HK1112214B - Optical recording medium, metal complex compound and organic dye compound - Google Patents

Description

Optical recording medium, metal complex and organic dye compound

Technical Field

The present invention relates to an optical recording medium and the like, and more particularly, to an optical recording medium and the like having excellent light resistance which can respond to a blue laser beam.

Background

At present, various optical recording media such as CD-R/RW, DVD-R/RW, and MO are widely known and popular as external storage devices in information processing apparatuses such as computers because they can store large amounts of information and are easy to access randomly (random access). Among these, an organic dye-based optical recording medium provided with a recording layer containing an organic dye compound, such as a CD-R or DVD-R, is considered to be advantageous from the viewpoint of low cost and ease of production.

On the other hand, since the amount of information to be handled is increasing, it is desired to increase the recording density of the medium, and in recent years, development of a high-density recordable and readable (japanese: reproduction) optical recording medium using a laser beam having a short excitation wavelength such as a blue laser beam has been proposed.

However, in general, in the case of a commercially available optical recording medium such as a CD-R or a DVD-R, the CD-R is designed to be suitable for recording and reading with a laser beam having a wavelength of about 780nm, and the DVD-R is designed to be suitable for recording and reading with a laser beam having a wavelength of about 600 to 700 nm. Such a recording medium suitable for optical recording and reading using a laser beam having a relatively long wavelength has a problem that, when recording and reading are performed using a laser beam having a shorter wavelength, the reflectance is low and recording and reading cannot be performed.

As the dye for recording of CD-R or DVD-R, for example, a dye using a metal-containing azo complex as an optical recording medium is used (see patent documents 1, 2 and 3)

Patent document 1: international publication No. 91/18950

Patent document 2: japanese patent laid-open No. 9-277703

Patent document 3: japanese patent laid-open No. 8-295811

Disclosure of Invention

Problems to be solved by the invention

In the optical recording medium described in patent document 1 or patent document 2, a compound having an N, N-dialkylaniline skeleton is generally used as a coupling agent (coupler) component of an azo compound used in a CD-R or DVD-R.

Although it is useful to use the N, N-dialkylaniline skeleton to obtain a dye having a very high molar absorption coefficient, the solution of the metal-containing azo complex using the above coupler component has a λ max of 500nm or more. Therefore, the absorption spectrum of the coating film containing the coloring matter shows that the coloring matter cannot be sufficiently absorbed by recording with a blue laser or a laser having a wavelength of about 350 nm. I.e. the absorption maximum wavelength is too long. For example, there is a problem that an absorption spectrum is hardly observed in the vicinity of-405 nm, which is a laser wavelength of an excitation center wavelength of a blue laser beam, and sensitivity to the blue laser beam tends to be low. Therefore, a coupler component having a large amount of absorption on the shorter wavelength side is required.

On the other hand, it is known that: the compound using a pyridone-based coupling agent component as described in patent document 3 has λ max at a shorter wavelength than the compounds described in patent documents 1 and 2. However, according to the study of the present inventors, it was found that: the compound described in patent document 3, even if it contains benzothiazole, thiazole or pyridine as a disazo component, has a very low absorption near a wavelength of 405nm ((405nm to 10nm) or more (405nm +5nm) or less) because of its too long absorption maximum wavelength, and thus cannot be expected to improve the performance as a dye. Therefore, in order to record in the above wavelength region, it is necessary to combine a diazo component and a coupler component suitable for absorption at a shorter wavelength.

The present invention has been made to solve the problem of the conspicuousness in developing an optical recording medium for recording and reading optical information at a higher density than a DVD by using such a blue laser beam having a short wavelength.

That is, an object of the present invention is to provide an optical recording medium capable of recording and reading high-density optical information by a short-wavelength laser beam having a wavelength of 350nm to 530nm, for example, 385nm to 410 nm.

Further, another object of the present invention is to provide a metal complex suitable for a recording layer of an optical recording medium or the like.

Still another object of the present invention is to provide an organic dye compound having improved light fastness.

Means for solving the problems

In order to solve the above problems, an organic dye compound containing a metal-containing pyridone azo compound is used in the present invention.

That is, according to the present invention, there is provided an optical recording medium for laser light having a short wavelength in a range from ultraviolet laser light to a wavelength region of blue laser light (particularly, 350nm to 530nm), comprising a substrate and a recording layer provided on the substrate directly or via another layer and capable of recording and/or reading information by irradiation with light, wherein the recording layer contains a metal complex containing an organic dye compound and a metal ion coordinated to the organic dye compound, and the organic dye compound contains a coupler component having a 6-hydroxy-2-pyridone structure and a diazo component selected from isoxazole, triazole and pyrazole.

The recording layer of the optical recording medium to which the present invention is applied contains a metal complex composed of the organic dye compound and a predetermined metal ion. The organic dye compound constituting the metal complex is a pyridone azo compound represented by any one of the following general formulae [ I ] to [ III ].

Chemical formula 1

(in the general formula [ I ]]General formula [ III]In, R₁～R₁₀Each independently is a hydrogen atom or a 1-valent functional group. )

As a general formula [ I]General formula [ III]R in (1)₁～R₁₀Specifically, in addition to hydrogen atoms, the following 1-valent functional groups are preferred.

Namely, R₁Preferably selected from the group consisting of a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group, a hydroxyl group, a linear or branched alkoxy group, a saturated or unsaturated heterocyclic group, an aryl group, an aralkyl group, -NR₁₂R₁₃The straight-chain or branched-chain alkyl group may be selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms and an alkoxy group having 2 to 10 carbon atomsA substituent selected from the group consisting of an alkoxyalkoxy group having 12 carbon atoms, an alkoxyalkoxyalkoxyalkoxyalkoxy group having 3 to 15 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, a heterocyclic group, a cyano group, a nitro group, a hydroxyl group, a mercapto group, a thioalkyl group, an alkylamino group having 1 to 10 carbon atoms, an alkylsulfonylamino group having 1 to 6 carbon atoms, a halogen atom, an alkylcarbonyl group, an alkoxycarbonyl group having 2 to 7 carbon atoms, an alkylcarbonoxy group having 2 to 7 carbon atoms, and an alkoxycarbonyloxy group having 2 to 7 carbon atoms, wherein R is as defined above₁₂、R₁₃Each independently represents any of a hydrogen atom, a hydrocarbon group, and a heterocyclic group, and these may be substituted as required.

R₂、R₃Represents any one selected from a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, a linear or branched alkenyl group having 2 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a cyano group, an acyl group, an amide group, a carbamate group, a carboxylate group, an acyloxy group, a carbamoyl group, a sulfonyl group, a sulfinyl group and a sulfonamide group.

R₄、R₅、R₈、R₉It is preferably any one selected from the group consisting of a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, a linear or branched alkenyl group having 2 to 18 carbon atoms, a saturated or unsaturated heterocyclic group, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a halogen atom, a nitro group, a cyano group, a formyl group, an acyl group, an amide group, a carbamate group, a carboxylate group, an acyloxy group, a carbamoyl group, a sulfonyl group, a sulfinyl group, a sulfamoyl group, a sulfonate group and a sulfonamide group.

R₇Represents a linear or branched alkyl group having 1 to 18 carbon atoms substituted with fluorineA halogen atom, a nitro group; cyano, formyl, acyl, carboxylate, acyloxy, carbamoyl, sulfonyl, sulfinyl, sulfamoyl, sulfonate.

R₆、R₁₀Preferably, the alkyl group is any one selected from a hydrogen atom, a linear or branched alkyl group, and a cycloalkyl group.

Further, the metal ion constituting the metal complex is preferably a 2-valent metal ion selected from groups 3 to 12 of the periodic table. Further, the metal ion is preferably at least 1 metal ion selected from nickel, cobalt, iron, zinc, copper, and manganese. Here the periodic table is of the long period type.

By using a metal-containing pyridone azo compound in which a 2-valent metal ion and a pyridone azo compound represented by general formulae [ I ] to [ III ] are combined, the light resistance of the recording layer of an optical recording medium can be improved.

The light used for recording and reading of the optical recording medium of the present invention is a laser beam having a wavelength of 350nm to 530nm, and a semiconductor laser beam having a wavelength of 385nm to 410nm is given as a specific example.

The present invention is an optical recording medium having a recording layer containing an organic dye, and the optical recording medium of the present invention has the following features: the organic dye contains a metal complex composed of a pyridone azo compound represented by the following general formulae [ I ] to [ III ] and a 2-valent metal ion selected from groups 3 to 12 of the periodic table coordinated to the pyridone azo compound.

Chemical formula 2

(in the general formula [ I ]]General formula [ III]In, R₁～R₁₀Each independently, is a hydrogen atom or a 1-valent functional group. )

Here, the pyridone azo compound represented by the general formulae [ I ] to [ III ] is preferably one having a molecular weight of 1000 or less.

Further, the present invention provides a metal complex characterized by containing a metal ion having a valence of 2 selected from the groups 3 to 12 of the periodic table and a pyridone azo compound represented by the following general formula [ I ] coordinated to the metal ion.

Chemical formula 3

(in the general formula [ I ]]In, R₁～R₅Each independently, is a hydrogen atom or a 1-valent functional group. )

That is, the metal complex compound to which the present invention is applied has a structure in which a pyridone azo compound represented by the general formula [ I ] is coordinated to a 2-valent metal such as nickel, cobalt, iron, zinc, copper, or manganese, and thus can be used as an organic dye that can obtain a maximum absorption wavelength at a wavelength of 500nm or less.

Further, the present invention provides an organic dye compound comprising a metal complex of a pyridone azo compound and a metal ion having a valence of 2, wherein the pyridone azo compound has a coupler component having a 6-hydroxy-2-pyridone structure and a diazo component having an isoxazole structure.

That is, the organic dye compound to which the present invention is applied can obtain excellent light fastness by using a pyridone azo compound having a structure in which a specific coupler component and a diazo component are combined and coordinating the pyridone azo compound with a 2-valent metal.

ADVANTAGEOUS EFFECTS OF INVENTION

According to the optical recording medium to which the present invention is applied, recording and reading of optical information with high sensitivity and high density can be performed by using a laser beam with a short wavelength.

Drawings

Fig. 1 is a diagram illustrating an optical recording medium to which the present embodiment is applied. Fig. 1(a) shows embodiment 1, and fig. 1(b) shows embodiment 2.

FIG. 2 is an absorption spectrum of a coating film of the metal complex (58) (example 1).

FIG. 3 is an absorption spectrum of a coating film of the metal complex (59) (example 2).

FIG. 4 is an absorption spectrum of a coating film of the metal complex (74) (example 17).

FIG. 5 is an absorption spectrum of a coating film of the metal complex (75) (example 18).

FIG. 6 is an absorption spectrum of a coating film of a metal-containing pyridone azo compound (comparative example 1) represented by the structural formula [13 ].

FIG. 7 is an absorption spectrum of a metal-containing pyridone azo compound represented by the structural formula [15] (comparative example 2) in a chloroform solution.

FIG. 8 is an absorption spectrum of a metal-containing azo complex represented by the structural formula [16] (comparative example 3) in a chloroform solution.

Description of the symbols

1-substrate

2-recording layer

3-reflecting layer

4-protective layer

5-protective coating

10. 20-optical recording medium

Detailed Description

Hereinafter, the best mode (hereinafter referred to as an embodiment) for carrying out the present invention will be described in detail. The present invention is not limited to the following embodiments, and various modifications can be made within the scope of the gist of the present invention. The drawings used are for explaining the present embodiment and do not show actual sizes.

