JPH02134366A - Infrared absorption compound and optical recording medium using the same compound - Google Patents

Abstract

NEW MATERIAL:A compound shown by formula I [R1 to R8 are H, halogen, OH, 1-8C (substituted) alkyl and alkoxy, (substituted) alkenyl and aralkyl or (substituted) alkynyl; at least one of Y1 to Y6 forms N-containing (substituted) heterocyclic ring; X<-> is anion] or formula II. USE:An optical recording medium having a thin film of organic dye, large absorption in an infrared part, being simply synthesized, having extremely increased durability and light stability resistance in repeated reproduction in optical disc or optical card. PREPARATION:A compound shown hy formula III (A is group shown by formula IV) is reacted with powdery tin in an aqueous solution of hydrogen chloride to form a diamine shown by formula V, which is then reacted with a compound shown by formula VI to give a compound shown by formula VII. This compound is reacted with H2 in the presence of a hydrogenating catalyst of Pd/C to form a compound shown by formula VIII, which is finally treated with silver perchlorate to give a compound shown by formula I or formula II where R1 to R8 are H.

Description

Detailed Description of the Invention [Field of Industrial Application] The present invention relates to an infrared absorbing compound and an optical recording medium using the same. This invention relates to an external absorption compound and an optical recording medium using the same.

[Prior Art] Generally, optical disks and optical cards have optically detectable small (
For example, bits (about 1 gm) can be placed in the form of spirals or circular and straight tracks to store high density information. To write information on such optical discs and cards, a focused laser is scanned over the surface of the laser-sensitive layer, and only the surface irradiated with this laser beam forms a bit, which is shaped into a spiral or circular shape. Formed in the form of a straight track. The laser sensitive layer absorbs laser energy to form an optically detectable bit. For example, in a heat mode recording method, the laser sensitive layer absorbs thermal energy and can form small recesses (bits) at that location by evaporation or melting. In another heat mode recording method, absorption of irradiated laser energy can form bits with optically detectable density differences at that location.

Here, by using an organic dye thin film as the recording Q layer having high reflectance, it is possible to set the optical contrast of the recording pits to be high. For example, as an organic dye thin film,
By using polymethine-based dyes, azulene-based dyes, cyanine-based dyes, biryllium-based dyes, etc. that have high light absorption against laser light, a light-absorbing and reflective film exhibiting metallic luster (reflectance lO ~ 50%) can be obtained, making it possible to record laser beams. This makes the optical recording medium capable of reflective reading. In particular, use of a semiconductor laser with an oscillation wavelength of 600 to 900 nm as a laser light source has the advantage that the device can be made smaller and lower in cost. However, organic dye thin films generally have a problem in that their recording/reproducing characteristics and storage stability deteriorate because of their tendency to change in substance when exposed to heat and light.

[Problems to be Solved by the Invention] The present invention has been made in view of the prior art as described above, and its purpose is to provide a material that has large absorption in the infrared region and is easy to synthesize. The object of the present invention is to provide possible new infrared absorbing compounds.

Another object of the present invention is to provide an optical recording medium in which the novel infrared absorbing compound according to the present invention is used in an optical recording medium that has significantly increased durability and light resistance during repeated reproduction.

[Means for Solving the Problems] and [Action] That is, the present invention solves the following problems by formula (I) or (II).
an infrared absorbing compound represented by, and the formula (I)
and/or an organic dye vj containing an infrared absorbing compound represented by the general formula (n);

(II) In general formula (I) and - formula (II).

R, to R6 are hydrogen atoms, halogen atoms, hydroxyl groups, substituted or unsubstituted alkyl groups or alkoxy groups having 1 to 8 carbon atoms, substituted or unsubstituted alkenyl groups, substituted or unsubstituted aralkyl groups, or substituted or Indicates an unsubstituted alkynyl group. The substituents of R+"Ra may be the same or different. Yl to Y6 form a substituted or unsubstituted heterocycle containing at least one nitrogen atom. x8 represents an anion.

