DE1769383A1 - Cyanine dyes - Google Patents

Description

bastman Kodak Company, 343 State Street, Rochester, New York State, United States of America

Cyanine dyes

The L'rfindunjT concerns cyanine dyes, consisting of two 5- or 6-membered, at least one nitrogen atom containing heterocyclic rings which are connected to one another via a double bond or a dimethine bridge, One of which is a desensitizing ring, which is connected to the dimethine bridge via one of its carbon atoms or is bound to the double bond.

It is known that direct-positive photographic images are produced by exposure and processing of certain photographic Let silver halide emulsions be obtained. For example, to produce direct positive images photographic emulsions have become known, which have a so-called Contain electron acceptor and their silver halo

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genid by means of a reducing compound and a compound of a metal that is more electropositive than Silver is, has been veiled. One of the advantages of such direct positive emulsions is that the areas of high light in the images obtained are practically free of veils. Disadvantage of the known direct positive photographic emulsions, however, is that they do not have as high sensitivity as that for various photographic purposes in themselves would be desirable. Disadvantages of such direct-positive photographic emulsions is also that they do not have the desired selective sensitivity, especially not to Radiation of the green to red areas of the electromagnetic spectrum. As a result, there is a need according to improved direct-positive photographic emulsions, which compared to known corresponding emulsions improved sensitivity and furthermore improved sensitivity to longer wavelengths of the Have light.

The invention was based on the finding that certain cyanine dyes, consisting of two 5- or 6-membered heterocyclic rings containing at least one nitrogen atom, which are connected to one another via a double bond or a dimethine bridge, one of which is a desensitizing ring, the via one of its carbon atoms to the dimethine bridge or to the double bond

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is rebunden, excellent electron acceptors and spectral sensitizing dyes, in particular for direct-positive, photographic silver halide emulsions are when the other ring is a complex fused pyrimidinedione ring is who via its 3-carbon atom to the Dimethine bridge or is bound to the double bond.

The new cyanine dyes are ideal for production of inverse systems, especially those with veiled ones Silver halide emulsions.

The new dyes are distinguished by the fact that they impart excellent sensitivity to silver halide photographic emulsions and to the silver halide Radiation of the green to red areas of the spectrum with maximum sensitivities of in most Cases etKa 520 to 560 ιπμ are able to sensitize. at Use of the new dyes in direct-positive emulsions clear and sharp images are obtained.

The complex, condensed pyrimidinedionrin pen acts it is pyrimidinedionrinpe, on whose 1- and 6-atoms another ring or rings are fused. The river Oder the fused-on rings can consist of cyclic rings, for example heterocyclic rings.

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the
MR3t "RsiKXXxK" rfcKiik * flHi are cyanine dyes of the invention

characterized by the following general structural formula:

ID Kf ΓΊ3 - ΓΊ! Ί ^ ___ C f - I _T ^^ ηΓ1 if

Herein mean:

ei = 1 or 2;

η = 1 or 2;

L is a methine group;

R * is an alkyl, alkenyl or aryl group;

Z which is used to complete a desensitivity

acting ring with 5 or 6 ring atoms required atoms and

Q to complete a condensing

th, heterocyclic ring with 5 or 6-rinjiatomen required atoms.

For example, L can be a group of the following formulas:

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ORIGINAL! IKZPcCTED

-CH =, -C (CH ₃ ) = and

- R ₁ can be a simple or substituted alkyl group, preferably a short-chain alkyl group with 1 to 4 carbon atoms, for example a methyl, ethyl, propyl, isopropyl, butyl, ilexyl, cyclohexyl, decyl or dodecyl group, or in the case of a substituted alkyl group, which is also preferably short-chain, a hydroxyalkyl group, 2, B, a ß-IIydroxyäthyl ^ or ω-hydroxybutyl group or an alkoxyalkyl group, z, B, a ß-methoxyethyl or ω-butoxybutyl group, or a carboxyalkyl group, z. B. a ß-Carboxyäthyl- or ω-Carboxybutylgruppe, or a SuIfoalkylgruppe, z, B, a ß-Sulfoäthyl- or ω-Sulfobutylgruppe, or a SuIfatoalkylgruppe, z. ß. a ß-sulfatoethyl or ω-sulfatobutyl group, or an acyloxyalkyl group, e.g. B. a ß-acetoxyethyl, γ-acetoxypropyl or ω-butyryloxybutyl group, or an alkoxycarbonylalkyl group, z, B, a ß-methoxycarbonylethyl or ui-ethoxycarbonylbutyl group, an aralkyl group, z, B, a benzyl or phenethyl group, possesses R- the meaning of an alkenyl group, this can for example consist of an allyl, 1-propenyl or 2-butenyl group. If R- has the meaning of an aryl group, this can for example consist of a phenyl, tolyl, naphthyl, methoxyphenyl or chlorophenyl group,

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For example, Z can represent the atoms required to complete one of the following rings:

A nitrobenzothiazole ring, e.g. B. a 5-nitrobenzothiazole, 6-nitrobenzothiazole or S-chloro-ö-nitrobenzothiazole ring;

a nitrobenzoxazole ring, e.g. B. a 5-nitrobenzoxazole, 6-nitrobenzoxazole or S-chloro-o-nitrobenzoxazole ring;

a nitrobenzoselenazole ring, e.g. B. a 5-nitrobenzoselenazole, δ-nitrobenzoselenazole or 5-chloro-6-nitrobenzoselenazole ring ;

imidazo a / ~ 4 _f 5-b_7chinoxalinringes, z, as an imidazo / ~ 4,5-b_7chinoxalinringes, or a 1 _t 3 Dialkyli "idazo - / '4,5-b_7chinoxalinringes, e.g., a. 1 _t 3-diethylimidazo / ~ 4,5-b_7-quinoxaline or 6-chloro-1, S-diethylimidazo ^^ jS-b_7-quinoxaline ring, or a 1,3-dialkenyliraidazo / ~ 4,5-b_7-quinoxaline ring, e.g. B. a 1,3-diallyliaidazo £ "" 4 _l 5-b_7-quinoxaline or 6-chloro-1,3-diallyliraidazo / '"4 _f 5-b_7-quinoxaline ring, or a 1,3-diaryliinidazo / ~ 4 _t 5-b-7-quinoxaline ring, for example a 1 _# 3-diphenylifflidazo / ~ 4 _# 5-b _e 7-quinoxaline or a 6-chloro- ₁ 3-diphenylimidazo ^ "" 4 _f 5-b-7-quinoxaline ring;

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of a 3,3-dialkyl-3H-pyrrolo / ~ 2 _> 3-b_7pyridine ring, ζ »D. of a 3,3-diinethyl-3Il-pyrrolo /" 2,3-b_7pyTidine or a 3,3-diethyl-3ii pyrrolo / 2,3-b ~ ₁ 7pyridinrinpes;

a 3,3-dialkyl-3H-nitroindolrinp: es, e.g. B. a 3,3-di-methyl-5-nitro-3II-indole, of a 3,3-diethyl-5-nitro-3H-indole, or a 3, S-dimethyl-b-nitro-SH-indolrinpes;

a thiazolo / ~ 4,5-b_7-quinoline ring or

a nitroquinoline ring, e.g. B. a 5-nitroquinoline or a 6-nitroquinoline ring.

