JP4817286B2 - Metal-containing squarylium compound and optical recording medium using the compound - Google Patents

Description

  The present invention relates to a metal-containing squarylium compound and an optical recording medium using the compound. More specifically, the present invention relates to recording and / or reproducing information using recording light having a wavelength of 300 nm to 530 nm, particularly blue laser light having a wavelength of 405 nm. The present invention relates to a write-once type optical recording medium suitable for the recording medium.

  Conventionally, magneto-optical recording media, phase change recording media, chalcogen oxides, and the like have been proposed as recording media for optically recording / reproducing information. Among them, information recording is performed only once by a laser. As a write-once type optical recording medium capable of recording, a CD-R is inexpensive and easy to manufacture, and is mass-produced and widely used. The recording capacity is about 0.65 GB, and the demand for higher-density and large-capacity optical recording media is increasing with a dramatic increase in the amount of information.

  In order to meet the above requirements, for the purpose of increasing the density of the recording medium, means such as shortening the wavelength of the laser used for recording and reproduction and reducing the beam spot by increasing the numerical aperture of the objective lens are used. Yes. Near-infrared laser wavelengths (usually 780 nm) are used for CD-R recording and reproduction, but in recent years, high-density, large-capacity recording has been realized using red semiconductor lasers with short wavelengths (630 nm to 680 nm). The organic dye-based optical recording medium (DVD-R) has been put into practical use, and a single-sided 4.7 GB DVD-R medium has been supplied to the market. Furthermore, in the future, higher density recording is required, and the amount of recorded information is expected to reach 15 to 30 GB per sheet, and high density recording using a blue semiconductor laser with a shorter wavelength (300 to 530 nm) is required. An optical recording medium capable of recording / reproducing is demanded, and an optical recording medium called a Blu-ray system using a blue semiconductor laser of 405 nm has already been put on the market.

  By the way, a general write-once optical recording medium is formed by sequentially laminating a recording layer made of an organic dye, a light reflecting layer made of a metal such as gold or silver, and a protective layer made of resin on a transparent disk-shaped substrate. Composed. Information is written (recorded) by irradiating the recording layer with laser light, the recording layer absorbs the light, and the temperature rises locally, causing a physical or chemical change (for example, generation of pits). Information is recorded using the change in optical characteristics. On the other hand, reading (reproduction) of information is also performed by irradiating a laser having the same wavelength as the recording laser, and the portion where the optical characteristics of the recording layer have changed (recorded portion) and the portion that has not changed (unrecorded portion) Information is reproduced by detecting the difference in reflectance from the.

  Therefore, as a dye used in an optical recording medium capable of high-density recording / reproduction using a blue semiconductor laser, an optical device for the wavelength of the blue laser light used to form and detect good pits on the substrate is used. In particular, there is a demand for a dye having a good absorption property and decomposition behavior, and particularly a dye having a maximum absorption wavelength of 300 to 530 nm.

  In addition, when a medium is produced by a coating method such as a spin coating method that is simple for forming a recording layer, high solubility is required to dissolve the dye in the coating solvent, and this point needs to be taken into consideration. .

  Patent Document 1 discloses a recording / reproducing method for recording and reproducing information by irradiating a laser beam having a wavelength of 530 nm or less from the recording layer side in an optical recording medium having a recording layer containing an organic dye. . Specific organic dyes used in the optical recording medium include cyanine dyes (Patent Document 2), dyes having a pyridone azo skeleton (Patent Document 3), dyes having a dicyanovinylphenyl skeleton (Patent Document 4), and coumarin. A compound (Patent Document 5), an azo metal chelate dye (Patent Document 6), and the like have been proposed.

  Patent Documents 7 and 8 propose a squarylium dye, but the absorption wavelength is in the range of 530 to 600 nm and is not appropriate because it is not in the wavelength region of blue laser light.

JP-A-4-074690 Japanese Patent Laid-Open No. 11-053758 JP-A-11-334204 Japanese Patent Laid-Open No. 11-334206 JP 2000-043423 A JP 2001-158862 A JP 2004-264805 A JP 2004-258514 A

As described above, it is necessary to select an organic dye that is suitable for the optical properties and the decomposition behavior with respect to the blue laser wavelength as the organic dye used in the recording layer. In particular, the organic dye is decomposed to cause a large refractive index change. Therefore, the recording / reproducing wavelength is selected so as to be located at the bottom of the long wavelength side of the maximum absorption wavelength.
In organic dyes, in order to have a maximum absorption wavelength in the vicinity of the blue laser wavelength, it is generally considered that the molecular skeleton is reduced or the conjugated system is shortened. A decrease in refractive index also occurs, making this an undesirable organic dye for use in the recording layer.

  Moreover, as an organic dye having a maximum absorption wavelength of 300 to 530 nm, an organic chelate complex or the like is known. However, the organic dye complex has low solubility in a coating solvent, and is suitable because a phenomenon in which crystals are precipitated during film formation is observed. There was a problem that the recording layer could not be formed and recording / reproduction was not possible.

