HK1138675A - Use of indolinium diazamethine cations for optical data recording - Google Patents

Description

Use of indolinium diazamethine cations for optical data recording

Technical Field

The present invention relates to the use of dye salts of indolium diazamethine type cations with azo metal complex anions based on pyridones in optical layers for optical data recording, preferably for optical data recording using lasers with a wavelength of up to 450 nm.

The invention further relates to a Write Once Read Many (WORM) type optical data recording medium capable of recording and reproducing information using blue laser radiation, which employs a dye salt of an indolium diazamethine type cation with a pyridone-based azo metal complex anion in the optical layer.

Background

Recently, organic dyes have attracted considerable attention in the field of diode-laser optical data storage. WORM-type optical data recording media, such as commercially recordable compact discs (CD-R) and recordable digital versatile discs (DVD-R), may contain dyes based on phthalocyanine, hemicyanine, cyanine and metallized azo structures in the recording layer. These dyes are suitable in their respective fields for laser wavelength standards. Other general requirements of dye media are strong absorption, high reflectivity, high recording sensitivity, enhanced light sensitivity, low thermal conductivity, and light and heat stability, storage durability, and non-toxicity. Good read stability is also an important criterion, which means a high number of cycles at a given laser intensity, and sufficient solubility of the dye in organic solvents typically used in spin-coating processes.

In the recording area of such an organic dye type optical data recording medium, the optical properties are changed not only by the change in optical characteristics and the decrease in layer thickness due to thermal decomposition of the dye but also by the deformation of the substrate.

The recording principle is the same for CD-R and DVD-R, with the difference in spot size and wavelength of the laser used. CD-R is writable at wavelengths of 770 to 830nm, while DVD-R is writable at wavelengths of 600 to 700nm by using more recent compact high-efficiency red diode lasers, achieving 6 to 8 times improvement in data storage density compared to conventional CDs.

However, in view of factors such as recent spread of electronic networks (e.g., the internet) and the emergence of high-definition television (HDTV) broadcasts, there is a need for inexpensive and convenient recording media capable of recording image information in even larger volumes. Although the DVD-R is currently sufficient as a high-capacity recording medium, demands for larger capacity and higher density have increased.

Optical disk (Optical discs are standards developed by Hitachi ltd, LGElectronics inc, Matsushita Electric Industrial co ltd, Pioneer Corporation, Royal Philips Electronics, samsung Electronics co ltd, Sharp Corporation, Sony Corporation, Thomson Multimedia) or HD-DVD discs (standards developed by Toshiba and NEC) will become the next milestone in optical data recording technology. With these new specifications, data storage can be increased up to 27 gigabytes per recording layer for a 12cm diameter disc. By using a 405nm wavelength blue diode laser (GaN or SHG laser diode), the pit size and track spacing can be further reduced, again allowing an order of magnitude increase in storage capacity.

The construction of these optical data recording media is known in the art. The optical recording medium preferably comprises a substrate having a guide groove for laser beam tracking, a recording layer containing an organic dye as a main component (this recording layer is hereinafter also referred to as an optical layer or a dye layer), a reflective layer and a protective layer. When recording/reading is performed through the substrate, a transparent substrate is used. As such a transparent substrate, for example, a substrate made of a resin such as polycarbonate, polymethacrylate, or amorphous polyolefin, a substrate made of glass, or a substrate having a resin layer made of a radiation curable resin (i.e., photopolymerizable resin) formed on glass can be used. Advanced optical data recording media may comprise further layers, such as protective layers, adhesive layers or even additional optical recording layers.

For optical data storage in blue diode lasers, various dye compounds have been proposed in the literature.

WO 2006/106110a discloses anionic azo metal complex dyes having triethylammonium or having as counter-ion the cation of commercially available cationic c.i. basic yellow dyes (c.i. stands for the color index international, 4 th edition,Society of Dyers and Colourists andAmerican Association of Textile Chemists and Colorists 2002)。

unfortunately, the dye compounds described to date still exhibit disadvantages which prevent their satisfactory use as dyes for optical data storage.

Disclosure of Invention

There is still a need for an optical data recording medium capable of recording data at high density, having improved recording characteristics, and having improved readout stability, and also requiring recording at speeds exceeding 1 times (i.e., 2-speed and 4-speed recording), and thus there is a need for an optical data recording medium having improved recording characteristics.

This object is achieved, surprisingly, by the use of salts of indolinium diazamethine type cations with anionic azo metal complex dyes based on pyridones.

Hereinafter, unless otherwise specified, "halogen" means F, Cl, Br or I, preferably F, Cl or Br, more preferably F or Cl, even more preferably Cl; unless otherwise indicated, "halide" means F-, Cl-, Br-or I-, preferably Cl-or I-; "alkyl" means straight and branched chain alkyl; and "alkoxy" means straight and branched chain alkoxy; unless otherwise indicated, any alkyl and cycloalkyl groups are unsubstituted, partially or fully substituted with halogen.

The subject of the present invention is the use of a compound of formula (I), which is a dye salt,

cat + is a compound of formula (II);

an-is a compound of formula (III);

m represents a trivalent metal atom, preferably selected from groups 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 of the periodic Table of the elements;

r9 is C_1-4Alkyl or NH-phenyl;

r1a is selected from H, O-C_1-4Alkyl, CO-phenyl, O-phenyl and S-phenyl;

r2a is selected from H, n-propyl, isopropyl, O-C_1-4Alkyl, CO-phenyl, O-phenyl and S-phenyl;

provided that if R2a is methoxy or H, then R1a is not H;

r10, R11, R12 and R13 are the same or different and are independently selected from the group consisting of: H. CN, CF₃Halogen, NO₂、OH、SH、SO₂-NR²¹R²²、CO-R²⁰、SO₂R²⁰、CO-NR²¹R²²，

C_1-10Alkyl radical, C_3-10Cycloalkyl radical, C_1-10Alkyl and the C_3-10Cycloalkyl is unsubstituted or substituted independently of one another by 1 to 4 identical or different substituents which are selected independently of one another from C_1-10Alkyl, halogen, OH, CN, CF₃、C_6-12Aryl and NR²¹R²²，

C₆-C₁₂Aryl, O-C_6-12Aryl, S-C_6-12Aryl radical, C_6-12Aryl and the group-C_6-12Aryl and the S-C_6-12Aryl is unsubstituted or substituted by 1 to 4 identical or different substituents which are selected independently of one another from C_1-10Alkyl radical, C_3-10Cycloalkyl, OH, NO₂CN, halogen, CF₃、C_6-12Aryl, O-C_1-10Alkyl, S-C_1-10Alkyl and NR²¹R²²，

O-C_1-10Alkyl, S-C_1-10Alkyl, O-C_3-10Cycloalkyl, S-C_3-10Cycloalkyl, NHCOR²⁰And NR²¹R²²；

The R is²¹And R²²The residues are identical or different and are independently selected from H, C_1-10Alkyl radical, C_6-12Aryl and C_1-12alkyl-NR²³R²⁴；

The R is²³And R²⁴The residues are identical or different and are independently selected from H, C_1-10Alkyl and C_6-12An aryl group;

the R is²⁰The residues are identical or different and are independently selected from OH, C_1-6Alkyl radical, C_6-10Aryl and O-C_1-6An alkyl group;

another subject of the invention is a compound of formula (I), which is a dye salt.

