US3515722A - Cyanine dyes - Google Patents

Cyanine dyes Download PDF

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US3515722A
US3515722A US604161A US3515722DA US3515722A US 3515722 A US3515722 A US 3515722A US 604161 A US604161 A US 604161A US 3515722D A US3515722D A US 3515722DA US 3515722 A US3515722 A US 3515722A
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dye
phenyl
emulsions
nucleus
dimethyl
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Earl J Van Lare
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Eastman Kodak Co
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Eastman Kodak Co
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    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/485—Direct positive emulsions
    • G03C1/48515—Direct positive emulsions prefogged
    • G03C1/48523—Direct positive emulsions prefogged characterised by the desensitiser
    • G03C1/4853—Direct positive emulsions prefogged characterised by the desensitiser polymethine dyes
    • C—CHEMISTRY; METALLURGY
    • C07—ORGANIC CHEMISTRY
    • C07D—HETEROCYCLIC COMPOUNDS
    • C07D209/00—Heterocyclic compounds containing five-membered rings, condensed with other rings, with one nitrogen atom as the only ring hetero atom
    • C07D209/02—Heterocyclic compounds containing five-membered rings, condensed with other rings, with one nitrogen atom as the only ring hetero atom condensed with one carbocyclic ring
    • C07D209/04—Indoles; Hydrogenated indoles
    • C07D209/08—Indoles; Hydrogenated indoles with only hydrogen atoms or radicals containing only hydrogen and carbon atoms, directly attached to carbon atoms of the hetero ring
    • C—CHEMISTRY; METALLURGY
    • C09—DYES; PAINTS; POLISHES; NATURAL RESINS; ADHESIVES; COMPOSITIONS NOT OTHERWISE PROVIDED FOR; APPLICATIONS OF MATERIALS NOT OTHERWISE PROVIDED FOR
    • C09B—ORGANIC DYES OR CLOSELY-RELATED COMPOUNDS FOR PRODUCING DYES, e.g. PIGMENTS; MORDANTS; LAKES
    • C09B23/00—Methine or polymethine dyes, e.g. cyanine dyes
    • C09B23/10—The polymethine chain containing an even number of >CH- groups
    • C09B23/105—The polymethine chain containing an even number of >CH- groups two >CH- groups
    • G—PHYSICS
    • G03—PHOTOGRAPHY; CINEMATOGRAPHY; ANALOGOUS TECHNIQUES USING WAVES OTHER THAN OPTICAL WAVES; ELECTROGRAPHY; HOLOGRAPHY
    • G03C—PHOTOSENSITIVE MATERIALS FOR PHOTOGRAPHIC PURPOSES; PHOTOGRAPHIC PROCESSES, e.g. CINE, X-RAY, COLOUR, STEREO-PHOTOGRAPHIC PROCESSES; AUXILIARY PROCESSES IN PHOTOGRAPHY
    • G03C1/00—Photosensitive materials
    • G03C1/005—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein
    • G03C1/06—Silver halide emulsions; Preparation thereof; Physical treatment thereof; Incorporation of additives therein with non-macromolecular additives
    • G03C1/08—Sensitivity-increasing substances
    • G03C1/10—Organic substances
    • G03C1/12—Methine and polymethine dyes

Definitions

  • This invention relates to novel photographic materials, and more particularly to a new class of cyanine dyes containing a 4-pyrazolyl nucleus that are especially useful as electron acceptors and spectral sensitizers for direct positive photographic silver halide emulsions, and to means for the preparation of such new dyes.
  • direct positive images can be obtained with certain types of photographic silver halide emulsions.
  • photographic emulsions have been proposed for this purpose comprising an electron acceptor and silver halide grains that have been fogged with a combination of a reducing agent and a compound of a metal more electropositive than silver.
  • One of the advantages of such direct positive emulsions is that the highlight areas of the images obtained with these materials are substantially free from fog.
  • known materials of this type have not exhibited the high speed required for many applications of photography.
