JP2008214196A - Imine metal chelate complex compound and dye for forming recording layer of optical recording medium using the compound - Google Patents

Abstract

<P>PROBLEM TO BE SOLVED: To provide a new dye for forming a recording layer of a recording medium containing a new imine metal chelate complex having excellent solubility in a coating solvent and light resistance and usable for blue laser recording. <P>SOLUTION: The invention provides an imine compound anion expressed by general formula (1), an imine metal chelate complex compound composed of the imine compound anion and a transition metal cation, and a dye for forming a recording layer of an optical recording medium containing the imine metal chelate complex compound (in the formula, rings A and B are each an aromatic ring which may have a substituent; R<SP>1</SP>to R<SP>3</SP>are each a hydrogen atom, an aromatic ring group which may have a substituent or a ≤20C univalent non-aromatic substitution group; R<SP>4</SP>and R<SP>5</SP>are each an aromatic group which may have a substituent or a ≤20C univalent non-aromatic substituent; and X is a direct bond or a group 15 or 16 element of the periodic table). <P>COPYRIGHT: (C)2008,JPO&INPIT

Description

The present invention relates to a novel imine metal chelate complex compound useful as a dye for forming a recording layer of an optical recording medium, a novel imine compound anion serving as a ligand thereof, and an optical recording medium containing the imine metal chelate complex compound. It relates to pigments. In particular, the present invention relates to a novel imine metal chelate complex compound useful as a recording layer forming dye of an optical recording medium compatible with blue laser light, and a recording layer forming dye of an optical recording medium containing this compound.
The present invention also relates to an optical recording medium having a recording layer using such a dye and a recording method of the optical recording medium.

  In recent years, since it is possible to record / store / reproduce information at a high density, development of an optical recording medium using a laser beam, particularly an optical disk, has been underway. Among the optical disks, a writable compact disk (CD-R) is recently attracting attention. The CD-R usually has a structure in which a recording layer mainly composed of a dye, a metal reflective film, and a protective film are sequentially laminated on a circular plastic substrate having guide grooves. Information is recorded on the CD-R mainly by irradiating the laser beam and absorbing the irradiation energy in the recording layer to decompose, evaporate, and dissolve into the recording layer, reflective layer, or substrate of the laser beam irradiated portion. It is performed by a method (heat mode) that causes thermal deformation such as. The recorded information is reproduced by reading the difference in reflectance with respect to the laser beam between the portion where thermal deformation or dye structure change due to laser light irradiation occurs and the portion where it does not occur. Therefore, it is necessary for the recording layer of the optical recording medium to efficiently absorb the energy of the laser beam, and a laser beam absorbing dye is generally used for the recording layer.

  An optical recording medium using an organic dye as a laser light absorbing dye can form a recording layer by a simple method of applying an organic dye solution, and is expected to become increasingly popular as an inexpensive optical recording medium in the future. .

  Also, in recent years, in order to increase the recording density, the wavelength of laser light used for recording has been shortened from a wavelength centered on the conventional semiconductor laser emission wavelength of 780 nm to a blue light region of about 405 nm or less. Is being considered.

  Further, in recent years, in order to increase the capacity of recording media, the creation of a double-layer recording medium that doubles the storage capacity by creating two recording layers on the recording medium and the speeding up of recording have been studied. For this reason, the dye compound for recording layers is required to have higher sensitivity to a recording laser.

  In addition, when forming a recording layer using a dye, the method of applying to a substrate using a spin coating method is generally advantageous in terms of cost compared to the vacuum deposition method. It is essential to show high solubility in the solvent. Currently, fluorine-based alcohol solvents such as 2,2,3,3-tetrafluoropropanol (TFP) and 2,2,3,3,4,4,5,5-octafluoropentanol (OFP) are used as coating solvents. In general, the recording layer forming dye is required to exhibit high solubility in these coating solvents.

  In general, both data recording and reading are performed by laser light, and the reading laser light having a lower intensity than the recording laser light is used. Accordingly, if the dye forming the recording layer of the optical recording medium is decomposed by irradiation with weak laser light that is reading light and the light resistance of the dye is low, a data error occurs when reading the recording data. Cause. In addition, since optical recording media are often exposed to sunlight or illumination on the recording surface for a long time due to their properties, if the dye is inferior in light resistance, it becomes difficult to store the recording data of the optical recording medium for a long period of time. . Accordingly, the recording layer forming dye is required to have high light resistance.

The imine compound is one of compounds expected to be applied to an optical recording medium because of its simple synthesis and maximum absorption mainly at a wavelength of 300 nm or more. Has been filed.
JP 2005-515914 A International Publication No. 2004-102551

  However, imine compounds generally have poor solubility in coating solvents when they are not metal complexes, but they are significantly inferior in light resistance. When they are metal complexes, light resistance is improved, but they are soluble in coating solvents. The performance is greatly reduced. That is, the imine compounds described in Patent Documents 1 and 2 are significantly inferior in either solubility in a coating solvent or light resistance.

  For example, in Patent Document 1, only an optical recording medium using an imine compound containing no metal is described as an example, and as a result of studies by the present inventors, the compound of the example is extremely inferior in light resistance. Became clear. In addition, as a result of studies by the present inventors, it has been found that the imine metal complex compounds listed as examples in Patent Document 2 are extremely inferior in solubility in a fluorinated alcohol solvent. Further, when a similar study was performed on a salen complex compound, which is a general compound among imine metal complex compounds, it was also found that the solubility in a fluorine-based alcohol solvent was remarkably inferior.

  The present invention has been made in view of the above circumstances, and is excellent in both solubility in a coating solvent and light resistance, and can be used for optical recording using blue laser light. An object is to provide an imine dye for formation.

  If the conventional imine compound is not a metal complex, the light resistance is significantly inferior because the imine structure is unstable to light. If it is a metal complex, the light resistance is improved. On the other hand, the reason why the solubility in the coating solvent is greatly reduced is that the compound becomes rigid due to the metal complexation, so that the stability is improved but the affinity with the solvent is reduced. It is done.

  As a result of intensive studies to solve the above-mentioned problems, the present inventors have applied an imine metal chelate complex compound comprising an imine compound anion having an indolenyl group and a transition metal cation represented by the following general formula (1). The present invention was completed by discovering that it was excellent in solubility in a solvent and light resistance in a thin film state, and that an optical recording medium using this in a recording layer could be recorded well with blue laser light.

  The present invention has been achieved based on such knowledge, and the gist thereof is as follows.

（一般式（１）中、環Ａおよび環Ｂは、それぞれ独立に、置換基を有していても良い芳香環を表し、Ｒ^１〜Ｒ^３は、それぞれ独立に、水素原子もしくは置換基を有していても良い芳香環基もしくは炭素数２０以下の１価の非芳香環置換基を表し、Ｒ^４およびＲ^５は、それぞれ独立に、置換基を有していても良い芳香環基もしくは炭素数２０以下の１価の非芳香環置換基を表し、Ｘは直接結合もしくは周期表第１５〜１６族元素を表す。なお、Ｘが周期表第１５族元素の場合、該Ｘは更に炭素数２０以下の１価の置換基を有していても良い。） [1] An imine metal chelate complex compound composed of an imine compound anion and a transition metal cation represented by the following general formula (1) (however, the total valence of the chelate complex composed of an imine compound anion and a transition metal cation is 1 or more) In some cases, the complex may further have a counter anion having a molecular weight of 600 or less so that the valence is zero.