Also, represented by the general formula [ I]General formula [ III]The 1-valent functional group R in the pyridone azo compound₁～R₁₀The compound may have a substituent as required. However, the "substituent" in this case, or "substituent" described in "may be … -substituted" or "… may have a substituent" does not contain an acidic water-soluble group such as a carboxyl group or a sulfonic acid group. By the general formula [ I]General formula [ III]The pyridone azo compounds represented by (a) are not preferable because they have poor solubility in organic solvents when they contain a water-soluble group such as a carboxyl group or a sulfonic acid group. Further, the recording layer of the optical recording medium has low water resistance and is difficult to form a stable film.

The term "as needed" means that the pyridone azo compounds represented by the general formulae [ I ] to [ III ] do not greatly affect the solubility in an organic solvent and the absorption in a specific wavelength region, but can be appropriately selected from the viewpoints of fine adjustment of the solubility in an organic solvent and the absorption in a specific wavelength region, and advantages in production processes such as the ease of purchase of reagents for synthesis and cost.

(pyridone azo Compound)

The metal-containing pyridone azo compound used for the optical recording medium to which the present embodiment is applied, which is composed of a metal ion and a pyridone azo compound represented by the above general formulae [ I ] to [ III ] (hereinafter, may be simply referred to as a pyridone azo compound), has a suitable absorption in the blue region having a wavelength of 350nm to 530nm, is suitable for recording by a blue laser, and can be used as an organic dye compound having a practically durable light resistance.

In the pyridone azo compounds represented by the general formulae [ I ] to [ III ], in general, the heteroaromatic ring on the left side of the azo group (-N ═ N-) is referred to as a diazo component, and the 6-hydroxy-2-pyridone structure on the right side is referred to as a coupler component.

Examples of the diazo component in the pyridone azo compounds represented by the general formulae [ I ] to [ III ] include isoxazole, 1, 2, 4-triazole, pyrazole, and the like.

The triazole has a tautomeric structure, and also has a structure represented by the following general formula [ II ]', and general formula [ II ] ", and the structure of the general formula [ II ] is described as a representative example.

Chemical formula 4

Here, in the general formula [ II]', general formula [ II]"in, although for convenience is described as R₆’、R₆"etc., but they employ R₆The same functional groups. Furthermore, R₇’、R₇"adopt and R₇The same functional groups.

Among these diazo components, when combined with the same coupling agent, the absorption maximum wavelength in the wavelength region of 400 to 500nm tends to be shifted toward the long wavelength side in the order of general formula [ I ] < general formula [ II ] < general formula [ III ]. The structure of the formula [ I ] is particularly preferable from the viewpoint of sensitivity improvement by increasing the absorption at a wavelength of 405 nm.

Then, it is represented by the general formula [ I]General formula [ III]The 1-valent functional group R in the pyridone azo compound₁～R₁₀The description is given.

General formula [ I]General formula [ III]Pyridones of the formulaIn the azo compound, R₁Represents a group selected from a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group, a hydroxyl group, a linear or branched alkoxy group, a saturated or unsaturated heterocyclic group, an aryl group, an aralkyl group, and a-COR group₁₁Acyl group represented by the formula, -NR₁₂R₁₃Amino group represented by the formula, -NHCOR₁₄Any one of the functional groups of the amide groups represented.

As R₁Examples of the preferable functional group include a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a saturated or unsaturated heterocyclic group, an aryl group having 6 to 12 carbon atoms, an aralkyl group having 7 to 16 carbon atoms, -NR₁₂R₁₃(at this time, R₁₂And R₁₃Excluding hydrogen atom), or-NHCOR₁₄Amide groups represented by the formula, and the like. Wherein, except amide groups as R₁And aryl as R₁In addition, the solubility was good.

R₂～R₅、R₇～R₉Each independently represents a straight-chain or branched alkyl group having 1 to 18 carbon atoms which may be substituted, such as a hydrogen atom, a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, or an n-heptyl group; cycloalkyl groups having 3 to 18 carbon atoms which may be substituted, such as cyclopropyl, cyclopentyl, cyclohexyl, and adamantyl; a linear or branched alkenyl group having 2 to 18 carbon atoms which may be substituted, such as a vinyl group, a propenyl group, or a hexenyl group; a saturated or unsaturated heterocyclic group which may be substituted such as 2-thienyl, 2-pyridyl, 4-azacyclohexyl or morpholino; an aryl group having 6 to 18 carbon atoms which may be substituted, such as a phenyl group, tolyl group, xylyl group, 2, 4, 6-trimethylphenyl group, naphthyl group, etc.; an optionally substituted aralkyl group having 7 to 20 carbon atoms such as benzyl group or phenethyl group, a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, a tert-butoxy group, or the like, a C1 to C18 groupLinear or branched alkoxy groups of (a); a linear or branched thioalkyl group having 1 to 18 carbon atoms which may be substituted such as methylthio, ethylthio, n-propylthio, n-butylthio, sec-butylthio, tert-butylthio, etc.; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, etc.; a nitro group; a cyano group; a mercapto group; a hydroxyl group; a formyl group; -COR₁₁An acyl group represented by; -NR₁₂R₁₃An amino group represented by; -NHCOR₁₄An amide group represented by; -NHCOOR₁₅A carbamate group represented by; -COOR₁₆A carboxylic acid ester group represented by; -OCOR₁₇An acyloxy group represented by; -CONR₁₈R₁₉A carbamoyl group represented by; -SO₂R₂₀A sulfonyl group represented by; -SOR₂₁A sulfinyl group represented by; -SO₂NR₂₂R₂₃A sulfamoyl group represented by; -SO₃R₂₄A sulfonate group represented by; -NHSO₂R₂₅Any one of the functional groups of the sulfonamide group represented.

Furthermore, R₆、R₁₀Is any one functional group selected from a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group and an acyl group.

Here, R₁₁、R₁₄～R₁₇、R₂₀、R₂₁、R₂₄、R₂₅Each independently represents a hydrocarbon group or a heterocyclic group. Furthermore, R₁₂、R₁₃、R₁₈、R₁₉、R₂₂、R₂₃Each independently represents 1 of a hydrogen atom, a hydrocarbon group and a heterocyclic group. These may be substituted as required.

Specifically, as R₁₁～R₂₅Examples of the hydrocarbyl group include a straight-chain or branched alkyl group having 1 to 18 carbon atoms such as a methyl group, an ethyl group, a propyl group, an isopropyl group, an n-butyl group, a sec-butyl group, a tert-butyl group, and an n-heptyl group; cycloalkyl groups having 3 to 18 carbon atoms such as cyclopropyl, cyclopentyl, cyclohexyl and adamantyl; C2-C18 linear or branched alkenyl radicals; a cycloalkenyl group having 3 to 18 carbon atoms such as a cyclopentenyl group or a cyclohexenyl group; aralkyl groups having 7 to 20 carbon atoms such as benzyl and phenethyl; and aryl groups having 6 to 18 carbon atoms such as phenyl, tolyl, xylyl, 2, 4, 6-trimethylphenyl, and the like.

The alkyl chain part and the aryl group part of these hydrocarbon groups may further have R described later₂～R₅The alkyl chain moiety of (3) may have a substituent. The position of these substituents is not particularly limited, and the number of the substituents may be from unsubstituted to plural. When a plurality of substituents are present, they may be the same or different.

Further, as R₁₁～R₂₅Examples of the heterocyclic group include saturated heterocyclic groups such as 4-azacyclohexyl, morpholino, 2-morpholino, piperazinyl (piperazyl), and the like; aromatic heterocycles such as 2-furoyl, 2-pyridyl, 2-thiazolyl and 2-quinolyl. These heterocyclic groups may further have a substituent even if they contain a plurality of heteroatoms, and the bonding position is not limited. Examples of the heterocyclic group having a preferable structure include a saturated heterocyclic ring having 5 to 6 membered rings, a monocyclic ring having 5 to 6 membered rings, and an aromatic heterocyclic ring having 2 condensed rings.

Then, specific chemical structures are exemplified for the above-mentioned acyl group, amino group, amide group, carbamate group, carboxylate group, acyloxy group, carbamoyl group, sulfonyl group, sulfinyl group, sulfamoyl group, sulfonate group, and sulfonamide group.

As acyl (-COR)₁₁) Examples of the functional group include those having the following structures.

Chemical formula 5

As amino groups (-NR)₁₂R₁₃) Examples of the functional group include those having the following structures.

Chemical formula 6

As an amide group (-NHCOR)₁₄) Examples of the functional group include those having the following structures.

Chemical formula 7

As carbamate group (-NHCOOR)₁₅) Examples of the functional group include those having the following structures.

Chemical formula 8

As carboxylic ester groups (-COOR)₁₆) Examples of the functional group include those having the following structures.

Chemical formula 9

As acyloxy (-OCOR)₁₇) Examples of the functional group include those having the following structures.

Chemical formula 10

As carbamoyl (-CONR)₁₈R₁₉) Examples of the functional group include those having the following structures.

Chemical formula 11

As sulfonyl (-SO)₂R₂₀) Examples of the functional group include those having the following structures.

Chemical formula 12

As sulfinyl (-SOR)₂₁) Examples of the functional group include those having the following structures.

Chemical formula 13

As a sulfamoyl group (-SO)₂NR₂₂ R₂₃) Examples of the functional group include those having the following structures.

Chemical formula 14

As sulfonate (-SO)₃R₂₄) Examples of the functional group include those having the following structures.

Chemical formula 15

As sulfonamide group (-NHSO)₂R₂₅) Examples of the functional group include those having the following structures.

Chemical formula 16

The general formula [ I]General formula [ III]In the pyridone azo compound represented, R is₁～R₁₀The alkyl chain moiety in the case of the straight-chain or branched alkyl group, the cycloalkyl group, the straight-chain or branched alkenyl group, the cycloalkenyl group, the straight-chain or branched alkoxy group, the straight-chain or branched thioalkyl group and R₁₁～R₂₅The alkyl chain moiety of the alkyl group may further have a substituent.

Examples of such a substituent include an alkoxy group having 1 to 10 carbon atoms such as a methoxy group, an ethoxy group, an n-propoxy group, an isopropoxy group, an n-butoxy group, a sec-butoxy group, and a tert-butoxy group; alkoxyalkoxy groups having 2 to 12 carbon atoms such as methoxymethoxy, ethoxymethoxy, propoxymethoxy, ethoxyethoxy, propoxyethoxy, methoxybutoxy and the like; alkoxyalkoxyalkoxyalkoxy having 3 to 15 carbon atoms such as methoxymethoxymethoxy, methoxymethoxyethoxy, methoxyethoxymethoxy, methoxymethoxymethoxy, and ethoxyethoxymethoxy; aryloxy groups having 6 to 12 carbon atoms such as phenoxy, tolyloxy, xylyloxy, naphthyloxy and the like; an alkenyloxy group having 2 to 12 carbon atoms such as an allyloxy group or a vinyloxy group.

Examples of the other substituent include a heterocyclic group such as a 2-thienyl group, a 2-pyridyl group, a 4-cyclohexylazanyl group, a morpholino group and the like; a cyano group; a nitro group; a hydroxyl group; a mercapto group; thioalkyl groups such as methylmercapto and ethylmercapto; an alkylamino group having 1 to 10 carbon atoms such as an amino group, an N, N-dimethylamino group, or an N, N-diethylamino group; alkylsulfonylamino having 1 to 6 carbon atoms such as methylsulfonylamino, ethylsulfonylamino and n-propylsulfonylamino; a halogen atom such as a fluorine atom, a chlorine atom, a bromine atom, etc.; alkyl carbonyl groups such as methyl carbonyl group, ethyl carbonyl group, and isopropyl carbonyl group; an alkoxycarbonyl group having 2 to 7 carbon atoms such as a methoxycarbonyl group, an ethoxycarbonyl group, an n-propoxycarbonyl group, an isopropoxycarbonyl group, and an n-butoxycarbonyl group; alkyl carbonyloxy having 2 to 7 carbon atoms such as methylcarbonyloxy, ethylcarbonyloxy, n-propylcarbonyloxy, isopropylcarbonyloxy and n-butylcarbonyloxy; and alkoxycarbonyloxy groups having 2 to 7 carbon atoms such as methoxycarbonyloxy, ethoxycarbonyloxy, n-propoxycarbonyloxy, isopropoxycarbonyloxy and n-butoxycarbonyloxy.

