Classifications

• • 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
• • 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
  • C09B23/02—Methine or polymethine dyes, e.g. cyanine dyes the polymethine chain containing an odd number of >CH- or >C[alkyl]- groups
  • C09B23/06—Methine or polymethine dyes, e.g. cyanine dyes the polymethine chain containing an odd number of >CH- or >C[alkyl]- groups three >CH- groups, e.g. carbocyanines
• • 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

Definitions

• This invention relates to novel cyanine dyes and novel photographic emulsions containing such dyes.
• novel dyes of this invention are especially useful as electron acceptors and spectral sensitizers for direct positive photographic silver halide emulsions.
• 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 high-light 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.
• Another object of this invention is to provide novel cyanine dyes which function as effective electron acceptors and spectral sensitizers in photographic silver halide emulsions.
• a further object of this invention is to provide novel photographic silver halide emulsions, including direct positive photographic emulsions, containing one or more of the novel dyes of the invention.
• Another object of this invention is to provide photographic emulsions containing novel cyanine dyes and a photographic color former.
• Still another object of this invention is to provide photographic elements comprising a support having thereon at least one layer of the novel emulsions of the invention.
• novel cyanine dyes of the invention comprise first and second 5- to 6-membered nitrogen containing heterocyclic nuclei joined together by a methine linkage containing from 2 to 3 carbon atoms in the methine chain (including those linkages wherein a methine group is substituted by alkyl, aryl or heterocyclic substituents); the first of said nuclei being selected from a pyrrolo[2,3-b] quinoxaline nucleus or a pyrrolo[2,3-b]pyrazine nucleus joined in each case at the 3-carbon atom thereof to said linkage; and, said second nucleus being selected from (a) a heterocyclic nitrogen containing nucleus of the type used in the production of cyanine dyes, when said linkage is a dimethine linkage, and (b) when said linkage is a trimethine linkage, said second nucleus is selected from the group consisting of a Z-arylindole nucleus, a pyrrolo- [
• novel cyanine dyes of the invention include those represented by the following general formula:
• R represents an alkyl group, including substituted alkyl (preferably a lower alkyl containing from 1 to 4 carbon atoms), e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, decyl, dodecyl, etc., and substituted alkyl groups, (preferably a substituted lower alkyl containing from 1 to 4 carbon atoms), such as a hydroxyalkyl groups, e.g., fl-hydroxyethyl, w-hydroxybutyl, etc., an alkoxyalkyl group, e.g., S-methoxyethyl, w-butoxybutyl, etc., a carboxyalkyl group, e.g., ,H-carboxyethyl, w-carboxybutyl,
• alkenyl group e.g., allyl, l-propenyl
• R represents an alkyl group, e.g., methyl, ethyl, propyl, isopropyl, butyl, decyl, dodecyl, etc., or an aryl group, e.g., phenyl, tolyl, naphthyl, etc.
• R and R each represents a hydrogen atom, an alkyl group (preferably a lower alkyl containing from 1 to 4 carbon atoms), e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, decyl, dodecyl, etc., or an aryl group, e.g., phenyl, tolyl, naphthyl