(In General Formula (1), Ring A and Ring B each independently represent an optionally substituted aromatic ring, and R ^{1 to} R ³ each independently represents a hydrogen atom or a substituent. Represents an aromatic ring group which may have or a monovalent non-aromatic ring substituent having 20 or less carbon atoms, and R ⁴ and R ⁵ each independently represents an aromatic ring group which may have a substituent or Represents a monovalent non-aromatic ring substituent having 20 or less carbon atoms, and X represents a direct bond or a group 15 to 16 element of the periodic table, and when X is a group 15 element of the periodic table, X further represents carbon. (It may have a monovalent substituent of several 20 or less.)

[2] The imine metal chelate complex compound according to [1], wherein the ring A and the ring B are each independently an aromatic hydrocarbon ring which may have a substituent.

[3] The imine metal chelate complex compound according to [1] or [2], wherein at least one of R ⁴ and R ⁵ is a benzyl group which may have a substituent.

[4] A dye for forming a recording layer of an optical recording medium, comprising the imine metal chelate complex compound according to any one of [1] to [3].

[5] It has at least a substrate and a recording layer formed on the substrate, and the recording layer is formed using the recording layer forming dye of the optical recording medium described in [4]. An optical recording medium characterized by the above.

[6] A recording method for an optical recording medium, wherein the optical recording medium according to [5] is recorded using a laser beam having a wavelength of 350 to 530 nm.

（一般式（１）中、環Ａおよび環Ｂは、それぞれ独立に、置換基を有していても良い芳香環を表し、Ｒ^１〜Ｒ^３は、それぞれ独立に、水素原子もしくは置換基を有していても良い芳香環基もしくは炭素数２０以下の１価の非芳香環置換基を表し、Ｒ^４およびＲ^５は、それぞれ独立に、置換基を有していても良い芳香環基もしくは炭素数２０以下の１価の非芳香環置換基を表し、Ｘは直接結合もしくは周期表第１５〜１６族元素を表す。なお、Ｘが周期表第１５族元素の場合、該Ｘは更に炭素数２０以下の１価の置換基を有していても良い。） [7] An imine compound anion represented by the following general formula (1).

(In General Formula (1), Ring A and Ring B each independently represent an optionally substituted aromatic ring, and R ^{1 to} R ³ each independently represents a hydrogen atom or a substituent. Represents an aromatic ring group which may have or a monovalent non-aromatic ring substituent having 20 or less carbon atoms, and R ⁴ and R ⁵ each independently represents an aromatic ring group which may have a substituent or Represents a monovalent non-aromatic ring substituent having 20 or less carbon atoms, and X represents a direct bond or a group 15 to 16 element of the periodic table, and when X is a group 15 element of the periodic table, X further represents carbon. (It may have a monovalent substituent of several 20 or less.)

  The novel imine metal chelate complex compound using the novel imine compound anion of the present invention is excellent in solubility in a solvent, light resistance and blue laser recording sensitivity. Therefore, by using a dye containing this imine metal chelate complex compound in the recording layer of an optical recording medium, a high-density optical recording medium having excellent recording characteristics with blue laser light and good light resistance can be obtained. Basically, it can be provided at a low cost.

  Embodiments of the present invention will be specifically described below, but 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.

[Imine compound anion and imine metal chelate complex compound]
The imine compound anion of the present invention is represented by the following general formula (1), and the imine metal chelate complex compound of the present invention comprises such an imine compound anion of the present invention and a transition metal cation. (However, when the total valence of the chelate complex composed of an imine compound anion and a transition metal cation is 1 or more, the complex further has a counter anion having a molecular weight of 600 or less so that the valence becomes 0. Is also good.)

（一般式（１）中、環Ａおよび環Ｂは、それぞれ独立に、置換基を有していても良い芳香環を表し、Ｒ^１〜Ｒ^３は、それぞれ独立に、水素原子もしくは置換基を有していても良い芳香環基もしくは炭素数２０以下の１価の非芳香環置換基を表し、Ｒ^４およびＲ^５は、それぞれ独立に、置換基を有していても良い芳香環基もしくは炭素数２０以下の１価の非芳香環置換基を表し、Ｘは直接結合もしくは周期表第１５〜１６族元素を表す。なお、Ｘが周期表第１５族元素の場合、該Ｘは更に炭素数２０以下の１価の置換基を有していても良い。）

(In General Formula (1), Ring A and Ring B each independently represent an optionally substituted aromatic ring, and R ^{1 to} R ³ each independently represents a hydrogen atom or a substituent. Represents an aromatic ring group which may have or a monovalent non-aromatic ring substituent having 20 or less carbon atoms, and R ⁴ and R ⁵ each independently represents an aromatic ring group which may have a substituent or Represents a monovalent non-aromatic ring substituent having 20 or less carbon atoms, and X represents a direct bond or a group 15 to 16 element of the periodic table, and when X is a group 15 element of the periodic table, X further represents carbon. (It may have a monovalent substituent of several 20 or less.)

  In addition, in the compound manufactured by the method described in the synthesis method of the imine metal chelate complex compound of the present invention described later, one kind of the imine metal chelate complex compound of the present invention may be contained alone. Two or more kinds may be mixed and contained.

{Explanation of words}
In the present invention, the aromatic ring means a ring having aromaticity, that is, a ring having a (4n + 2) π electron system (n is a natural number). The skeleton structure is usually an aromatic ring consisting of a 5- or 6-membered monocyclic ring or a 2-6 condensed ring. The aromatic ring includes an aromatic hydrocarbon ring, an aromatic heterocyclic ring, and an anthracene ring. , Condensed rings such as a carbazole ring and an azulene ring are also included. The “... ring group” such as “aromatic ring group” is a monovalent substituent obtained by removing one hydrogen atom from such a ring such as an aromatic ring.

“(Hetero) aryl” means both “aryl” and “heteroaryl”, and “(hetero) aralkyl” means both “aralkyl” and “heteroaralkyl”.
In the present invention, “may have a substituent” means that one or more substituents may be present.

{General formula (1)}
First, the imine compound anion represented by the general formula (1) will be described.
<Ring A and Ring B>
In General Formula (1), Ring A and Ring B each independently represent an aromatic ring that may have a substituent. Specific examples of the skeleton structure include a 5-membered monocyclic ring as a furan ring, a thiophene ring, a pyrrole ring, an imidazole ring, a thiazole ring, an oxadiazole ring, a 6-membered monocyclic ring as a benzene ring, a pyridine ring, a pyrazine ring, Examples of the condensed ring include a naphthalene ring, a phenanthrene ring, an azulene ring, a pyrene ring, a quinoline ring, an isoquinoline ring, a quinoxaline ring, a benzofuran ring, a carbazole ring, a dibenzothiophene ring, and an anthracene ring. Among these, an aromatic hydrocarbon ring is preferable for the reason of synthesis, a 6-membered ring such as a benzene ring or a naphthalene ring is more preferable, and a benzene ring is particularly preferable.