  • such known materials have not shown the desired selective sensitivity, especially to radiation in the green to red region of the spectrum. It is evident, therefore, that there is need in the art for improved direct positive photographic materials having both good speed and desirable sensitivity to longer wavelength radiations.
  • an object of this invention to provide a new class of cyanine dyes that function as electron acceptors and spectral sensitizers for photographic silver halide emulsions, and more particularly for direct positive photographic emulsions, such as fogged, direct positive emulsions. Another object is to provide means for preparing the new cyanine dyes of this invention. Other objects of this invention will be apparent from this disclosure and the appended claims.
  • the new class of cyanine dyes of the invention include those comprising first and second 5- to G-membered nitrogen heterocyclic nuclei joined by methine linkage; the first of said nuclei being a pyrazole nucleus joined, by the 4-carbon atom thereof, to the methine linkage, said second nucleus being a desensitizing quaternary salt nucleus joined by a carbon atom thereof to the methine. linkage; and, said methine linkage being selected from the group consisting of a dimethine linkage and a tetramethine linkage.
  • One highly useful class of the novel cyanine dye compounds of the invention include those represented by the following general formula:
  • Z represents the nonmetallic atoms necessary to complete a densensitizing heterocyclic nucleus selected from the group including a nitrobenzothiazole nucleus, e.g., S-nitrobenzothiazole, 6-nitrobenzothiazole, chloro-6-nitro- :benzothiazole, etc.; a nitrobenzoxazole nucleus, e.g., S-nitrobenzoxazole, 6-nitrobenzoxazole, 5-chloro-6-nitrobenzoxazole, etc.; nitrobenzoselenazole nucleus, e.g., S-nitrobenzoselenazole, fi-nitrobenzoselenazole, 5-chlo1o- 6-nitrobenzosele
  • nuclei containing nitro groups that are useful as desensitizers include nitrothiazole, nitronaphthothiazole, nitrooxazole, nitronaphthoxazole, nitroselenazole, nitronaphthoselenazole, and nitropyridine nuclei.
  • the desensitizing nuclei wherein Z in above Formula I represents the atoms necessary to complete a nitro substituted heterocyclic nucleus form particularly eflicacious desensitizing dyes and are a preferred dye species of the invention.
  • the cyanine dyes of the invention are powerful desensitizers for preparing direct positive photographic silver halide emulsions. In addition, they are also useful desensitizers in emulsions used in the process described in Stewart and Reeves, US. Pat. No. 3,250,618, issued May 10, 1966.
  • desensitizing nucleus refers to those nuclei which, when converted to a symmetrical carbocyanine dye and added to gelatin silver chlorobromide emulsion containing mole percent chloride and mole percent bromide, at a concentration of from 0.01 to 0.2 gram dye per mole of silver, cause by electron trapping at least about an percent loss in the blue speed of the emulsion when sensitometrically exposed and developed three minutes in Kodak developer D-l9 at room temperature.
  • the desensitizing nuclei are those which, when converted to a symmetrical carbocyanine dye and tested as just described, essentially completely desensitize the test emulsion to blue radiation (i.e., cause more than about to loss of speed to blue radiation).
  • cyanine dyes defined by Formula I above are conveniently prepared by heating a mixture of (1) a heterocyclic compound of the formula:
  • n, L, R R and R are as previously defined, in approximately equimolar proportions, in the presence of a condensing agent, if desired, such as anhydrous sodium acetate, a trialkylamine such as triethylamine, etc., piperidine, N-methylpiperidine, etc.,-in an inert solvent medium such as ethanol, acetic anhydride, glacial acetic acid, etc.
  • a condensing agent if desired, such as anhydrous sodium acetate, a trialkylamine such as triethylamine, etc., piperidine, N-methylpiperidine, etc.,-in an inert solvent medium such as ethanol, acetic anhydride, glacial acetic acid, etc.
  • a condensing agent if desired, such as anhydrous sodium acetate, a trialkylamine such as triethylamine, etc., piperidine, N-methylpiperidine, etc.,-in an in
  • one or more of the new dyes of the invention, as defined by Formula I above, are incorporated into direct positive type emulsions, especially into a suitably fogged silver halide emulsion.