Preferably, the first and second electrodes are formed of a metal,

m is selected from Co, Cr, Fe and Al;

r9 is C_1-4An alkyl group;

r1a is selected from H, methoxy, CO-phenyl, O-phenyl and S-phenyl;

r2a is selected from H, isopropyl, methoxy, CO-phenyl, O-phenyl and S-phenyl;

provided that if R2a is methoxy or H, then R1a is not H;

r12 is NO₂；

R11 is H or NO₂；

R10 is H or NHCOCH₃；

R13 is H.

More preferably still, the first and second liquid crystal compositions are,

m is selected from Co, Fe and Al, preferably Co;

r9 is n-butyl;

r1a is selected from H, methoxy, CO-phenyl, O-phenyl and S-phenyl;

r2a is selected from H, isopropyl and methoxy;

provided that if R2a is methoxy or H, then R1a is not H;

r12 is NO₂；

R10 is H or NHCOCH₃；

R11 and R13 are H.

In particular, it is possible to provide a device,

cat + is selected from the group of compounds consisting of compounds of formulae (1), (2), (3), (4), (5) and (7);

and is

An-is a compound of formula (10) or a compound of formula (11).

More particularly, the compound of formula (I) is selected from compounds of formulae (10_1), (10_2), (10_3), (10_4), (10_5), (11_1) and (11_ 2);

even more particularly compounds of formula (10_ 2); these chemical formulae are defined in Table (A).

Another subject of the present invention is a compound selected from the compounds of formulae (10_1), (10_2), (10_3), (10_4), (10_5), (11_1) and (11_2), preferably a compound of formula (10_2), further its use in an optical layer, preferably in an optical layer for optical data recording, more preferably as a dye in an optical layer for optical data recording.

Preparation of Compounds of formula (I)

A further subject of the invention is a process for the preparation of compounds of the formula (I), in particular of the formulae (10_1), (10_2), (10_3), (10_4), (10_5), (11_1) and (11_2), as well as of the compounds of the formula (I) in all of its preferred aspects as described above,

which is carried out by a metathesis reaction between the corresponding precursor salts, i.e. between the compound of formula (III 6) and the compound of formula (II salt),

compounds of formula (III) in all preferred aspects of formula (III) as described above,

compounds of formula (II) also in all preferred aspects of formula (II) as described above,

the anion (II) is selected from the group consisting of halide, sulfate and methylsulfate, preferably chloride, iodide, sulfate and methylsulfate, even more preferably chloride and iodide.

Metathesis reactions within the meaning of the present invention mean ion exchange between different salts.

Compounds of formula (III _6), especially compounds of formula (III _6_ R10 acet), more especially compounds of formula (11_6), as defined in Table (AA),

preferably by complex reaction of compounds of formula (IV), especially of formula (IV _ R10 acet), with metal salts, wherein R9, R10, R11, R12 and R13 have the same meanings as described above, including all preferred embodiments thereof,

more particularly compounds of formula (IV _11),

wherein the compound of formula (IV) is preferably prepared by azo coupling of the corresponding diazo component with the corresponding coupler.

The compounds of formula (IV) are referred to as azo ligands.

The complexing reaction is carried out using the stoichiometric ratio between the desired compound of formula (IV) and the metal salt; each of the reactants may be used in excess relative to the other reactants, preferably 1 equivalent of metal salt and 2 equivalents of compound of formula (IV) are used.

Preferably, the compound of formula (III 6) is prepared by the complex reaction of a solution of 1 equivalent of a metal salt with 2 equivalents of a boiling solution of the compound of formula (IV).

In a preferred embodiment of the invention, the metal of the metal salt is a trivalent metal. In another preferred embodiment of the invention, the metal of the metal salt is a divalent metal and in this case the complexing reaction is carried out under aerobic conditions in the presence of preferably 2.5 to 4, more preferably 2.9 to 3.2, in particular 3 equivalents of triethylamine per equivalent of ligand. This ensures that the divalent metal atom is converted to a trivalent metal atom during the complexation reaction and that the metal atom is incorporated into its quadruple coordination in the complex, thereby creating an anionic charge on the final complex.

More than one metal salt, preferably a mixture of 2 or 3 metal salts, may be used, preferably in the desired stoichiometric amounts with respect to the azo ligand.

The azo ligand may be added to the metal salt, or vice versa.

In a further preferred embodiment of the invention, Cat in the form of the compound of the formula (IIa salts) is already present during the complexing reaction⁺。

The metathesis reaction is preferably carried out by mixing the corresponding compound of the formula (III-6) with the corresponding compound of the formula (II-salt).

The complexing reaction and the metathesis reaction may be carried out in suspension or in solution, preferably they are carried out in suspension.

Solvents which can be used in the complexing reaction or in the metathesis reaction are water, solvents and mixtures thereof. The solvent is preferably selected from C_1-8Alcohols, nitriles (preferably acetonitrile), acetone, aromatic solvents (e.g. toluene or chlorobenzene), DMF, DMSO, NMP.

More preferably, the solvent is C_1-8Alcohols (especially ethanol) and acetonitrile.

The metal salt may also have been added to the resulting ligand suspension or solution at an earlier stage in the synthesis of the compound of formula (I) or a precursor thereof, preferably before, during or after the azo coupling reaction, which is preferably used for the preparation of the azo ligand, more preferably after the azo coupling reaction.

It is particularly preferred that the azo ligand is isolated after the synthesis and the complexing reaction is carried out in a separate step.

It is especially preferred that the compound of formula (III — 6) is isolated after synthesis and the metathesis reaction is carried out in a separate step.

Preferably, the ligand is present in suspension during the complexation reaction.

The complexing reaction and the metathesis reaction are generally carried out at a temperature of between 20 ℃ and 200 ℃, preferably at a temperature of between 50 ℃ and 170 ℃, particularly preferably at a temperature of between 80 ℃ and 150 ℃, and very particularly preferably at reflux temperature under atmospheric pressure.