The bonding position of these substituents is not particularly limited, and the number of the substituents may be from unsubstituted to plural. When a plurality of substituents are present, they may be the same or different.

To R₂～R₅、R₇～R₉The following are preferred from the viewpoints of ease of synthesis, solubility in a coating solvent, and the like, without particular limitation.

That is, examples thereof include a hydrogen atom, a C1-C12 linear or branched alkyl group, a C3-C10 cycloalkyl group, a C2-C12 linear or branched alkenyl group, and a C6-C1 linear or branched alkenyl group8 aryl group, saturated or unsaturated heterocyclic group, 7-18 aralkyl group, 1-12 alkoxy group, 1-12 thioalkyl group, halogen atom, nitro group, cyano group, mercapto group, hydroxyl group, formyl group, or-COR₁₁Acyl group represented by the formula, -NR₁₂ R₁₃Amino group represented by the formula, -NHCOR₁₄Amido group represented by, -NHCOOR₁₅A carbamate group represented by the formula, -COOR₁₆A carboxylic acid ester group represented by the formula, -OCOR₁₇Acyloxy group represented by-CONR₁₈ R₁₉Carbamoyl group, -SO₂R₂₀Sulfonyl group represented by, -SOR₂₁Sulfinyl group, -SO₂NR₂₂ R₂₃Sulfamoyl, -SO₃R₂₄Sulfonate group and-NHSO₂R₂₅The sulfonamide group is shown. Among the above, R is defined as R in view of synthesis or solubility₇～R₉Preferable examples thereof include a linear or branched alkyl group, a cycloalkyl group, an alkoxy group, a thioalkyl group, a mercapto group, a hydroxyl group, an acyl group, a carboxylate group, an acyloxy group, a carbamoyl group, a sulfonyl group, and a sulfinyl group.

Wherein R is₂Particularly preferred are a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, an aralkyl group having 7 to 18 carbon atoms, a linear or branched alkoxy group having 1 to 12 carbon atoms, an aryl group having 6 to 18 carbon atoms, a saturated or unsaturated heterocyclic group, a halogen atom, a cyano group, a hydroxyl group and-COR₁₁Acyl group represented by the formula, -NR₁₂R₁₃Amino group represented by the formula, -NHCOR₁₄Amido group represented by, -NHCOOR₁₅A carbamate group represented by, -COOR₁₆A carboxylic acid ester group of the formula, -OCOR₁₇Acyloxy group represented by-CONR₁₈R₁₉Carbamoyl group represented by, -SO₂R₂₀Sulfonyl group represented by, -SOR₂₁Sulfinyl group represented by, -NHSO₂R₂₅The sulfonamide group is shown.

Further, as R₃Preferably, the alkyl group is a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, a cycloalkyl group having 3 to 10 carbon atoms, a linear or branched alkenyl group having 2 to 12 carbon atoms, an aryl group having 6 to 18 carbon atoms, a saturated or unsaturated heterocyclic group, an aralkyl group having 7 to 18 carbon atoms, a linear or branched alkoxy group having 1 to 12 carbon atoms, a halogen atom, a hydroxyl group, -COR₁₁Acyl group represented by the formula, -NR₁₂ R₁₃Amino group represented by the formula, -NHCOR₁₄Amido, -NHCOOR₁₅A carbamate group represented by the formula, -COOR₁₆A carboxylic acid ester group represented by the formula, -OCOR₁₇Acyloxy group represented by-CONR₁₈R₁₉Carbamoyl, -NHSO₂R₂₅The sulfonamide group is shown.

In addition, the effect on the absorption maximum wavelength, the solubility in organic solvents, and the ease of synthesis are considered to be the case for R₂、R₃The functional groups described above can be selected respectively. For example, from the viewpoint of the index of synthesis or solubility, among the above-mentioned examples, preferable examples include a linear or branched alkyl group, a cycloalkyl group, a hydroxyl group, an acyl group, an amino group, a carboxylate group, an acyloxy group, a carbamoyl group, and the like.

As R₆、R₁₀May be desirably represented by a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group, -COR₁₁Acyl group as shown. Among these, hydrogen atom, C1-C8 linear or branched alkyl group, C3-C8 cycloalkyl group, -COR₁₁The acyl group is represented.

Wherein R is₆Particularly preferred are hydrogen atoms, linear or branched ones having 1 to 8 carbon atomsAn alkyl group. As R₁₀Particularly preferred is a linear or branched alkyl group having 1 to 8 carbon atoms. And also R₆、R₁₀Sometimes, the solubility, absorption maximum wavelength, and the magnitude of absorbance are affected. These R₂～R₁₀Substitutions may also be made as required.

In particular, it is known that the light resistance is influenced by the combination of the diazo component and the metal complex having a 6-hydroxy-2-pyridone structure as the skeleton of the coupler of the present invention. The following tendency can be seen: with respect to light resistance, having the general formula [ II]The metal complex of the present invention, namely, the substance whose diazo component is triazole is good because of its stability, and has the general formula [ III]The metal complex of the invention is then of the general formula [ I]The metal complexes of the present invention are inferior. It is also known that: lightfastness is sometimes seen with those substituents R₁～R₁₀And (4) correlating. The light resistance described in the present invention only includes the case where the light resistance becomes poor as a result of poor solubility. These results are shown in table 1. Stable and good in light resistance and having the general formula [ II]In the case of the metal complex of the present invention, R₁～R₃、R₆～R₇Any substance selected from the above-mentioned substances has good light resistance. In contrast, in the general formula [ III ]]The metal complex of the present invention and the metal complex having the general formula [ I ]]In the metal complex of the present invention, as described below, each substituent R has a specific combination of less desirable solubility and less desirable light resistance (see table 1).

An optical recording medium characterized in that the organic pigment compound is a pyridone azo compound represented by the following general formula [ I ],

chemical formula 17

General formula [ I]In, R₁Preferably, unsubstituted amino groups (-NH) are removed₂) Other 1-valent functional groups. Furthermore, R₂～R₅Preferably, each is independently a hydrogen atom or a 1-valent functional group. Namely, R₁Is unsubstituted amino (-NH)₂) By reaction with a substituent R₂～R₅The solubility is slightly lowered in the combination of (1) and (3), and as a result, the light resistance may be lowered.

Furthermore, can be seen as R₂With cyano radicals as R₃The combination of the alkyl groups (a) and (b) is more desirable.

Further, an optical recording medium characterized in that the organic dye compound is a pyridone azo compound represented by the following general formula [ IV ],

chemical formula 18

General formula [ IV ]]In, R₃₁Preferably a 1-valent functional group other than a hydrogen atom. Furthermore, R₂₆～R₃₀Preferably, each is independently a hydrogen atom or a 1-valent functional group.

If let R₃₁The solubility is slightly lowered for hydrogen atoms, and the light resistance may be deteriorated.

In addition, R can be seen as₂₇With cyano radicals as R₂₈The combination of the alkyl groups (a) and (b) is more desirable.

If the above-mentioned undesirable combinations are eliminated, the above-mentioned compounds of the general formula [ I ] are used]General formula [ III]R is a medium ideal₁～R₁₀And corresponds to R₁～R₁₀R of (A) to (B)₂₆～R₃₁The combination of (3) gives good light resistance.

(Metal ion)

Next, the metal ions will be explained.

The metal that forms the metal-containing pyridone azo compound by coordinating with the pyridone azo compound represented by the general formulae [ I ] to [ III ] is not particularly limited as long as it has a coordination forming ability with the pyridone azo compound, and is selected from transition elements and typical elements. The oxidation number of the metal is not limited. In the metal complex described later, the ratio of the metal and the pyridone azo compound is not particularly limited. In addition, the metal complex may be formed in a form containing a counter ion having a charge, in addition to the metal and the pyridone azo compound.

As the metal and pyridone azo compounds formed by complex structure of ideal structure, from the complex formation of easy view, because the pyridone azo compounds with (-1) price charge 3 meshing ligands, so ideally to each 2 valence metal to 2 pyridone azo compounds ratio coordination structure. That is, the metal ion forming a metal complex with the pyridone azo compound represented by the general formulae [ I ] to [ III ] is preferably a metal having a valence of 2 selected from groups 3 to 12 of the periodic table (long period phenotype). Among these 2-valent metals, particularly preferred is at least one metal selected from the group consisting of nickel, cobalt, iron, zinc, copper, and manganese.

The metal-containing pyridone azo compound may have a structure in which a plurality of pyridone azo compounds are coordinated to a metal. In addition, a plurality of metal-containing pyridone azo compounds may be contained in a recording layer of an optical recording medium described later.

The molecular weight of the pyridone azo compound represented by the general formula [ I ] to the general formula [ III ] is desirably 1000 or less, particularly desirably 700 or less. When the molecular weight is too large, the absorption coefficient decreases, and the absorption of the amount of the dye decreases, which is not preferable.

Specific examples of the pyridone azo compounds represented by the general formulae [ I ] to [ III ] include the following compounds (1) to (57).

Examples of the pyridone azo compound represented by the general formula [ I ] include the following compounds (1) to (20).

Chemical formula 19

Chemical formula 20

Examples of the pyridone azo compound represented by the general formula [ II ] include the following compounds (21) to (30).

Chemical formula 21

Examples of the pyridone azo compound represented by the general formula [ III ] include the following compounds (31) to (40).

Chemical formula 22

Examples of the pyridone azo compound represented by the general formulae [ I ] to [ III ] include the following compounds (41) to (57).

Chemical formula 23

Chemical formula 24

(optical recording Medium)

Next, an optical recording medium to which the present embodiment is applied will be described.

The optical recording medium to which the present embodiment is applied is composed of at least a substrate and a recording layer containing a metal complex of a pyridone azo compound represented by general formulae [ I ] to [ III ]. Further, a precoat layer, a reflective layer, a protective layer, and the like may be provided as necessary.

Fig. 1 is a diagram illustrating an optical recording medium to which the present embodiment is applied. Fig. 1(a) shows embodiment 1, and fig. 1(b) shows embodiment 2.

(embodiment 1)

An optical recording medium 10 shown in fig. 1(a) is formed by laminating a substrate 1 made of a light transmissive material, a recording layer 2 provided on the substrate 1, a reflective layer 3 laminated on the recording layer 2, and a protective layer 4 in this order. The optical recording medium 10 records and reads information by laser light irradiated from the substrate 1 side.

For convenience of explanation, in the optical recording medium 10, the side where the protective layer 4 is present is defined as the upper side, the side where the substrate 1 is present is defined as the lower side, and the surfaces of the respective layers corresponding to these directions are defined as the upper surface and the lower surface of the respective layers.