  Therefore, in order to solve the above problems, the object of the present invention is to have high light absorption characteristics in a wavelength region of 300 to 530 nm that can be recorded and reproduced with a blue semiconductor laser, and to have excellent thermal decomposition behavior and solubility in a solvent, An object of the present invention is to provide a metal-containing squarylium compound having excellent light resistance and durability and an optical recording medium using the compound.

  As a result of intensive studies, the present inventors have found that a specific metal-containing squarylium compound has high light absorption in the region of 300 to 530 nm, and has excellent thermal decomposition behavior and solubility in a solvent, light resistance and durability. It has been found that it is excellent in properties and useful as a recording layer of an optical recording medium, and the present invention has been completed.

  That is, the present invention is a metal-containing squarylium compound comprising a squarylium compound represented by the following general formula (A) or general formula (B) and a metal salt or metal ion.

In general formula (A), R ₁ represents a hydroxyl group, an amino group, or a sulfonamide group, and R ₂ , R ₃ , R ₄ , and R ₅ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, or a cyano group. , A nitro group, or an optionally substituted linear or branched alkyl group, halogenated alkyl group, cyanoalkyl group, aralkyl group, alkenyl group, alkoxy group, aryl group, heterocyclic ring, acyl group, or alkoxycarbonyl group X represents an optionally substituted linear or branched alkyl group, halogenated alkyl group, cyanoalkyl group, aralkyl group, alkenyl group, aryl group, or alkoxycarbonyl group.

（式中、Ｒ_１、Ｒ_２、Ｒ_３、Ｒ_４、Ｘは一般式（Ａ）と同じである。）

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and X are the same as those in the general formula (A).)

  In the metal-containing squarylium compound represented by the general formula (A) or the general formula (B), the metal may be Ni, Co, Zn, Cu, Pt, Ti, Al, V, Mn, Fe, A metal-containing squarylium compound, which is at least one metal selected from the group consisting of Mo, W, Sn, Ru, Cr, Pb, Eu, and Ir.

  Further, according to the present invention, in an optical recording medium having a recording layer on which information can be written and / or read by laser light on a substrate, the recording layer contains at least one of the metal-containing squarylium compounds. An optical recording medium characterized by the above.

  The present invention also provides an optical recording medium containing at least one of the above metal-containing squarylium compounds, wherein information is recorded and / or reproduced by a laser beam selected from a wavelength region of a wavelength of 300 nm to 530 nm.

In the metal-containing squarylium compound of the present invention, the metal interacts with one or more squarylium molecules as a metal salt even if the metal is present as a complex by binding to one or more squarylium molecules as a metal ion. A weak bond may be formed.
The coordination number in the case of a complex varies depending on the type of metal and the substituent of the squarylium compound.

  The present invention is a metal-containing squarylium compound comprising a squarylium compound represented by the general formula (A) or the general formula (B) and a metal salt or a metal ion, and these specific metal-containing squarylium compounds are 300 It has good light absorption in the region of ~ 530nm, has excellent thermal decomposition behavior and solubility in solvents, has excellent light resistance and durability, is useful as a recording layer for optical recording media, and further forms a recording layer It is most suitable as an optical recording medium.

  Hereinafter, the metal-containing squarylium compound of the present invention will be described in detail.

  The metal-containing squarylium compound of the present invention is a compound comprising a squarylium compound represented by the general formula (A) or the general formula (B) and a metal salt or metal ion.

In General Formula (A) or General Formula (B), R ₁ represents a hydroxyl group, an amino group, or a sulfonamide group.

The sulfonamide group is represented by —NHSO ₂ Y, wherein Y represents a substituted or unsubstituted linear or branched alkyl group, a substituted or unsubstituted unsaturated hydrocarbon, a substituted or unsubstituted aromatic ring, In particular, a linear or branched alkyl group having 1 to 6 carbon atoms substituted with a fluorine atom is preferable.

Specifically, a C1-C6 perfluoroalkyl group such as a trifluoromethyl group, a pentafluoroethyl group, a heptafluoropropyl group, 2, 2, 2-trifluoroethyl group, 3, 3, 3-trifluoropropyl, etc. And an alkyl group substituted with a perfluoroalkyl group having 2 to 6 carbon atoms in total such as a group, 2, 2, 3, 3, 3-pentafluoropropyl group, and the like. _{-CF 2 CF 3, -CH 2 CF} 3, -CF 3 is particularly preferred.

In general formula (A) or general formula (B), R ₂ , R ₃ , R ₄ , and R ₅ are each independently a hydrogen atom, a halogen atom, or a hydroxy group, a cyano group, a nitro group, or a substituted group. A linear or branched alkyl group, a halogenated alkyl group, a cyanoalkyl group, an aralkyl group, an alkenyl group, an alkoxy group, an aryl group, a heterocyclic ring, an acyl group, or an alkoxycarbonyl group may be used.

  Examples of the halogen atom include a fluorine atom, a chlorine atom, a bromine atom, and an iodine atom, and a fluorine atom is preferable.