Preferably, the compound of formula (I) is isolated according to standard methods, typically it forms a precipitate, which is preferably isolated by filtration and dried.

Preferably, the complexation reaction is carried out under aerobic conditions in the presence of triethylamine using a metal salt derived from a divalent metal, more preferably a divalent cobalt salt, even more preferably CoSO₄*7H₂O。

When preparing compounds of formula (I), especially when they are prepared by metathesis reactions, and also depending on the molar ratio between the compound of formula (III _6) and the compound of formula (il _ salt), the cation of the compound of formula (III _6) may not be completely exchanged by the cation of the compound of formula (il _ salt), resulting in a mixture of compounds comprising the compound of formula (III _6), (I) and possibly (il _ salt).

Preferably, the metathesis reaction is carried out using a compound of formula (10_6) or (11_6) as specified in table (AA).

Another subject of the invention is a compound of formula (11_6) and the use of the compound of formula (11_6) for the preparation of a compound of formula (I).

The compounds of the formula (10_6) are known from WO 2006/106110A.

Preparation of Cat +

Another subject of the invention is the preparation of compounds of formula (II _ salt), in particular of the compounds of formulae (1_ I), (2_ I), (3_ I), (4_ I), (1_ C1), (3_ C1), (5_ C1) and (7_ I) as defined in table (a1), by alkylation of the compound of formula (Vd) with methyl iodide or with dimethyl sulfate, in which compounds of formula (Vd) R1a and R2a have the same meanings as described above, including all their preferred embodiments.

The alkylation reaction is carried out in a non-aqueous solvent and in mixtures thereof. The non-aqueous solvent is preferably selected from aromatic solvents, alcohols, ketones or acetonitrile; more preferably from ketones or substituted benzenes, even more preferably ethyl methyl ketone or chlorobenzene are used.

Preferably, after the alkylation reaction, especially in the case of using dimethyl sulfate as alkylating agent, a sodium halide, preferably sodium chloride, is added. The added halide can replace iodide, methyl sulfate, or sulfate produced by the alkylation reaction. Preferably, in the case of an alkylation reaction using dimethyl sulfate, sodium chloride is added after the alkylation reaction and the sulfate is at least partially exchanged by chloride.

The alkylation reaction is preferably carried out using an excess of alkylating agent, more preferably a molar ratio of alkylating agent to compound of formula (Vd) of 5: 1.

The alkylation reaction is preferably carried out at a temperature of from 0 ℃ to 200 ℃, more preferably from 20 ℃ to 100 ℃, even more preferably from 30 ℃ to 90 ℃.

The alkylation reaction time is preferably 10 minutes to 1 week.

Preferably, the compound of formula (il salts) is isolated according to standard methods, preferably by filtration in case of a precipitate, preferably followed by drying.

The compound of formula (Vd) is preferably prepared by azo coupling of a corresponding compound of formula (Va) (also known as a coupler) with a corresponding compound of formula (Vb) (also known as a diazo component); the compound of formula (Vb) is preferably prepared by diazotization of the corresponding compound of formula (Vc) (also known as amine compound);

wherein R1a and R2a have the same meanings as described above, and all preferred embodiments thereof are included.

The diazo component preferably has chloride Cl-as a counter ion, since the diazotization reaction of the amine compound is preferably carried out in aqueous hydrochloric acid.

The amine compounds and coupling agents are known materials and can be prepared according to or analogously to known procedures.

The azo coupling reaction is carried out in water, a non-aqueous solvent and mixtures thereof. The non-aqueous solvent is preferably selected from the group consisting of: alcohols, more preferably methanol, ethanol, propanol, butanol, pentanol; dipolar aprotic solvents, preferably Dimethylformamide (DMF), DMSO, dimethylacetamide or N-methyl-pyrrolidone (NMP) and pyridine; and a water-immiscible solvent, preferably toluene or chlorobenzene. More preferably, the azo coupling reaction is carried out in water, methanol or a mixture thereof.

The azo coupling reaction is preferably carried out using a stoichiometric ratio of coupling component to diazo component. The azo coupling reaction is generally carried out at a temperature of from-30 ℃ to 100 ℃, preferably at a temperature of from-10 ℃ to 30 ℃ and particularly preferably at a temperature of from-5 ℃ to 20 ℃.

The azo coupling reaction can be carried out in an acidic medium as well as in a basic medium. Preferably, the pH is < 10, in particular a pH of 3 to 9 is selected.

Preferably, the azo ligand is isolated according to standard methods, in the case of a precipitate, preferably by filtration, preferably followed by drying.

The alkylation reaction of the compound of formula (Vd) and possible subsequent anion exchange leads to the formation of a compound of formula (il salt) and also to a mixture of compounds of formula (il salt) having the same compound of formula (II) but a different anion (II).

Another subject of the invention are compounds of formula (il salts), wherein the compound of formula (II) is preferably selected from compounds of formulae (1), (2), (3), (4), (5) and (7), the anion (II) is preferably selected from halide, sulfate and methylsulfate, preferably chloride, iodide, sulfate and methylsulfate, even more preferably chloride and iodide;

in particular compounds of formulae (1_ I), (2_ I), (3_ I), (4_ I), (1_ C1), (3_ C1), (5_ C1) and (7_ I) as defined in table (a1), more in particular compounds of formula (2_ I);

and the use of compounds of formula (il salts), including also all the preferred embodiments thereof as defined above, for the preparation of compounds of formula (I).

Another subject of the invention are compounds of formula (Vd), in which R1a and R2a have the same meaning as described above, including also all the preferred embodiments thereof, especially compounds of formula (Vd _1), (Vd _2), (Vd _3), (Vd _4), (Vd _5) or (Vd _7), more especially compounds of formula (Vd _ 2);

and the use of a compound of formula (Vd), including also all the preferred embodiments thereof as defined above, for the preparation of a compound of formula (il salts).

Preparation of the Compound of formula (IV)

R10 is not NHCOCH₃The compounds of formula (IV) in the case of (IV) are known compounds and can be prepared according to or analogously to known procedures, for example as described in WO 2006/106110a or the present application.

R10 is NHCOCH₃The compounds of formula (IV), in particular of formula (IV _ R10 acet), more in particular of formula (IV _11), in the case of (IV) are preferably prepared by azo coupling of the corresponding compound of formula (IVa) (also known as coupling agent) with the corresponding compound of formula (IVb) (also known as diazo component); the compounds of formula (IVb) are preferably prepared by diazotisation of the corresponding compounds of formula (IVc) (also known as amine compounds);

wherein R9, R11, R12 and R13 have the same meanings as described above, including all preferred embodiments thereof; in the case of preparing the compound of formula (IV _11), as shown in formulas (IVa _11), (IVb _11) and (IVc _11), R9 is n-butyl, R11 and R13 are H and R12 is nitro.