Various materials can be used for the substrate 1 as long as the material is a material that is substantially transparent in the wavelengths of the recording light and the reading light. Specifically, there may be exemplified resins such as acrylic resins, methacrylic resins, polycarbonate resins, polyolefin resins (particularly amorphous polyolefins), polyester resins, polystyrene resins, epoxy resins, and the like; and (3) glass. Further, for example, a structure in which a resin layer made of a radiation curable resin such as a photocurable resin is provided on glass can be given. In particular, polycarbonate resins used in injection molding methods are preferred from the viewpoints of high productivity, cost, resistance to moisture absorption, and the like; from the viewpoint of chemical resistance, moisture absorption resistance, and the like, amorphous polyolefins are preferable. Glass is preferable from the viewpoint of high-speed response and the like.

When the substrate 1 made of resin is used or when the substrate 1 having a resin layer provided on the side (upper side) adjacent to the recording layer is used, a guide groove or a pit for recording and reading light may be formed on the upper surface. Examples of the shape of the guide groove include a concentric shape or a spiral shape with respect to the center of the optical recording medium 10. When the spiral shape is formed, the pitch of the grooves is preferably about 0.2 to 1.2 μm.

The recording layer 2 is formed directly on the upper side of the substrate 1 or on the upper side of a precoat layer or the like provided on the substrate 1 as required, and contains a metal complex of a pyridone azo compound represented by general formulae [ I ] to [ III ]. Examples of the method for forming the recording layer 2 include various film forming methods that are generally performed, such as a vacuum deposition method, a sputtering method, a doctor blade method, a firing method, a spin coating method, and a dipping method. The spin coating method is preferable from the viewpoint of mass productivity and cost, and is more preferable than the coating method, the vacuum deposition method, and the like from the viewpoint of obtaining the recording layer 2 having a uniform thickness. When the film is formed by spin coating, the rotation speed is preferably 500 to 15000 rpm. Further, according to circumstances, the spin coating may be followed by heating, evaporation of solvent vapor, or the like.

In the case of the recording layer 2 formed by a coating method such as a doctor blade method, a firing method, a spin coating method, or a dipping method, a coating solvent for dissolving the metal complex of the pyridone azo compound represented by the general formulae [ I ] to [ III ] and coating the substrate 1 is not particularly limited as long as the solvent does not attack the substrate 1.

Specific examples thereof include ethanolic solvents such as diacetone alcohol and 3-hydroxy-3-methyl-2-butanone; cellosolve solvents such as methyl cellosolve and ethyl cellosolve; chain hydrocarbon solvents such as n-hexane and n-octane; a cyclic hydrocarbon solvent such as cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, n-butylcyclohexane, t-butylcyclohexane, and cyclooctane; perfluoroalkyl alcohol solvents such as tetrafluoro 1-propanol, octafluoropentanol and hexafluorobutanol; and hydroxycarboxylic acid ester solvents such as methyl lactate, ethyl lactate, and methyl 2-hydroxyisobutyrate.

When the vacuum vapor deposition method is used, for example, the recording layer component of the compound represented by the general formula (II a) and, if necessary, other coloring matters and various additives is placed in a crucible provided in a vacuum chamber, and the vacuum chamber is evacuated to 10 deg.C by an appropriate vacuum pump^-2～10^-5Pa or so, the crucible is heated to evaporate the recording layer component, and the recording layer component is deposited on a substrate placed opposite the crucible to form the recording layer 2.

The recording layer 2 may contain, in addition to the metal complex of the pyridone azo compound represented by the general formulae [ I ] to [ III ], a transition metal chelate (e.g., acetylacetone chelate, diphenyldithienyl, salicylaldoxime, bisdithio α -diketone, etc.) as a singlet oxygen quencher for improving stability or light resistance, or a recording sensitivity promoter such as a metal compound for improving recording sensitivity.

The metal compound is a substance in which a metal such as a transition metal is contained in the form of an atom, an ion, a cluster, or the like, and is an organic metal compound such as an ethylene diamine complex, a azomethine complex, a phenylhydroxylamine complex, a phenanthroline complex, a dihydroxyazobenzene complex, a dioxime complex, a nitrosophenol complex, a pyridyltriazine complex, an acetylacetone complex, an arylenemetal derivative complex, or a porphyrin complex. The metal atom is not particularly limited, and a transition metal is preferable.

Further, as necessary, a plurality of metal complexes of pyridone azo compounds represented by the general formulae [ I ] to [ III ] may be used in combination in the recording layer 2. In addition to the metal complex of the pyridone azo compound, other coloring matters may be used in the recording layer 2 as needed.

The dye of another system is not particularly limited as long as it has an appropriate absorption mainly in the excitation wavelength region of the recording laser beam. The optical recording medium 10 can be produced by using a dye suitable for recording/reading using a near-infrared laser beam having an excitation wavelength in a wavelength band region of 770 to 830nm in CD-R or the like and a dye suitable for recording/reading using an infrared laser beam having an excitation wavelength in a wavelength band region of 620 to 690nm in DVD-R or the like in the recording layer 2 together with the pyridone azo compound, and by using a dye suitable for recording/reading using a plurality of laser beams having different wavelength bands. Further, the dye of the CD-R or DVD-R is selected to have good light fastness and mixed in the compound of the present invention, so that the light fastness can be further improved.

Examples of the dye of the other system than the metal complex of the pyridone azo compound represented by the general formulae [ I ] to [ III ] include metal-containing azo dyes, benzophenone dyes, phthalocyanine dyes, naphthalocyanine dyes, anthocyanin dyes, azo dyes, squaraine dyes, metal-containing indoaniline dyes, triarylmethane dyes, cyanine dyes, azlenium dyes, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, xanthene dyes, oxapicrin dyes, pyrylium dyes, and the like.

Further, an adhesive, a leveling agent, an antifoaming agent, and the like may be used together as necessary. Examples of the preferable adhesive include polyvinyl alcohol, polyvinyl pyrrolidone, nitrocellulose, cellulose acetate, ketone resins, acrylic resins, polystyrene resins, polyurethane resins, polyvinyl butyral, polycarbonate, and polyalkene.

The film thickness of the recording layer 2 is not particularly limited since the film thickness to be applied varies depending on the recording method and the like, but a certain film thickness is required for recording, and therefore, the film thickness of the recording layer 2 is usually at least 1nm or more, preferably 5nm or more. However, it is usually 300nm or less, preferably 200nm or less, more preferably 100nm or less. If the film thickness of the recording layer 2 is too large, satisfactory recording may not be performed.

The reflective layer 3 is formed on the recording layer 2. The thickness of the reflective layer 3 is preferably 50nm to 300 nm. As a material of the reflective layer 3, a material having a very high reflectance at the wavelength of the reading light, such as metals of Au, Al, Ag, Cu, Ti, Cr, Ni, Pt, Ta, Pd, or the like, can be used alone or as an alloy. Among these, Au, Al, Ag, and Cu have high reflectance and are suitable as materials for the reflective layer 3. In addition, other materials may be contained in addition to these metals as main components. The main component herein means a substance having a content of 50% or more. Examples of the other materials than the main component include metals and metalloids such as Mg, Se, Hf, V, Nb, Ru, W, Mn, Re, Fe, Co, Rh, Ir, Cu, Zn, Cd, Ga, In, Si, Ge, Te, Pb, Po, Sn, Bi, Ta, Ti, Pt, Pd, Nd, and the like.

Among these metals and metalloids, those containing Ag as a main component are particularly preferable from the viewpoint of low cost, easy generation of high reflectance, and obtaining a white-backed and beautiful substance when a print-receiving layer described later is provided. For example, an alloy containing Ag in an amount of about 0.1 atomic% to 5 atomic% of one selected from Au, Pd, Pt, Cu, and Nd is preferable because of high reflectance, high durability, high sensitivity, and low cost. Specifically, the alloy may be, for example, an Ag Pd Cu alloy, an Ag Cu Au alloy, an Ag CuAuNd alloy, or an Ag CuNd alloy. As a material other than metal, a multilayer film in which a low refractive index thin film and a high refractive index thin film are alternately stacked may be used as the reflective layer 3.

Examples of a method for forming the reflective layer 3 include sputtering, ion plating, chemical vapor deposition, and vacuum vapor deposition. In addition, a known inorganic or organic intermediate layer or adhesive layer may be provided on the substrate 1 or below the reflective layer 3 for the purpose of improving the reflectance, improving the recording characteristics, improving the adhesiveness, and the like.

The protective layer 4 is formed over the reflective layer 3. The material of the protective layer 4 is not particularly limited as long as the reflective layer 3 is protected from an external force. Examples of the material of the organic substance include a thermoplastic resin, a thermosetting resin, an electron beam curing resin, and a UV curing resin. Examples of the inorganic substance include silicon oxide, silicon nitride, and MgF₂、SnO₂And the like.

When a thermoplastic resin or a thermosetting resin is used, the protective layer 4 can be formed by applying a coating solution prepared by dissolving the resin in an appropriate solvent onto the reflective layer 3 and drying the coating solution. When the UV curable resin is used, the protective layer 4 may be formed by coating the reflective layer 3 as it is, or by coating the reflective layer 3 with a coating solution prepared by dissolving the resin in an appropriate solvent and then curing the coating solution by irradiation with UV light.

As the UV curable resin, an acrylate-based resin such as urethane acrylate, epoxy acrylate, or polyester acrylate can be used. These materials may be used alone or in combination. The protective layer may be formed as a single layer or as a plurality of layers.

As a method for forming the protective layer 4, a coating method such as a spin coating method or a firing method, a sputtering method, a chemical vapor deposition method, or the like can be used as in the case of the recording layer 2, but among them, a spin coating method is preferable. The thickness of the protective layer 4 is required to be a certain thickness in order to fulfill its protective function, and is generally 0.1 μm or more, preferably 3 μm or more. However, it is usually 100 μm or less, preferably 30 μm or less. If the film thickness of the protective layer 4 is too large, not only the effect is not changed, but also time is required for forming the protective layer 4, which may increase the cost.

As described above, the optical recording medium 10 has been described as having a layer structure in which the substrate 1, the recording layer 2, the reflective layer 3, and the protective layer 4 are laminated in this order.

For example, another substrate 1 may be further bonded to the upper surface of the protective layer 4 in the layer structure of the above example, or to the upper surface of the reflective layer 3 without the protective layer 4 in the layer structure of the above example. The substrate 1 in this case may be a substrate itself without any layer provided thereon, or may be a substrate having an arbitrary layer such as the reflective layer 3 on the surface to be bonded or the surface opposite thereto. Further, the optical recording medium 10 also having the layer structure of the above example and the upper surface of the protective layer 4 and/or the reflective layer 3 of each of the optical recording media 10 in which the protective layer 4 is omitted from the layer structure of the above example are bonded together in opposed 2 pieces.

(embodiment 2)

Next, embodiment 2 of the optical recording medium will be described.

Fig. 1(b) is a diagram illustrating an optical recording medium according to embodiment 2. The same portions as those of the optical recording medium 10 of embodiment 1 are denoted by the same reference numerals, and description thereof is omitted.

The optical recording medium 20 shown in fig. 1(b) is formed by laminating a substrate 1 made of a light transmissive material, a reflective layer 3 provided on the substrate 1, a recording layer 2 laminated on the reflective layer 3, and a protective film 5 in this order. The optical recording medium 20 records and reads information by laser light irradiated from the protective film 5 side.

The protective film 5 may be formed by sticking a film or sheet-like material with an adhesive, or may be formed by coating, curing or drying a film-forming material with the same material as the protective layer 4. The thickness of the protective film 5 is required to be a certain thickness to fulfill its protective function, and is generally 0.1 μm or more, preferably 3 μm or more. However, it is usually 300 μm or less, preferably 200 μm or less. If the protective film 5 is too thick, not only the effect is not changed, but also time is required for forming the protective film 5, which may increase the cost.