The heterocyclic ring formed by Q with 5 to 6 Ring atoms can besides the nitrogen atom in the anpepebenen Position 1 also have a further heteroatom, for example an oxygen, sulfur, selenium or nitrogen atom. For example, Q can represent the atoms required to complete one of the following Rings, namely one:

Thiazole ring, e.g. B. a thiazole, 4-methylthiazole, 4-phenylthiazole, 5-methylthiazole, 5-phenylthiazole, 4,5-dimethylthiazole, 4,5-diphenylthiazole, 4- (2-thienyl) thiazole, Benzothiazole, 4-chlorobenzothiazole, 5-chlorobenzothiazole, 6-Chlorobenzothiazol-, 7-Chibr-obenz-othiazol-,

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4-methylbenzothiazole, 5-methylbenzothiazole, 6-methylbenzothiazole, 5-bronobenzothiazole, 6-bromobenzothiazole, O-phenylbenzothiazole, 5-phenylbenzothiazole, 4-methoxybenzothiazole, 5-methoxybenzothiazole, 6-methoxybenzothiazole, 5-iodobenzothiazole, 6-iodobenzothiazole, 4-ethoxybenzothiazole, 5-Xthoxybenzothiazole, tetrahydrobenzothiazole, 5,6-dimethoxybenzothiazole, 5, o-dioxymethylene benzothiazole, 5-hydroxybenzothiazole, 6-hydroxybenzotliiazole, a-naphthothiazole, ß-naphthothiazole, 5-methoxy-ß, ß-naphthothiazole, 5-ethoxy-ß-naphthothiazole, 8-methoxy-a-naphthothiazole, 7-methoxy-o-naphthothiazole, or a 4'-methoxythianaphtheno-7 ', 6', 4,5-thiazole ring;

an oxazole ring, e.g., a 4-methyloxazole, 5-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethyloxazole, 5-phenyloxazole, benzoxazole, 5-chlorobenzoxazole, 5-methylbenzoxazole, 5-phenylbenzoxazole, 6-methylbenzoxazole, 5,6-dimethylbenzoxazole, 4,6-dimethylbenzoxazole, 5-methoxybenzoxazole, 5-ethoxybenzoxazole, 5-chloroanphthoxazole, 6-methoxybenzoxazole, 5-hydroxybenzoxazole, 6-hydroxybenzoxazole, a-naphthoxazole or one β-naphthoxazole ring;

of a selenazole rinpes, e.g. B. a 4-methylselenazole, 4-phenylselenazole, Benzoselenazole, 5-chlorobenzoselenazole,

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ORIGINAL IWCPECTED

5-methoxybenzoselenazole, 5-hydroxybenzoselenazole, tetrahydrobenzoselenazole, a-x-naphthoselenazole, or ß-naphthoselenazole ring;

a thiazoline ring, e.g. B. a thiazoline or one 4-methylthiazoline ring;

a pyridine ring, e.g. B, μ a pyridine, 3-methylpyridine or 4-Methylpyridinringes;

a quinoline ring, e.g. B. a quinoline, 3-methylghinoline, 5-ethylquinoline, 6-chloroquinoline, 8-chloroghinoline or 6-methoxyquinoline ring;

a 3,3-dialkylindolenin ring, e.g. B, a 3,3-dimethylindolenine or a 3,3-diethylindolenine ring;

an imidazole ring, e.g. B. an IMidazole, 1-alkylimidazole, ™ 1-alkyl "4 _> 5-dimethylimidazole, benzimidazole, 1-alkylbenzimidazole, 1-aryl-5, 6-dichlorobenziinidazole, 1-alkylnaphthimidazole, 1-aryl -ß-naphthimidazole, or a 1-alkyl-5-methoxy-a-naphthijnidazole ring,

Other desensitizing rings listed in the specified Structural formei can be completed by Z ^ are for example nitrothiazole, nitronaphthothiazole, nitro

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oxazole, nitronaphthoxazole, nitroselenazole, nitronaphthoselenazole and nitropyridine rings.

Dyestuffs of the formula I indicated, in which 0 is used to complete of a fused-on pyrindine trinpes represents the required atoms, have proven to be particularly advantageous proven.

The new cyanine dyes of the invention are extremely effective electron acceptors for direct-positive, They are silver halide photographic emulsions. Furthermore, they are excellent desensitizers, for example in emulsions used in the process described, for example, in U.S. Patent 3,250,618 will.

A ring with a desensitizing effect is understood here to mean those rings which, after being converted into a symmetrical one Carbocyanine dye and addition of the carbocyanine dye to a gelatin-silver chlorobromide emulsion with 40 mol »-% Chloride and 60 ΜοΙ, -% bromide in a concentration of 0.01 to 0.2 grams of dye per mole of silver by electron trapping to at least about 80 ligen Loss of the blue sensitivity of the emulsion if it is exposed sensitometrically and for 3 minutes at room temperature is developed in a developer A of the following composition:

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ORIGINAL UÄEPZCTED

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Developer A

N-methyl-p-aminophenylene sulfate 2.0 g

Sodium sulfite (anhydrous) ...................... 90.0 g

Hydroquinone 8.0 g

Sodium carbonate (monohydrate) 52.5 g

made up to 1.0 liter with water.

Particularly advantageous, so-called desensitizing rings are those that are produced after conversion or conversion in a symmetrical carbocyanine dye and testing in the described iveise to an almost or almost complete desensitization of the current emulsion to blue light, d. H. a more than about 90 to 95% ΐσβη Loss of sensitivity to blue radiation.

The new cyanine dyes of the structural formula given are easy to prepare. A suitable method for Production of the cyanine dyes consists, for example, in a mixture consisting of / a heterocyclic Compound of the following structural formula:

II. R ₁ -N

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where η, R ₁ and Z have the meanings already given and X is an acid anion and R ^ is an alkyl, aralkyl or aryl group, for example a methyl, ethyl or benzyl group, and 2. a complex condensed pyrimidinedione compound of the following structural formula:

, —I

III. , C "C = L-NIl-R.

Il

where L and Q have the meaning already given and R- is an aryl group, for example a phenyl or tolyl group in preferably approximately equimolar amounts in the presence of a condensing compound, for example in the presence of a trialkylamine, e.g. B. triethylamine, or piperidine or N-methylpiperidine into one inert solvents, such as acetic anhydride, to heat.

The crude dyes formed in the reaction can easily be separated off from the reaction mixture and passed through one or more recrystallization from suitable solvents, for example hot ethanol, m-cresol or pyridine, clean.

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The ones used to make the new cyanine dyes Pyrimidine compounds of the formula III can be easily prepare, for example, by heating a mixture of approximately equimolar amounts of

(T) a compound of the following structural formula:

IV.

and (2) ethyl isoformanilide in an inert solvent, such as m-cresol or 1-methylpyrrolidinone, whereupon the reaction product is separated off and recrystallized from a suitable solvent such as pyridine can be.