R1 to R8 represent halogen atoms such as fluorine, chlorine, bromine, and iodine. As an alkyl group,
For example, methyl group, ethyl group, n-propyl group, 1s
o-propyl group, n-butyl group.

5ec-butyl group, 1so-butyl group, t-butyl group, n-amyl group, t-amyl group, n-hexyl 1, n-
Indicates octyl group, t-octyl group, etc., and other alkyl groups, such as substituted alkyl groups, such as 2-
Hydroxyethyl group, 3-hydroxypropyl group, 4-
Hydroxybutyl group, 2-acetoxyethyl group, carboxymethyl group, 2-carboxyethyl group, 3-carboxyfurovir group, methoxyethyl group, ethoxyethyl group,
Examples of the alkoxy group such as methoxypropyl group include methoxy group and ethoxy group.

Examples of alkenyl groups such as propoxy and butoxy groups include vinyl, propenyl, and butenyl groups.

Aralkyl groups such as pentenyl group, hexenyl group, heptenyl group, and octenyl group include, for example, benzyl group, p-chlorobenzyl group, p-methylbenzyl group, 2-
Phenylmethyl group, 2-phenylpropyl group, 2-phenylpropyl group.

Examples of alkynyl groups such as α-naphthylmethyl group and β-naphthylethyl group include propargyl group, butynyl group, pentynyl group, and hexynyl group.

xo is chloride ion, bromide ion, iodide ion, perchlorate ion, nitrate ion, benzenesulfonate ion, P-)-luenesulfonate ion, methyl sulfate ion, ethyl sulfate ion, propyl Sulfate ion, tetrafluoroborate ion, tetraphenylborate ion, hexafluorophosphate ion, benzenesulfinate ion, acetate ion, trifluoroacetate ion, propionacetate ion, benzoate ion , oxalate ion, succinate ion, malonate ion, oleate ion, stearate ion, citrate ion, -hydrogen diphosphate ion, dihydrogen-phosphate ion.

Pentachlorostannate ion, chlorosulfonate ion, fluorosulfonate ion, trifluoromethanesulfonate ion, hexafluoroarsenate ion, hexafluoroantimonate ion, molybdenum fusion salt ion, tankstate ion , titanate ion, zirconate ion, and other anions.

At least one of Y and ~Y6 has a nitrogen atom,
Six atoms Y and ~Y6 form a heterocycle. For example, etc. These heterocycles may be substituted with a lower alkyl group, a lower alkoxy group, a halogen group, a hydroxyl group, or the like.

The method for producing an infrared absorbing compound of the present invention is described in US Patent No. 1251881, US Patent No. 3575871, US Patent No. 3484467, and JP-A-516
The method described in No. 9991 etc. can be used. For example, it can be manufactured by the following process.
A-NO.

)12N-A-Ni! 2+ 41 +No2[NO2O
2 warts A-N-÷N02] 2--→[++, N (C tears)
-N -A -N-f(tNl+ 2) 2 The amino compound obtained by the above-mentioned fullman and quantitative reactions is alkylated by selective δ conversion, and vL conversion is performed by alkenylation, aralkylation, alkynylation, etc. Afterwards, the final product can be obtained by an oxidation reaction.

If R+ to R8 is asymmetric, this alkylation etc. needs to be carried out in multiple stages, and from the viewpoint of cost it is preferable that R1 to R8 are the same.

Next, one general formula (I) and general formula (II) according to the present invention
Here are some specific examples of infrared absorbing compounds represented by: mQ
(Otameni x, (y+y*y:+y4ysy6
).

(R+R2) (R:+R4) (RsRa) (R7Ra)
It is written as.

Example, t 4f, general formula (I) te, X0 is ClO2゜,
If Y, Y2Y3, Cf, , (CCCCNC),
(Written as C, H, C21(5)4.

Mata, general formula (IT), xo is AgF2, YIY
2Y: If R6 from 1Y4R5 is a propyl group, A
sF5. (CCNCNC), (Cll:+0 (:I
I:+0) *(C=C31+)2.

Compound no.