The same materials as those used for the optical recording medium 10 described above can be generally used for the recording layer 2, the reflective layer 3, and the like. However, in the present layer structure, the substrate 1 does not need to be transparent, and therefore, opaque resin, ceramics, metal (including alloy), or the like may be used in addition to the above-described materials. In such a layer structure, the layers may have any layers as necessary as long as the characteristics of the present invention are not impaired.

However, as a means for increasing the recording density of the optical recording media 10, 20, for example, the numerical aperture of the objective lens can be enlarged. This makes it possible to miniaturize the spot focused on the information recording surface. However, if the numerical aperture of the objective lens is increased, the aberration of the light spot is likely to be increased due to the curvature of the optical recording medium 10 or 20 when the laser beam is irradiated for recording and reading, and thus a good recording and reading signal may not be stably obtained.

Since such aberration is more likely to increase as the film thickness of the transparent substrate or the protective film through which the laser light is transmitted becomes thicker, it is preferable to make the substrate or the protective film as thin as possible in order to reduce the aberration. However, since the substrate 1 generally needs to have a certain thickness in order to ensure the strength of the optical recording media 10 and 20, it is preferable to adopt the structure of the optical recording medium 20 (the optical recording medium 20 basically having a layer structure including the substrate 1, the reflective layer 3, the recording layer 2, and the protective film 5). Since the protective film 5 of the optical recording medium 20 is easily thinner than the substrate 1 of the optical recording medium 10, it is preferable to use the optical recording medium 20.

However, even in the structure of the optical recording medium 10 (the optical recording medium 10 basically having a layer structure including the substrate 1, the recording layer 2, the reflective layer 3, and the protective layer 4), the aberration can be reduced by making the thickness of the transparent substrate 1 through which the recording/reading laser beam passes thin to about 50 μm to 300 μm.

After the formation of the other layers, for the purpose of surface protection or prevention of adhesion of dust and the like, an ultraviolet-curable resin layer, an inorganic thin film, or the like may be formed on the surface on which the recording/reading laser light is incident (usually, the lower surface of the substrate 1), or a print-receiving layer that can be filled or printed by various printers such as ink jet and thermal transfer, or various writing instruments may be provided on the surface other than the surface on which the recording/reading laser light is incident (usually, the upper surfaces of the reflective layer 3 and the protective layer 4).

In the optical recording media 10 and 20 to which the present embodiment is applied, the laser light used for recording and reading information is preferably shorter in wavelength, particularly preferably 350 to 530nm in wavelength, from the viewpoint of realizing high density recording. Typical examples of the laser include lasers having center wavelengths of 405nm, 410nm, and 515 nm.

The laser having a wavelength of 350nm to 530nm can be obtained by using a blue or blue 515nm high-power semiconductor laser having a wavelength of 405nm or 410 nm. Alternatively, the laser light source can be obtained by converting the wavelength of any of (a) a semiconductor laser beam having a fundamental excitation wavelength of 740 to 960nm and capable of continuous excitation and (b) a solid laser beam having a fundamental excitation wavelength of 740 to 960nm excited by the semiconductor laser beam, into a second harmonic generation element (SHG).

The SHG may be any piezoelectric element as long as it lacks mirror symmetry, but KDP, ADP, BNN, KN, LBO, compound semiconductor, and the like are preferable. As specific examples of the second harmonic, in the case of a semiconductor laser having a fundamental excitation wavelength of 860nm, for example, 430nm, which is a multiple of the fundamental excitation wavelength; in addition, in the case of a semiconductor laser excited solid laser, for example, LiSrAlF derived from Cr doping₆430nm which is a double wavelength of crystals (fundamental excitation wavelength of 860nm), and the like.

In recording information, the optical recording media 10 and 20 to which the present embodiment is applied are generally irradiated with a laser beam focused to a thickness of about 0.4 to 0.6 μm on the recording layer 2 (generally transmitted through the substrate 1 from the substrate 1 side). The portion of the recording layer 2 irradiated with the laser beam absorbs energy of the laser beam, and causes thermal denaturation such as decomposition, heat generation, and dissolution, thereby changing optical characteristics.

When reading information recorded on the recording layer 2, a laser beam having a lower energy is irradiated to the same recording layer 2 (usually from the same direction as the direction at the time of recording). In the recording layer 2, information is read by reading a difference between the reflectance of a portion where the optical characteristics change (that is, a portion where information is recorded) and the reflectance of a portion where the optical characteristics do not change.

Examples

The present embodiment will be described more specifically with reference to the following examples. The present embodiment is not limited to these examples as long as it does not exceed the gist thereof.

(Synthesis method of pyridone azo Compound)

The method for synthesizing the pyridone azo compounds represented by the general formulae [ I ] to [ III ] is not particularly limited, and a general production method such as a 6-hydroxy-2-pyridone structure is shown below.

(1) Condensation between cyanoacetamide derivatives and beta-ketoesters

As the most common production method, the following methods are known: by reacting cyanoacetamide derivatives and beta-ketoesters ("J.heterocyclic Chem.," 32, 979(1995), etc.), or by reacting cyanoacetic acid ethyl esters, amines and beta-ketoesters ("Dyes") in the presence of a basic catalyst&Pigments ", 15, 69(1991)) to synthesize 3-cyano-6-hydroxy-2-pyridone. Here, by changing R of amine in the cyanoacetamide derivative₁The substituent may be introduced into R₁Furthermore, by altering R of beta-ketoesters₃Substituents may also be introduced.

Chemical formula 25

(2) Condensation between 1, 3-dimethyl uracil and malonamide derivative

In addition, 3-substituted-2, 6-dihydroxypyridine can be synthesized by using 1, 3-dimethyluracil and a malonamide derivative as described below ("j.am. chem. soc., 101" (15), 4423 (1979)).

Chemical formula 26

(3) Michael addition of phenylpropanoic acid

In addition, the synthesis can be carried out by the reaction of N-allylamphetamine with diethyl oxalate as described below (J.Pharmacol., 99(6), 588 (1979)).

Chemical formula 27

Alternatively, a substituent may be introduced by reacting a commercially available reagent or a compound having a 2, 6-dihydroxypyridine structure with a starting material.

The thus-obtained 6-hydroxy-2-pyridone compound is diazotically coupled with a diazotized heteroaromatic cyclic amine to obtain a pyridone azo compound represented by general formulae [ I ] to [ III ]. The pyridone azo compound is coordinated with a metal to obtain a metal-containing pyridone azo compound (metal complex of the pyridone azo compound).

(example 1)

(a) Synthesis example

(a-1)

22.63g (0.2 mol) of ethyl cyanoacetate represented by the following structural formula [1], 26.03g (0.2 mol) of ethyl 3-carbonylbutyrate represented by the structural formula [2] and 14.63g (0.2 mol) of n-butylamine represented by the structural formula [3] were dissolved in 20ml of ethanol, 6ml of piperidine was added dropwise thereto, and half reflux was carried out for 26 hours under stirring. After the reaction solution was cooled, it was stirred in 200ml of a 10% hydrochloric acid aqueous solution to precipitate a solid. The precipitated solid was filtered, washed with water, suspended in 100ml of a hexane solution, stirred for about 30 minutes, filtered, and the filtrate was dried under vacuum by heating to obtain 11.3g (yield 27.4%) of the following compound [4] (1-n-butyl-3-cyano-4-methyl-6-hydroxy-2-pyridone).

Chemical formula 28

n-C₄H₉NH₂------[3]

Chemical formula 29

2.94g (0.03mo1) of 3-cyano-5-methylisoxazole represented by the following structural formula [5] was dissolved in 30ml of acetic acid, 10ml of propionic acid, 2ml of concentrated sulfuric acid solution with stirring, and cooled to 0 to 5 ℃. 10.62g of 43% nitrososulfuric acid was added dropwise thereto, and the mixture was diazotized while maintaining at 10 ℃ or lower to prepare a diazo solution.

Chemical formula 30

On the other hand, in another container, 6.8g (0.033mol) of the above compound [4], 9g of sodium acetate and 1.2g of urea were dissolved in 100ml of methanol and 20ml of water with stirring, adjusted to pH 5 with hydrochloric acid, and cooled to 0 to 5 ℃. A previously prepared diazo solution is added dropwise to the solution at 5 ℃ or lower while maintaining the pH of the solution at 4-5 with a 14% aqueous ammonia solution. After completion of the dropping, the mixture was stirred for 30 minutes, and the reaction mixture was filtered. To remove inorganic salts, the filtrate was suspended in 500ml of water, stirred for about 30 minutes, and filtered. The filtrate was suspended in 200ml of methanol, filtered while stirring, and dried under heating in vacuo to obtain 7.74g (yield: 81.8%) of the compound represented by the example compound (41). MS measurement of this compound confirmed that m/z was 315.

Chemical formula 31

(a-2) NMR results

Furthermore, 1H-NMR (CDCl) was measured₃(δ ppM)270MHz) and a peak of 0.96(3H, t, N-CH)₂ CH₂ CH₂ CH₃)、1.37(2H、sextet、N-CH₂ CH₂ CH₂CH₃)、1.59(2H、m、N-CH₂CH₂ CH₂ CH₃)、2.48(3H、s、5’-CH₃)、2.55(3H、s、4-CH₃)、3.96(2H、t、N-CH₂CH₂ CH₂ CH₃) 6.3(1H, s, 4' -H), in accordance with the object compound.

This exemplary compound (41) had a λ max of 391nm in chloroform and a molar absorption coefficient of 3.5 × 10⁴。

3.78g (0.012 mol) of the exemplified compound (41) was dissolved in 100ml of tetrahydrofuran with stirring, and the solution was filtered until no impurities were mixed, and then 1.79g (0.0072 mol) of a nickel acetate/27 ml methanol solution was added dropwise to the filtrate.The reaction mixture was stirred for 1 hour, and then 500ml of isopropyl ether was added to precipitate a solid, which was then filtered. The filtrate was suspended in 100ml of water, stirred for about 30 minutes, and filtered. The filtrate was washed with isopropyl ether and dried under heating in vacuo to obtain 2.91g (yield 70.6%) of the following structural formula [6]]The metal-containing pyridone azo compound (as the metal complex (58)) is shown. The compound has a lambda max of 435.5nm in chloroform and a molar absorption coefficient of 5.6X 10⁴。

Chemical formula 32

(b) Evaluation of optical recording Medium

The metal complex (58) (the metal-containing pyridone azo compound represented by structural formula [6 ]) was dissolved in octafluoro-n-pentanol and adjusted to 1 wt%. The filtered solution was dropped on an injection-molded polycarbonate resin substrate having a diameter of 120mm and a thickness of 1.2mm, coated by a spin coating method (500rpm), and dried at 100 ℃ for 30 minutes. The maximum absorption wavelength (. lamda.max) of the coating film was 442.5 nm.

Fig. 2 is an absorption spectrum of the coating film of the metal complex (58).

The cut piece of the optical disk coated with the metal complex (58) was irradiated with Xe lamp at 63 ℃ and 550mW for 40 hours using a light resistance tester (Suntest XLS +, manufactured by Toyo Seiki Seisaku-Sho Ltd.). Then, the absorbance (I) at λ max before the Xe lamp was irradiated was measured with a UV measuring instrument₀) And the absorbance (I) at λ max after irradiation of the Xe lamp. Then I and I are obtained₀Ratio of (I/I)₀) (%), light resistance was evaluated (the higher the value, the better the light resistance).

As a result, the light resistance ((I/I) of the metal complex (58)₀) (%)) of 63.2%, and showed extremely good dye film having a maximum absorption wavelength (. lamda.max) of 500nm or lessGood light resistance.