For the production of direct positives. " photographic silver halide emulsions One or more of the novel cyanine dyes can be incorporated into appropriately fogged silver halide emulsions.

The emulsions can be obscured in any of the known ways, for example by exposure by light or by the action of chemical concealers, for example stannous chloride, formaldehyde or thio-

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urea dioxide. The emulsion can advantageously also by adding a: reducing compound, such as thiourea dioxide, and a compound a metal that is more electropositive than silver, for example gold, ζ. B. in the form of potassium chloroaurate, that is described, for example, in British Patent 723 019, can be obfuscated.

Typical reducing compounds suitable for concealment are, for example, stannous salts, e.g. stannous chloride, Hydrazine, sulfur-containing compounds, for example thiourea dioxide, phosphonium salts, ζ. Β, Tetra (hydroxyroerhyl) phosphonium chloride and the like. Typical suitable metal compounds, the metal of which is more electropositive than silver, are gold, rhodium, platinum, palladium bond Iridium compounds, preferably in the form of their soluble salts, for example potassium chloroaurate, Aurich lorid or (NtK) -PdCIg can be used.

The concentrations of reducing compound and metal compound (e.g. metal salt) can vary widely be. The use of about 0.05 to 40 mg of reducing compound per has been found to be advantageous Mol of silver halide and 0.5 to 15.0 mg of metal compound per mole of silver halide. Particularly advantageous results are obtained at low concentrations of both reducing compound and metal

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ORIGINAL K: CFcC7ED

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connection achieved.

The concentration of the cyanine dye in the emulsion can also be very different. Preferably about 50 to 2000 mg, in particular about 400 to 800 mg, Cyanine dye per mole of silver halide in the case of direct positives Emulsions used.

Here and in the following text, an emulsion is referred to as fogging which contains silver halide grains which produce a density of at least 0.5 when they are developed without exposure for 5 minutes at 20 ^° C. in a developer B of the following composition when the emulsions are thereby is developed in the form of an emulsion layer, e by applying the emulsion to a support in

a strength corresponding to 50 to 500 mg of silver per 0.0929 m was obtained.

Develop eggs B

N-methyl-p-aminophenp.lsulfat ...- ,. 2.5 g

Sodium sulfite (anhydrous). 30.0 g

Hydroquinone ........................ 2.5 g

Sodium metaborate. .. · ................... 10.0 g

made up to 1.0 liter with water.

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origina

The new cyanine dyes can also advantageously be incorporated into direct-positive emulsions, whose silver halide grains have a water-insoluble silver salt core and an outer shell made of a veiled, have silver salt insoluble in water, without Exposure to silver is developable. In this case, the new cyanine dyes are preferably the external ones ™ shell of the silver halide grains of such emulsions incorporated. Such emulsions are described, for example in U.S. patent application Ser.No. 448 467.

The shell of such grains drops; for example generate by precipitation of a light-sensitive silver salt which is insoluble in water and which can be masked, the veil being made by a bleaching process. removed can, on the nuclei of the silver halide grains. The shell ^ should have sufficient strength to advance of the developer during the development of the emulsion to the core. The silver salt shell becomes a surface covering subjected, so that they can be developed into metallic silver when used, conventional surface developer is.

It has proven to be expedient to conceal the silver salt of the casing sufficiently so that a density of

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is generated at least about 0.5 when the emulsion of the composition described below is for 6 minutes at 2O ⁰ C in a developer C developed, after the emulsion to a manager in a layer thickness corresponding to 100 mg of silver applied per 0,0929 m has been.

Such obfuscation may be due to chemical sensitization compared to veils with the sensitizing Ver-Dindimgen, which are used to chemically sensitize the core emulsion can be achieved through action of high intensity light and other known processes used for fogging photographic silver halide emulsions are known. While the kernels of the silver halide grains the emulsion is not too sensitive to haze will need, the shell is veiled. A concealment by a reducing is advantageously acting sensitizer, a noble metal salt, for example a gold salt, and a reducing effect Sensitizer, a sulfur sensitizer, high pH and low pAg, in silver halide precipitation and the like, brought about,

The shell of the silver halide grains can furthermore optionally be coated on a support after the emulsion has been coated to be veiled.

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Developer C

N-methyl-p-aminophenol sulfate, 2.5 ρ

Ascorbic acid 10.0 ρ

Potassium metaborate., .., ..... 35.0 jt

Potassium bromide, 1.0 g

made up to 1.0 liter with water

pH value adjusted to · ,, ... 9.6,

Before the shell of water-insoluble silver salt is produced on the silver salt cores, the core emulsion is first chemically or physically pretreated in order to generate centers which promote the precipitation of photolytic silver, ie core centers which generate latent images. The centers can be generated by various known methods. Chemical sensitization processes as described, for example, in the journal "Science et Industries Photographiques", Volume XXVIII, January 1957, Seigen 1-23 and January 1957, pages 57-65 have proven to be particularly advantageous. The chemical sensitization processes described can be divided into 3 main classes, namely the sensitization by means of gold or other noble metal compounds, the sensitization by means of sulfur, for example compounds with labile sulfur atoms, and the so-called reduction sensitization, ie. the

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Treatment of the silver halide with a strongly reducing agent Compound, which tiny spots or spots of metallic silver in silver salt crystals or grains generated.

The new cyanine dyes of the invention are particularly advantageous electron acceptors for highly sensitive direct positive silver halide emulsions with fogged silver halide grains, as described, for example, in Belgian patent specification 695 366. The fogged silver halide grains of such emulsions are characterized in that after application in the form of a photographic silver halide emulsion to a support to produce a maximum density of at least about 1, after b minutes of development at 20 ^° C. in a developer B, they lead to a maximum density which is greater by at least about 3Oi than the maximum density of an identical schematically a device under test, 6 minutes, developed at about 20 ⁰ C in the same developer B long after about 10 minutes long i

Composition:

For 10 minutes at 20 ° C in a bleach bath of the folpenden

Potassium cyanide ......................... 50 mg

Glacial acetic acid. 3.47 cm ³

Sodium acetate, ...................... "........ 11.49 g

Potassium bromide. ,, ... 119 mg

made up to 1.0 liter with water

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has been bleached.

The grains of such emulsions lose at least about 25 3>, generally irindestens about 40% of her veil when they are bleached at 2O ⁰ C in a Kaliumc.yanidbleidibad the composition given 10 minutes. This loss of fog can be illustrated by applying the silver halide grains in the form of a photographic silver halide emulsion to a support to achieve a maximum density of at least 1.0 after developing for 0 minutes at about 20 ^° C. in developer U- and comparing the density of the test piece with an identical test specimen which was developed for 6 minutes at 20 ° C. in developer H after the test specimen had been bleached for about 10 minutes at 20 ° C. in the potassium cyanide bleaching bath of the composition described,

As already stated, the maximum density of the unbleached test lens is at least 30 % greater, "generally at least 60 % greater, than the maximum density of the bleached test lens.