• a thiazole nucleus e.g., thiazole, 4-rnethylthiazole, 4- phenylthiazole, S-methylthiazole, S-phenylthiazole, 4,5- dimethylthiazole, 4,5-diphenylthiazole, 4 (2 thienyl) thiazole, benzothiazole, 4-chlorobenzothiazole, 4- or S-nitrobenzothiazole, S-chlorobenzothiazole, 6-chlorobenzothiazole, 7-chlorobenzothiazole, 4-methylbenzothiazole, S-methylbenzothiazole, 6-methylbenzothiazole, 6-nitrobenzothiazole, S-bromobenzothiazole, 6-bromobenzothiazole, S-chloro-6-nitrobenzothiazole, 4-phenylbenzothiazole, 4-methoxybenzothiazole, S-methoxybenzothiazole, 6-methoxybe'nzothi
• an oxazole nucleus e.g., 4-methyloxazole, 4-nitro-oxazole, S-methyloxazole, 4-phenyloxazole, 4,5-diphenyloxazole, 4-ethyloxazole, 4,5-dimethoxazole, S-phenyloxazole, benzoxazole, S-chlorobenzoxazole, S-methylbenzoxazole, S-phenylbenzoxazole, 5- or 6-nitr0benzoxazole, 5-chloro-6-nitrobenzoxazole, 6-methylbenzoxazole, 5,6- dirnethylbenzoxazole, 4,6-dimethylbenzoxazole, 5-methoxybenzoxazole, S-ethoxybenzoxazole, 5-chlorobenzoxazole, 6-methoxybenzoxazole, S-hydroxybenzoxazole, 6-hydroxybenzoxazole, naphth [2,1-d] oxazole, naph
• a selenazole nucleus e.g., 4-rnethylselenazole, 4- nitro selenazole, 4-phenylselenazole, benzoselenazole, S-chlorobenzoselenazole, S-methoxybenzoselenazole, 5-hydroxybenzoselenazole, 5- or 6-nitrobenzoselenazole, 5- chloro 6 nitrobenzoselenazole, tetrahydrobenzoselenazole, naphtho [2,1-d] selenazole, naphtho 1,2-d] selenazole, nitro group substituted naphthoselenazoles, etc.,
• thiazoline nucleus e.g., thiazoline, 4-methylthiazoline
• a pyridine nucleus e.g., 2-pyridine, 5-methyl-2-pyridine, 4-pyridine, 3-methyl-4-pyridine, nitro group substituted pyridines, etc.;
• a quinoline nucleus e.g., 2-quinoline, 3-methyl-2-quinoline, 5-ethyl-2-quinoline, 6-chloro-2-quinoline, 6-nitro- Z-quinoline, 8-chloro-2-quinoline, 6-methoxy-2-quinoline, S-ethoxy-Z-quinoline, 8-hydroxy 2 quinoline, 4- quinoline, 6 methoxy-4-quinoline, 6-nitro-4-quinoline, 7-rnethyl-4-quinoline, 8-chloro-4-quinoline, 1-isoquinoline, 6-nitro-1-isoquinoline, 3,4-dihydro-l-isoquinoline, 3-isoquinoline, etc.;
• a 3,3-dialkylindolenine nucleus preferably having a nitro or cyano substituent, e.g., 3,3-dimethyl-5 or 6-nitroindolenine, 3,3-dimethy1-5- or 6-cyanoindolenine, etc; and
• imidazole nucleus e.g., imidazole, l-alkylimidazole,
• 1-alkyl-4-phenylimidazole 1-alkyl-4,S-dimethylimidaZ- ole, benzimidazole, l-allrylbenzirnidazole, 1-aryl-'5,6- dichlorobenzimidazole, 1-alkyl-lH-naphthimidazole, 1- aryl-3H-naphth 1,2-d] imidazole, l-alkyl-S-methoxy- 1H-naphth[ 1,2-d]imidazole, or
• an imidazo[4,5 b]quinoxaline nucleus e.g., 1,3 dialkylimidazo[4,5-b]quinoxaline such as 1,3-diethy1imidazo- [4,5-b1quinoxaline, 6-chloro-1,3-diethylirnidaz0 [4,5-b] quinoxaline, etc., 1,3-dialkylenylimidazo[4,5-b]quinoxaline such as 1,3-diallylimidazo[4,5-b1quinoxaline, 6- chloro-1,3-diallylimidazo[4,5 -b]quinoxaline, etc., 1,3- diarylimidazo[4,5-b]quinoxaline such as 1,3-diphenylimidazo[4,5-b]quinoxaline, 6-chloro 1,3 diphenylimidazo [4,5-b] quinoxaline, etc.;
• a 1,3,3-trialkyl-3H-pyrrolo[2,3-b]pyridine nucleus e.g.,
• Nuclei wherein Z represents an irnidaz0[4,5-b]quinoxaline nucleus, a 1,3,3-trialkyl-3H-pyrrolo[2,3-b] pyridine nucleus, a thiazolo[4,5b]quinoline nucleus, at nitro group substituted thiazole, oxazole, selenazole, thiazoline, pyridine, quinoline, 1,3,3-trialkylindolenine, or imidazole nucleus are desensitizing nuclei.