  Examples of the substituent that the aromatic rings A and B may have include a chain alkyl group, a chain alkenyl group, a chain alkynyl group, a hydrocarbon ring group, a heterocyclic group, an alkoxy group having 20 or less carbon atoms. Group, alkylcarbonyl group, (hetero) aryloxy group, (hetero) aralkyloxy group, amino group optionally having substituent, nitro group, cyano group, ester group, optionally having substituent Examples thereof include a carbamoyl group, a halogen atom, and a hydroxyl group.

  Examples of chain alkyl groups include methyl, ethyl, propyl, isopropyl, butyl, iso-butyl, sec-butyl, tert-butyl, hexyl, octyl, etc. Examples thereof include 1 to 20, preferably 1 to 10 linear or branched ones.

  Examples of the chain alkenyl group include a linear group having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms, such as a vinyl group, a propenyl group, a butenyl group, a 2-methyl-1-propenyl group, a hexenyl group, and an octenyl group. Or a branched thing is mentioned.

  Examples of the chain alkynyl group include straight chain having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms such as ethynyl group, propynyl group, butynyl group, 2-methyl-1-propynyl group, hexynyl group and octynyl group. Or a branched thing is mentioned.

  The hydrocarbon ring group usually has 3 to 20 carbon atoms such as a cyclopropyl group, cyclohexyl group or tetradecahydroanthranyl group, preferably 5 to 10 carbon atoms such as a cycloalkyl group or cyclohexenyl group. And preferably an aryl group having 6 to 18 carbon atoms, preferably 6 to 10 carbon atoms, such as a cycloalkenyl group, a phenyl group, an anthranyl group, a phenanthryl group, a ferrocenyl group, and the like.

  Examples of the heterocyclic group include a heteroaryl group consisting of a 5-6 membered monocyclic ring or a 2-6 condensed ring, a heterocycloalkyl group consisting of a 5-6 membered monocyclic ring or a 2-6 condensed ring, Examples of the hetero atom include a nitrogen atom, an oxygen atom, and a sulfur atom. Specifically, 5-membered ring such as thienyl group, 6-membered ring such as pyridyl group, 2-piperidinyl group, 2-piperazinyl group, benzothienyl group, carbazolyl group, quinolinyl group, octahydroquinolinyl group or the like 5 or A group derived from a 6-membered 2-6 condensed ring is exemplified.

  Examples of the alkoxy group include a methoxy group, an ethoxy group, an iso-propoxy group, a butoxy group, an iso-butoxy group, a sec-butoxy group, a tert-butoxy group, a hexyloxy group, and an octyloxy group. To 9, preferably 2 to 8.

  Examples of the alkylcarbonyl group include those having 2 to 18 carbon atoms, preferably 2 to 8 carbon atoms, such as a methylcarbonyl group, an ethylcarbonyl group, an isopropylcarbonyl group, a tert-butylcarbonyl group, and a cyclohexylcarbonyl group.

  Examples of (hetero) aryloxy groups include aryloxy groups having 6 to 18, preferably 6 to 10 carbon atoms, such as phenoxy groups and naphthyloxy groups, 2-thienyloxy groups, 2-furyloxy groups, Examples thereof include heteroaryloxy groups having 2 to 18 carbon atoms such as 2-quinolyloxy group, preferably 5 to 10, preferably including nitrogen atom, oxygen atom, sulfur atom and the like as a hetero atom.

  Examples of (hetero) aralkyloxy groups include aralkyloxy groups such as benzyloxy group, phenethyloxy group, naphthylmethoxy group and the like, which usually have 7 to 18, preferably 7 to 12 carbon atoms, 2-thienylmethoxy group, 2 -Heteroaralkyloxy groups having 6 to 18, preferably 6 to 10 carbon atoms, such as a furylmethoxy group and a 2-quinolylmethoxy group, and those containing a heteroatom selected from a nitrogen atom, an oxygen atom, a sulfur atom and the like Etc.

Examples of the amino group which may have a substituent include an amino group, an alkylamino group, and a (hetero) arylamino group.
Examples of the alkylamino group include those having 2 to 20 carbon atoms, preferably 3 to 10 carbon atoms, such as an ethylamino group, a dimethylamino group, a methylethylamino group, a dibutylamino group, and a piperidyl group.
Examples of (hetero) arylamino groups include arylamino groups having 6 to 30, preferably 6 to 15 carbon atoms such as diphenylamino group, dinaphthylamino group, naphthylphenylamino group, and ditolylamino group, and di (2 -Thienyl) amino group, di (2-furyl) amino group and the like having 5-30 carbon atoms, preferably 6-15, and heteroaryls including heteroatoms selected from nitrogen atoms, oxygen atoms, sulfur atoms, etc. Examples thereof include arylheteroarylamino groups having 11 to 30, preferably 12 to 16, carbon atoms such as an amino group and a phenyl (2-thienyl) amino group.

Examples of the carbamoyl group which may have a substituent include a carbamoyl group and an alkylcarbamoyl group.
Examples of the alkylcarbamoyl group include those having 2 to 20 carbon atoms, preferably 2 to 10 carbon atoms such as an N-methylcarbamoyl group, an N, N-dimethylcarbamoyl group, and an N-ethyl-N-cyclohexylcarbamoyl group.

  Examples of the ester group include a methoxycarbonyl group, an ethoxycarbonyl group, a propoxycarbonyl group, an isopropoxycarbonyl group, a tert-butoxycarbonyl group, an acetyloxy group, a benzoyloxy group and the like having 2 to 20, preferably 2 to 10 are listed.

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

  In addition, when the rings A and B have two or more substituents, the substituents may be bonded to each other to form a cyclic structure. For example, when ring A is a benzene ring, the following structures are exemplified as examples in which substituents of the benzene ring are bonded to each other to form a cyclic structure that may contain a hetero atom. In the following, the dotted line is the bonding position to the hydrazide skeleton.

  Ring A preferably has these substituents because it improves the solubility of the dye in the solvent used when forming the recording layer, but it does not have ring A in terms of synthesis. . About ring B, in order to improve the solubility to a coating solvent, it is preferable to have polar groups, such as an alkoxyl group and an alkoxycarbonyl group.

<R ^{1 to} R ³ >
In the general formula (1), R ^{1 to} R ³ each independently represent a hydrogen atom, an aromatic ring group which may have a substituent, or a monovalent non-aromatic ring substituent having 20 or less carbon atoms.
Specific examples of the aromatic ring group which may have a substituent include groups derived from aromatic rings described as specific examples of the rings A and B, and monovalent non-aromatic ring substitution having 20 or less carbon atoms. Specific examples of the group include those except for the aromatic ring group among those described as the substituents that the rings A and B may have.

R ¹ and R ² are each preferably a hydrogen atom, and R ³ is preferably not a hydrogen atom in terms of synthesis.