(I)-1 (I)-2 (I)-3 (I)-4 ClO2, (ccccsc), (n-C3117n-
C31L7)4Cρ04. (+IC:CCNC), (
t-C4H* t-C4HJaSbFa, (CCNC
NC), (Czlls CaB6)4SbF,,
(CCNCNC), (/C1120H20CH, CI
l□CHJC)I:+)4(I)-6 (I)-7 (I)-8 (I)-9 (I)-1゜(I)-11 (I)-12 ClO2, (CCN( :NC), (CIl□CH=
CH2CH2(:1l=cH,)4Br, (CCC
(:NC:), (iso-C3)1t 1so-C3
11t)4AsFe+ (CNCCN(:), (n-C
4H9n-C4HJ3(C419GHzCtl=(:H
□)BF4. (CCC(:NG), (n-(:81
(,7n-CJ(+7)(0(:H:+0Ctl+)
zCρ0. , (CNCCNC,), (C112
CEC1l C1 et al Cmi C11) 4AsF6. (CNCN(:), (n-C31(7n-C*117)
+(C,1l(7Cj(4C=CH2)CI(,,be=
γSO2, (CCCCNC), (CI(, -C611
, -ClC1+2-C, 1L-Cl),.

(I)-14Gβ0-, (CCNCNC), (CJ
a C2H3) - Compound No.

(II) -1Cl204', (CGCGNG),
(n-CJt n-C3H7)n(II)-2CP0
4. (CCCCNC), (t-C4H,t, -C4
H9)4(II)-3 CH)-4 (II)-5 (II)-6 (II)-7 (II)-8 (rl)-9 (II)-10 Cj)0. , (CCN(:NG).

1. (CNNCC).

Br, (CNNCNN).

CI! 0. , (CCNCNC).

AsFa, (CNCCNC).

CI! 04. (CCCCNC).

SbF, (CCNCNC).

BF4. (CNIIC:NN).

(II) -II CI! 0. , CCCCCNC)
.

(II) -128F4. ((:NCCNC).

(II) I:l AsF5. (CCNC
NC).

CH3CH3 (Tl:H2C=C1, CH, C=CH,).

(CsHl IC5l111) 4 (Oil:JS O(:2H,).

(C)120c21ts C1l□0C211s)4C
CH, C=C31+, (:Il, C=C31+,)
4(C11□C6H5(:LC6115) (C2Hs
C2118) 5(Clt20CH20CII:+
CI□Ofl:H20CH,).

(C611,3C6H,3)3(C,Hl, C,H,
0CR) C1h C1+3 ((:H2ClIC83CIl, CH(Jl,).

(iso-C, H, 1so-C, 117) BaC2H8C
2HS) (CH211; II□0CII, C11,C
H20C)I□)4 The infrared absorbing compounds made of the aminium salt compounds or diimmonium salt compounds exemplified above have a maximum absorption wavelength of 900 nm or more, and have a large absorption coefficient of about 10 to 10 degrees. Has a peak.

In addition to being used as materials for optical recording media, such infrared absorbing compounds are used in heat insulating films, sunglasses, and the like.

Further, the infrared absorbing compound of the present invention can be used by being included in an organic dye thin film of an optical recording medium.

As the near-infrared absorbing dye that forms the organic dye thin film used together with these infrared absorbing compounds as an optical recording medium, commonly known dyes are used, such as cyanine dyes, merocyanine dyes, Croconium pigment, squalium pigment.

These include azulenium pigments, polymethine pigments, naphthoquinone pigments, pyrylium pigments, and phthalocyanine pigments.

Addition of an infrared absorbing compound consisting of the aminium salt compound of the general formula (I) or the diimmonium salt compound of the general formula (n) to these dyes may be carried out in an amount of 1 to 1 to 100% of the recording layer based on the total solid content. A suitable amount is 60% by weight, preferably 5-40% by weight, more preferably 10-30% by weight.