The customary known photographic silver halides can be used to prepare the silver halide emulsions. h, for example silver bromide, silver iodide, Silb.erchl-Q.r-id, silver chlorobromide, silverbr.o.moipd-id and. syllable rchlorobroroid. »

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Silver halide emulsions have proven to be particularly advantageous with silver halide grains of an average Grain size less than about 1 micron, especially less to be about 0.5 microns. The silver halide grains can thereby have a regular structure or any other of the known structures, for example a cubic one or octahedral structure, as for example in the Beirischen patent 695 366 can be described.

The grains also preferably have a uniform distribution of diameter, as is also described in Belgian patent specification 695,366. For example, at least 95% by weight of the silver halide grains can have a diameter which deviates from the mean grain diameter by no more than about 40%, preferably no more than about 30%.

Mean grain diameter, d, Iv. average grain sizes, can easily be determined by methods described, for example, in The Photographic magazine Journal ", Volume LXXIX, 1949, pages 330-338.

The veiled silver halide grains of these direct-positive, Photographic emulsions produce a density of at least 0.5 if, without being exposed, Developed for 5 minutes at 20 ° C in developer B, after the grains in the form of the silver halide emulsion

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in a layer thickness of 50 to about 500 ng of silver per

2
0.0929 π carrier surface can be applied to a carrier.

Such silver halide emulsions have proven to be particularly advantageous proved, the silver halide grains of which consist of at least 50 mol-Si of bromide, very particularly advantageous Silver halide emulsions according to the invention are silver broiro iodide emulsions, especially those with less than about 10 mole percent iodide.

The photographic "over halide emulsions" of the invention can advantageously in such a way Thickness can be applied to the usual photographic carrier

2 denotes that about 50 to about 500 mg of silver are accounted for on a carrier area of 0.0929 m.

In the preparation of silver halide photographic emulsions the dyes are preferably incorporated into the washed, finished silver halide emulsion in which they are distributed thoroughly.

Methods for incorporating dyes and other additives into photographic silver halide emulsions are known and easy to carry out, For example, it has proven advantageous to use the dyes in the form of To incorporate solutions in suitable solvents into the emulsion, being of course only such solvents

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can be used that the photosensitive emulsion do not affect adversely. Suitable solvents are, for example, methanol, isopropanol and pyridine and water, either alone or in a mixture with one another.

With the new cyanine dyes the usual ^ known and various types of photographic silver halide emulsions raise awareness. Such emulsions ■ know in known KLise using the most diverse hydrophilic colloids produced vferden, for example using naturally occurring binders such as Gelatin, albumin, agar-agar, gum arabic, alginic acid and the like, or using hydrophilic synthetic Resins such as polyvinyl alcohol, polyvinyl pyrrolidone, cellulose ethers, partially hydrolyzed cellulose acetates and the like

The binders of the emulsions can also be dispersed, contain polymerized vinyl compounds like them for example, in U.S. Patents 3,142,56R; 3 193 38ö; 3,0b2,674 and 3,220,844. to such polymerized vinyl compounds include, for example, the water-insoluble polymers of Alkyl acrylates and alkyl methacrylates, acrylic acid, suIfoalkyl acrylates or sulfoalkyl methacrylates.

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Optionally, the silver halide emulsions, which the new cyanine dyes are added, also contain so-called color formers, for example so-called color couplers.

The silver halide emulsions containing a or more of the new cyanine dyes can be resolved apply the usual photogrankic Trüper, for example on supports made of glass, foils, for example made of cellulose acetate, cellulose acetate butyrate, polyesters, e.g. B. polyethylene terephthalate, on substrates made of paper, baryta-coated papers, rit polyolefin-coated papers, for example Paper coated with polyethylene or polypropylene and which is used to improve adhesion the L-emulsion may have been irradiated with electrons.

The following examples are intended to illustrate the invention in more detail :

example 1

3- / ~ (1,3-Diethyl-2 (1Ii) -iiridazo / ~ 4,5-k_7quinoxalinylidene) -äthyliden_7-2H-pyrimido / ~ 2,1 -j2_7-benzothiazol-2, 4 (3Fl) -diene

1 0 9 BI h I I b J 0

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Line r-iischunp, consisting of 0.8 ρ 3-AniHnor: ethylene-2lipyrir. "Iido /" 2,1-b_7ben-zothia-zol - 2,4 (3Ii) -dian, u, 7 p; 1 »3 ~ diethyl-2-n! Ethyliniidazochinoxaliniu; np-toliaoIsuironat unci U, 2 r Triiithylai'.in, was 15 '! Inutes lanp in 20 ml Lssi? - SMii-eimhydrid on ki'-ckfIuJ? temperature heated. The reaction mixture was then allowed to dry by means of a rotating oven. The LLC residue. Was dissolved in methanol "Open cnouiien, Korauf was filtered. The solid was then hot iir ;.. ¹ PyriUin, filtered vrorauf the solution and was collected. Letii--anol added. I.'ach cooling the The resulting crystals were filtered off and washed with methanol. The crude dye was then dissolved in chloroform, before the solution was passed through a column filled with aluminum oxide (activity II). The dye was then added isolated by concentrating the Chlorofprirösunp · under Veruendunp a rotating evaporator. The yield of red crystals was 16%. The crystals had a melting point of more than 310 tons.

The manufactured dye that acts as a desensitizing agent core a 1,3-diethylin.idazo / 4,5-b_7chinoxalinkern was found to be useful as an electron acceptor and spectral sensitizing agent for veiled, direct-positive, photographic silver halopenidnacii Tested with the following procedure:

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Line Gelatine-Silberbromcnoclider.mlsion with 2.5 Niol-% Jodie! as iialogeride so; ie an average grain size of about 0.2 microns was prepared by adding an aqueous solution of potassium bromide and potassium iodide and an aqueous solution of silver nitrate to an aqueous gelatin solution at a temperature of 70 ⁰ C. The resulting emulsion, after solidification, was then noodled by cooling and washed in the usual way in k / alter.i kasser.

The Lnmlsion was then obscured by their zunfichst ö, thiourea dioxide 2 mg per mole of silver was added and the Lmulsion lane 60 minutes at 65 ⁰ C was heated, whereupon its further incorporated 4.0 mg of potassium chloroaurate per mol of silver and the biiiulsion again for 60 minutes was heated to 65 C.

Then so much 3- / ~ 1,3-üiethyl-2- (lii) -imidazo- / 4,5-b_7quinoxalinyliden) äthyliden_7-2H-pyrimido / "2.1 -b_7-benzothiazole-2,4 (3Il) -dione added that the dye was present at a concentration of 0.08 g per mole of silver.

The resulting emulsion was then subjected to a usual level. looseacetatfilmträper applied in such a way that on a Träper-

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area of 0.0929 m 100 ir-p silver and 400 r-ψ. Gelatine was omitted.

A line sample of the film obtained was then exposed in a customary Sensi toi'ieter (type F.astrian Th) using a Volfrair.la ^^ e, - whereupon the exposed film was developed for 6 minutes at a normal ¹ - "temperature in the developer Λ became.