^{<R 4, R} 5>
R ⁴ and R ⁵ each independently represents an aromatic ring group which may have a substituent or a monovalent non-aromatic ring substituent having 20 or less carbon atoms. Specific examples of the aromatic ring group which may have a substituent include groups derived from aromatic rings described as specific examples of rings A and B, and monovalent non-aromatic ring substitution having 20 or less carbon atoms. Specific examples of the group include those except for the aromatic ring group among those described as the substituents that the rings A and B may have.

From the viewpoint of improving the characteristics of the recording medium, it is preferable that either one of R ⁴ and R ⁵ is a benzyl group which may have a substituent, and in that case, the other may have a substituent. An alkyl group is preferred.

<X>
In the general formula (1), X represents a direct bond or a Group 15-16 element of the periodic table. Specific examples of the 15th to 16th group elements of the periodic table include N, O, P, S, and the like. From the viewpoint of synthesis, an element of the second period is preferable.
When X is a Group 15 element in the periodic table, X may further have a monovalent substituent having 20 or less carbon atoms. Specific examples thereof include those described as substituents that ring A and ring B may have. When X has a substituent, the substituent is preferably a monovalent non-aromatic ring substituent having 20 or less carbon atoms.

<Anion tautomerism>
The imine compound anion of the present invention represented by the general formula (1) has tautomerism and can have, for example, the following resonance structures, but these are substantially the same structure.

{Imine metal chelate complex compound}
Next, the imine metal chelate complex compound of the present invention composed of an imine compound anion represented by the above general formula (1) and a transition metal cation will be described.

<Transition metal cation>
The transition metal cation in the present invention may be anything as long as it can form a metal complex with the imine compound anion represented by the general formula (1). Specific examples include Ti, V, Cr, Mn, Fe, Co, Ni, Cu, Mo, Ru, Rh, Pd, Ag, Pt, Au, Er cations, and the like.
In view of economy, the cation is preferably one in the fourth period of the periodic table, and particularly preferably Fe or Co in terms of improving light resistance.
Moreover, the valence of a transition metal cation is 1-6 normally, it is preferable that it is 2-3 from a synthetic surface, and it is especially preferable that it is 2.

<Ratio of anion to cation>
The component ratio of the imine compound anion and the transition metal cation in the chelate complex compound of the present invention is not particularly defined as long as it can stably form a chelate complex, but is usually anion: cation = 1: 1 to 3: 1. 2: 1 is particularly preferable in terms of stability.

<Counter anion>
When the total valence of the chelate complex comprising the imine compound anion and the transition metal cation in the present invention is 1 or more, the chelate complex is further neutralized, that is, the total valence is 0. Thus, you may have a counter anion with a molecular weight of 600 or less.
Specific examples of the counter anion include alcohol, phenol, carboxylic acid, phosphonic acid, halogen, perchloric acid, periodic acid, cyanic acid, isocyanic acid, isothiocyanic acid, azide, nitric acid, carbonic acid, bicarbonate, substituted or non-substituted. Substituted sulfuric acid (sulfuric acid, hydrosulfuric acid, methylsulfuric acid, etc.), methanesulfonic acid, trifluoromethanesulfonic acid, tosylic acid, substituted or unsubstituted phosphoric acid (phosphoric acid, hydrogen phosphate, dihydrogen phosphate, phenyl Phosphoric acid, phosphorous hexafluoride, antimony hexafluoride, substituted or unsubstituted phosphinic acid (phosphinic acid, methylphosphinic acid etc.), substituted or unsubstituted boronic acid (tetraphenylboronic acid etc.), benzenesulfonic acid , Acetic acid and trifluoroacetic acid, which are anionized.
Among these, in order to make it water-insoluble, it is preferable that perchlorate anion, boron tetrafluoride anion, phosphorus hexafluoride anion, organic anion, etc. are included. An organic anion having the above absorption is more preferable.

<Molecular weight>
The imine metal chelate complex compound of the present invention usually has a molecular weight of 2,000 or less, particularly preferably 1,500 or less, from the viewpoint of prevention of sensitivity reduction due to a decrease in absorbance.

  The imine metal chelate complex compound of the present invention is usually preferably insoluble in water for the purpose of improving the storage stability of the recording medium. Here, “water-insoluble” means that the solubility in water at 25 ° C. and 1 atm is usually 0.1% by weight or less, preferably 0.01% by weight or less.

{Concrete example}
Although the specific example of the imine metal chelate complex compound of this invention is illustrated in the following Tables 1-9, this invention is not limited to these, unless the summary is exceeded. In the following, Me represents a methyl group, Et represents an ethyl group, Ac represents an acetyl group, Ph represents a phenyl group, and Fc represents a ferrocenyl group.

{Synthesis method}

  The imine ligand constituting the imine compound anion of the present invention represented by the general formula (1) can be synthesized by various methods. For example, two types of reaction substrates (1-a), ( It can be easily obtained by dehydrating condensation of 1-b) in the presence or absence of a solvent.

（上記式中、環Ａ，Ｂ、Ｒ^１〜Ｒ^５、Ｘは一般式（１）におけると同義である。）

(In the above formula, rings A, B, R ^{1 to} R ⁵ and X have the same meanings as in general formula (1).)

  The imine metal chelate complex compound of the present invention can be easily obtained by subjecting the imine ligand synthesized by the above method to a chelate complex formation reaction with a transition metal salt in the presence or absence of a base.

{Light resistance, solubility in coating solvent, film properties, and laser sensitivity}
Among the imine metal chelate complex compounds of the present invention, preferred ones are characterized by excellent light resistance and solubility in a coating solvent, and further excellent film properties and sensitivity to laser when used as a coating film.

In this case, excellent light resistance means that an imine metal chelate complex compound thin film formed to have a film thickness of about 50 nm is irradiated with a temperature of 58 ° C., a humidity of 50%, and a xenon lamp (intensity 0.55 W / m ² ). Even if the light resistance test under the conditions is performed for 40 hours, it means that 70% or more, preferably 80% or more, particularly preferably 90% or more of the imine metal chelate complex compound in the thin film remains without deterioration. Here, the degree of deterioration is determined by the absorption reduction rate of the absorption maximum at 300 to 500 nm.

Specifically, this light resistance test is performed as follows.
First, a solution containing an imine metal chelate complex compound is applied on a substrate so that the film thickness after drying is about 50 nm, and then dried to obtain a layer containing an imine metal chelate complex compound. The layer containing the resulting imine metal chelate complex compound is irradiated with a xenon lamp (intensity 0.55 W / m ² ) for a predetermined time under conditions of a temperature of 58 ° C. and a humidity of 50%, and the absorption maximum wavelength before and after the irradiation. This is carried out by comparing the absorbances of the imine metal chelate complex compounds.

In addition, excellent solubility in a coating solvent means that 0.7% by weight or more, preferably 1.0% by weight in 2,2,3,3-tetrafluoropropanol (TFP) at 20 ° C. under normal pressure. Above, it shows that it dissolves more preferably 1.5 wt% or more. Determination of dissolution is performed based on whether or not a crystal residue of the compound remains in the solvent when the compound and TFP are mixed at a specific concentration.
In the application of the present invention, the upper limit of the solubility is not particularly limited, but is usually 20% by weight or less, particularly about 10% by weight or less.

