JP2961549B2 - Cyanine dye and optical recording medium containing the same - Google Patents

Description

Description: TECHNICAL FIELD The present invention relates to a pentamethine or heptamethine cyanine dye having 3H-pyrrolopyridine as a nucleus and a light absorbing composition using the compound. More specifically, the present invention relates to a cyanine dye that absorbs near-infrared light from red light and an optical recording medium using the compound.

[Background of the Invention]

Various uses are considered for the dye that selectively absorbs red light or near-infrared light, and it has been strongly demanded than before.
Until now, I couldn't get anything suitable

Examples of applications of these conventional dyes are as follows.Near infrared filters include, for example, safe light filters for infrared light-sensitive materials, infrared cut filters harmful to human eye tissues, and filters for blocking heat rays. No. Further, it can be used for red light or near infrared light absorbing ink such as ink for ink jet printers and ink for bar codes. Furthermore, it can also be used for a laser recording layer, a liquid crystal element for thermal writing, an electrophotographic photosensitive member, a toner for electrophotography, and the like.

However, conventional general organic dye-based near-infrared absorbers have poor storage stability, poor solubility in water or organic solvents, many have small molecular extinction coefficients, and there are few practically satisfactory ones. .

On the other hand, in recent years, optical recording using a laser has been particularly developed in order to enable high-density information storage and reproduction. An example of the optical recording is an optical disk. The optical disc performs high-density information recording by irradiating a thin recording layer provided on a circular substrate with a laser beam focused to about 1 μm.

The recording is performed by generating thermal deformation such as decomposition, evaporation, and dissolution in the recording layer at that location by absorbing the irradiated laser light energy. Reproduction of the recorded information is performed by reading the difference in reflectance between the portion where the deformation has occurred and the portion where the deformation has not occurred due to the laser beam. Therefore, as an optical recording medium, it is necessary to efficiently absorb the energy of laser light, so that it has a large absorption for the laser light of a specific wavelength used for optical recording. It is necessary that the reflectance to the laser light of a specific wavelength to be used is high.

Conventionally, various types of optical recording media of this type have been known. For example, JP-A-55-97033 discloses a phthalocyanine dye, JP-A-58-83344 describes a phenalene dye, JP-A-58-224798 describes a naphthoquinone dye,
JP-A-67068 and JP-A-63-33477 disclose those in which a cyanine dye is provided in each recording layer.

However, phthalocyanine dyes have low sensitivity,
Further, it has a problem that it has a high decomposition point and is difficult to vapor-deposit. Further, it has a problem that its solubility in an organic solvent is extremely low and it cannot be used for coating by application.

In addition, phenalene dyes and naphthoquinone dyes have an advantage that they are easy to vapor-deposit, but have a low reflectance. If the reflectance is low, the difference in reflectance between the portion recorded by the laser beam and the unrecorded portion is small, the contrast becomes low, and it becomes difficult to reproduce the recorded information.
Further, although the cyanine dye has a large molecular extinction coefficient and many advantages, it has a drawback that storage stability is poor and solubility in water or an organic solvent is poor.

[Object of the invention]

Accordingly, an object of the present invention is to provide a dye having high solubility in water or an organic solvent, capable of being coated by coating, and having a large molecular extinction coefficient and excellent storage stability, and an optical recording medium containing the dye. It is in.

[Configuration of the invention]

The above object of the present invention has been attained by a pentamethine or heptamethine cyanine dye having 3H-pyrrolopyridine as a mother nucleus, and an optical recording medium containing the dye.

The dye compound of the present invention is represented by the following general formulas (I), (II) and (III).

In the formula, R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ each represent an alkyl group, and the alkyl group represented by R ₁ and R ₄ may be substituted. Z ₁ and Z ₂ each represent a group of nonmetallic atoms necessary to form a pyridine ring.

Y ₁ and Y ₂ represents a non-metallic atomic group necessary for forming a pyridine ring, and in the Y ₁ ring And within the ring of Y ₂ Shall be included.

 L represents a methine group; Represents an anion. m is 3
Or an integer of 4, and n represents an integer of 1 or 2. However
And if m is 3, then R₁And R_FourIs preferably a substituted alkyl group
N is 1 when the dye forms an inner salt.