Subsequently uer FiIw was fixed pewaschen and dried. The results obtained are summarized in Table I below.

When this dye was used, a raxiral density was obtained in the unexposed districts of 2.44 and a · 'ininumdielite achieved in the exposed areas of 0.08. The rr.axiir.ale ü'i; .sensitivity of liwulsion Ia ^ at 530 py at a relative sensitivity of 295.

From the results obtained it follows that the new Cyanine dye as both electron acceptor and spectral Sensitizing agent works.

Using the one produced in the described manner 'Photographic material became direct-positive images excellent quality received.

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BATH

" ^2S " 176938

Excellent purple dye images were obtained when the lipulsion used 1- (2,4,6-trichloropheriyl) -3.3 ^l - (2 ", 4" -di-t. -Arylphenoxyacetani do ) benz ir.iidazo-5 -pyrazblon one body and the lirulsion applied to a conventional carrier, by means of a Wolfrari.-Lichtauelle through filters (Krattenfilter ^ _T ^ β ·] _unc j, ν _{Γ <} ^ j ^ _{0. was} licitet and in the usual! '/ ice after the Uir.verkehrverf ahren _§ v.ie it for example in the USA patent 3 Ü4b 129
is described, with the exception that the Schwarz - '.' eiP development was omitted, was developed. The color development could be shortened to a period of one minute. The development takes place in total darkness until after the fixation, in ¹ individual the procedure was as follows:

(1) color developing agent; 1 minute

(2)! Clear 5 minutes

(3) silver bleaching? Minutes

(4) fix 3 minutes.

It was then washed and dried. The color developer used had the following composition:

BATH
109815 / 1B20

Water, - 21 to 27 ⁰ C 1.0 liter

Denzyl alcohol 0.0 cw

Sodium hexainetaphosphate. 2.0 g

Sodium sulfite, dehydrated 5.0. G

-Trisodium pneumonia, 40.0 g

Potassium bromide,., 0.25 g

0.1% i;! E solution of potassium iodide ..... 10.0 cm

sodium hydroxide. ........... 6.5 g \

4-amino ~ N- (ß ~ methanesul eonamidoethyl) -m-tolu-

idinsesquisulfate monohydrate .................... 11.33 g

Ethylene diairine sulfate -...- 7.8 g

Citrazinic acid (C2,6-di-hydroxyisonicotinic acid). ,, 1.5 g

The clarification bath had the following composition:

V.'asser ,, 1.0 liter

Sodium bisulfite 10.0 g

The silver bleach bath had the following composition:

Sodium ferricyanide 60.0 g

Sodium hypophosphate. IUQ. 17.6 g

Sodium bromide 15.0 g

Sodium hydroxide ..., ....., .. ,, ....,. ,,., .., ..... 3.5 g

Sodium thiocyanate 5.0 g

made up to 1.0 liter with water.

1098 15/1620 BAD Oü

176938

The fixer used had the following composition:

Water, (27 ⁰ C) 1.0 liter

Katriur.ithiosulphate 95.0 σ

Sodium bisulfite 20.0 #

Example 2

³ ~ / ~ Oi 3-diethyl-2C1H) -imidazo / "4,5-b_7" quinoxalinylidene) ethylidene-7-2ii-pyrimido / ~ 1,2-a-7benziipidazül-2,4 (3Ii) -dione

C = CIi-CH = C

A mixture of 3.06 ρ 3-anilinomethylene-ZH-pyriinido- / 1,2-α-7benzinudazole-2,4 (3ii) -dione, 0.2 ml acetic anhydride and 30 ml of 1-methylpyrrolidinone was added to the boiling point the mixture heated. Thereupon 2.76 g of 1,3-diethyl-2-methylimidazo / 4,5-b-7-quinolxalinium chloride were added and 2 g of triethylamine were added, whereupon the mixture was 1 minute

109815/1820

heated to reflux temperature for a long time and then to room temperature has been cooled down. The excruciating fall asleep; was filtered off and washed with methanol. After extraction of the solid precipitate with boiling pyridine was the Falling asleep dissolved in hot m-cresol, whereupon the Lüsunp filtered and methanol was added. After cooling, the dyestuff which had precipitated out was filtered off and repeated crystallization in the manner described Orange-red crystals rit a sharp point from above 31Ü C received. The yield of dye is: U.

The dye obtained, which as a desensitizing ring contained a T, 3-diethylir.i (] azo / ~ 4,5-b-7-quinolxalinfr, was tested according to the method described in Example 1. The results obtained are shown in fol. pencien table 1 zusammenfestellt. from the results obtained daP · the dye arises, a designated effective from ^ ezeich- Λ electron acceptor for i ^ erschleierte, direct positive ■ represents photociraphische Silberhalopenidemulsionen.

Example 3

3- £ ~ (1, 3-diethyl-2C1i;) - imidazo / "4,5-b_7-quinoxalinylidene) Ethylidene_7-2ii-pyrido / ~ 1, 2-a_7pyrimidine-2,4 (3H) -dione

1 0.98 1 5 / Ί 620 _B AD OBiCx ^ä .a * .L

C = CH-CiI = C

Line riischunp from 1,3 ρ 3-anilinonethylene-2t '.- ryrido / 1,2- £ _7-pyrimidine-2,4 (310-dione, 1, <"ρ 1, 3-diithyl -2-rrethylirMuazo- / ~ 4,5-b__7-quinoxalinium iodide and 0.0 ρ triethylairin was heated to reflux temperature for 5 minutes in 25 liters of lissipic acid anhydride heated. The reaction mixture was then left to cool and stored for 2 hours at a ierreq-ieratur. The solid precipitate was then filtered off and Wash with acidic anhydride.

The crude dye was then celusted in hot m-cresol, before the solution obtained was filtered and methanol was added to the filtrate. After cooling and filtering, the filtered precipitate was treated again in the manner described, orange-red crystals with a melting point of 281 to 23 ° C. (dec.) Were obtained. The yield of dye was 27 ^f ₀ .

The dye obtained, acting as a desensitizing agent Ivinp contained a 1,3-diethyl inidazo / "4,5-l · ^ 7quinoxalinrinr ·,

9 8Ij / 1b 2 0

BATH

176 3383

was after deir. in 3example 1 described method tested. The results obtained are shown in Table 1 below. From the results obtained, it can be seen that. the dye is an excellent Hlektronenakzeptor and an excellent spectral Sensibilisierunfrsmittel for fogged direct-positive photographic Silberhalofjenidemulsionen is "When using the dye described densities were respectively for the ä unexposed and exposed areas of 2.38, obtained 0.04. The maximum sensitivity of the dye was about 550 my while the relative sensitivity of the emulsion was 1000.