  Moreover, it is said that it is excellent in film property that whitening is not confirmed visually in the layer of the imine metal chelate complex compound of this invention created by the above-mentioned method.

In addition, this compound is excellent in laser sensitivity when the imine metal chelate complex compound layer of the present invention prepared by the above method is irradiated with blue laser light having a central wavelength of 405 nm and NA = 0.85. It means that pits can be formed even at an intensity of 12 mW or less, preferably 10 mW or less, particularly preferably 7.5 mW or less.
Note that good recording pits can be formed here when the chelate complex compound layer is irradiated with blue laser light having a specific laser intensity, and that the formation of pits can be confirmed visually or using an optical microscope. To tell.

  When this compound is used in an optical recording medium, the high light resistance is the storage stability of the disc, and the high solubility and film property are the high laser sensitivity for the disc manufacturability. Are advantageous for high-speed recording on a disc.

The reason why the imine metal chelate complex compound of the present invention is excellent in light resistance and solubility in a coating solvent is that the imine metal chelate complex is stabilized by metal chelation, the indenyl group of the imine compound anion is sterically bulky, For example, the overlap between molecules is minimized and the solubility is improved.
Further, since the coordination point is 4 and the indenyl group is relatively reactive, it is expected to be stable under normal conditions but unstable under recording laser irradiation conditions, that is, high sensitivity.

[Dye for recording layer formation of optical recording medium]
The recording layer forming dye of the optical recording medium of the present invention (hereinafter referred to as “the recording layer forming dye of the optical recording medium of the present invention” or simply “the dye of the present invention”) is used in the present invention. Only one type of the imine metal chelate complex compound may be used, or two or more types of the imine metal chelate complex compound of the present invention may be used in any combination and ratio. Moreover, in addition to the 1 type or 2 or more types of imine metal chelate complex compound of this invention, you may use together 1 type (s) or 2 or more types of another pigment | dye.
However, when a dye other than the imine metal chelate complex compound of the present invention is used in combination, the imine metal of the present invention with respect to the total of all the dyes from the viewpoint of sufficiently exhibiting the excellent characteristics of the imine metal chelate complex compound of the present invention. The ratio of the chelate complex compound is usually 50% by weight or more, preferably 70% by weight or more.

As another type of dye that can be used in combination with the imine metal chelate complex compound of the present invention, it has absorption in the laser light wavelength region for recording, absorbs the energy of the irradiated laser light, and the recording layer of the irradiated portion, It is preferable to form pits with thermal deformation such as decomposition, evaporation, and dissolution on the reflective layer or the substrate. In addition, a dye suitable for recording with a near-infrared laser beam having a wavelength selected from the range of 770 to 830 nm for CD-R and a red laser beam selected from the range of 620 to 690 nm for DVD-R is used in combination. Thus, an optical recording material corresponding to recording with laser beams in a plurality of wavelength regions can be used.
Specific examples of other types of dyes that can be used in combination include metal-containing azo dyes, phthalocyanine dyes, naphthalocyanine dyes, cyanine dyes, azo dyes, squarylium dyes, metal-containing indoaniline dyes, tria. Examples include reel methane dyes, merocyanine dyes, azurenium dyes, naphthoquinone dyes, anthraquinone dyes, indophenol dyes, xanthene dyes, oxazine dyes, pyrylium dyes, and the like. Or two or more of them may be used in combination.

  Of these other dyes, a near infrared laser beam having a wavelength selected from a range of 770 to 830 nm for CD-R and a red laser beam selected from a range of 620 to 690 nm for DVD-R. In combination with a dye suitable for recording, an optical recording material corresponding to recording with laser beams in a plurality of wavelength ranges can be obtained.

[Optical recording medium]
{Recording layer}
The recording layer of the optical recording medium of the present invention is formed using the recording layer forming dye of the optical recording medium of the present invention containing at least one kind of the imine metal chelate complex compound of the present invention.
That is, the recording layer of the optical recording medium of the present invention contains one or more of the imine metal chelate complex compounds of the present invention.

The proportion of the dye of the present invention in the recording layer is usually 10% by weight or more, preferably 50% by weight or more, particularly preferably 90% by weight or more.
If the ratio of the dye is too small, the recording sensitivity is remarkably lowered, which is not preferable. When two or more kinds of dyes are used in combination as the dye of the present invention, the sum thereof satisfies the above range. In addition, when using the binder and various additives described below, the amount of the binder or additive used should be adjusted so that the ratio of the dye of the present invention in the formed recording layer is within the above range. Is preferred. From the viewpoint of sufficiently exhibiting the excellent characteristics of the dye of the present invention, it is particularly preferable that no binder or additive is used in the recording layer according to the present invention.

The recording layer may contain a binder in order to improve the film formability. As the binder, known ones such as polyvinyl alcohol, polyvinyl pyrrolidone, ketone resin, nitrocellulose, cellulose acetate, polyvinyl butyral, and polycarbonate can be used singly or in combination of two or more.
When the ratio of the binder in the recording layer is too high, the recording sensitivity is remarkably lowered. Therefore, when the binder and further various additives described below are used, the ratio of the dye of the present invention in the formed recording layer is within the above range. Use an amount such that

  The recording layer may contain a singlet oxygen quencher for improving stability and light resistance, a recording sensitivity improver, and the like.

  Examples of the singlet oxygen quencher include chelate compounds of acetylacetonate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-α-diketone and the like and transition metals, and these may be used alone. Two or more kinds may be used in combination.

  Examples of the recording sensitivity improver include metal compounds in which a metal such as a transition metal is contained in the form of atoms, ions, clusters, etc., for example, ethylenediamine complex, azomethine complex, phenylhydroxyamine complex, phenanthroline. And organometallic compounds such as complex, dihydroxyazobenzene complex, dioxime complex, nitrosoaminophenol complex, pyridyltriazine complex, acetylacetonate complex, metallocene complex, and so on. You may use, and may use 2 or more types together. The type of metal atom is not particularly limited, but a transition metal is preferable.

The singlet oxygen quencher is usually used in an amount of about 5 to 30% by weight based on the dye, and the recording sensitivity improver is usually used in an amount of about 10 to 30% by weight based on the dye.
When two or more types of singlet oxygen quenchers are used in combination, or when two or more types of recording sensitivity improvers are used in combination, the total is made to satisfy the above range.

In order to form a recording layer of an optical recording medium using the dye of the present invention containing the imine metal chelate complex compound of the present invention, a vacuum deposition method, a sputtering method, a doctor blade method, a cast method, a spin coating method, an immersion method, etc. The thin film forming method generally used can be used.
Of these, spin coating is preferred from the standpoints of mass productivity and cost.
When the recording layer is formed by spin coating, the rotational speed is preferably 500 to 5000 rpm, and after spin coating, treatment such as heating or exposure to solvent vapor may be performed as necessary.