Further, the other substrate coated with the metal complex (58) was allowed to stand in a constant temperature and humidity bath at 85 ℃ and a relative humidity of 85% for 200 hours. Thereafter, the spectrum was measured and compared with the absorption intensity (the same wavelength as λ max before the test) before being left in the constant temperature and humidity chamber, and the storage stability was evaluated. The result was extremely good, 97.3%.

If necessary, a reflective layer is formed by depositing Ag or the like on the coating film thus formed by sputtering, and an ultraviolet curable resin is cured by coating or UV irradiation by spin coating or the like to form a protective film, thereby forming an optical recording medium. The optical recording medium can be recorded and read by using a lambda max value of the coating film, such as a semiconductor laser light having a central wavelength of 405 nm. Namely, it can be seen that: the metal pyridone azo compound of the metal complex (58) is a compound having an effective structure for recording with a blue laser.

Also, the optical recording medium is modulated as follows.

The metal complex (58) was dissolved in octafluoro-n-pentanol to adjust the solution to 1.4 wt%. The filtered solution was dropped on an injection-molded polycarbonate resin substrate having a groove width of 200nm and a groove depth of 70nm and a track pitch of 400nm and a diameter of 120mm and a thickness of 0.6mm, and the substrate was coated by a spin coating method. Also, the coating was raised from 600rpm to 4900rpm over 25 seconds and held at 4900rpm for 5 seconds. Then, the resultant was dried at 100 ℃ for 30 minutes to prepare a recording layer.

Then, a silver alloy was formed into a film having a thickness of 100nm by sputtering to form a reflective layer. Thereafter, a protective coating agent made of a UV curable resin was applied by a spin coating method, and a protective layer having a thickness of 5 μm was formed by irradiation with UV light. The surface having the protective layer was bonded to a polycarbonate substrate having a thickness of 0.6mm with a delayed curing adhesive to prepare an optical recording medium for evaluation.

(c) Example of recording

While the optical recording medium for evaluation was rotated at a linear velocity of 6.61 m/sec, a single frequency signal of 8T mark/8T space (8Tmark/8Tspace) was recorded on the groove with a laser beam having a wavelength of 405nm (numerical aperture NA of objective lens: 0.65). Also, T is a reference clock period corresponding to a frequency of 65 MHz. As a recording pulse strategy, the number of divided pulses was n T in mark length, and (n-1), the leading recording pulse width 2T, the subsequent recording pulse width 0.6T, the bias power (a bias power)1.5mW, the read power 0.4mW, and the recording power were adjusted. As a result, a signal with a modulation degree of 51% can be recorded at 7 mW. It is considered that the modulation degree can be further increased in accordance with optimization of recording conditions such as a pulse strategy.

(example 2)

(a) Production example

18.61g of citrazinic acid [7] below was suspended in 500ml of ethanol, and 27ml of concentrated sulfuric acid was added dropwise thereto at room temperature under stirring, followed by refluxing for 4 hours. After the reaction solution was cooled, it was put into 1000ml of water to precipitate a solid. The precipitate was filtered, washed with water, and dried in vacuo to synthesize 14.88g of the following compound [8] (yield 67.7%).

Chemical formula 33

Chemical formula 34

Then, 3.5g (0.025mol) of 3-amino-5-tert-butylisoxazole represented by the following structural formula [9] was dissolved in 25ml of acetic acid, 8.3ml of propionic acid, and 1ml of concentrated sulfuric acid solution with stirring, and cooled to 0 to 5 ℃. 8.85g of 43% nitrososulfuric acid was added dropwise thereto, and diazotization was performed while maintaining the temperature at 10 ℃ or lower to prepare a diazo solution.

Chemical formula 35

On the other hand, in another vessel, 4.81g (1.05 equiv) of the above-mentioned compound [4]]7.5g of sodium acetate and 1g of urea are suspended in 100ml of methanol and 25ml of water, the pH is adjusted to 5 by hydrochloric acid, and the mixture is cooled to 0-5 ℃. A previously prepared diazo solution is added dropwise to the solution at a temperature of 5 ℃ or lower while maintaining the pH of the solution at 4 to 5 with a 14% aqueous ammonia solution. After completion of the dropping, the mixture was stirred for 30 minutes, and the reaction mixture was filtered. To remove inorganic salts, the filtrate was suspended in 500ml of water, stirred for about 30 minutes, and filtered. The filtrate was suspended in 1500ml of methanol, filtered while stirring, and dried under heating in vacuum to obtain 6.69g (yield: 80%) of the exemplified compound (42). The compound (42) was exemplified as having a λ max of 379.5nm in chloroform and a molar absorption coefficient of 3.1 × 10⁴。

Chemical formula 36

2.0g (0.006mol) of the compound represented by the example compound (42) was dissolved in 40ml of tetrahydrofuran under stirring, and the mixture was filtered until no impurities were mixed, and then 0.9g (0.0036mol) of a nickel acetate/13 ml methanol solution was added dropwise to the filtrate. After the reaction solution was stirred for 1 hour, the reaction solution was transferred to an eggplant type flask, and the solvent was removed by an evaporator and dried and solidified. To remove unreacted nickel acetate, the resulting solid was suspended in 60ml of water, stirred and filtered. The filtrate was washed with isopropyl ether and dried under heating in vacuo to obtain 2.14g (yield 98.2%) of the following structural formula [10]]The metal-containing pyridone azo compound is shown. (as metal complex (59)) lambda max of this compound in chloroform was 425nm, and molar absorption coefficient was 4.0 as a reference10⁴。

Chemical formula 37

(b) Evaluation of optical recording Medium

The metal complex (59) (the metal-containing pyridone azo compound represented by the structural formula [10 ]) was dissolved in octafluoro-n-pentanol and adjusted to 1 wt%. The filtered solution was dropped on an injection-molded polycarbonate resin substrate having a diameter of 120mm and a thickness of 1.2mm, coated by a spin coating method, and dried at 100 ℃ for 30 minutes. The maximum absorption wavelength (. lamda.max) of the coating film was 436.5 nm.

Fig. 3 is an absorption spectrum of the metal complex (59).

Also, the following modulation of the optical recording medium.

The cut piece of the optical disk coated with the dye was irradiated with Xe lamp at 63 ℃ and 550mW for 40 hours using a light resistance tester (Suntest XLS + manufactured by Toyo Seiki Seisaku-Sho Ltd.) in the same manner as in example 1, and the light resistance was evaluated.

As a result, the light resistance of the metal complex (59) containing the metal pyridone azo compound was 59%, and the dye film had a maximum absorption wavelength (λ max) at a wavelength of 500nm or less and exhibited extremely good light resistance.

Further, the substrate additionally coated with the metal complex (59) was allowed to stand in a constant temperature and humidity bath for 200 hours at 85 ℃ and 85% relative humidity as in example 1. Thereafter, the spectrum was measured, and the storage stability was evaluated to find that 68.9%.

The metal complex (59) was dissolved in octafluoro-n-pentanol to adjust the solution to 0.9 wt%. The filtered solution was dropped on an injection-molded polycarbonate resin substrate having a groove width of 200nm and a groove depth of 70nm and a track pitch of 400nm and a diameter of 120mm and a thickness of 0.6mm, and the substrate was coated by a spin coating method. Also, the coating was raised from 600rpm to 4900rpm over 25 seconds and held at 4900rpm for 5 seconds. The resultant was dried at 100 ℃ for 30 minutes to prepare a recording layer. Then, a silver alloy was formed into a film having a thickness of 100nm by sputtering to form a reflective layer. Thereafter, a protective coating agent made of a UV curable resin was applied by a spin coating method, and a protective layer having a thickness of 5 μm was formed by irradiation with UV light. The surface having the protective layer was bonded to a polycarbonate substrate having a thickness of 0.6mm with a delayed curing adhesive to prepare an optical recording medium for evaluation.

(c) Example of recording

While the optical recording medium for evaluation was rotated at a linear velocity of 6.61 m/sec, a single frequency signal of 8T mark/8T space (8Tmark/8Tspace) was recorded on the groove with a laser beam having a wavelength of 405nm (numerical aperture NA of objective lens: 0.65). Also, T is a reference clock period corresponding to a frequency of 65 MHz. As a recording pulse strategy, the number of divided pulses was adjusted such that (n-1), the leading recording pulse width 2T, the subsequent recording pulse width 0.75T, the bias power (a bias power)2.4mW, the read power 0.4mW, and the recording power were adjustable with the track length nT. As a result, a signal with a modulation degree of 42% can be recorded at 8 mW. It is considered that the modulation degree can be further increased in accordance with optimization of recording conditions such as a pulse strategy.

(examples 3 to 16)

Thereafter, the metal complexes (60) to (73) were synthesized in the same manner as in the above-described synthesis method, a coating film was formed in the same manner as in example 1, and the absorption spectrum of the coating film was measured. The maximum absorption wavelength (. lamda.max) in solution (chloroform), molar absorption coefficient, and maximum absorption wavelength (. lamda.max) of the coating film (except that octafluoro-n-pentanol was used as the coating solvent) of these compounds were measured.

(example 17)

(a) Synthesis example

Under the same reaction conditions as in example 1, 2-ethoxyethylamine represented by the following structural formula [11] was used as an amine to obtain a compound represented by the following structural formula [12 ].

Chemical formula 38

C₂H₅OC₂H₄NH₂------[11]

Then, 2.5g (0.0258mol) of 3-amino-5-methylpyrazole represented by the following structural formula [13] was dissolved in 75ml of water and 12.5g of concentrated hydrochloric acid solution with stirring, and cooled to 0 to 5 ℃. 1.96g of sodium nitrite/6 ml of an aqueous solution was dropped thereinto, and diazotization was carried out while keeping the temperature at 10 ℃ or lower.

Chemical formula 39

On the other hand, in another vessel, 5.21g (0.0235mol) of the above-mentioned structural formula [12]]The compound and 1.0g of urea were dissolved in 100ml of methanol under stirring, and cooled to 0 to 5 ℃. The previous nitrogen solution was dropped into the solution at 0 ℃ or lower. After completion of the dropping, the reaction mixture was stirred for 30 minutes and filtered. To remove inorganic salts, the filtrate was suspended in 500ml of water, stirred for about 30 minutes, and filtered. This was dried by heating in vacuo to obtain 6.48g (yield 83%) of the following structural formula [14]]The compounds represented. The compound has a lambda max of 423.5nm in chloroform and a molar absorption coefficient of 3.7X 10⁴。

Chemical formula 40

Next, 1g (0.003mol) of the compound represented by the above structural formula [14] was dissolved in 40ml of THF, and the reaction vessel was cooled in an ice bath. To this mixture were added 0.15g (0.0036mol) of sodium hydride (oily, 60% strength) and 1.3g (0.006mol) of n-propyl p-toluenesulfonate represented by the following formula [15], the temperature was raised to 70 ℃ and the mixture was stirred for 4.5 hours, and then 0.3g of sodium hydride and 2.6g of n-propyl p-toluenesulfonate were added and the mixture was reacted for 2 hours, followed by cooling. The reaction solution was added to water, and the pH was adjusted to neutrality, followed by filtration.

Chemical formula 41

The obtained solid was a semi-oil, and was dissolved in THF to remove the solvent with an evaporator to obtain a solid, which was washed with isopropyl ether, filtered, and the solid was dried in vacuo to obtain 0.79g (yield 63%) of a pyridone azo compound represented by the exemplary compound (55).