The diazo component preferably has chloride Cl-as a counter ion, since the diazotization reaction of the amine compound is preferably carried out in aqueous hydrochloric acid.

The amine compounds and coupling agents are known materials and can be prepared according to or similar to known procedures.

The azo coupling reaction is carried out in water, a non-aqueous solvent, and mixtures thereof. The non-aqueous solvent is preferably selected from the group consisting of: alcohols, more preferably methanol, ethanol, propanol, butanol, pentanol; dipolar aprotic solvents, preferably Dimethylformamide (DMF), DMSO, dimethylacetamide or N-methyl-pyrrolidone (NMP) and pyridine; and a water-immiscible solvent, preferably toluene or chlorobenzene. More preferably, the azo coupling reaction is carried out in water.

The azo coupling reaction is preferably carried out using a stoichiometric ratio of coupling component to diazo component. The azo coupling reaction is generally carried out at a temperature of from-30 ℃ to 100 ℃, preferably at a temperature of from-10 ℃ to 30 ℃ and particularly preferably at a temperature of from-5 ℃ to 20 ℃.

The azo coupling reaction can be carried out in an acidic medium as well as in a basic medium. Preferably, the pH is < 10, in particular a pH of 3 to 9 is selected.

Preferably, the azo ligand is isolated according to standard methods, preferably by filtration in the case of a precipitate, preferably followed by drying.

Another subject matter of the invention is a compound of the formula (IV _ R10 acet), in particular of the formula (IV _11), and the use of a compound of the formula (IV _ R10 acet), in particular of the formula (IV _11), as ligand, preferably as ligand in azo metal complex dyes.

Another subject of the present invention is an optical layer, preferably for optical data recording, comprising at least one compound of formula (I) (which is also in all the described embodiments thereof), in particular at least one compound of formula (10_1), (10_2), (10_3), (10_4), (10_5), (11_1) or (11_ 2); and the use of the optical layer for optical data recording media. The optical layer of the present invention may also comprise a mixture of two or more, preferably two or three, more preferably two compounds of formula (I). Accordingly, a further subject of the present invention is an optical data recording medium comprising an optical layer comprising at least one compound of the formula (I).

Furthermore, the present invention relates to a method of manufacturing an optical layer, preferably for optical data recording, comprising the steps of:

(a) providing a base material, and preparing a substrate,

(b) dissolving at least one compound of formula (I), in particular at least one compound of formula (10_1), (10_2), (10_3), (10_4), (10_5), (11_1) or (11_2), in an organic solvent to form a solution,

(c) applying the solution (b) to the substrate (a),

(d) the solvent is evaporated to form the optical layer.

(a) Base material

The substrate serving as a support for the layers applied thereto is advantageously translucent (transmission T > 10%) or preferably transparent (transmission T > 90%). The support may have a thickness of 0.01 to 10mm, preferably 0.1 to 5 mm.

Suitable substrates are, for example, glass, minerals, ceramics and thermosetting or thermoplastic plastics. Preferred carriers are glass and homo-or copolymer plastics. Suitable plastics are, for example, thermoplastic polycarbonates, polyamides, polyesters, polyacrylates and polymethacrylates, polyurethanes, polyolefins, polyvinyl chloride, polyvinylidene fluoride, polyimides, thermosetting polyesters and epoxy resins. Most preferably the substrate is Polycarbonate (PC) or Polymethylmethacrylate (PMMA).

The substrates may be in pure form or may also comprise customary additives, for example UV absorbers, as light stabilizers for the optical layer.

The substrate is advantageously transparent over at least a portion of the range of 350nm to 500nm, so that it is transparent to at least 90% of incident light of the writing or reading wavelength.

(b) Organic solvent

The organic solvent is selected from C_1-8Alcohol, halogen-substituted C_1-8Alcohol, C_1-8Ketones, C_1-8Ether, halogen substituted C_1-4An alkane, nitrile (preferably acetonitrile) or amide or mixtures thereof.

Preferably C_1-8Alcohol or halogen-substituted C_1-8The alcohol is, for example, methanol, ethanol, isopropanol, diacetone alcohol (DAA), 2, 3, 3-tetrafluoropropan-1-ol, trichloroethanol, 2-chloroethanol, octafluoropentanol or hexafluorobutanol, more preferably 2, 2, 3, 3-tetrafluoropropan-1-ol.

Preferably C_1-8Ketones are, for example, propanol, methyl isobutyl ketone, methyl ethyl ketone or 3-hydroxy-3-methyl-2-butanone.

Preferably halogen-substituted C_1-4Alkanes are, for example, chloroform, dichloromethane or 1-chlorobutane.

Preferred amides are, for example, DMF, dimethylacetamide or NMP.

(c) Coating method

Suitable coating methods are, for example, dipping, pouring, brushing, knife coating and spin coating, and also vapor deposition methods carried out under high vacuum. When using the casting method, it is usually used as a solution in an organic solvent. When a solvent is used, care should be taken that the carrier used is not sensitive to said solvent. The optical layer is preferably applied by spin coating with a dye solution.

(d) Optical layer

The optical layer is preferably disposed between the transparent substrate and the reflective layer. The recording layer has a thickness of 10nm to 1000nm, preferably 30nm to 300nm, more preferably 70nm to 250nm, especially about 80nm, for example 60hm to 120 hm.

The optical layer comprises the compound of formula (I) preferably in an amount sufficient to substantially affect the refractive index, for example at least 30 wt%, more preferably at least 60 wt%, most preferably at least 80 wt% of the total weight of the optical layer.

Additional conventional ingredients are stabilizers (e.g. for¹O₂-triplet or luminescence quenchers), melting point depressants, decomposition promoters or any other additives already described in optical data recording media. It is preferable to add a stabilizer or a fluorescence quencher as necessary.

Stabilizer (a)¹O₂Triplet or luminescence quenchers) are metal complexes of, for example, N-or S-containing enolates, phenoxides, bisphenoxides, thiolates or dithiolates; hindered phenols and their derivatives, such as o-hydroxyphenyl-triazole or o-hydroxyphenyl-triazine, or other UV absorbers, such as sterically hindered amines (TEMPO or HALS, and nitroxides or NOR-HALS); and also as cationic diimmonium, Paraquat^TMOr salts of ortho quats, e.g.IRG 022、IRG 040; optionally also as radical ions, for example N, N, N ', N' -tetrakis (4-dibutylaminophenyl) -p-phenylene-ammonium hexafluorophosphate, ammonium hexafluoroantimonate or ammonium perchlorate. The latter is commercially available from Organica (Wolfen/DE);the trade mark is available from Nippon Kayaku co.ltd.

