbon atom of 1 which may have a substituent, respectively.
Alkyloxycarbonyl group having 10 to 10, monoalkylaminocarbonyl group having 1 to 10 carbon atoms which may have a substituent or dialkylaminocarbonyl group having 2 to 20 carbon atoms which may have a substituent Represents ) 3. An azo chelate compound of an azo compound and a metal, wherein the azo compound in the metal chelate compound according to claim 1 is a compound represented by the following general formula (3). Embedded image (Where R ⁷ , R ⁸ , R ⁹ Each R ¹⁰ is independently methyl, ethyl, n- propyl group, an i- propyl, X ² , Y ² Each represents a cyano group, a linear or branched alkoxycarbonyl group having 1 to 3 carbon atoms, a linear or branched monoalkylaminocarbonyl group having 1 to 3 carbon atoms, or a linear or branched carbon atom; Represents 2 to 6 dialkylaminocarbonyl groups. ) 4. The metal chelate compound according to claim 1, wherein the metal is Ni, Co or Cu. 5. An optical recording medium having a recording layer on which information can be written and / or read by a laser on a substrate, wherein the recording layer is any one of claims 1 to 3. An optical recording medium comprising the metal chelate compound of the azo compound and a metal according to claim 1. 6. The optical recording medium according to claim 5, wherein a metal reflective layer and a protective layer are provided on the recording layer. Optical recording medium. 7. An optical recording medium according to claim 5, wherein recording and reproduction are performed with a laser beam having a center wavelength of 600 to 700 nm. Optical recording medium.