The pyridone azo compound represented by the exemplary compound (55) had a λ max of 437nm and a molar absorption coefficient of 4.4 × 10 in a chloroform solution⁴。

A nickel complex was synthesized as a pyridone azo compound represented by the exemplary compound (55) in the same manner as in example 1 to obtain the following compound [16]](as a metal complex (74)). The metal complex (74) had a λ max of 466nm and 492nm in a chloroform solution, and a molar absorption coefficient of 8.5 × 10⁴、8.5×10⁴。

Chemical formula 42

(b) Evaluation of optical recording Medium

The metal complex (74) was dissolved in octafluoro-n-pentanol and adjusted to 1 wt%. The filtered solution was dropped on an injection-molded polycarbonate resin substrate having a diameter of 120mm and a thickness of 0.6mm, and the substrate was coated by a spin coating method (500rpm), and then dried at 100 ℃ for 30 minutes. The maximum absorption wavelength (. lamda.max) of the coating film was 469.5nm and 500 nm.

Further, fig. 4 is an absorption spectrum of the coating film of the metal complex (74). As shown in fig. 4, it can be seen that: the metal complex (74) has λ max at a longer wavelength than the metal complex (58) in example 1, but absorbs at 405nm to some extent, and can be used as a dye for an optical recording medium.

(example 18)

(a) Synthesis example

Under the same reaction conditions as in example 1, n-hexylamine represented by the following structural formula [17] was used as an amine to obtain a compound represented by the following structural formula [18 ].

Chemical formula 43

n-C₆H₁₃NH₂------[17]

Then, 6.08g (0.04mol) of 3-amino-5-trifluoromethyl-1, 2, 4(H) -triazole represented by the following structural formula [19] was dissolved in 15ml of acetic acid, 5ml of propionic acid, and 4ml of concentrated sulfuric acid with stirring, and cooled to 0 to 5 ℃.14g of nitrosulfonic acid was added dropwise thereto, and diazotization was carried out while maintaining at 10 ℃ or lower to prepare a diazotized solution.

Chemical formula 44

On the other hand, 10.5g (0.045mol) of the above structural formula [18] was charged in another vessel]The compound, 1.5g of urea and 15g of sodium acetate were dissolved in 100ml of methanol +10ml of water with stirring, and cooled to 0 to 5 ℃. The previous diazo solution was dropped into this solution at 5 ℃ or lower. After completion of the dropping, the reaction mixture was stirred for 30 minutes and filtered. To remove inorganic salts, the filtrate was suspended in 600ml of water, stirred for about 30 minutes, and filtered. The filtrate was suspended in 200ml of methanol, filtered, and the substance was dried under heating in vacuo to obtain 7.84g (yield 49%) of the following structural formula [20 ]]The compounds represented. The compound has a lambda max of 391.5nm in chloroform and a molar absorption coefficient of 3.0X 10⁴。

Chemical formula 45

2g (0.005mol) of the above-mentioned structural formula [20 ]]The compound represented by the formula and 1.4g of potassium carbonate were suspended and dissolved in 20ml of N-methyl-2-pyrrolidone, and the mixture was heated to 90 ℃. 2.1g (0.015mol) of 1-bromobutane was added thereto and heated for 1 hour. Then, the reaction solution was cooled, and placed in water, and the precipitated solid was filtered off, suspended in methanol, stirred, and the solid obtained by filtration was dried in vacuo to obtain 1.31g (yield 58%) of a pyridone azo compound represented by the exemplary compound (56). The pyridone azo compound had a lambda max of 480nm in chloroform and a molar absorption coefficient of 2.7X 10⁴。

As a pyridone azo compound represented by the exemplary compound (56), a nickel complex was synthesized in the same manner as in example 1 to obtain a pyridone azo compound represented by the following structural formula [21 ]]The compound represented (as the metal complex (75)). The metal complex (75) had a lambda max of 463 nm and 491.5nm in a chloroform solution, and a molar absorption coefficient of 8.2X 10⁴、8.0×10⁴。

Chemical formula 46

(b) Evaluation of optical recording Medium

The metal complex (75) was dissolved in octafluoro-n-pentanol and adjusted to 1 wt%. The filtered solution was dropped on an injection-molded polycarbonate resin substrate having a diameter of 120mm and a thickness of 0.6mm, and the substrate was coated by a spin coating method (500rpm), and then dried at 100 ℃ for 30 minutes. The maximum absorption wavelength (. lamda.max) of the coating film was 469.5nm and 500 nm.

Fig. 5 is an absorption spectrum of the coating film of the metal complex (75). As shown in fig. 5, it can be seen that: compared with the metal complex (58) in example 1, it has λ max at a longer wavelength, but absorbs at 405nm to some extent, and can be used as a dye for an optical recording medium.

If necessary, an optical recording medium can be prepared by forming a reflective layer on the coating film formed in this way by sputtering Ag or the like, and curing the ultraviolet curable resin by coating and UV irradiation by a spin coating method to form a protective layer.

The optical recording medium can be recorded and read by using a lambda max value of the coating film, such as a semiconductor laser light having a central wavelength of 405 nm. Namely, it can be seen that: a metal-containing pyridone azo compound comprising a 2-valent transition metal and a pyridone azo compound represented by general formulae [ I ] to [ III ] is a compound having an effective structure for recording with a blue laser beam.

(example 19)

The metal complex (76) was synthesized by the same method as in example 1 using the pyridone azo compound shown by the above exemplified compound (57), and the maximum absorption wavelength (. lamda.max) in the solution (chloroform), the molar absorption coefficient, and the maximum absorption wavelength (. lamda.max) of the coating film were measured in the same manner as in example 1 (except that octafluoro-n-pentanol was used as the coating solvent).

The measurement results of the maximum absorption wavelength (. lamda.max) of the metal complex prepared in examples 1 to 19 in the solution (chloroform), the molar absorption coefficient, and the maximum absorption wavelength (. lamda.max) of the coating film (except that octafluoro-n-pentanol was used as the coating solvent) are shown in Table 1.

TABLE 1

Examples	Metal complexes	Organic pigment Compound (exemplary Compound No.)	Coordinated metal (Metal salt used)	In solution at max (nm) (in CHCl)Middle)	Molar absorptivity (× 10000)	Lambda max (nm) of coating film	Light resistance I/I
								1	(58)	I(41)	Ni Ni(CHCOO)·4HO	436	5.5	442.5	63.2％
2	(59)	I(42)	Ni Ni(CHCOO)·4HO	425	4	436.5	59.0％
								3	(60)	I(43)	Ni Ni(CHCOO)·4HO	435.5	5	444	62.2％
4	(61)	I(44)	Ni Ni(CHCOO)·4HO	438.5	5.4	442.5	79.3％
								5	(62)	I(45)	Ni Ni(CHCOO)·4HO	436	7.4	441	62.6％
6	(63)	I(45)	Co Co(CHCOO)·4HO	445	3.9	448
								7	(64)	I(46)	Ni Ni(CHCOO)·4HO	461.5	6.2	460
8	(65)	I(47)	Ni Ni(CHCOO)·4HO	439	5.1	442.5
								9	(66)	II(48)	Ni Ni(CHCOO)·4HO	459，486.5	6.3，6.1	462，494.5
10	(67)	II(48)	Co Co(CHCOO)·4HO	462.5	5.1	465
								11	(68)	II(49)	Ni Ni(CHCOO)·4HO	463	8.2	470.5	98.5％
12	(69)	I(50)	Ni Ni(CHCOO)·4HO	435.5	5.4	442	63.2％
								13	(70)	I(51)	Ni Ni(CHCOO)·4HO	435	5.1	445	55.5％

14	(71)	I(52)	Ni Ni(CHCOO)·4HO	437	4.7	440.5
								15	(72)	I(53)	Ni Ni(CHCOO)·4HO	447	2.8	453.5
16	(73)	I(54)	Ni Ni(CHCOO)·4HO	436	4.5	442
								17	(74)	III(55)	Ni Ni(CHCOO)·4HO	466，492	8.5，8.5	469.5，500	89.0％
18	(75)	II(56)	Ni Ni(CHCOO)·4HO	463，491.5	8.2，8.0	470.5，504	98.5％
								19	(76)	I(57)	Ni Ni(CHCOO)·4HO	438.5	4.6	435	51.5％
20	(77)	I(57)	Co Co(CHCOO)·4HO	452	4.5	436	69.3％
								21	(78)	I(58)	Ni Ni(CHCOO)·4HO	431.5	4.5	444	74.2％
22	(79)	I(58)	Cu CuCl·2HO	400	3.6	407	50.5％
								23	(80)	I(59)	Ni Ni(CHCOO)·4HO	431.5	3	434.5	19.0％
24	(81)	II(60)	Ni Ni(CHCOO)·4HO	450.5	5.8	466.5	88.1％
								25	(82)	III(61)	Ni Ni(CHCOO)·4HO	465	6.8	473.5	67.5％
26	(83)	III(62)	Ni Ni(CHCOO)·4HO	425	3.9	446.5	14.5％
								27	(84)	III(63)	Ni Ni(CHCOO)·4HO	435	4.6	454	42.3％

Comparative example 1

For comparison, compound [13] shown below was synthesized and evaluated as an optical recording medium.

(a) Production example

2-amino-6-methylbenzothiazole represented by the following structural formula (manufactured by Tokyo Kaisha) (the following Compound [11]]) Diazotization was carried out in a similar manner, and the resulting compound [12] was coupled and synthesized under the same conditions as in example 1]Lambda max in chloroform was 453.5nm, molar absorption coefficient was 3.2X 10⁴。

Further, compound [12] was reacted with nickel acetate]The metal-containing compound of the following formula [13]The lambda max of the metal-containing pyridone azo compound in the chloroform solution is 524nm, and the molar absorption coefficient is 7.4 multiplied by 10⁴。

Chemical formula 47

Chemical formula 48

Chemical formula 49

(b) Examples of optical recording media

The metal-containing pyridone azo compound represented by the above structural formula [13] was dissolved in octafluoro-n-pentanol and adjusted to 1% by weight, but the solubility was low and half of the insoluble matter was present. The filtered solution was dropped on an injection-molded polycarbonate resin substrate having a diameter of 120mm and a thickness of 0.6mm, and the substrate was coated by a spin coating method (500rpm), and then dried at 100 ℃ for 30 minutes. The maximum absorption wavelength (. lamda.max) of the coating film was 542.5 nm. However, it was found that the absorption was only slight at a wavelength of 405nm, and recording was not expected with respect to a laser beam having a central wavelength of 405 nm.

FIG. 6 is an absorption spectrum of a coating film containing a metal pyridone azo compound represented by the structural formula [13 ]. From the results shown in fig. 6, it can be seen that: the metal-containing pyridone azo compound represented by the structural formula [13] is not sufficient as a pigment compound for recording with a blue laser beam if isoxazole, 1, 2, 4-triazole or pyrazole is not selected as a diazo component, even if it is a metal-containing pyridone azo compound.

Comparative example 2

For comparison, a metal-containing pyridone azo compound represented by the following structural formula [15] was synthesized and evaluated as an optical recording medium.

(a) Production example

A compound [14] synthesized by diazotizing 2-amino-5-methyl-1, 3, 4-thiadiazole (Tokyo chemical Co., Ltd.) in a similar manner and coupling the diazotized compound under the same conditions as in example 1]Lambda max in chloroform was 409.5nm, molar absorptivity was 3.0X 10⁴。

Chemical formula 50

Compound [14] likewise with nickel acetate](ii) Structure containing metallization [15]The lambda max of the shown metal-containing pyridone azo compound in chloroform solution is 494nm, and the molar absorption coefficient is 7.1X 10⁴。

FIG. 7 is an absorption spectrum of a metal-containing pyridone azo compound represented by the structural formula [15 ]. From the results shown in fig. 7, it can be seen that: the metal-containing pyridone azo compound represented by the structural formula [15] is near the end of absorption at a wavelength of about 405nm, and recording characteristics are not expected much.