  The film thickness of the recording layer is not particularly limited, but is usually 10 nm to 5 μm, preferably 20 nm to 2 μm, and more preferably 50 nm to 300 nm. When the thickness of the recording layer is larger than this lower limit value, the influence of thermal diffusion can be suppressed, and good recording is easy. In addition, since the recording signal is hardly distorted, the signal amplitude can be easily increased. When the film thickness of the recording layer is smaller than the above upper limit value, the reflectance is easily increased and the reproduction signal characteristic is easily improved.

  When the recording layer is formed by a doctor blade method, a cast method, a spin coating method, a dipping method, etc., first, the recording layer forming dye, binder, singlet oxygen quencher, recording sensitivity improver and other agents of the present invention are used. A pigment is dissolved in a solvent to prepare a coating solution.

  As the solvent, use of TFP is particularly preferable from an industrial viewpoint. However, the solvent is not limited to TFP as long as it does not attack the substrate, such as diacetone alcohol and 3-hydroxy-3-methyl-2-butanone. Ketone alcohol solvents, cellosolve solvents such as methyl cellosolve and ethyl cellosolve, chain hydrocarbon solvents such as n-hexane and n-octane, cyclohexane, methylcyclohexane, ethylcyclohexane, dimethylcyclohexane, n-butylcyclohexane, t- Alicyclic hydrocarbon solvents such as butylcyclohexane and cyclooctane, ether solvents such as diisopropyl ether and dibutyl ether, 2,2,3,3,4,4,5,5-octafluoropentanol (OFP), Fluorine alkylal such as hexafluorobutanol Lumpur solvents, methyl lactate, ethyl lactate, may also be used hydroxy ester solvents such as methyl isobutyrate and the like. In addition, although these solvents may be used individually by 1 type and may be used in mixture of 2 or more types, it is preferable to use 1 type independently from an industrial surface.

The concentration of the dye of the present invention in the coating solution is appropriately determined according to the solvent solubility, but is usually 0.7% by weight or more, preferably 1.0% by weight or more, and usually 10% by weight or less, preferably Is 3.0% by weight or less. If the dye concentration in the coating solution is excessively low, the formation efficiency of the recording layer is deteriorated. If the dye concentration in the coating solution is excessively high, problems such as dye crystallization occur in the film forming process.
In order to efficiently recover the surplus dye after spin coating, the dye is usually used as a coating solvent even at a concentration of 1.5 times or more, preferably 2 times or more the dye concentration of the coating solution described above. It is preferable that it is soluble.

{Layer structure of optical recording medium}
The optical recording medium of the present invention has a recording layer formed on a substrate as described above using the recording layer forming dye of the present invention.

  As the substrate of the optical recording medium on which the recording layer is formed, a substrate transparent to the laser beam to be used, such as glass and various plastics, is preferably used. Examples of plastics include acrylic resin, methacrylic resin, polycarbonate resin, vinyl chloride resin, vinyl acetate resin, nitrocellulose, polyester resin, polyethylene resin, polypropylene resin, polyimide resin, polystyrene resin, epoxy resin, etc., In view of cost, moisture absorption resistance and the like, polycarbonate resin injection molded is preferable.

  Usually, a layer other than the recording layer such as a reflective layer, a protective layer, and an undercoat layer is further provided on the substrate as necessary, and used as an optical recording medium.

Examples of the reflective layer include those made of a metal such as gold, silver, aluminum, or an alloy thereof, but silver is preferable to gold or aluminum because of the reflectance with respect to laser light having a wavelength of 550 nm or less. The metal reflective layer is formed on the recording layer by vapor deposition, sputtering, ion plating, or the like. Here, an intermediate layer may be provided between the metal reflective layer and the recording layer for the purpose of improving the adhesion between the layers or for increasing the reflectance.
The thickness of the reflective layer is usually in the range of 50 nm to 300 nm.

The material of the protective layer formed on the reflective layer is not particularly limited as long as it protects the reflective layer from external force. Examples thereof include organic substances such as thermoplastic resins, thermosetting resins, electron beam curable resins, UV (ultraviolet) curable resins, and inorganic substances such as SiO ₂ , SiN ₄ , MgF ₂ , and SnO ₂ .
A thermoplastic resin, a thermosetting resin, or the like can be formed by dissolving in an appropriate solvent, applying a coating solution, and drying.
The UV curable resin can be formed by preparing a coating solution as it is or by dissolving it in a suitable solvent, and then applying the coating solution and curing it by irradiating with UV light. Examples of the UV curable resin include acrylate resins such as urethane acrylate, epoxy acrylate, and polyester acrylate. These materials may be used alone or in combination of two or more, and may be used not only as one layer but also as a multilayer film.

  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 usually in the range of 0.1 μm or more and 100 μm or less.

  An undercoat layer may be used between the layers in order to increase the adhesion between the layers. The type of the undercoat layer is not particularly limited as long as it enhances the adhesive strength of each layer and does not affect the properties of each layer, but is preferably an organic layer from the viewpoint of ease of handling.

  In addition, two optical recording media having the above configuration are bonded together via an adhesive layer, or a reflective layer, a recording layer, a protective layer, etc. are provided on both sides as well as on one side of the substrate. Also good. Further, a multilayer optical recording medium may be obtained by forming two or more pairs of a reflective layer and a recording layer on a substrate via an intermediate layer and providing a protective layer thereon.

[Recording method of optical recording medium]
{Laser light}
Information recording on the optical recording medium obtained as described above is usually performed by irradiating the recording layer with laser light focused to about 0.4 to 0.6 μm. When the recording layer absorbs the energy of the laser beam, thermal deformation such as decomposition, heat generation, and melting occurs in the laser beam irradiated portion. The recorded information is reproduced by reading the difference in reflectance between the portion where the thermal deformation is caused by the laser beam and the portion where the thermal deformation does not occur.

  For high-density recording, the shorter the wavelength of the laser beam used during recording, the better. In particular, the optical recording medium of the present invention has the advantage of containing the above-described imine metal chelate complex compound of the present invention in its recording layer. From the viewpoint of sufficiently exerting, a laser beam having a wavelength of 350 nm to 530 nm is preferable (hereinafter, a recording method using such a laser beam is appropriately referred to as “recording method of optical recording medium of the present invention” or simply “recording method of the present invention”. That said.)

  Typical examples of such laser light include blue laser light having center wavelengths of 405 nm and 410 nm, and blue-green high-power semiconductor laser light having a center wavelength of 515 nm. Other than these, (a) a semiconductor laser beam capable of continuous oscillation having a fundamental oscillation wavelength of 740 to 960 nm, or (b) a solid-state laser beam capable of continuous oscillation having a fundamental oscillation wavelength of 740 to 960 nm that is excited by the semiconductor laser beam. The light etc. which are obtained by wavelength-converting either by a 2nd harmonic generation element (SHG) are also mentioned.

The SHG may be any piezo element that lacks reflection symmetry, but KDP (KH ₂ PO ₄ ), ADP (NH ₄ H ₂ PO ₄ ), BNN (Ba ₂ NaNb ₅ O ₁₅ ), KN (KNbO ₃ ), LBO (LiB ₃ O ₅ ), a compound semiconductor, and the like are preferable. As a specific example of the second harmonic, in the case of a semiconductor laser having a fundamental oscillation wavelength of 860 nm, a wavelength of 430 nm of its harmonic wave, and in the case of a solid-state laser excited by a semiconductor laser, a Cr-doped LiSrAlF ₆ crystal (basic oscillation wavelength The wavelength of the double wave from 860 nm) is 430 nm.
Of these, it is particularly preferable to use blue laser light having a center wavelength of 405 nm.