In a preferred aspect, the present invention provides an optical layer suitable for use in high density recording materials in the laser wavelength range around 350-450nm, preferably 405nm, e.g. in the WORM disc format.

Preparation of optical data recording media

The method of manufacturing an optical data recording medium comprising an optical layer of the present invention typically comprises the additional steps of:

(e) a metal layer (also referred to as a reflective layer) is applied to the optical layer,

(f) a second layer based on a polymer (also referred to as a cover layer or protective layer) is applied to complete the optical disc.

(e) Reflective layer

The application of the metallic reflective layer is preferably achieved by sputtering, vacuum vapor deposition or by Chemical Vapor Deposition (CVD). The sputtering technique is particularly preferred for the application of the metallic reflective layer.

Suitable reflective materials for the reflective layer include, inter alia, metals that provide good reflection of laser radiation for recording and playback, such as metals of main groups III, IV and V of the periodic table and metals of sub-groups. Al, In, Sn, Pb, Sb, Bi, Cu, Ag, Au, Zn, Cd, Hg, Sc, Y, La, Ti, Zr, Hf, V, Nb, Ta, Cr, Mo, W, Fe, Co, Ni, Ru, Rh, Pd, Os, Ir, Pt, Ce, Pr, Nd, Pm, Sm, Eu, Gd, Tb, Dy, Ho, Er, Tm, Yb and Lu and alloys thereof are particularly suitable. Reflective layers of aluminum, silver, copper, gold, or alloys thereof are preferred for their high reflectivity and ease of fabrication.

(f) Covering layer

Suitable materials for the cover layer include plastics, which are applied in the form of thin layers directly or by means of adhesive layers to the carrier or the uppermost layer. The material of the cover layer may, for example, be the same as the material of the substrate. It is advantageous to select mechanically and thermally stable plastics with good surface properties which can be further modified.

The plastic can be a thermoset plastic and a thermoplastic. Radiation-cured (e.g., using UV radiation) protective layers are preferred, which are particularly simple and economical to manufacture. A wide variety of radiation curable materials are known. Examples of radiation-curable monomers and oligomers are acrylates and methacrylates of diols, triols and tetraols, aromatic tetracarboxylic acids and compounds having C in at least two ortho positions to the amino group₁-C₄Polyimides of aromatic diamines with alkyl groups, and oligomers having dialkylmaleimide groups (e.g., dimethylmaleimide groups).

The high-density optical data recording medium of the present invention is therefore preferably a recordable optical disc comprising: a first substrate which is a transparent substrate having a groove; an optical layer (recording layer) formed on a surface of the first substrate using the compound of formula (I); a reflective layer formed on the optical layer; a second substrate that is a transparent substrate connected to the reflective layer with a connecting layer.

The optical data recording medium of the present invention is preferably a WORM-type recordable optical disc. Which can be used, for example, as a playable HD-DVD (high-density digital versatile disc) orOptical discs, for use as storage media for computers or as identification and security cards or for the manufacture of diffractive optical elements (e.g. holograms).

The optical data recording medium of the invention may also have further layers, for example interference layers. An optical data recording medium having a plurality of (e.g., two) recording layers may also be constructed. The structure and use of these materials are known to those skilled in the art. If present, preferably arranged between the recording layer and the reflective layer and/or between the recording layer and the substrate and made of TiO₂、Si₃N₄An interference layer composed of a dielectric material of ZnS or silicone resin.

These optical data recording media of the present invention can be manufactured by methods known in the art.

Read-out method

The structure of the optical data recording medium of the present invention is mainly determined by the readout method; known functional principles include measuring changes in transmittance or preferably reflectance, but it is also known to measure, for example, fluorescence, instead of transmittance or reflectance.

When the optical data recording medium is constructed for reflectivity variation, the following structure may be used: transparent support/recording layer (optionally multilayered)/reflective layer and, if appropriate, protective layer (not necessarily transparent); or the support (not necessarily transparent)/the reflective layer/the recording layer and, if appropriate, the transparent protective layer. In the first case, light is incident from the carrier side, whereas in the latter case, radiation is incident from the recording layer side or, where applicable, from the protective layer side. In both cases, the light detector is located on the same side as the light source. The first-mentioned structure of the recording material usable according to the invention is generally preferred.

When constructing an optical data recording medium for light transmittance change, the following different structures are considered: a transparent support/recording layer (optionally multilayered) and, if appropriate, a transparent protective layer. The light for recording and for readout may be incident from the carrier side or from the recording layer side or, where applicable, from the protective layer side, in which case the light detector is always located on the opposite side.

Suitable lasers are those having a wavelength of 330-500nm, for example commercially available lasers having a wavelength of 405 to 414nm, in particular semiconductor lasers. For example by modulating the laser precisely according to the mark length and focusing its radiation on the recording layer. As is known from the specialist literature, other methods are currently being developed which may also be suitable for use.

The method of the invention allows the storage of information with great reliability and stability, which is distinguished by very good mechanical and thermal stability and high light stability and a clear boundary region of the information pits. Particular advantages include high contrast, low jitter and unexpectedly high signal/noise ratio, so that excellent readout is achieved.

The readout of the information is performed by recording the change in absorption or reflection using laser radiation according to methods known in the art.

The invention accordingly also relates to a method of optical data recording, storing and reproducing information, in which the optical data recording medium of the invention is used. The recording and playback is advantageously carried out in the wavelength range of 330 to 500 nm.

The compounds of formula (I) provide particularly preferred properties when used in the optical layer of the optical data recording medium of the present invention. They have the desired optical properties that are demonstrated when used in solid film form:

advantageously homogeneous, amorphous and low-scattering optical layers,

high refractive index flanking the longer wavelength of the absorption band, which preferably achieves an n-value of the refractive index in the range of from 330 to 500nm of from 1.0 to 3.0,

high sensitivity under high power density laser radiation and good playback characteristics in the desired spectral range,

enhanced photosensitivity and stability (in sunlight and under laser radiation of low power density) compared to dyes known in the art,

uniform instruction code width and high contrast,

absorption maximum (λ max) in the preferred range between 330nm and 500nm, more precisely 400 to 500nm, as is preferred for blue laser applications

A Decomposition Point (DP) in the preferred temperature range between 180 ℃ and 300 ℃, more precisely between 250 ℃ and 300 ℃,

full exotherm (HR).