Example 4

3- / ~ (6-Chloro-1,3-dinhenyl-2 (1H) -imidazo / "4,5-b ^ _7-quinoxalinylidene) -ethylidene__7-2II-pyrido /" i , 2-a._7pyrimidine-2,4C3H) -dione

10 981 5/1 ö 20

liine mixture of 2.6 g of 3-anilinomethylene-2-li-pyrido / "" i, 2-a._7-pyrimidine-2,4 (3HJ-dione, 5.4 ρ ö -chloro-2-methyl-i, 3 Diphenylimidazo / ~ 4 _> 5-b _i _7-quinoxalinium- £ -toluolsul £ onat and 1.1 g of triethylamine were refluxed for 5 minutes in 25 ml of Hssipsic anhydride The crude dye was then dissolved in 400 ml of hot ethanol, whereupon the solution was filtered and 5 ml of triethylamine were added to the filtrate having a melting point 282-286 ⁰ C (dec.) was obtained The yield of dye was 30%.

The dye obtained was made according to that described in Example 1 Procedure tested. The results obtained are shown in Table 1 below. The results obtained show that densities in the unexposed and exposed areas of 2.04 and 0.04 were obtained. The maximum sensitivity was 550 my, with a relative sensitivity of 501. From the As a result, the dye was found to be an excellent electron acceptor and an excellent one represents a spectral sensitizer for fogged direct positive photographic emulsions.

109815/1620

176938

example 5

3- / ~ (3 -; \ tliyl-0-nitro-2-benzothiazolinylidene); it] iylidene_7 · 2ii-f yrido / ~ 1, 2-a 7-pyripidin-2, 4 (3Ii) -dione

O:

C = CIi-CIi =

liine! aschunp from 2, op 3-AHilinor _; ethylene-2i; -pyrido / 1,2-a_7-pyriniidin-2,4 (3i;) -dione, 3.9 ρ S-ethyl - ^ - rethi-o-nitrobenzothiazolium-ε-toluenesulfonate and 1.1 q triethylamine v. was heated to reflux temperature for 5 minutes in 25 ml of acetic anhydride. The Reaktionsmischunc- i \ ^T urde then cooled, filtered off the precipitated preceded ICiederschlap and advises methanol was washed. The raw dye was then placed in hot ;; m-cresol was dissolved, whereupon the solution was filtered and ethanol and 5 μl of triethylamine were added to the filtrate. After the solution had cooled, the dyestuff which had precipitated out was filtered off and washed with methanol. Dark, shiny crystals with a melting point of 277 to 279 ° C (dec.) Were obtained. The yield of dye

10 9815/1620

176938

uetrup 04

The dye obtained with a 3-yitliyl-0-nitro-2-benzothiazolrinp was then according to that described in Example 1 Procedure tested. The results obtained are compiled in Table 1 below. From the received Results shows that the dye to maximum Densities of 1, ^ 2 and 0.04 in the unexposed and exposed areas, with a maximum Ii sensitivity of 550 ημ 'and a relative sensitivity of 436 were obtained. From the results obtained it follows that that the dye is an excellent electron acceptor and an excellent spectral sensitizer for veiled, photographic reversal emulsions aarstelIt.

Equally favorable results were obtained when the Production of the dye instead of 3-ethyl .- '2-methyl t) -nitrobenzotiiiazolium- £ -toluolsul fön at iinuivalent sets another alternative 3-alkyl-2-methyl-O-nitrobenzoxazolium salts were used, for example the corresponding methyl, ethyl, propyl, isopropyl, butyl, ilexyl, hecyl or dodecyl derivatives or, correspondingly, the chlorides, bromides, iodides, perchlorates or other pVI'oluenesulfonates.

Correspondingly favorable results were also obtained, if instead of 3-Xthyl-2-methyl-0-nitrobenzothiazolium p-toluenesulfonate other quaternary 3-alkyl -2-irethy 1-0-

10 9 8 Ί5 / 1U 2 0

BAD ORiGiNAL

Λ ^Γ

- 37 -

nitrobenzoselenazolium salts were used, for example the corresponding methyl, ethyl, propyl, iso-. propyl, butyl, iiexyl, decyl or dodecyl derivatives and / or the corresponding chlorides, bromides, iodides, perchlorates or p_-toluenesulfonates.

In this l / else example, the following electron acceptors and spectral sensitizers can be obtained like:

3- / ~ (3-ethyl-t> -nitro-2-benzoxazolinylidene) ethylidene_7-2H-pyrido / ~ 1,2-a7-pyrimidine-2,4 (3U) -dione; 3- / ~ C3-ethyl-6-nitro-2-benzoselenazolinylidene) ethylidene_7-2n-pyTido / ~ 1,2-a7pyrimidine-2,4 (3Ii) -dione and derpl.

The S-Anilinornethylen-ZH-pyrido / 1, 2-a7pyrimidine-2,4 (311) -dione used as Auspangskomponente can continue to use _Λ

Equimolar amounts of the most varied of other compounds falling under the formula III are replaced, for example by 3-anilinomethylene-2Ii-pyrimido / 2,1 -b_7benzo-.tiiiazol-2,4 (311) -dione or S-anilinoethylene-ZIl-pyrimido - / "1 , 2- £ _7-benzimidazole-2,4 (3li) -dione. In all cases were Cyanine dyes are obtained which are extremely effective electron acceptors and spectral sensitizers.

10 98 IL) / 1 b 20 . . _BP £ -

- 3 '- 176S383

Example 6

3 - / "(u, 7-dichloro-1, 3-diphenyl-2 (1L) -imidazo / ~ 4, 5-L_7-quinoxalinylidene) äthyliden_7-2H-pyrido / ~ 1, 2-_a_7pyrir> idin · 2,4 (3Ii) -dione

Line mixture of 2.2 r 3-anilinoinethylene-2II-r> yrido / 1 _f 2-_a_7 pyriiridin-2,4 (3il) -dione and 5.3 <? b, 7-I) Iloro-2-methyl-1,3-dipjienylipidazo / 4,5- £ 7-quinoxalinium iodide was heated to reflux temperature in 50 ml of acidic anhydride for 1 minute. The reaction conditions? was then filtered hot, whereupon the solid mass obtained was stirred in 300 inl ethanol with a content of 1.2 ρ diazobicyclo-octane for 2 hours. The crude dye was then filtered off and washed with ethanol. The dye was then purified by dissolving it in 25 ml of ni-cresol, by filtering the solution and adding 350 ml of methanol containing 2 ρ diazobicyclooctane to the resulting filtrate, chilling the solution for 4 hours and depositing the crystals

109815 / 1b20 bad or.;.:.; M

aofiltered. 1: s were bright green crystals with a melting point of 298-299 ⁰ L (dec.). The yield of dye was 17%.