  • the emulsion can be fogged in any suitable manner, such as by light or with chemical fogging agents, e.g., stannous chloride, formaldehyde, thiourea dioxide and the like.
  • the emulsion may be fogged by the addition thereto of a reducing agent such as thiourea dioxide and a compound of a metal more electropositive than silver such as a gold salt, for example, potassium chloroaurate, as described in British Pat. 723,019 (1955).
  • Typical reducing agents that are useful in providing such emulsions include stannous salts, e.g., stannous chloride, hydrazine, sulfur compounds such as thiourea dioxide, phosphonium salts such as tetra (hydroxymethyl) phosphonium chloride, and the like.
  • Typical useful metal compounds that are more electropositive than silver include gold, rhodium, platinum, palladium, iridium, etc., preferably in the form of soluble salts thereof, e.g., potas-. sium chloroaurate, auric chloride, (NH PdCl and the like.
  • the concentration of added dye can vary widely, e.g., from about 50 to 2000 mg. and preferably from about 400 to 800 mg. per mole of silver halide in the direct positive emulsions.
  • fogged refers to emulsions containing silver halide grains which produce a density of at least 0.5 when developed, without exposure, for 5 minutes at 68F. in developer Kodak DK-SO having the composition set forth below, when the emulsion is coated at a silver coverage of 50 mg. to 500 mg. per square foot.
  • the dyes of this invention are also advantageously incorporated in direct positive emulsions of the type-in which a silver halide grain has a water-insoluble silver salt center and an outer shell composed of a fogged waterinsoluble silver salt that develops to silver without exposure.
  • the dyes of the invention are incorporated,
  • the shell of the grains in such emulsions may be prepared by precipitating over the core grains a light-sensitive waterinsoluble silver salt that can be fogged and which fog is removable by bleaching.
  • the shell is of sufiicient thickness to prevent access of the developer used in processing the emulsions of the invention to the core.
  • the silver salt shell is surface fogged to make developable tometallic silver with conventional surface image developing compositions.
  • the silver salt of the shell is sufficiently fogged to produce a density of at least about 0.5 when developed for 6 minutes at 68 F. in Developer A below when the emulsion is coated at a silver coverage of mg. per square foot.
  • fogging can be effected by chemically sensitizing to fog with the sensitizing agents described for chemically sensitizing the core emulsion, high intensity light and the like fogging means well known to those skilled in the art. While the core need not be sensitized to fog, the shell is fogged. Fogging by means of a reduction sensitizer, a noble metal salt such as gold salt plus a reduction sensitizer, a sulfur sensitizer, high pH and low pAg silver halide precipitating conditions, and the like can be suitably utilized.
  • the shell portion of the subject grains can also be coated prior to fogging.
  • Such chemical sensitization includes three major classes, namely, gold or noble metal sensitization, sulfur sensitization, such as by a labile sulfur compound, and reduction sensitization, e.g., treatment of the silver halide with a strong reducing agent which introduces small specks of metallic silver into the silver salt crystal or grain.
  • the dyes, reducing agents and metal compounds of the invention are advantageously incorporated in the washed, finished silver halide emulsion and should, of course, be uniformly distributed throughout the emulsion.
  • the methods of incorporating dyes and other addenda in emulsions are relatively simple and well known to those skilled in the art of emulsion making. For example, it is convenient to add them from solutions in appropriate solvents, in which case the solvent selected should be completely free from any deleterious effect on the ultimate light-sensitive materials. Methanol, isopropanol, pyridine, water, etc., alone or in admixtures, have proven satisfactory as solvents for this purpose.
  • the type of silver halide emulsions that can be sensitized with the new dyes include any of those prepared with hydrophilic colloids that are known to be satisfactory for dispersing silver halides, for example, emulsions comprising natural materials such as gelatin, albumin, agar-agar, gum arabic, alginic acid, etc. and hydrophilic synthetic resins such as polyvinyl alcohol, polyvinyl pyrrolidone, cellulose esthers, partially hydrolyzed cellulose acetate, and the like.