  Examples of the linear or branched alkyl group which may be substituted include methyl group, ethyl group, n-propyl group, isopropyl group, n-butyl group, isobutyl group, sec-butyl group, tert-butyl group, n- Pentyl group, isopentyl group, 2-methylbutyl group, 1-methylbutyl group, neopentyl group, 1,2-dimethylpropyl group, 1,1-dimethylpropyl group, cyclopentyl group, n-hexyl group, 4-methylpentyl group, 3 -Methylpentyl group, 2-methylpentyl group, 1-methylpentyl group, 3,3-dimethylbutyl group, 2,3-dimethylbutyl group, 1,3-dimethylbutyl group, 2,2-dimethylbutyl group, 1 , 2-dimethylbutyl group, 1,1-dimethylbutyl group, 2-ethylbutyl group, 1-ethylbutyl group, 1,2,2-trimethylbutyl group, , 1,2-trimethylbutyl group, 1-ethyl-2-methylpropyl group, cyclohexyl group n-heptyl group, 2-methylhexyl group, 3-methylhexyl group, 4-methylhexyl group, 5-methylhexyl group, 2,4-dimethylpentyl group, n-octyl group, 2-ethylhexyl group, n-decyl group, n-dodecyl group, 1,3,5,7-tetraethyloctyl group, 4-butyloctyl group, n-octadecyl group Examples thereof include linear or branched alkyl groups having 1 to 20 carbon atoms, and preferred are linear or branched alkyl groups having 1 to 8 carbon atoms.

  The halogenated alkyl group is represented by the following general formula (C).

（式中、Ｘはハロゲン原子を示し、ｎは１〜１２の自然数、ｍは１〜２５の自然数を示す。）

(In the formula, X represents a halogen atom, n represents a natural number of 1 to 12, and m represents a natural number of 1 to 25.)

  The halogenated alkyl group is a linear or branched halogenated alkyl group having 1 to 12 carbon atoms which may be substituted. If the number of carbon atoms exceeds 12, the mass extinction coefficient of the squarylium compound may decrease. The halogen atom of the halogenated alkyl group is not particularly limited, but a fluorine atom, that is, a fluorinated alkyl group is particularly preferable from the viewpoint of excellent effects of improving the heat resistance and light resistance of the squarylium compound.

  Examples of the fluorinated alkyl group include trifluoromethyl group, 2,2,2-trifluoroethyl group, 3,3,3-trifluoropropyl group, 4,4,4-trifluorobutyl group, 5,5,5, 5-trifluoropentyl group, 6,6,6-trifluorohexyl group, 8,8,8-trifluorooctyl group, 2-methyl-3,3,3-trifluoropropyl group, perfluoroethyl group, perfluoropropyl Group, perfluorobutyl group, perfluorohexyl group, perfluorooctyl group, 2-trifluoromethyl-perfluoropropyl group and the like.

  Examples of the cyanoalkyl group include a cyanomethyl group, 2-cyanoethyl group, 3-cyanopropyl group, 2-cyanopropyl group, 4-cyanobutyl group, 3-cyanobutyl group, 2-cyanobutyl group, 5-cyanopentyl group, 4- Cyanopentyl group, 3-cyanopentyl group, 2-cyanopentyl group, 6-cyanohexyl group, 5-cyanohexyl group, 4-cyanohexyl group, 3-cyanohexyl group, 2-cyanohexyl group, etc. Preferably, it is preferably a linear or branched cyanoalkyl group having 1 to 8 carbon atoms which may be substituted, and the number of substituted cyano groups is preferably 1 to 3.

  Examples of the aralkyl group include benzyl group, phenethyl group, α-methylbenzyl group, α, α-dimethylbenzyl group, 1-naphthylmethyl group, 2-naphthylmethyl group, furfuryl group, 2-methylbenzyl group, and 3-methyl. Benzyl group, 4-methylbenzyl group, 4-ethylbenzyl group, 4-isopropylbenzyl group, 4-tert-butylbenzyl group, 4-n-hexylbenzyl group, 4-n-nonylbenzyl group, 3,4-dimethyl Benzyl group, 3-methoxybenzyl group, 4-methoxybenzyl group, 4-ethoxybenzyl group, 4-n-butyloxybenzyl group, 4-n-hexyloxybenzyl group, 4-n-nonyloxybenzyl group, 3- Examples include a fluorobenzyl group and a 4-fluorobenzyl group. The aromatic ring may have a substituent, and is at least one selected from the group consisting of an alkyl group, a hydroxyl group, a sulfonic acid group, an alkylsulfonic acid group, a nitro group, an amino group, an alkoxy group, a halogenated alkyl group, and a halogen. You may have the substituent of.

  As said alkenyl group, C2-C20 linear or branched which may be substituted, such as vinyl, allyl, 1-propenyl, 2-pentenyl, 1,3-butadienyl, 2-octenyl, and 3-dodecenyl group The straight chain or branched alkenyl group having 3 to 6 carbon atoms is preferable.