The recording performance of a compound is related to specific parameters measured for an optical disc, such as:

low emulated bit error Rate (SbER)

Low inner parity error Rate (PI error)

High reflectance (R)

Low laser recording power (Pw: power, or OPC: optimum power control): the lower the better

Good read stability at different laser read powers

Appropriate local response signal-to-noise ratio (PRSNR): the higher the better

The absorption edge is surprisingly steep even in the solid phase.

The compounds of formula (I) also exhibit a narrow decomposition temperature of 180 ℃ to 350 ℃ which meets thermal requirements. In addition, these compounds exhibit high solubility in organic solvents, which is desirable for spin coating methods for producing optical layers.

The recording medium of the invention advantageously has a homogeneous, amorphous and low-scattering recording layer as a result of the use of the dyes of the invention. Further advantages are the light stability in daylight and at 0.4mW laser radiation, combined with a high sensitivity at moderate laser radiation, which means as low a power density as possible (OPC preferably less than 8.0mW for 1 x speed and preferably less than 11mW for 2 x speed), good thermal and storage stability. Especially in the case of recording at higher speeds, the required OPC should be as low as possible.

Detailed Description

Examples

UV-vis

For UV-vis spectroscopy, the values of. lamda.max and. epsilon.of the compounds were determined by dissolving the compounds in CH using a UV-vis spectrophotometer₂Cl₂In DMSO or tfp. The values were obtained by balancing the measurements made for three different concentrations of compound solution.

Melting Point (MP)

For melting point determination, a compound or composition is introduced into a glass capillary. The capillary tube was heated using the following profile: a temperature range of 20 ℃ to 350 ℃, a heating rate of 2 ℃/min.

Thermal decomposition: decomposition Point (DP) and exotherm (HR)

For the DP and HR measurements, compounds were introduced into sealed aluminum pans. The analysis conditions were as follows: a temperature range of 25 ℃ to 400 ℃, a heating rate of 10 ℃/min, a nitrogen flow rate of 50 ml/min. Values were determined by a single measurement. In addition, thermal decomposition was also observed while measuring the melting point.

Partial response signal-to-noise ratio (PRSNR)

The definition and measurement technique of PRSNR is described in the book available from DVD Format Logilicensing Co., Ltd, such as Annex H of Version 0.9, PART 1Physical Specifications, DVD Specifications for High DensityRead-Only Disk. The higher the PRSNR, the better.

Emulated bit error Rate (SbER)

The definition and measurement of SbER is described in a book available from DVD Format Logo licensing Co., Ltd, such as Annex H of Version 0.9, PART 1physical Specifications, DVD Specifications for High Density Read-Only disk. The lower the SbER, the better.

PRSNR and SberMeasured in a state where information has been recorded in an adjacent track.

Reflectance (R)

The definition and measurement techniques for light reflectance (R) are described in a book available from DVD Format LogiLicepting Co., Ltd, such as Annex D of Version 0.9, PART 1Physical Specifications, DVD Specifications for High DensityRead-Only Disk. The higher R, the better.

Number of cycles

Various parameters, such as PRSNR and the degree of degradation of SbER due to repeated readouts, were measured. The higher the number of cycles until the minimum specification or equivalent performance is reached, the better.

"ex." means examples and "comp.ex." means comparative examples.

"nd" means not determined.

Example 1

Diazotization reaction and azo coupling reaction

32.2g of concentrated aqueous HCl solution are added dropwiseTo a solution consisting of 12.4g of 2-methoxyaniline in 100ml of water. The temperature was reduced to 0 ℃ using an ice bath and 20.8ml of aqueous sodium nitrite (33.3 wt%) was added dropwise while maintaining the temperature below 5 ℃. The resulting solution was stirred at 0 ℃ for 1 hour and added dropwise at 10 ℃ to a mixture of 17.6g of 1, 3, 3-trimethyl-2-methyl-indoline, 31.8g of Na₂CO₃100ml of methanol and 30ml of water.

After complete addition, the resulting mixture was stirred at 10 ℃ for 1 hour. Concentrated aqueous HCl was then added until pH 7. The resulting precipitate was filtered, washed with 1000ml of water and air-dried to give 28.3g of a yellow intermediate, i.e. the compound of formula (Vd _ 1).

Alkylation Process A

28.3g of the compound of the formula (Vd _1) obtained are taken up in 200ml of methyl ethyl ketone, 47g of methyl iodide are added and the mixture obtained is refluxed for 48 hours at atmospheric pressure. The temperature was cooled to room temperature and the precipitate formed was filtered, washed 3 times with 15ml of methyl ethyl ketone each time and dried under vacuum at 60 ℃ for 24 hours. 22.4g of the compound of formula (1_ I) are obtained in the form of an orange solid.

Examples 2 to 8: diazotization and coupling reaction

The diazotization and coupling reactions according to example 1 were carried out using the corresponding aniline compounds to give compounds of formulae (2_ I), (3_ I), (4_ I), (1_ Cl), (3_ Cl), (5_ Cl) and (7_ I) via the intermediate compounds of formulae (Vd _2), (Vd _3), (Vd _4), (Vd _5) and (Vd _ 7).

Examples 2 to 4 and 8: alkylation Process A

The alkylation reaction according to example 1 was carried out using the corresponding intermediate. In case the desired final compound does not precipitate, the reaction mixture is evaporated to dryness and the compound is used without further purification, as is the case for example 4.

Example 5: alkylation Process B

The solid obtained from the diazotization and coupling reaction of example 5 was taken up in 120ml of chlorobenzene and the mixture was heated to 80 ℃. 3.18g N-ethyldiisopropylamine was added dropwise followed by 14.9g of dimethyl sulfate. The resulting mixture was stirred at 85 ℃ for 10 hours. The chlorobenzene was steam distilled. To the resulting mixture was added 45g of NaCl and the resulting mixture was evaporated to dryness. The resulting solid was dried under vacuum at 60 ℃ for 24 hours. 71g of a substance containing the compound of the formula (1_ Cl) was obtained.

Examples 6 and 7: alkylation Process B

The alkylation reaction according to example 5 was carried out using the corresponding intermediate to yield compounds of formulae (3_ Cl) and (5_ Cl).

The combinations and details are given in tables (A2) and (A3).

Table (a4) shows the physico-chemical properties of the compounds of formulae (1_ I) to (5_ Cl).