The compounds represented by the general formulas (I), (II) and (III) may contain an acid group. Examples of the acid group include a sulfonic acid group, a carboxylic acid group, and a phosphonic acid group. Each acid group includes its salt. Examples of the salt include alkali metal salts such as sodium and potassium, and organic ammonium salts such as ammonium, triethylammonium, and pyridinium.

Further, the compounds represented by the general formulas (I), (II) and (III) may contain a CH ₂ CH ₂ OR group. R represents a hydrogen atom or an alkyl group.

The alkyl group represented by R is preferably a lower alkyl group having 4 or less carbon atoms.

As the substituent containing a -CH ₂ CH ₂ OR group, such as hydroxyethyl group, hydroxyethoxy ethyl group, methoxyethoxyethyl group, hydroxymethyl diethylcarbamoylmethyl group, hydroxyethoxy diethylcarbamoylmethyl group,
N, N-dihydroxyethylcarbamoylmethyl group, hydroxyethylsulfamoylethyl group, methoxyethoxyethoxycarbonylmethyl group and the like can be mentioned.

Z ₁ , Z ₂ , Y ₁ and Y ₂ may have various substituents in addition to the above-mentioned acid group and —CH ₂ CH ₂ OR group, and other substituents include a hydroxyl group and a cyano group. Groups, alkyl groups (eg, methyl, ethyl groups, etc.), alkoxy groups (eg, methoxy, ethoxy groups, etc.), aryl groups (eg, phenyl groups), halogen atoms (eg, fluorine, chlorine, bromine atoms, etc.) and the like. Can be

The alkyl group represented by R ₁ , R ₂ , R ₃ , R ₄ , R ₅ and R ₆ is preferably a lower alkyl group having 1 to 8 carbon atoms (for example, methyl, ethyl, propyl, i-propyl, butyl And the like, and may have a substituent other than the aforementioned acid substituent or —CH ₂ CH ₂ OR group.

The methine group represented by L may have a substituent, and the substituent is a substituted or unsubstituted lower alkyl group having 1 to 5 carbon atoms (for example, methyl, ethyl, 3-hydroxypropyl, 2-sulfoethyl). Group), a halogen atom (for example,
Examples thereof include a fluorine, chlorine, and bromine atom), an aryl group (for example, a phenyl group), and an alkoxy group (for example, a methoxy and ethoxy group). Further, a 6-membered ring containing three methine groups (eg, 4,4,4-
A dimethylcyclohexane ring).

 X The anion represented by is not particularly limited,
Physically, a halogen ion, p-toluenesulfonic acid
ON, ethyl sulfate ion and the like. According to the present invention
The cyanine dyes represented by the general formulas (I) to (III)
= 3 pentamethine cyanine dye and m = 4 heptamethine
Tincyanine dye, preferably hepta with m = 4
It is a methine cyanine dye.

Dyes represented by the general formulas (I), (II) and (III) used in the present invention (hereinafter referred to as dyes of the present invention)
Are shown below, but the present invention is not limited to these.

The dyes of the present invention are available from Journal of the Chemical
The compound can be synthesized with reference to J. Chem. Soc., Page 189 (1933), U.S. Pat. No. 2,895,955, JP-A-62-123454, and the like.

Examples of the mother nucleus of the dye of the present invention include the following compounds.

Compound (A) can be synthesized by the method described in J. Chem. Soc., 3202 (1959) and the method described in British Patent 870,753.

Compound (B) can be synthesized by the method described in J. Chem. Soc., 584 (1961).

Compound (C) can be synthesized by the method described in British Patent No. 841,588.

Using these mother nuclei, quaternization, sulfonation, and the like can be performed as necessary. Or J. Chem. Soc., 3202 (19
59) and J. Chem. Soc., 584 (1961), by synthesizing N-alkyl-N-pyridylhydrazine, subjecting it to a cyclization reaction via a hydrazone and, if necessary, acid treatment. 1-alkyl-substituted-3H-pyrrolopyridine derivatives are obtained, which can also be used as starting materials.

The compound of the present invention can be easily obtained by reacting an appropriate methine chain supplier using these quaternized and, if necessary, sulfonated mother nucleus compounds.

Use of glutaconaldehyde dianyl hydrochloride as a methine chain donor gives a heptamethine dye, and use of propenedianyl hydrochloride gives a pentamethine dye.

The pentamethine or heptamethine cyanine dye of the present invention having 3H-pyrrolopyridine as a nucleus can be used for various applications as described above.