Chemical formula 51

(b) Examples of optical recording media

The metal-containing pyridone azo compound represented by the structural formula [15] was dissolved in octafluoro-n-pentanol, adjusted to 1% by weight, but the solubility was very low and almost insoluble. The solution obtained by filtration was dropped on an injection-molded polycarbonate resin substrate having a diameter of 120mm and a thickness of 0.6mm, coated by a spin coating method (500rpm), and dried at 100 ℃ for 30 minutes. However, since the solubility was low, the absorption spectrum of the coating film was not obtained.

Comparative example 3

For comparison, a metal-containing azo complex represented by the following structural formula [16] was synthesized and evaluated as an optical recording medium.

(a) Production example

The following structural formula [16] synthesized from m-N, N-diethylaniline using the above-mentioned patent document 2 (JP-A-9-277703)]The compound has 2 absorption peaks at 552.5nm and 516nm at lambda max in chloroform solution, and molar absorption coefficients of 1.1 × 10⁵、8.6×10⁴。

FIG. 8 is an absorption spectrum of a metal-containing azo complex represented by the structural formula [16] in a chloroform solution.

Chemical formula 52

(b) Examples of optical recording media

The metal-containing azo complex represented by the above structural formula [16] was dissolved in octafluoro-n-pentanol to adjust the amount to 1 wt%. The solution obtained by filtration was dropped on an injection-molded polycarbonate resin substrate having a diameter of 120mm and a thickness of 0.6mm, coated by a spin coating method (500rpm), and dried at 100 ℃ for 30 minutes. The maximum absorption wavelength (. lamda.max) of the coating film was 565.5nm and 524.5 nm.

From the absorption spectrum of the metal-containing azo compound represented by the structural formula [16 ]: even if the diazo component has an isoxazole-containing structure, almost no absorption is observed at a wavelength of about 405 nm.

As a result, it was found that: the metal-containing azo complex represented by the structural formula [16] is a dye compound which does not contain a pyridone skeleton as a coupler component even when the metal-containing azo complex contains isoxazole as a diazo component, and is not sufficient for recording with a blue laser.

(example 20 to example 27)

In the same manner as the synthesis method of example 1, metal complexes (77) to (84) were synthesized using an exemplary compound (57) and a pyridone azo compound represented by the following exemplary compound (58) to exemplary compound (63), and the maximum absorption wavelength (. lamda.max) in a solution (chloroform), the molar absorption coefficient, and the maximum absorption wavelength (. lamda.max) of a coating film were measured in the same manner as in example 1 (except that octafluoro-n-pentanol was used as a coating solvent). The measurement results are shown in table 1.

In view of the stability against light, that is, the pigment holding ratio (I/I in Table 1)₀(%)) in the recording and reading in the short wavelength region described in the present invention, the organic dye for short wavelength recording and reading which has been known in the related art is less than 10%, and it can be said that the dye retention ratio, which is the light resistance, is extremely good as long as it is 60% or more.

From the evaluation criteria, the metal complexes shown in table 1 are extremely good. In particular, examples 23, 26 and 27 are compounds which are superior in light resistance to known pigments and show good light resistance which is sufficiently practical. However, the metal complex is somewhat inferior to the other metal complexes in table 1.

That is, as described above, example 23 (light resistance 19.0%) showed the general formula [1] in comparison with example 1 (light resistance 63.2%)]R of (A) to (B)₁Is unsubstituted amino (-NH)₂) Not too muchGood results are obtained. However, even in example 23, the level was sufficiently good as compared with the known substances by reacting with the substituent R₂～R₅The combination of the two can improve solubility and light resistance.

Further, it is displayed that: as is clear from comparison with example 25 (light resistance 67.5%), example 26 (light resistance 14.5%) and example 27 (light resistance 42.3%) are represented by the general formula [ III ]]R of (A) to (B)₁₀In the case of a hydrogen atom, the light resistance is poor. Further, when example 26 and example 27 were compared with example 25 (light resistance 67.5%) and example 17 (light resistance 89%), it was found that the formula [ III ]]R of (A) to (B)₁Is a hydrogen atom, and R₃The combination of carboxylic acid esters may deteriorate light resistance. It is understood that the copper complex (example 22) in table 1 is slightly inferior to the other metal complexes in table 1, but in any case, it is said to be a very good compound compared with the known organic coloring matter for short wavelength such as blue laser.

Chemical formula 53

Also, the present application is based on Japanese application filed on 29.3.2005 in 2005 (Japanese application No. 2005-95905), which is incorporated herein by reference in its entirety.

Claims (7)

1. An optical recording medium, characterized in that it has

Substrate and

a recording layer provided on the substrate directly or via another layer and capable of recording and/or reading information by irradiating a laser beam having a wavelength of 350nm to 530nm,

the recording layer contains a metal complex compound which,

the metal complex is composed of an organic dye compound and a 2-valent metal ion selected from groups 3 to 12 of the periodic table,

the organic dye compound is a pyridone azo compound represented by any one of the following general formulae [ I ] to [ III ],

in the general formula [ I ] to the general formula [ III ],

R₁represents a group selected from a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group, a hydroxyl group, a linear or branched alkoxy group, a saturated or unsaturated heterocyclic group, an aryl group, an aralkyl group, -NR₁₂R₁₃Any one of the amino group and the amide group represented by the formula, wherein the linear or branched alkyl group may be substituted by a group selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkoxyalkoxyalkoxyalkoxy group having 3 to 15 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, a heterocyclic group, a cyano group, a nitro group, a hydroxyl group, a mercapto group, a thioalkyl group, an alkylamino group having 1 to 10 carbon atoms, an alkylsulfonylamino group having 1 to 6 carbon atoms, a halogen atom, an alkylcarbonyl group, an alkoxycarbonyl group having 2 to 7 carbon atoms, an alkylcarbonyloxy group having 2 to 7 carbon atoms, and an alkoxycarbonyloxy group having 2 to 7 carbon atoms, and R is a group₁₂、R₁₃Each independently represents any of a hydrogen atom, a hydrocarbon group and a heterocyclic group, which may be substituted as required,

R₂、R₃represents any one selected from the group consisting of a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, a linear or branched alkenyl group having 2 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a cyano group, an acyl group, an amide group, a carbamate group, a carboxylate group, an acyloxy group, a carbamoyl group, a sulfonyl group, a sulfinyl group and a sulfonamide group,

R₄、R₅、R₈、R₉represents any one selected from the group consisting of a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, a linear or branched alkenyl group having 2 to 18 carbon atoms, a saturated or unsaturated heterocyclic group, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a halogen atom, a nitro group, a cyano group, an acyl group, an amide group, a carbamate group, a carboxylate group, an acyloxy group, a carbamoyl group, a sulfonyl group, a sulfinyl group, a sulfamoyl group, a sulfonate group and a sulfonamide group,

R₇represents any one selected from the group consisting of a linear or branched alkyl group having 1 to 18 carbon atoms and being substituted with fluorine, a halogen atom, a nitro group, a cyano group, an acyl group, a carboxylate group, an acyloxy group, a carbamoyl group, a sulfonyl group, a sulfinyl group, a sulfamoyl group and a sulfonate group,

R₆、R₁₀represents any one selected from a hydrogen atom, a linear or branched alkyl group, and a cycloalkyl group.

2. The optical recording medium according to claim 1, wherein the metal ion is at least 1 metal ion selected from the group consisting of nickel, cobalt, iron, zinc, copper, and manganese.

3. The optical recording medium according to claim 1, wherein the light is laser light having a wavelength of 385nm to 410 nm.

4. A metal complex characterized in that it comprises

A 2-valent metal ion selected from groups 3 to 12 of the periodic Table and

a pyridone azo compound represented by the following general formula [ I ] coordinated to the metal ion,

in the general formula [ I ],

R₁represents a group selected from a hydrogen atom, a linear or branched alkyl group, a cycloalkyl group, a hydroxyl group, a linear or branched alkoxy group, a saturated or unsaturated heterocyclic group, an aryl group, an aralkyl group, -NR₁₂R₁₃Any one of the amino group and the amide group represented by the formula, wherein the linear or branched alkyl group may be substituted by a group selected from the group consisting of an alkoxy group having 1 to 10 carbon atoms, an alkoxyalkoxy group having 2 to 12 carbon atoms, an alkoxyalkoxyalkoxyalkoxy group having 3 to 15 carbon atoms, an aryloxy group having 6 to 12 carbon atoms, an alkenyloxy group having 2 to 12 carbon atoms, a heterocyclic group, a cyano group, a nitro group, a hydroxyl group, a mercapto group, a thioalkyl group, an alkylamino group having 1 to 10 carbon atoms, an alkylsulfonylamino group having 1 to 6 carbon atoms, a halogen atom, an alkylcarbonyl group, an alkoxycarbonyl group having 2 to 7 carbon atoms, an alkylcarbonyloxy group having 2 to 7 carbon atoms, and an alkoxycarbonyloxy group having 2 to 7 carbon atoms, and R is a group₁₂、R₁₃Each independently represents any of a hydrogen atom, a hydrocarbon group and a heterocyclic group, which may be substituted as required,

R₂、R₃represents any one selected from the group consisting of a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, a linear or branched alkenyl group having 2 to 18 carbon atoms, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a cyano group, an acyl group, an amide group, a carbamate group, a carboxylate group, an acyloxy group, a carbamoyl group, a sulfonyl group, a sulfinyl group and a sulfonamide group,

R₄、R₅represents a group selected from a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cycloalkyl group having 3 to 18 carbon atoms, a linear or branched alkenyl group having 2 to 18 carbon atoms, a saturated or unsaturated heterocyclic group, an aryl group having 6 to 18 carbon atoms, an aralkyl group having 7 to 20 carbon atoms, a halogen atom, a nitro group, a cyano group, an acyl groupAny one of an amine group, a carbamate group, a carboxylate group, an acyloxy group, a carbamoyl group, a sulfonyl group, a sulfinyl group, a sulfamoyl group, a sulfonate group, and a sulfonamide group.

5. The metal complex of claim 4, wherein the metal is at least one selected from the group consisting of nickel, cobalt, iron, zinc, copper, and manganese.

6. The optical recording medium according to claim 1, wherein the organic pigment compound is a pyridone azo compound represented by the following general formula [ I ],

in the general formula [ I]In, R₁Represents any one selected from a hydrogen atom, a linear or branched alkyl group which may be substituted with an alkoxy group having 1 to 10 carbon atoms, a cycloalkyl group, a linear or branched alkoxy group, and a saturated or unsaturated heterocyclic group,

R₂、R₃each independently represents any one selected from a hydrogen atom, a cyano group, a carboxylate group and a sulfonyl group,

R₄、R₅each independently represents any one selected from a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a halogen atom, and a carboxylate group.

7. The optical recording medium according to claim 1, wherein the organic pigment compound is a pyridone azo compound represented by the following general formula [ IV ],

in the general formula [ IV ],

R₂₆represents a hydrogen atom or a linear or branched alkyl group which may be substituted with an alkoxy group having 1 to 10 carbon atoms,

R₂₇、R₂₈represents any one selected from a hydrogen atom, a linear or branched alkyl group having 1 to 12 carbon atoms, a cyano group, and a carboxylate group,

R₂₉、R₃₀represents any one selected from a hydrogen atom, a linear or branched alkyl group having 1 to 18 carbon atoms, a cyano group, and a carboxylate group,

R₃₁represents a linear or branched alkyl group having 1 to 8 carbon atoms.