• the dyes defined above are powerful electron acceptors and spectral sensitizers for 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 40 mole percent chloride and 60 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 an percent loss in the blue speed of the emulsion when sensitomerically 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 complete desensitize the test emulsion to blue radiation (i.e., cause more than about to loss of speed to blue radiation).
• R R R R R and X are as previously de fined, R represents an alkyl group (preferably a lower alkyl containing from 1 to 4 carbon atoms), e.g., methyl, ethyl, propyl, isopropyl, butyl, hexyl, cyclohexyl, decyl, dodecyl, etc., or an aryl group, e.g., phenyl, tolyl, naphthyl, chlorophenyl, nitrophenyl, methoxyphenyl, etc., or a heterocyclic radical containing from 5 to 6 atoms in the heterocyclic ring and having a hetero nitrogen, oxygen or sulfur atom, preferably a heterocyclic radical selected from pyridyl (e.g., 2-, 3- or 4-pyridyl), 3-indolyl, or 2 thienyl; R
• quinoxalinocarbocyanine p-toluenesulfonate 1-butyl-7- chloro-3 -ethyl-6-nitro-3 -pyrrolo [2,3 -b] quinoxalinothiacarbocyanine p-toluenesulfonate 1,3 -diallyl-1-butyl-7-chloroimidazo [4,5 -b] quinoxalino- 3-pyrrolo[2,3-b] quinoxalinocarbocyanine bromide 1'-butyl-7 '-chloro-1,3 3 -trimethyl-5-nitroindo-3 '-pyrrolo [2,3-b] quinoxalinocarbocyanine bromide 3 '-ethyl-1-methyl-6'-nitro-2-p-tolyl-3-pyrr0lo[2,3-b]
• cyanine dyes defined by Formula I above are conveniently prepared, for example, by heating a mixture of (1) a heterocyclic compound of the formula:
• n, R X and Z are as previously defined, and R represents methyl, ethyl, benzyl, etc., and (2) a heterocyclic compound of the formula:
• R R R R and X are as previously defined, with (2) a complex of phosphoryl chloride, phosgene, oxalyl chloride, etc. and dimethyl formamide in excess dimethylformamide, as solvent, in approximate proportions of 1 mole of 1) to 3 or more moles of (2).
• the reaction mixtures are cooled, diluted with ice-water mixture, and then made alkaline by addition of aqueous alkali metal hydroxide solution such as aqueous sodium hydroxide.
• the product is then separated by conventional methods, for example, by extraction of the mixture with a water-insoluble solvent such as chloroform, the residue being purified, if desired, by one or more recrystallizations from appropriate solvents such as dimethyl formamide.
• cyanine dyes defined by Formula II above are conveniently prepared, for example, by heating a mixture of (1) a compound of Formula IV above and (2) a compound of the formula:
• novel and improved direct positive photographic silver halide emulsions are prepared by incorporating one or more of the cyanine dyes of the invention into a suitable fogged silver halide emulsion.
• the emulsion can be fogged in any suitable manner, such as by light or with chemical fogging agents, e.g., stannaous 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., potassium chloroaurate, auric chloride, (NH PdCl and the like.
• reducing agent and metal compound e.g., metal salt
• concentrations of reducing agent and metal compound can be varied over a considerable range.
• good results are obtained using about .05 to 40 mg. reducing agent per mole of silver halide and 0.5 to 15.0 mg. metal compound per mole of silver halide. Best results are obtained at lower concentration levels of both reducing agent and metal compound.
• the concentration of added dye can very 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 68 F. 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, preferably, in the outer shell of such emulsions.
• These emulsions can be prepared in various ways, such as those described in Berriman US. patent application Ser. No. 448,467, filed Apr. 15, 1965, now US. Pat. 3,367,778 issued Feb. 6, 1968.
• the shell of the grains in such emulsions may be prepared by precipitating over the core grains a light-sensitive water-insoluble 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 tomake it developable to metallic 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 8 silver coverage of 100 mg. per square foot.
• Such 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 subect grains can also be coated prior to fogging.
• the core emulsion is first chemically or physically treated by methods previously described in the prior art to produce centers which promote the deposition of photolytic silver, i.e., latent image nucleating centers.
• centers can be obtained by various techniques as described herein. Chemical sensitization techniques of the type described by Antoine Hautot and Henri Sauvenier in Science et Industries Photographiques, Vol. XXVIII, January 1957, pages 1 to 23 and January 1957, pages 57 to are particularly useful.