In addition to these compounds, a binder may be contained in the recording layer consisting of an organic dye thin film. Examples of the binder include nitrocellulose, cellulose phosphate, cellulose sulfate, cellulose acetate, cellulose propionate,
Cellulose acetate, cellulose myristate, cellulose parimitate, cellulose acetate/propionate, acetic acid/cellulose
Cellulose esters such as butycellulose, cellulose ethers such as methylcellulose, ethylcellulose, propylcellulose, and methylcellulose, vinyl resins such as polystyrene, polyvinyl chloride, polyvinyl acetate, polyvinyl butyral, polyvinyl acetal, polyvinyl alcohol, and polyvinylpyrrolidone, Copolymer resins such as styrene-butadiene copolymer, styrene-acrylonitrile copolymer, styrene-butadiene-acrylonitrile copolymer, vinyl chloride-vinyl acetate copolymer, polymethyl methacrylate, polymethyl acrylate, polybutyl acrylate, polyacrylic acid, polymethacrylate acids, acrylic resins such as polyacrylamide and polyacrylonitrile, polyesters such as polyethylene terephthalate, poly(4,4'-
Isopropylidene diphenylene-co-1,4-cyclohexylene dimethylene carbonate), poly(ethylenedioxy-3,3'-phenylene thiocarbonate), poly(4,4'-isopropylidene diphenylene carbonate) terephthalate), poly(4,4'-isopropylidene diphenylene carbonate), poly(4,4
'-5ee-butylidene diphenylene carbonate)
, polyarylate resins such as poly(4,4'-isopropylidene diphenylene carbonate bronchoxyethylene), or polyamides, polyimides, epoxy resins, 5 phenolic resins, polyethylene,
Polyolefins such as polypropylene and chlorinated polyethylene can be used.

Further, the recording layer may contain surfactants, antistatic agents, stabilizers, dispersible flame retardants, lubricants, plasticizers, and the like.

Further, an undercoat layer may be provided between the recording layer and the substrate, and a protective layer may be provided on L of the recording layer.

As an undercoat layer, the protective layer should be protected against scratches and
It is used for protection from dust, dirt, etc. and for environmental stability of the recording layer.

The materials used for these are mainly inorganic compounds, metals, or organic polymer compounds. Examples of inorganic compounds include 5iOz, MgF2. Sin, Ti1t
.

Examples of metals include Zn, such as ZnO, TiN, and SiN.

Cu, Ni, Ai', Cr, Ge, Se,
Cd, etc., and organic polymer compounds such as ionomer resins, polyamide resins, vinyl resins, natural polymers, epoxy resins, and silane coupling agents can be used.

As the substrate, plastics such as polyester, polycarbonate, acrylic resin, polyolefin resin, phenol resin, epoxy resin, polyamide, polyimide, glass, or metals can be used.

The organic solvent used during coating varies depending on whether the IE is dispersed or dissolved, and generally includes alcohols such as methanol, ethanol, isopropanol, diacetone alcohol, acetone, methyl ethyl ketone, Ketones such as cyclohexanone, N, N
Amides such as dimethylformamide and N,N-dimethylacetamide, sulfoxides such as dimethyl sulfoxide, ethers such as tetrahydrofuran, dioxane, and ethylene glycol monomethyl ether, esters such as methyl acetate, ethyl acetate, butyl acetate,
Aliphatic halogenated hydrocarbons such as chloroform, methylene chloride, dichloroethylene, carbon tetrachloride, trichloroethylene, and benzene.

Aromatics such as toluene, xylene, monochlorobenzene, dichlorobenzene, and aliphatic hydrocarbons such as n-hexane and cyclohexanoligroin can be used.

Coating methods include dip coating method, spray coating method, spinner coating method, bead coach ink method,
This can be carried out using a coating method such as a wire bar coating method, a plate coating method, a roller coating method, or a curtain coating method.

The thickness of the recording layer formed using such a solvent is 50
Approximately 100 gm, preferably 200 to 11 gm.

[Example] Next, examples of the present invention will be described.

Synthesis Example 1 After dissolving 15 parts of 2-amino-5-nitropyridine in 120 parts of 2N hydrochloric acid aqueous solution, 14 parts of powdered tin was added and stirred for 2 hours. After 0 reaction, 600 parts After dipping into ice water and filtering, the furnace liquid was diluted with 2N NaO.
t (neutralized with water to obtain the desired product, 2,5-diaminopyridine.