First, when used for near-infrared filters, one or more of the cyanine dyes of the present invention may be synthesized using polystyrene, AS resin, ABS resin, methacrylic resin, polyvinyl chloride, polycarbonate, fluorine resin, epoxy resin, etc. After mixing and heating with a resin and additives such as a plasticizer and a curing agent which may be added as necessary, the mixture is molded into a plate or film.

At this time, it is preferable to add one or more of the cyanine dyes of the present invention to the synthetic resin in a weight ratio of 0.0001 to 5%, preferably 0.01 to 1%.

Further, when used for a thermal writing liquid crystal element, one or more of the cyanine dyes of the present invention are added to the liquid crystal in an amount of 0.01 to 10% by weight, preferably 0.1 to 5% by weight, to prepare a liquid crystal composition. .

As a liquid crystal compound for preparing this liquid crystal composition, biphenyl, terphenyl, phenylcyclohexane, dichlorohexylcyclohexane, ester, pyrimidine, dioxane, cyclohexylmethyl ether, Schiff, azo, There are mixed systems of azoxy-based nematic liquid crystals having negative dielectric anisotropy and mixed systems of smectic liquid crystals having positive dielectric anisotropy.
Cholesteric liquid crystals to be added to nematic liquid crystals having negative dielectric anisotropy include cholesteryl bromide,
Cholesteryl acetate, cholesteryl propionate, cholesteryl hexyl ether or Schiff type,
Azo-based, azoxy-based, ester-based, biphenyl-based, and terphenyl-based liquid crystals have optically active 2-methylbutyl group, 3-methylbutyl group, or the like introduced at the terminal.

As a writing light source for a thermal writing liquid crystal element using the liquid crystal composition containing a cyanine dye of the present invention, it is convenient to use a semiconductor laser having an oscillation wavelength of 750 to 850 nm.

Further, the cyanine dye of the present invention can be used as an optical recording medium. When used for an optical disk memory, one or more of the cyanine dyes of the present invention are dissolved in a solvent, applied to a substrate, and dried. If necessary, a resin binder or the like may be added. Examples of the solvent used include dichloromethane, dichloroethane, acetone, methyl ethyl ketone, methanol, water and the like. As a coating method, it is applied to a thickness of 10 to 1000 nm, preferably 50 to 200 nm using a spray or a spinner. The material of the substrate on which the recording layer is formed is not particularly limited, and may be any of various resins, glass, ceramics, metals, etc., but is difficult to mold, handle, preserve, and prevent migration of the dye onto the substrate. From the viewpoint of the above, an acrylic resin or a polycarbonate resin plate is preferable.

In order to improve the stability and light resistance of the recording medium, a transition metal chelate compound (for example, acetylacetonate chelate, bisphenyldithiol, salicylaldehyde oxime, bisdithio-α-diketone, etc.) is used as a singlet oxygen quencher in the recording layer. ) May be contained. As the laser beam used for the optical recording medium, N ₂ , He-Cd, A
Examples thereof include r, He-Ne, ruby, semiconductor, and dye laser. A semiconductor laser is preferable from the viewpoint of light weight, easy handling, compactness, and the like.

〔Example〕

Next, the present invention will be described in more detail by way of examples, but embodiments of the present invention are not limited thereto.

Example 1 (Synthesis of Compound Example 31) Compound (B) synthesized according to the above-mentioned literature was quaternized with propane sultone according to a conventional method, and 5.0 g of the quaternized product was obtained.
Was dissolved in 40 ml of acetic acid with heating, 1.0 g of glutaconaldehyde dianyl hydrochloride, 9 ml of acetic anhydride and 13 ml of pyridine were added, and the mixture was heated with stirring at a bath temperature of 80 to 85 ° C. for 30 minutes.