The dye obtained, which contained a ο, 7-IHchlor-i, 5-dirhenyl-2 (11) -in ⁱ idazo / ~ 4, 5-b_7-quinoxalinrinp as desensitizing Rinp, according to the method described ¹ : ^{1 in Example 1} petestet. Pie Got! F.rre-bnisim ¹ in Table 1 to be filed later ^ estelIt. * From the results obtained ercibt itself, the dye is an excellent Hlektronenalcze ^ tor and an excellent effective spectral Sensibilisierunrsi .- daf. Edium -Door fogged direct-positive, representing photoqrarhiscLe Hrulsionen. As can be seen from Table 1, a relative sensitivity of 1330 was determined for this dye. The densities in the unexposed and. exposed areas of the obtained iJilder lapen at 1, £ 4 and 0.03, respectively. The maximum noise sensitivity lap at SbS ρμ,

Example 7

3- / (3-N'-ethyl-o-nitro-2-benzoselenazolinylidene) ethylidene 2h-pyrido / "i, 2- £ _7pyrin! Idin-2,4 (31i) -dione

CH- 109815/1620

76ο

I / VJ

- 40 -

2.13 ρ 2, 3-Din; et.hyl-6-nitrobenzoselenazoliur- £ -toluene sulfonate and 1.27 ρ 2, 3-dintethylaiiiinoni6tIiylen-2n-pyrido / 1,2- ά / pyrimidine, 4 (3Π) - dion-Hydrochloric 'were mixed with one another in 20 ir. was heated to reflux temperature. The Reaktionsr'ischunp was tann koltpestellt where rough the dye obtained in Γοπ.ι ^r of the hydrochloride salt is filtered off, pewaschen with acetone and was dried, After two ^ of the dye in £ -cresol, EinpiePen crystallization by dissolving the solution in methyl alcohol and G ¹ I ■ erführung of the dye in the free Dase by Zupabe of diazabicyclo-octane of the pure dye was obtained in a yield of 38%. The dye pre-had a melting point. 301 to 3O2 ° C (dec).

The desensitizing ring obtained is a nitrobenzoselenazolrinp The dye containing the dye was then tested according to the procedure described in Example 1. the The results obtained are shown in Table 1 below compiled. The results show that the Dye an excellent electron acceptor and an excellent spectral sensitizer for veiled, direct-positive, photographic emulsions represents. From the results of Table 1 that the dye has a relative! immunosensitivity

109815/1620 ^BAD

176 93.8

of 795 leads and that the images obtained have densities in the unexposed and exposed areas of 1.82 and 0.17, respectively. The maximum painful sensitivity lap at 5 70 my.

T a b e 1 1 e 1

I '> a-
game
K r. Dye con
centering in
g / mole
silver Rela
tive limp
sensitive Maximum
Density un-
lent
ter districts Minimal
Density in
exposed
Districts Maximum
Sensation
opportunity
Om) 1 0.080 295 2.44 0.08 5 30 2 0.460 91 2.26 0.30 - 3 0.450 100Q 2.38 0.04 550 4th 0.650 501 2.04 0.04 550 5 0.650 436 1.8 2 0.04 550 6th 0.650 1380 1.84 0.03 565 7th 0.750 795 1.82 0.17 5 70

In the following the production of some of the starting compounds is given used condensed pyrimidinediones described.

1 09 8 1 5/1620

BATH.

A) 3-Anilinoip.etkylen-2h-pyrido / ~ 1,2-α-7-pyrimidine-2,4 (3ii) dione

C = CiI-NIi-C ₆ H ₅

A mixture of 8.1 ρ 2ti-pyrido / ~ 1, 2-a._7pyriirddin-2,4- (311) -dione and 100 ml of m-cresol was heated to reflux temperature, whereupon 8.3 g of ethyl isoforinanilide were added. The reaction mixture was then cooled, whereupon the reaction product was precipitated by adding! - 'ethanol. After recrystallization from pyridine (50 ml / g), light yellow crystals of the reaction product were obtained in a yield of 40 % .

In the manner described under A) 3-anilinomethylene · 2I-pyrimido / "2,1 -b_7benzothiazol ~ 2,4 (311) -dione was obtained from 3.6 g of 2H-pyrimido ^ ~ 2,1 -b__7benzothiazol-2,4 (3H) -dione and 2.8 g prepared A'thylisoforir.anilid. This gave pale yellow crystals. The yield of the reaction product was 611th

1098 15/1620

ORIGINAL

ι / η: -. ο η

176938ο

3-anilinoethylene-2n-pyrimido / "i, 2-_a_7-henzimidazol-2, 4-i) -dion

C = CL-NhC, Ii ^b

A line mixture of 10 ρ 2Ii-pyrinido / 1,2-_a_7-benzir; idazol-2,4 (3l.) -Dione and 100 ml of 1-methylpyrrolidine was heated until the solution was complete, whereupon 8.3 g ^ tliylisoformanilid were added. The reaction process ;; was then cooled and methanol was added. The whole was then placed in the cold, whereupon the precipitated reaction product was filtered off and washed with methanol. The yield of cream-colored crystals was 64 %,

The following is the preparation of veiled, direct positive, photORraphic silver halide emulsions described in more detail of the invention.

To 4.08 kg of a gelatin-silver chloride emulsion with an equivalent of TOO g of silver nitrate was added 0.017 g of 3 - / "(1.3

1098 15/1620

.44-176S383

Diethyl-2 (1H) -imidazo / "4,5-b_7-quinoxalinylidene) ethylidene_7-2H-pyrido /" "i , 2-ji_7pyrimidine-2,4- (3II) -dione correspondingly Example 3 added.

The resulting emulsion was then applied to a non-glossy paper support, followed by the resulting emulsion layer was flash-exposed with white light, so that after development in a developer, the following Composition after dilution with 2 parts of water per part of stock developer solution a density of 1.2 was obtained .

K-methyl-p-aminophenol sulfate 3.1 g

Sodium sulfite, dehydrated 45 g

Hydroquinone 12 g

Sodium carbonate, dehydrated. 67.5 g

Potassium bromide 1.9 g

made up to 1.0 liter with water.

The material obscured by exposure then became image correct exposed with light modulated by a No. 15 Wratten filter. A direct-positive image was obtained obtain.

Similar results were obtained when, instead of the dye of Example 3, the dye of Example

1 ü 9 8 IG / 1 G 2 0 ORIGINAL USPECTED

Ί '7 L' Π ^P JU

176938 °

6 was used.

II.

3.175 kg of a gelatin-silver chloride emulsion with an equivalent of 100 g of silver nitrate were ^{heated to 40 °} C., whereupon the pH of the emulsion was adjusted to 7.8. Then, a 40% formalin solution were added to 8 ml and the emulsion for 10 minutes at 40 C was ER- g heated. Subsequently, the pH of the emulsion was adjusted to 6.0, followed by 0.125 g of 3- / ~ (3-ethyl-6-nitro-2-benzothiazolinylidene) äthyliden_7-2H-pyrido / 1,2-a_7pyrimidin ~ _2-t 4 (3H) -dione, corresponding to Example 5, were added. The emulsion was then applied to a support, whereupon the material obtained was exposed to light in the manner described. Direct positive images of excellent quality were obtained. Similar results were obtained when the dye of Example 7 was used instead of the dye of Example 5, ™

In the preparation of a photographic material using a silver halide emulsion according to the invention The silver halide emulsion layer as well as other layers of the photographic material can be used in a conventional manner cured using conventional curing agents, for example with aldehyde curing agents, e.g. formaldehyde and mucochloric acid, aziridine hardeners, hardeners made from derivatives of dioxane or from oxypoly-

109815/1620 original tisfict: -

saccharides, such as oxidized starch or oxydieiten plants ^ ummis, exist and the like.