  • the dyes, reducing agents and metal compounds of the invention can be used with emulsions prepared with any of the light-sensitive silver halide salts including silver chloride, silver bromide, silver chlorobromide, silver bromoiodide, silver chlorobromoiodide, etc.
  • Particularly useful are direct positive fogged emulsions in which the silver salt is a silver bromohalide comprising more than 50 mole percent bromide.
  • certain dyes of this invention are also useful in emulsions which contain color formers. This is unexpected since related prior art dyes cannot be used in emulsions containing a color former.
  • novel emulsions of this invention may be coated on any suitable photographic support, such as glass, film base such as cellulose acetate, cellulose acetate butyrate, polyesters such as polyethylene terephthalate, paper, baryta coated paper, polyolefin coated paper, .e.g., polyethylene or polypropylene coated paper, which may be electron bombarded to promote emulsion adhesion, to produce the novel photographic elements of the invention.
  • film base such as cellulose acetate, cellulose acetate butyrate
  • polyesters such as polyethylene terephthalate, paper, baryta coated paper, polyolefin coated paper, .e.g., polyethylene or polypropylene coated paper, which may be electron bombarded to promote emulsion adhesion, to produce the novel photographic elements of the invention.
  • the oily layer was separated from the supernatant liquid by decantation and then washed with ether.
  • the oily layer was dissolved in acetone and treated with an aqueous solution of sodium iodide. After chilling, the crude dye was collected on a filter and washed with water and then acetone. After recrystallization from methyl alcohol, 1.1 g. (38%) of pure dye was obtained as yellow crystals, M.P. 202203 C., decomposes.
  • the above prepared dye containing the desensitizing 1,3-diallylimidazo[4,5-b]quinoxalinium salt nucleus was photographically tested for its usefulness as an electron acceptor and spectral sensitizer for fogged direct positive photographic silver halide emulsions by the following procedure.
  • a gelatin silver bromoiodide emulsion is reduction and gold sensitized, i.e., fogged, by first adding stannous chloride and heating for minutes at 55 C. and then adding potassium chloroaurate and heating for 20 minutes at 55 C., as described in British Pat. 723,019.
  • the above prepared dye 1,3-diallyl-2-[3,S-dimethyl-l-phenyl-4-pyrazolyl)viny1]imidazo[4,5-b]quinoxalinium iodide is then added to the above fogged emulsion in amount sufficient to give a concentration of 0.50 gram of the dye per mole of silver.
  • the resulting emulsion is then coated on a cellulose acetate film support at a coverage of mg. of silver and 400 mg. of gelatin per square foot of support.
  • a sample of the coated support is then exposed on an Eastman Ib sensitometer using a tungsten light source and processed for 6 minutes at room temperature in Kodak D-19 developer which has the following composition:
  • the dye of this example has a maximum density in the unexposed areas of 1.76 and a minimum density in exposed areas of 0.03, a maximum sensitivity of 485 my. and a relative speed of 603. This result indicates that the dye compound of the above example is especially well suited to function as both an electron acceptor and spectral sensitizer. It thus provides excellent quality direct positive photographic silver halide emulsions.
  • Example A containing a sensitizing 3- ethylbenzothiazolium iodide nucleus in place of the desensitizing 1,3-diallylimidazo[4,5-b]quinoxalinium iodide nucleus of above Example 1, but otherwise of similar structure, is included here for comparison purposes.
  • the tar was treated with 100 ml. of chloroform and chilled.
  • the crude dye was collected on a filter and washed with chloroform.
  • the dye was purified by recrystallization from methyl alcohol. A yield of 0.9 g. (38%) of pure dye was obtained as bright yellow crystals, M.P. 225-226 C., dec.
  • Example A The above dye was photographically tested by the exact procedure described in above Example 1. The results are shown in Table 1 hereinafter. Referring to the table, it will be seen that the dye of Example A containing the sensitizing nucleus had a relative speed of only 191 as compared with 603 for the dye of Example 1 containing the specified desensitizing nucleus. It will be further noted that the dye of Example A had a maximum density in the unexposed areas of only 1.50 and a relatively high minimum density in the exposed areas of 0.14, whereas the dye of Example 1 showed densities of 1.76 and 0.03, respectively, thereby indicating a marked superiority in contrast over that of Example A.