Example 9

23.6g of 2-amino-4-nitro-6-acetamidophenol are added to 190ml of water, followed by dropwise addition of 36g of concentrated aqueous HCl. The temperature was cooled to 0 ℃ and 25.5ml of aqueous sodium nitrite solution (33.3 wt%) was added dropwise while maintaining the temperature below 5 ℃. The yellow mixture was stirred at this temperature for 1 hour. The mixture is then transferred to a mixture of 23.1g of the compound of the formula (IVa _ butyl) and 45.9g of sodium acetate in 210ml of water.

After complete addition, the resulting mixture was stirred at room temperature for 1 hour. The resulting brown-yellow precipitate was filtered, washed with 800ml of water and dried under vacuum at 60 ℃ for 24 hours. 37.5g of the compound of the formula (IV _11) are obtained in the form of a yellow solid.

Example 10

22.9g of the compound of formula (IV _11) prepared according to example 9, 15.0g of CoSO₄*7H₂O and 1000ml acetonitrile were refluxed at atmospheric pressure for 20 minutes. 16.3g of triethylamine was added dropwise and the resulting mixture was refluxed at atmospheric pressure for 1 hour 30 minutes. After cooling to room temperature, the solution was filtered and most of the solvent was removed by distillation. To the resulting purple slurry 160ml of ethanol were added dropwise and the mixture was refluxed at atmospheric pressure for 1 hour. After cooling to room temperature, the green-brown precipitate was filtered, washed with 60ml of ethanol and then with 180ml of water and dried under vacuum at 60 ℃ for 24 hours. 24.2g of the compound of formula (11_6) are obtained in the form of a brownish black solid. Table (A5) shows the physico-chemical properties of the compounds of formulae (IV _11) and (11_ 6).

Example 11

71.0g of the solid containing the compound of formula (1. multidot. Cl) prepared according to example 5 are stirred in 700ml of ethanol for 1 hour. The resulting mixture was filtered. The filtrate was then added dropwise to a mixture of 64.4g of the compound of formula (10. sup. st. 6) and 640ml of ethanol at reflux under atmospheric pressure. After complete addition, the mixture was refluxed at atmospheric pressure for 4 h. After cooling to room temperature, the precipitate was filtered, washed with 750ml ethanol and then 5000ml water and dried under vacuum at 65 ℃ for 24 hours. 72.0g of the compound of the formula (10_1) was obtained in the form of an orange-brown solid.

Examples 12 to 17

The preparation according to example 11 was carried out using the corresponding precursors comprising the compounds of formulae (1) to (5), the corresponding precursors comprising the compounds of formulae (10) and (11).

The combinations and details are given in table (a 6).

Table (A7) shows the physico-chemical properties of the compounds of formulae (10_1), (10_2), (10_3), (10_4), (10_5), (11_1) and (11_ 2).

Application example 1

The optical and thermal properties of the compounds of formula (I) were studied. The compounds of formula (I) show high absorption at the desired wavelength. In addition, the absorption spectrum shape, which is still critical for the disc reflectivity and the formation of sharp mark edges, consists of a main band comprised in the range of 330 to 500 nm.

More precisely, the value of n for the refractive index is evaluated between 1.0 and 2.7. The light stability was found to be comparable to commercial dyes that have been stabilized with quenchers for optical data recording.

The clear threshold for thermal decomposition in the desired temperature range is a characteristic of the compounds of formula (I) which are intended for use in the optical layers of optical data recording.

Application example 2 optical layer and optical data recording Medium

1.4% by weight, based on the weight of the solvent, of the compound of formula (10_1) prepared according to example 11 was dissolved in 2, 2, 3, 3-tetrafluoropropan-1-ol and the solution was filtered through a polytetrafluoroethylene (Teflon) filter with a pore size of 0.2 microns and applied by spin coating at 1000 rpm to the surface of a 120mm diameter 0.6mm thick grooved polycarbonate optical disc. Excess solution was spun off by increasing the rotation speed. Upon evaporation of the solvent, the dye remains as a uniform, amorphous solid layer (optical layer).

After drying the optical layer in a circulating air oven at 70 ℃ (10min) in a vacuum coating apparatus, a 100 μm thick silver layer was then applied to the recording layer by atomization. A protective layer of UV curable photopolymer (650-020, DSM) having a thickness of 6 μm was then applied thereto by spin coating. Finally, a second substrate is provided to be bonded with the resin protective layer using the connection layer. This completes the manufacture of a high-density recordable optical disc (optical data recording medium).

The evaluation test was performed using an optical disk evaluation apparatus available from Pulse Tech co.

The test conditions were as follows:

numerical Aperture (NA) of optical head: 0.65

Laser wavelength for recording and reproduction: 405nm

Constant Linear Velocity (CLV): 6.61m/sec.

Track pitch: 400nm

Amplitude of the wobble of the groove track: 14nm

Groove depth: 90 nm.

Comparative example 1

Application example 2 was carried out using a compound of formula (d6CoBY28) prepared according to WO 2006/106110 a.

The results of the test according to application example 2 with various compounds are summarized in table (D).

Tests were conducted for each of the write-once optical discs manufactured with the recording layers to evaluate the degree of degradation due to repeated reproduction. Readout was performed at readout laser power of o.4mw and then the degree of degradation of PRSNR and SbER was measured. The maximum number of cycles was found to be within specification.

Claims (29)

1. Use of a compound of formula (I) in an optical layer for optical data recording,

An-*Cat+(I)

cat + is a compound of formula (II);

an-is a compound of formula (III);

m represents a trivalent metal atom, preferably selected from groups 3, 4, 5, 6, 7, 8, 9, 10, 11 and 12 of the periodic Table of the elements;

r9 is C_1-4Alkyl or NH-phenyl;

r1a is selected from H, O-C_1-4Alkyl, CO-phenyl, O-phenyl and S-phenyl;

r2a is selected from H, n-propyl, isopropyl, O-C_1-4Alkyl, CO-phenyl, O-phenyl and S-phenyl;

provided that if R2a is methoxy or H, then R1a is not H;

r10, R11, R12 and R13 are the same or different and are independently selected from the group consisting of: H. CN, CF₃Halogen, NO₂、OH、SH、SO₂-NR²¹R²²、CO-R²⁰、SO₂R²⁰、CO-NR²¹R²²，

C_1-10Alkyl radical, C_3-10Cycloalkyl radical, C_1-10Alkyl and the C_3-10Cycloalkyl is unsubstituted or substituted independently of one another by 1 to 4 identical or different substituents which are selected independently of one another from C_1-10Alkyl, halogen, OH, CN, CF₃、C_6-12Aryl and NR²¹R²²，

C_6-C12Aryl, O-C_6-12Aryl, S-C_6-12Aryl radical, C_6-12Aryl and the O-C_6-12Aryl and the S-C_6-12Aryl is unsubstituted or substituted by 1 to 4 identical or different substituents which are selected independently of one another from C_1-10Alkyl radical, C_3-10Cycloalkyl, OH, NO₂CN, halogen, CF₃、C_6-12Aryl, O-C_1-10Alkyl, S-C_1-10Alkyl and NR²¹R²²，O-C_1-10Alkyl, S-C_1-10Alkyl, O-C_3-10Cycloalkyl, S-C_3-10Cycloalkyl, NHCOR²⁰And NR²¹R²²；

The R is²¹And R²²The residues are identical or different and are independently selected from H, C_1-10Alkyl radical, C_6-12Aryl and C_1-12alkyl-NR²³R²⁴；

The R is²³And R²⁴The residues are identical or different and are independently selected from H, C_1-10Alkyl and C_6-12An aryl group;

the R is²⁰The residues are identical or different and are independently selected from OH, C_1-6Alkyl radical, C_6-10Aryl and O-C_1-6An alkyl group.