The emulsion layers can also contain additional additives, as are normally used during manufacture photographic materials are used, such as lubricants or lubricants, stabilizers, sensitivity increasing compounds, light absorbing dyes, plasticizers and the like. Des furthermore, the photographic silver halide emulsions can optionally additionally have spectrally sensitizing properties Contain dyes. Furthermore, the silver halide emulsions contain color couplers according to the invention or optionally be developed in solutions that Contain color couplers or other color-producing compounds. Suitable color couplers include the monomeric and polymeric color formers, for example pyrazolone color couplers, as well as phenolic, heterocyclic and open-chain color couplers with a reactive methylene group. *

The dye-forming couplers can be used in the direct-positive photographic silver halide emulsions of the invention be incorporated by known conventional methods, such as are described, for example, in the United States patents 2,322,027; 2 801 171 and 1 055 155 as well as 1 102 028 and 2 186 849. Furthermore, they can for example

10 9 8 15/1620 " ^0R1G1NAL ^ ^{? E}

■ 1 ^r /

be developed by means of incorporated developers, for example using rolyhydroxybenzenes, aminophenols and 3-pyrazolidones,

1098 15/1 b20

Claims (1)

176938 Pat e η t a η s ρ r ü c Ii c 1. Cyanine dyes, characterized by the following structural formula: R ₁ -NC-CiI = CIi) - ^ j- CC = LL) ₁₁ === C 3 ? c Il ^x - <3 ' mean: m = 1 or 2; η = 1 or 2; L a methine run; R. an alkyl, alkenyl or aryl group; Z to complete ;; one desensi- ring with 5 or 6 ring atoms required atoms and Q the to complete, ", one ankonden sated heterocyclic ring with 5 or 6 Γ ingatons required atons, 1 Q 9 8 ι ..) / 1 ο Z 0 ORIGINAL IMSPECTED -49- '.17-6 938 " 2. Cyanine dyes according to claim 1, characterized in that in the given formula Z to complete of a mitrobenzoxazole, nitrobenzoselenazole or imidazo ^ ~ 4,5-b_7quinoxalinringes required Represents atoms. 3. cyanine dyes according to claim 1, characterized in that ([ net that in the given formula n, L and R .. the aii- * have given meaning and to complete a condensed thiazole, oxazole, selenazole, thiazoline, ■ Pyridiii-, quinoline-, 3,3-dialkylindolenine-, Imidazole or oxazole ring required atoms to complete a nitrobenzothiazole-, nitrobenzoselenazole-, imidazo ^ 4, S-bJ- quinoxaline-, 3,3-dialkyl-3H-pyrrolo / "2,3-b_7-pyridine-, 3,3-J) ialkyl- 3H-nitroindole, thiazolo- ^ "4,5-b_7quinoxaline or nitroquinoline ring represent required atoms. 1098 I o / Ib 2 0 OTOT: AL HÄPECTED '-so. 176 938 4. Cyanine dyes according to claim 1, characterized in that they consist of: 3- / ~ (1, 3-diethyl-2 (1Ii) ircidazo- / ~ 4,5-b iquinoxalinylidene) ethylidene J ^ -ZH-pyriniido ^ 2 , 1 -b_7-b.enzothiazole-2,4- (3Ii) -dione; 3 - / "(1,3-diethyl-2 (1Ii) -imidazo ^ ~ 4,5-b j ^ quinoxalinylidene) ethylidene _7 ~ 2H-pyrinido- [" λ , 2-a jbenzinidazole-2,4- (3iI) -dione; 3- ^ ~ (1,3-Diethyl-2- (1U) -imidazo ^ "4,5-b J? Quinoxalinylidene) ethylidene J-2 \ [- pyrido / ~ 1,2-ei J7pyrimidine-2,4 ( 3H) -dione; 3- / "(6-chloro-1,3-diphenyl-2 (1H) -imidazo ^ ~ 4,5-b _7-quinoxalinylidene) -ätliyliden_7-2II-pyrido /" i, 2-aJ7pyrimidin- 2,4C3H) -dbn; 3 - ^ "(3-ethyl-6-nitro-2-benzothiazolinylidene) ethylidene_7" 2H-pyrido ^ "i, 2-a_7pyrimidine-2,4C3n) -dione; 3 - /" (6,7-dichloro-1, 3-diphenyl-2 (111) -imidazo- ^ 4,5-b _7quinoxalinyliden) ethylidene _ / - 2K-pyrido / ~ 1 ^ -a Jpyrimidin-2,4 (3H) -dione or 3- ^ ~ (3-methy1 -6-nitro-2-benzoselenazolinylidene) ethylidene J- ^ ~ 1,2-a 7pyriraidin-2,4 (3H) -dione. 5. Use of cyanine dyes according to Claims 1 to 4, as electron acceptors and / or spectral sensitizers in photographic silver halide emulsions, especially direct-positive photographic silver shark ogenidemulsions. 1098 16/1620 176 238 3 6. Silver halide photographic emulsion with a content on a cyanine dye, characterized in that they have a cyanine dye ^ cmäil · Ans -]) back 1 to 4 contains. 7. Photographic silver halide emulsion. Claim 6, characterized in that it consists of a direct positive Silver halide emulsion. " S. Photographic silver halide absorption according to claim 6, characterized in that the silver halide grains of the emulsion are obscured. 9. Silver halide photographic emulsion according to claim 8, characterized in that the silver halide grains of the emulsion are replaced by a reducing agent and a gold compound are veiled. 10. The silver halide photographic emulsion of claims 6 to 9, characterized in that it contains a color former, in particular a color coupler. 1 0 9 8 1 b / 1. Β 2 0 ORIQINAt INSPECTED . ₅₂ . 176S383 11. Photographic silver halide emulsion according to claims ö to 10, characterized in that f. their silver halide grains are such that the emulsion after application to a conventional carrier to achieve a maximum Density of at least 1 after 6 minutes of development at 20 c in a developer of the following composition: N-I-ethyl-p-aminophenol sulfate 2.5 g Sodium sulfite (anhydrous) 30.0 g Hydroquinone 2.5 g Sodium metaborate 10.0 g Potassium bromide 0.5 g made up to 1.0 liter with water; a maximum density is greater by at least 3 (H than the maximum density of a corresponding photographic material, which was developed in the same manner after 10 minutes at 2O ⁰ C in a bleaching solution having the following composition: Potassium cyanide 50 mg Glacial acetic acid 3, 47 cm ³ Sodium acetate 11 49 g Potassium bromide 119 mg topped up with 'water 1 liter bleached BAD OF = KMMAL COPY - S3 - ■ 1768383 12. riioto ^ rapuisclie silver halide emulsion according to claims 6 to 11 characterized in that at least 95% by weight of the fogged silver halide grains have a diameter which is no more than 401 of the median diameter of the horn abweidit.- 1098 15/1620