0.1 mol of 2.5-diaminopyridine, 0.43 mol of p-nitrochlorobenzene, 0.23 mol of anhydrous potassium carbonate, and 2 parts (by weight) of copper powder were refluxed under stirring in 130 parts of dimethylformamide for 4 days. Ta. After the reaction, the reaction mixture was filtered, and the furnace was thoroughly washed with dimethylformamide, water, and acetone, and then dried.

Reddish brown tetrakis(p-nitrophenyl)-2゜5-
26 parts of diaminopyridine were obtained.

Add 24 parts of the compound obtained above into an autoclave together with 2 parts of 95 parts of dimethylformamide palladium-carbon hydrogenation catalyst, apply hydrogen gas at 5.0 kg/am'', and stir at 90°C to 100°C until hydrogen absorption stops. did.

After the reaction, the reaction solution was filtered, washed with dimethylformamide, and then poured into 330 parts of ice water. After stirring for a while, the precipitate was filtered out. Recrystallize with ethanol dimethylformamide mixed solvent to obtain tetrakis (
P-aminophenyl)-2,5-diaminopyridine 10
I got the department. Purity was measured by high performance liquid chromatography and found to be 98.7%.

Synthesis of Compound No. I-2 3 parts of the above amino compound were mixed with 18 parts of dimethylformamide, 0.7 parts of anhydrous sodium bicarbonate, and 3 parts of t-butylfuromite.
．． The mixture was heated and stirred at 100°C to 130°C with 9 parts. After reacting for 36 hours, the reaction solution was poured into 100 parts of ice water and extracted with ethyl acetate. After drying, it was purified using a silica gel column. The amount obtained was 3.5 copies. Disappearance of absorption due to NH stretching vibration of the amino group was confirmed by infrared absorption analysis.

Disperse 1 part of this compound in 20 parts of acetone.

While stirring, equimolar amount of silver perchlorate was added. After reacting at room temperature for 1 hour, the precipitated silver was separated in a furnace, diluted with isopropyl ether, which is a furnace liquid, and allowed to stand, and the precipitated crystals were taken out in the furnace. The amount obtained was 0.8 parts.

Compound No. I-2 synthesized in this manner was a compound having a large absorption region in the infrared region with a maximum absorption wavelength of 1110 nm and an extinction coefficient of 938,000.

Synthesis of Compound No. 11-2 Tetrakis (p) used in the synthesis of Compound No. 1-2
1 part of -dibutylaminophenyl)-2,5-diaminopyridine was dispersed in 20 parts of acetone, and 2 times the mole of silver perchlorate was added with stirring. After reacting at room temperature for 1 hour, the precipitated silver was separated in a furnace, and the liquid was diluted with isopropyl ether. 0.60 parts of precipitated crystals were collected.

The example explained above is the case where the anion is perchloric acid, but when using other anions, the desired compound can be easily obtained by using the corresponding silver salt. For example, Ag5bFr.

AgBF4. AgSO4, AgN0. , Ag5O3
lji such as C, H<C11ff, Ag5O3CF3
Salt can be used. In addition, it can also be obtained by electrolytic oxidation.

Synthesis Example 2 The reaction was carried out in the same manner as in Synthesis Example 1 except that 2-amino-5-nitropyridine used in Synthesis Example 1 was changed to 2-amino-5-nitropyrimidine, and tetrakis(p-aminophenyl)- 23 parts of 2,5-diaminopyrimidine were obtained.

Synthesis of Compound ThNo, I-4 4 parts of the amino compound obtained in Synthesis Example 2 was dissolved in dimethylformamide 2
4 parts, 1.0 parts of anhydrous sodium bicarbonate, 10 parts with 4.0 parts of 2-ethoxyethyl bromide at 10 °C to 130 °C.
The mixture was heated and stirred at °C. After reacting for 36 hours, the reaction solution was poured into 150 parts of ice water and extracted with ethyl acetate. After drying, it was purified using a silica gel column. The amount obtained was 3.8 copies.