  Examples of the alkoxy group include methoxy group, ethoxy group, n-propyloxy group, isopropyloxy group, n-butyloxy group, isobutyloxy group, tert-butyloxy group, sec-butyloxy group, n-pentyloxy group, and isopentyloxy. Group, tert-pentyloxy group, sec-pentyloxy group, cyclopentyloxy group, n-hexyloxy group, 1-methylpentyloxy group, 2-methylpentyloxy group, 3-methylpentyloxy group, 4-methylpentyloxy group Group, 1,1-dimethylbutyloxy group, 1,2-dimethylbutyloxy group, 1,3-dimethylbutyloxy group, 2,3-dimethylbutyloxy group, 1,1,2-trimethylpropyloxy group, , 2,2-Trimethylpropyloxy group, 1-ethylbutylo A linear or branched alkoxy group having 1 to 20 carbon atoms, such as cis group, 2-ethylbutyloxy group, 1-ethyl-2-methylpropyloxy group, cyclohexyloxy group, methylcyclopentyloxy group, etc. Preferably, it is a C1-C6 linear or branched alkoxy group.

  Examples of the aryl group include phenyl group, 4-methylphenyl group, 3-methylphenyl group, 2-methylphenyl group, 4-ethylphenyl group, 3-ethylphenyl group, 2-ethylphenyl group, 4-n-propyl. Phenyl group, 4-isopropylphenyl group, 2-isopropylphenyl group, 4-n-butylphenyl group, 4-isobutylphenyl group, 4-sec-butylphenyl group, 2-sec-butylphenyl group, 4-tert-butyl Phenyl group, 3-tert-butylphenyl group, 2-tert-butylphenyl group, 4-n-pentylphenyl group, 4-isopentylphenyl group, 4-n-hexylphenyl group, 4- (2′-ethylbutyl) Phenyl group, 4-n-octylphenyl group, 4- (2'-ethylhexyl) phenyl group, 4-n-decylph Nyl group, 4-cyclohexylphenyl group, 4- (4′-methylcyclohexyl) phenyl group, 3-cyclohexylphenyl group, 2,3-dimethylphenyl group, 2,6-dimethylphenyl group, 3,4-dimethylphenyl group 2,6-diethylphenyl group, 1-naphthyl group, 2-naphthyl group, 4-ethyl-1-naphthyl group, 5-indanyl group, 4-methoxyphenyl group, 3-methoxyphenyl group, 4-ethoxyphenyl group 3-ethoxyphenyl group, 2-ethoxyphenyl group, 4-n-propyloxyphenyl group, 4-n-butyloxyphenyl group, 4-isobutyloxyphenyl group, 2,3-dimethoxyphenyl group, 2,4- Dimethoxyphenyl group, 3,4-dimethoxyphenyl group, 3,5-dimethoxyphenyl group, 3,5-diethoxyphene Group, 2-methoxy-1-naphthyl group, 4-methoxy-1-naphthyl group, 5-ethoxy-1-naphthyl group, 6-n-butyloxy-2-naphthyl group, 6-n-hexyloxy-2- Naphthyl group, 7-methoxy-2-naphthyl group, 7-n-butyloxy-2-naphthyl group, 4-phenylphenyl group, 3-phenylphenyl group, 2-phenylphenyl group, 3-methyl-4-phenylphenyl group An aryl group having 6 to 18 carbon atoms such as 3-methoxy-4-phenylphenyl group, and the aromatic ring may have a substituent, an alkyl group, a hydroxyl group, a sulfonic acid group, an alkylsulfonic acid group , A nitro group, an amino group, an alkoxy group, a halogenated alkyl group and at least one substituent from the group consisting of halogen. A substituted or unsubstituted aryl group having 6 to 12 carbon atoms is preferred.

  Examples of the heterocycle include furan ring, pyrrole ring, thiophene ring, carbazole ring, pyridine ring, quinoline ring, isoquinoline ring, acridine ring, pyrimidine ring, pyrazine ring, phenazine ring, imidazole ring, triazole ring, oxazole ring, Examples include a thiazole ring, a thiadiazole ring, an oxadiazole ring, and the like.

  Examples of the acyl group include formyl group, methylcarbonyl group, ethylcarbonyl group, n-propylcarbonyl group, isopropylcarbonyl group, n-butylcarbonyl group, isobutylcarbonyl group, sec-butylcarbonyl group, tert-butylcarbonyl group, n- Such as pentylcarbonyl group, benzoyl group, 2-methylbenzoyl group, 3-methylbenzoyl group, 4-methylbenzoyl group, 4-ethylbenzoyl group, 4-n-propylbenzoyl group, 4-nitrobenzylcarbonyl group, cinnamoyl group, etc. Examples thereof include an optionally substituted linear or branched acyl group having 2 to 18 carbon atoms, preferably a linear or branched acyl group having 3 to 9 carbon atoms.

  Examples of the alkoxycarbonyl group include methoxycarbonyl group, ethoxycarbonyl group, propoxycarbonyl group, isopropoxycarbonyl group, butoxycarbonyl group, 2-methoxyethoxycarbonyl group, pentyloxycarbonyl group, hexyloxycarbonyl group, octyloxycarbonyl group, Examples thereof include linear or branched alkoxycarbonyl groups having 2 to 18 carbon atoms such as undecyloxycarbonyl group, dodecyloxycarbonyl group, hexadecyloxycarbonyl group, octadecyloxycarbonyl group, etc., preferably carbon It is a linear or branched alkoxycarbonyl group of 2-8.