  • Example A The maximum sensitization for Example A was 455 m while that of Example 1 was at 485 m Accordingly, these results indicate that the dye of Example 1 containing a desensitizing nucleus is markedly superior to dyes containing a sensi tizing nucleus, as exemplified by Example A, as an elec' tron acceptor and spectral sensitizer for fogged direct positive photographic silver halide emulsions.
  • EXAMPLE 2 2 (3,5 -dimethyl- 1 -phenyl-4-pyrazolyl vinyl] 1 ,3- diethyl-imidazo [4,5 -b] quinox alinium iodide /N 01/ LE.
  • diphenylimidazo [4,5-b] quinoxalinium iodide A mixture of 2.6 g. (1 mol.) of 2-methyl-1,3-diphenylimidazo[4,5-b] quinoxaliniump-toluenesulfonate, 1.1 g. (l mol.+10% excess) of 3,5-dimethyl-l-phenyl-4-pyrazolecarboxaldehyde and 15 ml. of acetic anhydride was refluxed ten minutes. The reaction mixture was chilled and treated with 100 ml. of ether. The oily layer was separated from the supernatant liquid by decantation and then washed with ether.
  • the 1,3,5-trimethylpyrazole intermediate was prepared as follows:
  • the oily layer was separated from the supernatant liquid by decantation and washed with ether and then treated with acetone and chilled.
  • the crude dye was collected on a filter and Washed with acetone. After recrystallization from ethyl alcohol, 4.5 g. (79%) of pure dye was obtained as brownish yellow needles, M.P. 202- 204 C., dec.
  • This dye contains the desensitizing 6-nitrobenzothiazolium salt nucleus and as indicated by the photographic test procedure of Example 1, and as shown in Table 1, it constitutes an excellent electron acceptor and spectral sensitizer, having a speed of 692 and maximum sensitivity at 500 m for fogged, photographic reversal emulsions.
  • 3-ethyl-2-methyl-6-nitrobenzothiazolium p-toluenesulfonate there can be substituted an equivalent amount of other intermediates such as a 3-alkyl (e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, decyl, dodecyl, etc.) -2-methyl 6 nitrobenzoxazolium quanternary salt, e.g., the chloride, bromide, iodide, perchlorate, p-toluenesulfonate, etc.
  • a 3-alkyl e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, decyl, dodecyl, etc.
  • 6 nitrobenzoxazolium quanternary salt e.g., the chloride, bromide, iodide, perchlor
  • salts or a 3-alkyl (e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, decyl dodecyl, etc.) -2-methyl-6-nitrobenzoselenazolium quanternary salts, e.g., the chloride, bromide, iodide, perchlorate, p-toluenesulfonate, etc.
  • a 3-alkyl e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, decyl dodecyl, etc.
  • 2-methyl-6-nitrobenzoselenazolium quanternary salts e.g., the chloride, bromide, iodide, perchlorate, p-toluenesulfonate, etc.
  • the 3,5- dimethyl l phenyl 4 pyrazole carboxaldehyde can also be substituted in the above example by an equivalent amount of other related aldehydes such as, for example, 3,5 dimethyl 1 phenyl 4 pyrazole acrylaldehyde to give the corresponding cyanine dye 2-[(3,5 dimethyl-1- phenyl 4 pyrazolyl)butadienyl] 3 ethyl 6 nitrobenzothiazolium p toluenesulfonate having generally similar properties as an electron acceptor and spectral sensitizer for fogged, direct positive photographic silver halide emulsions.
  • other related aldehydes such as, for example, 3,5 dimethyl 1 phenyl 4 pyrazole acrylaldehyde to give the corresponding cyanine dye 2-[(3,5 dimethyl-1- phenyl 4 pyrazolyl)butadienyl] 3 ethyl 6 nitrobenzothiazolium p
  • the oily layer was disolved in acetone and treated with an aqueous solution of sodium iodide. After chilling, the crude dye was collected on a filter and washed with water and then with acetone. After recrystallization from ethyl alcohol, 1.4 g. (29%) of pure dye was obtained as orange plates, M.P. 233235 d.