Disappearance of absorption due to Nil stretching vibration of the amino group was confirmed by infrared absorption analysis.

One part of this compound was dispersed in 20 parts of acetone, and the same mole of silver hexafluoroantimonate was added while stirring. At room temperature 1
After reacting for a certain period of time, the precipitated silver was filtered out, the furnace liquid was diluted with isopropyl ether and allowed to stand, and the precipitated crystals were collected from the furnace. The amount obtained was 0.7 parts. Also, the maximum absorption wavelength is 1
It was 120n■.

Synthesis of Compound No. H-13 Tetrakis(p-jethoxymethylaminophenyl)-2,5- obtained during the synthesis of Compound No. I-4
0.5 part of diaminopyridine was dispersed in 20 parts of acetone, and while stirring, 2 times the mole of silver perchlorate was added at room temperature, and the mixture was stirred for 1 hour. After the reaction, the precipitated silver salt was filtered out and thoroughly washed with acetone. After distilling off acetone from the furnace solution, it was washed with wood and dried under reduced pressure. The yield was 0.40 parts, 11
It was an infrared absorbing compound with a maximum peak at 80 mm.

Next, examples will be described in which infrared absorbing compounds represented by formulas (I) and (II) are used as optical recording materials.

Example 1 A 50 μm pregroove was provided on a polymethyl methacrylate (hereinafter referred to as PMMA) substrate with a diameter of 1301φ and a thickness of 1.21 mm, and an organic dye of polymethine dye (IR-820, manufactured by Nippon Kayaku Co., Ltd.) was attached to -L of the pregroove. and the infrared absorbing compound No.
800 recording layers were formed by spin coating a solution in which I-2 was dissolved in 1,2-dichloroethane at a weight ratio of 90:10. O
, :l+*m spacers were sandwiched therebetween, and the optical recording medium was bonded to another PMMA substrate using an ultraviolet curable resin adhesive to obtain an optical recording medium having an air sandwich structure.

This was rotated at 1800 rpm, and a recording power of 6 m'# was recorded from the substrate side using a semiconductor laser with a wavelength of 830 nm.
, writing was performed at a recording frequency of 3 Ml (z).

Next, reproduction was performed with a read power of 0.8 st#, and the C/N ratio was measured by spectrum analysis. Subsequently, the C/N ratio was measured after 100,000 readings and reproductions.

Furthermore, l KW/m was added to the optical recording medium prepared under the above conditions.
A light resistance stability test was conducted by irradiating the sample with xenon lamp light of No. 2 for 100 hours, and the reflectance and C/N ratio were measured. The results are shown in Table-1.

Table 1 A recording layer was formed using a liquid containing (butyl azulenyl)-2,4-pentadienol perchlorate and the infrared absorbing compound No. I-1 in a weight ratio of 90:10.

The same test as in Example 1 was conducted using the optical recording medium thus obtained. The results are shown in Table-2.

Table 2 27,5565523,553 Examples 3 to 8 Similarly to Example 1, optical recording media having the compositions shown in Table 3 were prepared, and the same tests as in Example 1 were conducted. Table 4 shows the results.
Shown below.

Example 2 l-guaiazulenyl-5-(6'-t-Table 3 1,5-diquaiazulenyl-2,4- Pentadienol perchlorate l-6 90:10 (p-diethylaminophenyl)-(p-butylphenyl)methylene-1-cyclopent-2-2-3-(p-dimethylaminophenyl)=(p-ethoxyphenyl)carbonylum・Perchlorate 85:15 1,S-bis(diethylaminophenyl)-i,s-diphenyl-2,4-pentagenol ・Perchlorate II-II 80:20 1.1'-dimethoxyethyl-3,3,3' , 3'-tetramethyl = 2,2'-indotricarbocyanine perchlorate 85:15 NK-1414 (Japanese photosensitive dye type) ll-2075:
251-guaiazulenyl-5,5 bis(diethylaminophenyl)-2,4-pentagenol hexafluoroantimonate I-2,[-2 70: Is: 15 Comparative Examples 1 to 3 Examples 1.2 and 5 Optical recording media were prepared and evaluated in the same manner as in Examples 1.2 and 5, except that the infrared absorbing compound used was omitted. The results are shown in Table 4.