In general formula (A) or general formula (B), X is an optionally substituted linear or branched alkyl group, halogenated alkyl group, cyanoalkyl group, aralkyl group, alkenyl group, aryl group, or alkoxycarbonyl. A linear or branched alkyl group, or a linear or branched halogenated alkyl group which may be substituted, specifically mentioned above as specific examples of R ₂ , R ₃ , R ₄ and R ₅ Represents an optionally substituted linear or branched cyanoalkyl group, an aralkyl group, an optionally substituted linear or branched alkenyl group, an aryl group, or an optionally substituted linear or branched alkoxycarbonyl group . In addition, an aromatic ring substituted with an aralkyl group or an aryl group may have a substituent, an alkyl group, a hydroxyl group, a sulfonic acid group, an alkyl sulfonic acid group, a nitro group, an amino group, an alkoxy group, a halogenated group. You may have at least 1 or more types of substituents from the group which consists of an alkyl group and a halogen.

  Although the preferable specific example (compound (1)-(30)) of the squarylium compound in the metal-containing squarylium compound of this invention is given to the following, this invention is not limited to these.

  In the present invention, as a metal salt that forms a complex with a squarylium compound, various metal salts that form a complex can be used. Ni, Co, Zn, Cu, Pt, Ti, Al, V, Mn, Fe, Mo, W, Sn, Ru, Cr, Pb, Eu, and Ir salts are preferable, and Ni, Zn, Co, Ti, and Al salts are particularly preferable in terms of solubility in various solvents, light resistance, and durability.

  The metal-containing squarylium compound of the present invention is obtained by synthesizing a squaric acid dichloride of the following general formula (D) by a known method and reacting with an alkoxybenzene derivative compound represented by, for example, the general formula (E) or (F). The obtained squarylium compound is obtained by reacting a metal salt compound in an organic solvent such as methanol, tetrahydrofuran, acetone, dioxane, DMF or the like.

式中、Ｒ_２〜Ｒ_５は一般式（Ａ）と同じ

In the formula, R _{2 to} R ₅ are the same as those in the general formula (A).

式中、Ｒ_２〜Ｒ_５は一般式（Ｂ）と同じ

In the formula, R _{2 to} R ₅ are the same as those in the general formula (B).

  The optical recording medium of the present invention has a recording layer containing at least one metal-containing squarylium compound represented by the general formula (A) or (B) in the present invention on a substrate, and two or more different types A metal-containing squarylium compound may be contained.

  Further, the metal-containing squarylium compound of the present invention may form a J-type aggregate or an H-type aggregate.

  Since the metal-containing squarylium compound represented by the general formula (A) or the general formula (B) has an optical constant suitable for recording / reproducing with a laser beam in a short wavelength region of 300 nm to 530 nm, It is extremely useful as a compound used in an optical recording medium for recording and reproduction.

  As a preferable configuration of the optical recording medium of the present invention, a recording layer, a light reflection layer, and a protective layer are sequentially formed on a disc-like substrate on which pregrooves having a constant track pitch are formed. The recording layer and the light reflection layer are sequentially formed on the transparent disk-shaped substrate on which the light reflection layer, the recording layer, and the protective layer are sequentially formed, or the pre-groove having a constant track pitch is formed. A configuration in which the two laminated bodies are joined such that the recording layers are inwardly directed. Hereinafter, the optical recording medium will be described in detail.

  The material of the substrate in the optical recording medium of the present invention can be arbitrarily selected from various materials used as a substrate of a conventional optical recording medium. Examples of the substrate material include glass, polycarbonate resin, acrylic resin such as polymethyl methacrylate, polyvinyl chloride resin such as polyvinyl chloride resin and vinyl chloride copolymer, epoxy resin, amorphous polyolefin resin, and polyester resin. Among these materials, injection molded polycarbonate is preferable from the viewpoints of moisture resistance, dimensional stability, and price. A resin substrate or a resin layer may be provided in contact with the recording layer, and guide grooves or pits for recording / reproducing light may be provided on the resin substrate or resin layer. When the guide groove has a spiral shape, the groove pitch is preferably about 0.2 to 1.0 μm.

  The recording layer is formed by a generally used thin film forming method such as a vapor phase method such as a vacuum deposition method, a sputtering method, or a CVD method, a liquid phase method such as a doctor blade method, a cast method, a spin coating method, or an immersion method. However, the spin coating method is preferable from the viewpoint of mass productivity and cost.