After allowing to cool, isopropyl ether was added to perform decantation. Further, Methinol, acetone and isopropyl ether were added and the mixture was decanted and purified to obtain Compound (31). ▲ λ ^MeOH _max ▼ 739 nm Example 2 (Synthesis of Compound Example 32) Compound (A) synthesized according to the above-mentioned literature was quaternized with propane sultone according to a conventional method, and then reacted under the same reaction conditions as compound (31). After the reaction, purification was performed to obtain compound (32). ▲ λ ^MeOH _max ▼ 731 nm Example 3 (Synthesis of Compound Example 20) The above compound (A) was quaternized with propane sultone, and then sulfonated with concentrated sulfuric acid and fuming sulfuric acid. 2.6 g of the sulfonate was dissolved in 10 ml of N, N-dimethylformamide,
Glutaconaldehyde dianyl hydrochloride 1.0 g, pyridine 2 m
l, 2 ml of acetic anhydride was added, and the mixture was heated and stirred at a bath temperature of about 100 ° C for 20 minutes. Isopropyl ether was added to the reaction mixture, followed by decantation and purification to obtain a compound (20). ▲ λ
^MeOH _max ▼ 737 nm Example 4 (Synthesis of Compound Example 33) 2,3,3-Trimethyl-5-chloro-3H-pyrrolo [3,2-b] pyridine was synthesized according to the above-mentioned literature. This is quaternized with propane sultone according to a conventional method, and then quaternized.
0.41 g was dissolved in 3 ml of acetic acid, and 0.19 g of glutaconaldehyde dianyl hydrochloride, 0.7 ml of acetic anhydride, and 1 ml of pyridine were added, and the mixture was heated and stirred at a bath temperature of 90 to 105 ° C. for 1 hour.

After cooling, 40 ml of ethyl acetate was added to the reaction solution, and the mixture was stirred and filtered to obtain 0.36 g of compound (33) as a yellow-green solid. ▲
λ ^MeOH _max ▼ 747 nm Example 5 (Synthesis of Compound Example 34) 2,3,3-Trimethyl-5-methoxy-3H-pyrrolo [3,2-b] pyridine was synthesized according to the above-mentioned literature. This was quaternized in the same manner as in the synthesis of compound (33), and then condensed to obtain compound (34). ▲ λ ^MeOH _max ▼ 767 nm Example 6 (Synthesis of Compound Example 36) In the synthesis of Compound (31) of Synthesis Example 1, after purification by decantation, this was further combined with 100 ml of saturated saline and 2
After stirring for an hour, the mixture was filtered to obtain a yellow-green solid of Compound (36). ▲ λ ^MeOH _max ▼ 739 nm Example 7 (Synthesis of Compound Example 37) In the synthesis of Compound (34) of Synthesis Example 5, after purification by decantation, the compound (34) was treated with saturated saline in the same manner as in the above Compound (36). 37).

▲ λ ^MeOH _max ▼ 767 nm Example 8 1 g of the cyanine dye (36) obtained in Example 6 was dissolved in a small amount of 50 g of a mixture of fluorinated alcohol and methanol,
An optical recording medium was obtained by applying to an acrylic substrate with a spinner and drying. When this coating film was irradiated with a semiconductor laser beam having a center wavelength of 780 nm, pits with clear contours were formed.

The storage stability (60 ° C., 80% RH) of this coating film was good. When a low output 780 nm semiconductor laser was incident on this optical recording medium and reflected light was detected, the S / N
A waveform with a high ratio was obtained.

Example 9 The cyanine dyes (33), (37), (40) and (4) of the present invention
Each of the optical recording media was prepared according to Example 8 using 1).

In each optical recording medium, a pit with a sharp outline was formed by a semiconductor laser (780 nm), and its signal could be easily read by the semiconductor laser, and a waveform having a high S / N ratio was obtained.

Example 10 Using the cyanine dyes (50) and (54) of the present invention, optical recording media were respectively prepared according to Example 8.

When these coating films were irradiated with He-Ne laser light having a center wavelength of 633 nm, pits with clear contours were formed.

When the coating film was irradiated with a semiconductor laser beam having a center wavelength of 650 nm, pits with clear contours were formed.
The storage stability (60 ° C., 80% RH) of these coating films was good.

〔The invention's effect〕

A cyanine dye having 3H-pyrrolopyridine as a mother nucleus and exhibiting strong absorption in the near infrared region from red light was obtained. It has high solubility in water or organic solvents, can be coated by application, and has a large molecular extinction coefficient and excellent storability. It has high utility value as a material.

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Claims (3)

(57) [Claims] A pentamethine or heptamethine cyanine dye having 3H-pyrrolopyridine as a core. However, the pentamethine dye has a substituted alkyl group as a quaternizing group. 2. A heptamethine cyanine dye having 3H-pyrrolopyridine as a nucleus. 3. An optical recording medium comprising a pentamethine or heptamethine cyanine dye having 3H-pyrrolopyridine as a nucleus.