Table-4 27,5 25,4 25,9 36,0 32,7 24,9 22,0 20,1 20,5 30,5 21,8 20,2 19,7 27,2 26,0 14, 132 15,235 14,030 Examples 9 to 12 OLED size 0.4 m thick polycarbonate (hereinafter abbreviated as rPcJ)! ! A pregroove was formed on the Li board by a hot press method, and a liquid mixture of an organic color chart shown in Table 5 below and an infrared absorbing compound mixed in diacetone alcohol was applied thereon by a barcode method. After drying, a recording layer of 850 people was obtained. Furthermore, an optical recording medium having a close contact structure was prepared by bonding an O-red size PC board with a thickness of 0:1 mm on top of the ethylene-acetate dry film by a hot roll method.

The optical recording medium of each example produced in this way was mounted on a stage driven in the X-Y direction, and an organic thin film recording layer was layered from the PC substrate side with a thickness of 0.4 cm using a semiconductor laser with an oscillation wavelength of 830 cm. Then, a recording pulse of 8011. is applied at a recording power of 4.0 mW. sec, write information in the Y-axis direction, reproduce it with a read power of 0.41, and calculate the contrast ratio of A-B' (: A → signal strength of unrecorded area, B →
The signal strength of the Q part) was measured.

Furthermore, the same optical recording medium produced under the above conditions was used in Example 1.
A light resistance stability test was conducted under the same conditions as .

The reflectance and contrast ratio were then measured. The results are shown in Table-6.

Table 5 IR-820 (manufactured by Nippon Kayaku) 10 (p-diethylaminophenyl)-(p-ethoxyphenyl)methylene-1-cyclopent-2-2-3-(p-dimethylaminophenyl)-(p- ethoxyphenyl) carbonium perchlorate 85:15 90:10! 1 1,5-bis(dipropylaminophenyl)-1,5-diphenyl-2,4-pentadienol perchlorate 75:25 12 II+-820 (Nippon Kayaku) 70::10 Comparative Example 5.6 Optical recording media were prepared and evaluated in the same manner as in Examples 9 and 11 except that the infrared absorbing compound was omitted. The results are shown in Table-6.

Table 6 Initial After light resistance test, when used as an optical recording medium, it became possible to obtain an optical recording medium with significantly increased durability and stability during repeated reproduction.

Example 9 14.8 0.74 12.8 0
．． 70 Example 10 15.4 0.73 13.4
0.69 Example 11 15.2 0.70 1
3.2 0.67 Example 12 15.0 0.73
12.9 0.68 Comparative Example 5 14.9 0
．． 69 11.7 0.64 Comparative Example 6 15. +
0.70 10.2 0.60 [Effects of the Invention] As explained above, the infrared absorbing compounds represented by the general formula (I) and -numerical formula (II) of the present invention have large absorption in the infrared region. , and can be easily synthesized.

Claims (2)

[Claims] (1) An infrared absorbing compound represented by the following general formula (I) or general formula (II). ▲There are mathematical formulas, chemical formulas, tables, etc.▼ ▲There are mathematical formulas, chemical formulas, tables, etc.▼ (In the formula, R_1 to R_8 are hydrogen atoms, halogen atoms, hydroxyl groups, substituted or unsubstituted alkyl groups having 1 to 8 carbon atoms or represents an alkoxy group, a substituted or unsubstituted alkenyl group, a substituted or unsubstituted aralkyl group, or a substituted or unsubstituted arginyl group.R_1 to R_
The substituents (8) may be the same or different. Y_1 to Y_6 form a substituted or unsubstituted heterocycle containing at least one nitrogen atom. X^e represents an anion. ) (2) An optical recording medium comprising an organic dye thin film containing an infrared absorbing compound represented by the general formula (I) and/or the general formula (11) according to claim 1.