  The solvent for the liquid phase method is not particularly limited as long as it does not attack the substrate. For example, esters such as butyl acetate, ethyl lactate and cellosolve acetate; ketones such as methyl ethyl ketone, cyclohexanone and methyl isobutyl ketone; chlorinated hydrocarbons such as dichloromethane, 1,2-dichloroethane and chloroform; amides such as dimethylformamide; Hydrocarbons; ethers such as dibutyl ether, diethyl ether, tetrahydrofuran, dioxane; alcohols such as ethanol, n-propanol, isopropanol, n-butanol, diacetone alcohol; fluorines such as 2,2,3,3-tetrafluoropropanol Solvents: Glycol agents such as ethylene glycol monomethyl ether, ethylene glycol monoethyl ether, propylene glycol monomethyl ether And the like Le acids. The above solvents can be used alone or in combination of two or more in consideration of the solubility of the compound used.

  The thickness of the recording layer is generally in the range of 20 to 500 nm, preferably in the range of 30 to 300 nm, and more preferably in the range of 50 to 150 nm.

  The recording layer may use a singlet oxygen quencher in order to improve the light resistance of the recording layer. Examples of singlet quenchers include transition metal chelate complexes such as acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, and bisdithio-α-diketone, aromatic nitroso compounds, aminium compounds, iminium compounds, and bisiminium compounds.

  A light reflection layer may be formed on the recording layer, and the thickness thereof is preferably 50 to 300 nm. As a material of the light reflecting layer, a material having a sufficiently high reflectance at the wavelength of the reproduction light, for example, Au, Al, Ag, Cu, Ti, Cr, Ni, Pt, Ta, and Pd metal alone or in an alloy is used. It is possible to use. Among these, Au, Al, and Ag have high reflectivity and are suitable as the material for the reflective layer. The reflective layer can be formed on the substrate or the recording layer, for example, by vapor deposition, sputtering or ion plating of the light reflective material. The thickness of the light reflection layer is generally in the range of 10 to 300 nm, preferably in the range of 50 to 200 nm.

The material for the protective layer formed on the reflective layer is not particularly limited as long as it protects the reflective layer from external force. Specifically, examples of the organic material include a thermoplastic resin, a thermosetting resin, an electron beam curable resin, and a UV curable resin. Examples of the inorganic material include SiO ₂ , Si ₃ N ₄ , MgF ₂ , SnO _{2 and the} like.

  A protective layer using a thermoplastic resin or a thermosetting resin is formed by applying a coating solution obtained by dissolving the resin in a suitable solvent to the surface of the substrate on which the recording layer or the light reflecting layer is formed, and drying. Can do.

  A protective layer using a UV curable resin is obtained by applying a coating solution dissolved in the resin alone or in an appropriate solvent to the surface of a substrate on which a recording layer or a light reflecting layer is formed, and then irradiating and curing the UV light. Can be formed. As the UV curable resin, for example, acrylate resins such as urethane acrylate, epoxy acrylate, and polyester acrylate can be used. These materials may be used alone or in combination, and a single layer or a multilayer film may be formed.

  As a method for forming the protective layer, a coating method such as a spin coating method and a casting method, a sputtering method, a chemical vapor deposition method, and the like are used as in the recording layer. Among these, a spin coating method is preferable. The thickness of the protective layer is generally in the range of 0.1 to 100 μm, but is preferably 3 to 30 μm in the present invention.

  The laser beam used for the optical recording medium of the present invention is selected to have a short wavelength region capable of high-density recording, preferably a blue-violet semiconductor laser beam having an oscillation wavelength of 300 to 530 nm, more preferably 390 to 390. Blue-violet semiconductor laser light having an oscillation wavelength of 420 nm is used.

  Recording on the optical recording medium of the present invention is performed by irradiating a recording layer provided on both sides or one side of the substrate with a laser beam focused to about 0.1 to 0.6 μm. In the portion irradiated with laser light, thermal deformation of the recording layer, such as decomposition, heat generation, and dissolution, due to absorption of laser light energy occurs, optical characteristics change, and recording pits are formed. The recorded information is reproduced by irradiating the playback laser beam and detecting the difference in reflectance between the part where the optical characteristics of the recording layer have changed (recorded part) and the part that has not changed (unrecorded part). Is done.

  EXAMPLES The present invention will be specifically described below with reference to examples, but the present invention is not limited to these examples. In the examples, “part” represents “part by mass”.

Example 1
(1) Into a three-necked flask equipped with a condenser tube, 12.3 parts of 3,4-dichloro-3-cyclobutene-1,2-dione and 10.9 parts of anhydrous aluminum chloride are added, and 100 ml of anhydrous chloroform is added thereto. And stirred at room temperature under a nitrogen atmosphere. Thereto, 10.0 parts of m-methylanisole dissolved in 20 ml of anhydrous chloroform was added dropwise at room temperature. After completion of dropping, the mixture was stirred with heating for 10 hours. After completion of the reaction, 100 ml of water was added in a state cooled to 10 ° C. or lower, the organic layer was washed with water, and the solvent was distilled off under reduced pressure. The obtained solid was collected by filtration under reduced pressure, washed with toluene, and dried under reduced pressure to give 3-chloro-4- (4-methoxy-2-methyl-phenyl) -cyclobut-3-ene-1,2-dione. 11.6 parts were obtained.