  • the above prepared dye containing the desensitizing 3H-pyrrolo[2,3-b]pyridinium salt nucleus was tested by the exact procedure of Example 1 and found, as shown in Table 1, to have a relative speed of 955, together with other desirable properties set forth in the table, which results indicate that this dye is an excellent electron acceptor and spectral sensitizer for fogged, photographic reversal emulsions.
  • the indicated relative speeds are 1000, 603, and 1820, respectively
  • the indicated maximum density in the unexposed areas are 1.62, 1.48 and 1.12 respectively
  • the indicated minimum density in the ex posed areas are 0.05, 0.02 and 0.03, respectively
  • the indicated maximum sensitization at 545, 500 and 535 m respectively are markedly superior to the comparison dye of Example A with indicated values of only 1.91 for relative speed, 0.14 for minimum density in the unexposed areas, and maximum sensitization at only 455 m
  • the dye of above Example 9 is outstanding in all the desired properties for preparing superior fogged, photographic reversal emulsions.
  • EXAMPLE 12 2- 3,5 -dimethy1- 1-phenyl-4-pyrazolyl) vinyl] -1-ethyl-6- nitroquinolinium iodide
  • the reaction mixture was chilled and treated with ml. of ether.
  • the oily layer was separated from the supernatant liquid by decantation and then treated with ethyl alcohol.
  • the crude dye was extracted with 450 ml.
  • Photographic testing in accordance with the procedure of Example 1 indicated that the above prepared dye containing the desensitizing 6-nitroquinolinium salt nucleus, is a moderately good electron acceptor and spectral sensitizer for fogged, photographic reversal emulsions.
  • the results are listed in Table 1 hereinafter.
  • EXAMPLE 14 6-chloro- 1, 3 -diphenyl-2- 1 -phenyl-4-pyrazolyl vinyl] imidazo[4,5-b] quinoxalinium p-toluenesulfonate
  • the reaction mixture was chilled and the crude dye collected on a filter and washed with acetone. After recrystallization from methyl alcohol, 3.4 g. (49%) of pure dye was obtained as yellowish plates, M.P. 291292 C., dec.
  • the dyes of above Examples 13 and 14, each containing a desensitizing 1,3-diallylimidazo [4,5-b1quinoxalinium salt nucleus, were tested by the exact procedure of Example 1 and found, as shown in Table 1 hereinafter, to be relatively good electron acceptors and spectral sensitizers for fogged, direct positive photographic silver halide emulsions.
  • the dye of Example 13 showed the best relative speed of 603 as compared to 263 for the dye of Example 14. In all other properties both dyes were about the same.
  • Example 15 and 16 containing the desensitizing 6-nitrobenzothiazolium salt nucleus were tested by the procedure described in Example l and found, as shown in Table 1 hereinafter, to be moderately good electron acceptors and spectral sensitizers (with relative speeds of 398 and 479, respectively) for fogged, direct positive photographic silver halide emulsions.
  • EXAMPLE 17 To 9.0 pounds of a silver chloride gelatin emulsion containing an equivalent of grams of silver nitrate is added 0.017 gram of 1,3-diallyl-2-[(3,5-dimethyl-1- phenyl 4 pyrazolyl)vinyl]imidazo [4,5-b] quinoxalinium iodide (dye of Example 1). The emulsion is coated on a non-glossy paper support, and is flashed with white light to give a density of 1.2 when developed in the following developer, diluted 1 part to 2 parts of water:
  • EXAMPLE 18 Seven pounds of a silver chloride gelatin emulsion containing the equivalent of 100 g. of silver nitrate is heated to 40 C. and the pH is adjusted to 7.8. Eight cc. of full strength (40%) Formalin solution is added and the emulsion is held at 40 C. for minutes. At the end of the holding period, the pH is adjusted to 6.0 and 0.125 g. of 2-[(3,5 dimethyl-1-phenyl-4-pyrazolyl)vinyl]-3-ethyl-6- nitrobenzothiazolium-p-toluenesulfonate (dye of Example 7) is added to the emulsion. The emulsion is coated on a support, and provides good direct positive images.