  Of the absorption wavelength and absorbance of the optical recording medium, the maximum absorption wavelength (λmax) of the absorption spectrum of the imine metal chelate complex compound of the present invention in acetonitrile is 380 to 500 nm, and the OD coefficient at λmax (in 1 L of solvent) The absorbance (assuming that 1 g is dissolved) is preferably 50 or more in terms of film thickness control and high sensitivity to laser.

{Film property}
Moreover, the pigment | dye of this invention is excellent in film property. That is, it is industrially advantageous in that no whitening phenomenon derived from crystallization of the compound is observed on the disk surface after the recording layer is formed by spin coating.

  EXAMPLES Hereinafter, the present invention will be described more specifically with reference to examples. However, the present invention is not limited to the following examples unless it exceeds the gist.

In the following, DEI-MS (desorption ionization mass spectrometry) analysis uses a JMS-700 MStation mass spectrometer manufactured by JEOL Ltd., acceleration voltage: 10 kV, temperature rise condition: 0-0.9 A, 1 A / Performed under the condition of minutes.
Moreover, the ultraviolet visible absorption spectrum was analyzed with Shimadzu Corporation UV-3150 ultraviolet visible near infrared spectrophotometer.

[Example 1]
<Synthesis of imine ligand (L-1)>

2- (1,3,3-trimethylindoline-2-ylidene) acetaldehyde (0.65 g) and 3-amino-4-hydroxycoumarin (0.57 g) in the presence of acetic acid (0.1 ml) in methanol (20 ml) ) For 6 hours under reflux. The reaction mixture was cooled to room temperature, extracted with methylene chloride, and washed with water. After drying with sodium sulfate, the solvent was distilled off. The obtained residue was purified by silica gel column chromatography to obtain an orange solid (1.0 g, yield 86%) of the target compound (imine ligand (L-1)).
The obtained compound was identified by thin layer chromatography (TLC) and high performance liquid chromatography (HPLC). HPLC purity (area ratio) was 98%.

<Synthesis of Exemplary Compound (A-1)>

Compound (L-1) (0.50 g) was dissolved in hot methanol (10 ml). Triethylamine (0.25 ml) and cobalt acetate tetrahydrate (0.20 g) as a metal salt were added to the solution in this order, and the mixture was stirred at 50 ° C. for 1 hour. After cooling the reaction mixture to room temperature, the produced solid was filtered off and washed with methanol (10 ml) to obtain the target compound (A-1) as a yellow solid (0.37 g, yield 68%). .
λmax (CH ₃ CN): 435 nm
OD at λmax: 96

  The obtained compound (A-1) was tested for solubility in a coating solvent by the following method. As a result, the compound (A-1) was completely dissolved at a concentration of 0.7% by weight, and the insoluble component was found at a concentration of 1.0% by weight. Slightly confirmed.

<Solubility test>
As a coating solvent, 2,2,3,3-tetrafluoropropanol was used, the concentration of compound (A-1) was 0.7% by weight, and 1.0% by weight, at 20 ° C. and normal pressure for 30 minutes. After ultrasonic treatment, the solution is dropped on a filter paper (quantitative filter paper “No. 5C” manufactured by Toyo Roshi Kaisha, Ltd.), dried at room temperature for 24 hours, and visually observed whether crystal residues of undissolved components are present on the filter paper. did.

[Example 2]
<Synthesis of Exemplary Compound (A-2)>

A pale yellow solid (0.40 g, yield) of the target compound (A-2) was prepared by the same method as the synthesis of the compound (A-1) except that nickel acetate tetrahydrate (0.20 g) was used as the metal salt. 73%).
λmax (CH ₃ CN): 420 nm
OD at λmax: 110
The compound (A-2) thus obtained was tested for solubility in a coating solvent by the method shown in Example 1. As a result, it was completely dissolved at a concentration of 0.7% by weight, and at a concentration of 1.0% by weight. Even insoluble components were confirmed to be slight.

[Example 3]
<Synthesis of imine ligand (L-2)>

2- (1-Ethyl-3-benzyl-3-methylindoline-2-ylidene) acetaldehyde (1.3 g) and 3-amino-4-hydroxycoumarin (0.67 g) in the presence of acetic acid (0.1 ml) The mixture was heated to reflux in methanol (20 ml) for 3 hours. The reaction mixture was cooled to room temperature, extracted with methylene chloride, and washed with water. After drying with sodium sulfate, the solvent was distilled off. The obtained residue was purified by silica gel column chromatography to obtain an orange solid (1.7 g, yield 96%) of the target compound (imine ligand (L-2)).
The obtained compound was identified by TLC and HPLC. HPLC purity (area ratio) was 97%.

<Synthesis of Exemplary Compound (A-11)>

Compound (L-2) (1.0 g) was dissolved in hot methanol (30 ml). Triethylamine (0.33 ml) and cobalt acetate tetrahydrate (0.29 g) were added to the solution in this order, and the mixture was stirred at 50 ° C. for 1 hour. The reaction mixture was concentrated to 10 ml and then cooled to -20 ° C. The produced solid was separated by filtration and washed with cold methanol (10 ml) to obtain a yellow solid (0.55 g, yield 53%) of the target compound (A-11).
λmax (CH ₃ CN): 450 nm
OD at λmax: 73

  About the obtained compound (A-11), the solubility with respect to a coating solvent was tested by the method shown in Example 1. As a result, it was found that the compound (A-11) was completely obtained at both concentrations of 0.7% by weight and 1.0% by weight. It was confirmed that it was dissolved.

<Preparation of dye layer>
The obtained compound (A-11) was dissolved in 2,2,3,3-tetrafluoropropanol at a concentration of 1.0% by weight and fine dust was removed by filtration. Then, it is dropped onto an injection-molded polycarbonate substrate with a thickness of 1.2 mm, applied by spin coating (4900 rpm), and dried at 80 ° C. for 30 minutes to form a transparent coating film (pigment layer) having a thickness of about 50 nm. did.

  When the obtained dye layer was tested for sensitivity to laser by the following method, the maximum sensitivity at which formation of pits was confirmed was 5.0 mW.

<Laser sensitivity test>
A semiconductor laser beam having a central wavelength of 404 nm and NA = 0.85 was irradiated, and the maximum sensitivity at which formation of pits was confirmed by an optical microscope was measured.

  When the light resistance of the obtained dye layer was tested by the method described below, the dye residual ratio was 85%.

<Light resistance test>
For the recording layer after irradiation with a xenon lamp for 40 hours at an irradiation intensity of 0.55 W / m 2 under the conditions of a temperature of 58 ° C. and a humidity of 50%, the residual ratio of the dye is determined based on the absorbance before and after irradiation at the absorption maximum wavelength. It was.