  (2) In a three-necked flask equipped with a condenser, 11.6 parts of 3-chloro-4- (4-methoxy-2-methyl-phenyl) -cyclobut-3-ene-1,2-dione and acetic acid: 200 parts of a water = 1: 1 mixed solution was added and heated and stirred at 100 ° C. for 8 hours. After the reaction, the mixture was cooled to room temperature, the solvent was removed under reduced pressure, and the precipitated solid was collected by filtration under reduced pressure. After washing with water and drying under reduced pressure, 8.6 parts of 3-hydroxy-4- (4-methoxy-2-methyl-phenyl) -cyclobut-3-ene-1,2-dione as compound (5) was obtained. It was.

  (3) In a three-necked flask equipped with a cooling tube, 8.6 parts of 3-hydroxy-4- (4-methoxy-2-methyl-phenyl) -cyclobut-3-ene-1,2-dione and nickel acetate・ 3.2 parts of tetrahydrate was added, 100 parts of THF was added thereto, and the mixture was heated and stirred at 60 ° C. for 4 hours. After the reaction, the reaction mixture was cooled to room temperature, and the precipitated solid was collected by filtration under reduced pressure. After washing with water and drying under reduced pressure, 5.0 parts of 3-hydroxy-4- (4-methoxy-2-methyl-phenyl) -cyclobut-3-ene-1,2-dione-nickel complex was obtained.

(Examples 2 to 5)
It replaces with 10.0 parts of m-methylanisole used in Example 1, and it describes in Table 1 similarly to Example 1 except having used the compound shown in Table 1 and various metal salts of the same mole number. The metal-containing squarylium compound was obtained.

(Example 6)
(1) 3-Chloro- obtained by the same operation as in Example 1 using 2,4-dimethyl-1- (2-phenyl-propoxy) -benzene as a starting material in a three-necked flask equipped with a condenser. 4- [2,6-dimethyl-3- (2-phenyl-propoxy) -phenyl] -cyclobut-3-ene-1,2-dione (14.7 parts) and 2M ammonia-methanol solution (50 parts) And stirred for 8 hours. After the reaction, the reaction mixture was cooled to room temperature, and the precipitated solid was collected by filtration under reduced pressure. After washing with water and drying under reduced pressure, the compound (26) 3-amino-4- [2,6-dimethyl-3- (2-phenyl-propoxy) -phenyl] -cyclobut-3-ene-1,2 is obtained. -8.7 parts of dione were obtained.

  (2) To a three-necked flask equipped with a condenser, 3-amino-4- [2,6-dimethyl-3- (2-phenyl-propoxy) -phenyl] -cyclobut-3-ene-1,2- 8.7 parts of dione and 1.9 parts of zinc acetate dihydrate were added, and 100 parts of THF was added thereto, followed by heating and stirring at 60 ° C. for 4 hours. After the reaction, the reaction mixture was cooled to room temperature, and the precipitated solid was collected by filtration under reduced pressure. After washing with water and drying under reduced pressure, 3-amino-4- [2,6-dimethyl-3- (2-phenyl-propoxy) -phenyl] -cyclobut-3-ene-1,2-dione-zinc complex 6 .9 parts were obtained.

(Example 7)
(1) 3-amino-4- (3) obtained in the same manner as in Example 7 using 1-ethoxy-3-fluoro-benzene as a starting material in a three-necked flask equipped with a cooling tube in a nitrogen atmosphere. -Ethoxy-5-fluoro-phenyl) -cyclobut-3-ene-1,2-dione (7.8 parts) and trifluoromethanesulfonic anhydride (9.4 parts) were added and stirred at 70 ° C. for 3 hours. After the reaction, the reaction mixture was cooled to room temperature, and the precipitated solid was collected by filtration under reduced pressure. After washing with water and drying under reduced pressure, the compound (30) N- [2- (3-ethoxy-5-fluoro-phenyl) 3,4-dioxo-cyclobut-1-enyl] -C, C, C- 6.5 parts of trifluoro-methanesulfonamide were obtained.

  (2) N- [2- (3-Ethoxy-5-fluoro-phenyl) 3,4-dioxo-cyclobut-1-enyl] -C, C, C-tri is added to a three-necked flask equipped with a condenser. 6.5 parts of fluoro-methanesulfonamide and 1.5 parts of cobalt acetate tetrahydrate were added, and 100 parts of THF was added thereto, followed by heating and stirring at 60 ° C. for 7 hours. After the reaction, the reaction mixture was cooled to room temperature, and the precipitated solid was collected by filtration under reduced pressure. After washing with water and drying under reduced pressure, N- [2- (3-ethoxy-5-fluoro-phenyl) 3,4-dioxo-cyclobut-1-enyl] -C, C, C-trifluoro-methanesulfonamide -Obtained 5.1 parts of cobalt complex.

  Table 1 shows the metal-containing squarylium compounds prepared from the raw material alkoxybenzene derivative compounds and metal salts used in Examples 1-7.