2. Use of a compound of formula (I) according to claim 1, wherein

M is selected from Co, Cr, Fe and Al;

r9 is C_1-4An alkyl group;

r1a is selected from H, methoxy, CO-phenyl, O-phenyl and S-phenyl;

r2a is selected from H, isopropyl, methoxy, CO-phenyl, O-phenyl and S-phenyl;

provided that if R2a is methoxy or H, then R1a is not H;

r12 is NO₂；

R11 is H or NO₂；

R10 is H or NHCOCH₃；

R13 is H.

3. Use of a compound of formula (I) according to claim 1 or 2, wherein

M is selected from Co, Fe and Al;

r9 is n-butyl;

r1a is selected from H, methoxy, CO-phenyl, O-phenyl and S-phenyl;

r2a is selected from H, isopropyl and methoxy;

provided that if R2a is methoxy or H, then R1a is not H;

r12 is NO₂；

R10 is H or NHCOCH₃；

R11 and R13 are H.

4. Use of a compound of formula (I) according to one or more of claims 1 to 3, wherein Cat + is selected from compounds of formulae (1), (2), (3), (4), (5) and (7);

and An-is a compound of formula (10) or (11)

5. Use of a compound of formula (I) according to one or more of claims 1 to 4, wherein the compound of formula (I) is selected from the compounds of formulae (10_1), (10_2), (10_3), (10_4), (10_5), (11_1) and (11_2), which formulae are defined in Table (A),

wherein the An-and the Cat + in the Table (A) are as defined in claim 4.

6. A compound of formula (I) as defined in claim 1.

7. A compound of formula (I) according to claim 6, wherein

M, R9, R1a, R2a, R10, R11, R12 and R13 are as defined in claim 2.

8. A compound of formula (I) according to claim 6 or 7, wherein

M, R9, R1a, R2a, R10, R11, R12 and R13 are as defined in claim 3.

9. The compounds of the formula (I) according to one or more of claims 6 to 8, wherein

Cat + is as defined in claim 4; and is

An-is as defined in claim 4.

10. A compound of formula (I) according to one or more of claims 6 or 9, wherein the compound is selected from the compounds as defined in claim 5.

11. A process for preparing compounds of the formula (I) as defined in one or more of claims 6 to 10 by metathesis reaction between the corresponding compounds of the formula (III _6) and the corresponding compounds of the formula (II _ salts),

compound of formula (III) compound of formula (6) (III _6)

The compound of formula (III) is as defined in claim 1,

compound of formula (II): anion (II) (II _ salt)

The compound of formula (II) is as defined in claim 1 and the anion (II) is selected from halide, sulfate and methylsulfate.

12. A compound of the formula (11-6),

compound of formula (11) compound of formula (6) (11_6)

The compound of formula (6) is as defined in claim 11 and the compound of formula (11) is as defined in claim 4.

13. Use of a compound of formula (11_6) according to claim 12 for the preparation of a compound of formula (I) as defined in one or more of claims 6 to 10.

14. A process for the preparation of a compound of formula (11_6) according to claim 12 by complex reaction of a compound of formula (IV _11) with a divalent cobalt salt in the presence of triethylamine,

15. a compound of formula (IV _11) as defined in claim 14.

16. Use of a compound of formula (IV _11) as defined in claim 14 for the preparation of a compound of formula (11_6) as defined in claim 12.

17. A process for the preparation of a compound of formula (IV _11) as defined in claim 14, by azo coupling of a compound of formula (IVa _11) with a compound of formula (IVb _11),

18. a compound of formula (il salts) as defined in claim 11.

19. A compound of formula (il salt) according to claim 18, wherein the compound of formula (II) is selected from compounds of formulae (1), (2), (3), (4), (5) and (7) as defined in claim 4, and the anion (II) is as defined in claim 11.

20. The compound of formula (il _ salt) according to claim 18 or 19, wherein the compound is selected from the compounds of formula (1_ I), (2_ I), (3_ I), (4_ I), (1_ C1), (3_ C1), (5_ C1) and (7_ I) as defined in table (a1),

the compound of formula (II) in the table (a1) is as defined in claim 4.

21. Use of a compound of formula (il salts) according to one or more of claims 18 to 20 for the preparation of a compound of formula (I) according to one or more of claims 6 to 10.

22. A process for preparing compounds of the formula (IIsalts) according to one or more of claims 18 to 20 by alkylation of compounds of the formula (Vd) with methyl iodide or with dimethyl sulfate,

the R1a and R2a are as defined in one or more of claims 6 to 10.

23. A compound of formula (Vd) as defined in claim 22.

24. The compound of formula (Vd) according to claim 23, wherein the compound is selected from compounds of formula (Vd _1), (Vd _2), (Vd _3), (Vd _4), (Vd _5) or (Vd _7),

25. use of a compound of formula (Vd) according to claim 23 or 24 for the preparation of a compound of formula (il _ salt) according to one or more of claims 18 to 20.

26. A process for the preparation of a compound of formula (Vd) according to claim 23 or 24 by azo coupling of a corresponding compound of formula (Va) with a corresponding compound of formula (Vb),

the R1a and R2a are as defined in one or more of claims 6 to 10.

27. Optical layer comprising a compound of formula (I) as defined in one or more of claims 6 to 10.

28. A method of making an optical layer according to claim 27, comprising the steps of:

(a) providing a base material, and preparing a substrate,

(b) dissolving at least one compound of formula (I) as defined in one or more of claims 6 to 10 in an organic solvent to form a solution,

(c) applying the solution (b) to the substrate (a),

(d) the solvent is evaporated to form the optical layer.

29. An optical data recording medium comprising an optical layer according to claim 27.