[Example 4]
<Synthesis of Exemplary Compound (A-12)>

The compound (L-2) (0.76 g) synthesized in Example 3 was dissolved in hot methanol (20 ml). Triethylamine (0.25 ml) and iron (II) chloride tetrahydrate (0.17 g) were added to the solution in this order, and the mixture was stirred at 50 ° C. for 1 hour. The produced solid was filtered off and washed with cold methanol (10 ml) to obtain the target compound (A-12) as a yellow solid (0.58 g, yield 73%).
λmax (CH ₃ CN): 429 nm
OD at λmax: 64
The obtained compound (A-12) was tested for solubility in a coating solvent by the method shown in Example 1. As a result, it was found that the compound (A-12) was completely removed at both concentrations of 0.7% by weight and 1.0% by weight. It was confirmed that it was dissolved.

<Preparation of dye layer>
A dye layer was produced in the same manner as in Example 3 for the obtained compound (A-12).
When the recording sensitivity of the obtained dye layer was tested by the method shown in Example 3, the highest sensitivity at which formation of pits was confirmed was 5.0 mW.
Furthermore, when the obtained dye layer was tested for light resistance by the method shown in Example 3, the dye residual ratio was 70%.

[Example 5]
<Synthesis of imine ligand (L-3)>

2- (1-ethyl-3-benzyl-3-methylindoline-2-ylidene) acetaldehyde (0.56 g) and 3-amino-4-hydroxy-1-methyl-2-quinolone (0.30 g) were combined with acetic acid ( The mixture was heated to reflux in methanol (20 ml) in the presence of 0.1 ml) for 6 hours. The reaction mixture was cooled to room temperature, extracted with methylene chloride, and washed with water. After drying with sodium sulfate, the solvent was distilled off. The obtained residue was purified by silica gel column chromatography to obtain a red solid (0.55 g, yield 70%) of the target compound (imine ligand (L-3)).
The obtained compound was identified by TLC and HPLC. HPLC purity (area ratio) was 97%.

<Synthesis of Exemplary Compound (A-73)>

Compound (L-3) (0.55 g) was dissolved in hot methanol (30 ml). Triethylamine (0.18 ml) and cobalt acetate tetrahydrate (0.16 g) were added to the solution in this order, and the mixture was stirred at 50 ° C. for 1 hour. After the reaction mixture was concentrated to 10 ml, the produced solid was filtered off and washed with cold methanol (10 ml) to obtain the yellowish green solid (0.45 g, yield 84%) of the target compound (A-73). Obtained.
λmax (CH ₃ CN): 446 nm
OD at λmax: 71
With respect to the obtained compound (A-73), the solubility in a coating solvent was tested by the method shown in Example 1. As a result, it was found that the compound (A-73) was completely obtained at both concentrations of 0.7% by weight and 1.0% by weight. It was confirmed that it was dissolved.

<Preparation of dye layer>
A dye layer was produced in the same manner as in Example 3 for the obtained compound (A-73).
When the recording sensitivity of the obtained dye layer was tested by the method shown in Example 3, the highest sensitivity at which formation of pits was confirmed was 5.0 mW.
Furthermore, when the obtained dye layer was tested for light resistance by the method shown in Example 3, the dye residual ratio was 78%.

[Comparative Example 1]

  For the compound (B-1) described in Patent Document 1, a dye layer was produced in the same manner as in Example 3, and the obtained dye layer was tested for light resistance by the method described above. Was less than 10%.

[Comparative Example 2]
The compound (B-2) described in Patent Document 2 was tested for solubility in a coating solvent by the method shown in Example 1. As a result, the concentration was 0.7% by weight and 1.0% by weight. It was confirmed that there were many insoluble components.

[Comparative Example 3]
In the compound (B-3) which is a salen metal complex compound, the solubility in the coating solvent was tested by the method shown in Example 1. As a result, the concentration was 0.7% by weight or 1.0% by weight. It was also confirmed that there were many insoluble components.

  The results of the solubility test shown in Examples 1 to 5 and Comparative Examples 2 and 3 are summarized in Table 10 below.

From Table 10, the following is clear.
The imine metal chelate complex compounds shown in Examples 1 to 5 have high solubility because almost no undissolved components are confirmed on the filter paper even when 0.7 to 1.0 wt% TFP solution is used.
On the other hand, the solubility of the compound shown in Comparative Example is remarkably poor, and it is clear that the compound of the present invention is excellent in solubility in a coating solvent.

  Table 11 summarizes the results of the laser sensitivity test and the light resistance test shown in Examples 3 to 5 and Comparative Example 1.

表１１から、本発明のイミン金属キレート錯体化合物を用いて作成された光学記録媒体が、青色レーザー光に対する感度および耐光性の面で優れていることが明らかである。

From Table 11, it is clear that the optical recording medium prepared using the imine metal chelate complex compound of the present invention is excellent in terms of sensitivity and light resistance to blue laser light.

Claims (7)

The imine metal chelate complex compound composed of an imine compound anion and a transition metal cation represented by the following general formula (1) (however, when the total valence of the chelate complex composed of the imine compound anion and the transition metal cation is 1 or more, The complex may further have a counter anion having a molecular weight of 600 or less so that the valence is zero.

(In General Formula (1), Ring A and Ring B each independently represent an optionally substituted aromatic ring, and R ^{1 to} R ³ each independently represents a hydrogen atom or a substituent. Represents an aromatic ring group which may have or a monovalent non-aromatic ring substituent having 20 or less carbon atoms, and R ⁴ and R ⁵ each independently represents an aromatic ring group which may have a substituent or Represents a monovalent non-aromatic ring substituent having 20 or less carbon atoms, and X represents a direct bond or a group 15 to 16 element of the periodic table, and when X is a group 15 element of the periodic table, X further represents carbon. (It may have a monovalent substituent of several 20 or less.)   The imine metal chelate complex compound according to claim 1, wherein the ring A and the ring B are each independently an aromatic hydrocarbon ring which may have a substituent. The imine metal chelate complex compound according to claim 1 or 2, wherein at least one of R ⁴ and R ⁵ is a benzyl group which may have a substituent.   A dye for forming a recording layer of an optical recording medium, comprising the imine metal chelate complex compound according to any one of claims 1 to 3.   It has at least a substrate and a recording layer formed on the substrate, and the recording layer is formed using the recording layer forming dye of the optical recording medium according to claim 4. An optical recording medium.   6. A recording method for an optical recording medium, wherein the optical recording medium according to claim 5 is recorded using a laser beam having a wavelength of 350 to 530 nm. An imine compound anion represented by the following general formula (1).

(In General Formula (1), Ring A and Ring B each independently represent an optionally substituted aromatic ring, and R ^{1 to} R ³ each independently represents a hydrogen atom or a substituent. Represents an aromatic ring group which may have or a monovalent non-aromatic ring substituent having 20 or less carbon atoms, and R ⁴ and R ⁵ each independently represents an aromatic ring group which may have a substituent or Represents a monovalent non-aromatic ring substituent having 20 or less carbon atoms, and X represents a direct bond or a group 15 to 16 element of the periodic table, and when X is a group 15 element of the periodic table, X further represents carbon. (It may have a monovalent substituent of several 20 or less.)