(Physical properties of compounds)
Measurement result of maximum absorption wavelength (hereinafter abbreviated as “λmax”) in methanol of the metal-containing squarylium compound obtained in Example 1 (Hitachi High-Technologies, U-3500) is 330 nm, and the mass absorption coefficient at λmax Was 75.4 l · g ⁻¹ cm ⁻¹ . As a result of differential thermal analysis (Seiko Instruments, TG / DTA6300), the decomposition point was 430 ° C. The obtained metal-containing squarylium compound was dissolved in tetrafluoropropanol to 2 wt%, and a thin film was formed on a flat polycarbonate disk by spin coating. As a result of measuring the absorption spectrum of this coating film by the transmission method, it was as shown in FIG. 2, and λmax was 350 nm. For reference, the absorption spectrum of the solution measured by the transmission method is shown in FIG.

  The results of Examples 1 to 7 measured in the same manner are shown in Table 2.

(Comparative Example 1)
As Comparative Example 1, the characteristics of the squarylium compound before metal complex chlorination obtained in Example 1 shown in Table 1 were measured in the same manner as in Example 1, and the results are shown in Table 2.

(Comparative Example 2)
As Comparative Example 2, the following compound G (Aldrich reagent) was used, and the properties of the compound were measured in the same manner as in Examples. The results are shown in Table 2.

  As shown in Table 2, the metal-containing squarylium compounds of Examples 1 to 7 of the present invention have light absorption in the wavelength region of 300 to 530 nm and a high mass extinction coefficient. In case of 1, the mass absorption coefficient was small. Similarly, Comparative Example 2 has a small mass absorption coefficient and cannot be dissolved in tetrafluoropropanol, so that an organic film cannot be formed.

(Light resistance test of coating film)
The coating films of Examples 1 to 7 and Comparative Example 1 were irradiated for a predetermined time in a 500 W xenon lamp at 40 ° C. atmosphere. The initial absorbance at λmax was taken as 100%, and the percentage of absorbance after a predetermined time was calculated as the dye residual ratio. These results are shown in Table 3.

  As shown in Table 3, although the coating films of Examples 1 to 7 of the present invention have a high light resistance with a dye residual ratio exceeding 80% even after 8 hours of irradiation, Comparative Example 1 has 1 hour of irradiation. After the lapse of time, the residual ratio of the dye changed to 5% at maximum and the squarylium compound was changed, and the light resistance could not be maintained.

(Production of optical recording medium)
The obtained metal-containing squarylium compound was dissolved in tetrafluoropropanol, adjusted to 2 wt%, and this compound solution was placed on a disc-shaped substrate made of polycarbonate resin and having continuous guide grooves (track pitch: 0.55 μm). A recording layer was formed by spin coating at 1500 rpm and drying at 70 ° C. for 1 hour. On this recording layer, an optical recording medium was prepared in which an Ag reflecting layer (thickness 120 nm) and a protective layer (thickness 5 μm) made of an ultraviolet curable resin were sequentially laminated.

  Using this optical recording medium, an optical disk evaluation device DDU-1000 (wavelength: 405 nm, NA: 0.65) manufactured by Pulstec Industrial Co., Ltd., recording frequency 9.7 MHz, recording laser power 8.0 mW, linear velocity Recording was performed with 9.0 m / s and the shortest pit length of 0.30 μm. Good-shaped pits were regularly formed and recorded with high density. After recording, when the reproduction was performed at a linear velocity of 9.0 m / s with a reproduction laser power of 0.6 mW, the pit could be read. Although reproduction was repeated, the pits could be read and the reproduction light stability was excellent.

UV-Vis absorption spectrum of the solution of Example 1 UV-Vis absorption spectrum of the coating film of Example 1

Claims (4)

A metal-containing squarylium compound comprising a squarylium compound represented by the following general formula (A) or general formula (B) and a metal salt or metal ion.

(In the formula, R ₁ represents a hydroxyl group, an amino group, or a sulfonamide group, and R ₂ , R ₃ , R ₄ , and R ₅ each independently represent a hydrogen atom, a halogen atom, a hydroxy group, a cyano group, or a nitro group. Or an optionally substituted linear or branched alkyl group, halogenated alkyl group, cyanoalkyl group, aralkyl group, alkenyl group, alkoxy group, aryl group, heterocycle, acyl group, or alkoxycarbonyl group, X represents an optionally substituted linear or branched alkyl group, halogenated alkyl group, cyanoalkyl group, aralkyl group, alkenyl group, aryl group, or alkoxycarbonyl group.

(In the formula, R ₁ , R ₂ , R ₃ , R ₄ and X are the same as those in the general formula (A).) The metal-containing squarylium compound according to claim 1, wherein the metal is Ni, Co, Zn, Cu, Pt, Ti, Al, V, Mn, Fe, Mo, W, Sn, Ru, Cr, Pb, Eu, Ir. A metal-containing squarylium compound, wherein the metal-containing squarylium compound is at least one metal selected from the group consisting of: An optical recording medium in which a recording layer capable of writing and / or reading information with a laser beam is formed on a substrate, and the recording layer contains at least one metal-containing squarylium compound according to claim 1 or 2. An optical recording medium characterized by the above. 4. The optical recording medium according to claim 3, wherein information is recorded and / or reproduced by a laser beam selected from a wavelength region of a wavelength of 300 nm to 530 nm.

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