  • the photographic silver halide emulsion and other layers present in the photographic elements made according to the invention can be hardened with any suitable hardener, including aldehyde hardeners such as formaldehyde, and mucochloric acid, aziridine hardeners, hardeners which are derivatives of dioxane, oxypolysaccharides such as oxy starch or oxy plant gums, and the like.
  • the emulsion layers can also contain additional additives, particularly those known to be beneficial in photographic emulsions, including, for example, lubricating materials, stabilizers, speed increasing materials, absorbing dyes, plasticizers, and the like. These photographic emulsions can also contain in some cases additional spectral sensitizing dyes.
  • these emulsions can contain color forming couplers or can be developed in solutions containing couplers or other color generating materials.
  • useful color formers are the monomeric and polymeric color formers, e.g. pyrazolone color formers, as Well as phenolic, heterocyclic and open chain couplers having a reactive methylene group.
  • the color forming couplers can be incorporated into the direct positive photographic silver halide emulsion using any suitable technique, e.g., techniques of the type shown in Jelley et al. US. Pat. 2,322,027, issued June 15, 1943, Fierke et al. US. Pat. 2,801,171, issued July 30, 1957, Fisher U.S. Pats.
  • a cyanine dye selected from those represented by the following general formula:
  • nitroselenazole nitronaphthoselenazole and nitropyridine nuclei, the alkyl groups in said desensitizing nuclei containing from 1 to 4 carbon atoms.
  • a cyanine dye as defined by claim 1 wherein said Z represents the non-metallic atoms necessary to complete a nitrobenzothiazole nucleus.
  • a cyanine dye as defined by claim 1 wherein said Z represents the non-metallic atoms necessary to complete a nitrobenzoselenazole nucleus.
  • a cyanine dye as defined by claim 1 wherein said Z represents the non-metallic atoms necessary to complete an imidazo [4,5-b] quinoxaline nucleus.
  • a cyanine dye selected from the group consisting of 1,3 -diallyl-2-[ (3,5-dimethyl-1-phenyl-4-pyrazolyl) vinyl] imidazol [4,5 -b] quinoxalinium salt,

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  • Chemical & Material Sciences (AREA)
  • Organic Chemistry (AREA)
  • Physics & Mathematics (AREA)
  • Chemical Kinetics & Catalysis (AREA)
  • Engineering & Computer Science (AREA)
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  • General Physics & Mathematics (AREA)
  • Spectroscopy & Molecular Physics (AREA)
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US604161A 1966-03-11 1966-12-23 Cyanine dyes Expired - Lifetime US3515722A (en)

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US53344866A 1966-03-11 1966-03-11
US53344066A 1966-03-11 1966-03-11
US53340066A 1966-03-11 1966-03-11
US60416166A 1966-12-23 1966-12-23
US60418166A 1966-12-23 1966-12-23
US60414666A 1966-12-23 1966-12-23
US60976267A 1967-01-17 1967-01-17
US60979367A 1967-01-17 1967-01-17
US61832067A 1967-02-24 1967-02-24

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Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB797144A (en) * 1955-11-15 1958-06-25 Ilford Ltd Improvements in or relating to pyrazole compounds
US3073820A (en) * 1960-08-10 1963-01-15 Arnold F Plue 2-pyrazolinyl-vinyl-1, 3, 3 trimethyl indolenines

Patent Citations (2)

* Cited by examiner, † Cited by third party
Publication number Priority date Publication date Assignee Title
GB797144A (en) * 1955-11-15 1958-06-25 Ilford Ltd Improvements in or relating to pyrazole compounds
US3073820A (en) * 1960-08-10 1963-01-15 Arnold F Plue 2-pyrazolinyl-vinyl-1, 3, 3 trimethyl indolenines

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