• Such chemical sensitization includes three major classes, namely, gold or noble metal sensitization, sulfur sensitization, such as by a liabile 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 of this invention are highly useful electron acceptors in high speed direct positive emulsions comprising fogged silver halide grains and a compound which accepts electrons, as described and claimed in Illingsworth US. patent application Ser. No. 609,794, filed Jan. 17, 1967, and titled Photographic Reversal Materials III," and continuation-in-part application Ser. No. 619,936 filed Mar. 2, 1967, now US. Pat. 3,501,307 issued Mar. 17, 1970.
• the fogged silver halide grains of such emulsions are such that a test portion thereof, when coated as a photographic silver halide emulsion on a support to give a maximum density of at least about one upon processing for six minutes at about 68 F.
• Kodak DK-SO- developer in Kodak DK-SO- developer, has a maximum density which is at least about 30% greater than the maximum density of an identical coated test portion which is processed for six minutes at about 68 F. in Kodak DK-SO developer after being bleached for about 10 minutes at about 68 F. in a bleach composition of:
• the grains of such emulsions will lost at least about 25% and generally at least about 40% of their fog when bleached for ten minutes at 68 F. in a potassium cyanide bleach composition as described herein.
• This fog loss can be illustrated by coating the silver halide grains as a photographic silver halide emulsion on a support to give a maximum density of at least 1.0 upon processing for six minutes at about 68 F. in Kowak DK-50 developer and comparing the density of such a coating with an identical coating which is processed for six minutes at 68 F. in
• the maximum density of the unbleached coating will be at least greater, generally at least 60% greater, then the maximum density of the bleached coating.
• the silver halides employed in the preparation of the photographic emulsions useful herein include any of the photographic silver halides as exemplified by silver bromide, silver iodide, silver chloride, silver chlorobromide, silver bromoiodide, silver chlorobromide, and the like.
• the silver halide grains can be regular and can be any suitable shape such as cubic or octahedral, as desscribed and claimed in Illingsworth U.S. patent application Ser. No. 609,778, filed Jan. 17, 1967, and titled Direct Positive Photographic Emulsions I, and continuation-in-part application Ser. No.
• Such grains advantageously have a rather uniform diameter frequency distribution, as described and claimed in Illingsworth U.S. patent application Ser. No. 609,790, filed Jan. 17, 1967, and titled Photographic Reversal Emulsions II, and continuationin-part application Ser. No. 619,948 filed Mar. 2, 1967, now U.S. Pat. 3,501,305 issued Mar. 17, 1970.
• at least 95%, by weight, of the photographic silver halide grains can have a diameter which is within about preferably within about 30% of the mean grain diameter.
• Mean grain diameter i.e., average grain size
• Mean grain diameter can be determined using conventional methods, e.g., as shown in an article by Trivelli and Smith entitled Empirical Relations Between Sensitometric and Size-Frequency Characteristics in Photographic Emulsion Series in The Photographic Journal, vol. LXXIX, 1949, pages 330-338.
• the fogged silver halide grains in these direct-positive photographic emulsions of this invention produce a density of at least 0.5 when developed without exposure for five minutes at 68 F. in Kodak DK-50 developer when such an emulsion is coated at a coverage of 50 to about 500 mg. of silver per square foot of support.
• the preferred photographic silver halide emulsions comprise at least 50 mole percent bromide, the most preferred emulsions being silver bromoiodide emulsions, particularly those containing less than about ten mole percent iodide.
• the photographic silver halides can be coated at silver coverages in the range of about 50 to about 500 milligrams of silver per square foot of support.
• the dyes 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 incroporating 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 dispering 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 ethers, partially hydrolyzed cellulose acetate, and the like.
• the binding agents for the emulsion layer of the photographic element can also contain dispersed polymerized vinyl compounds.
• dispersed polymerized vinyl compounds are disclosed, for example, in U.S. Pats. 3,142,568; 3,193,386; 3,062,674 and 3,220,844 and include the water insoluble polymers of alkyl acrylates and methacrylates, acrylic acid, sulfoalkyl acrylates or methacrylates and the like.
• the dyes, reducing agents and metal compounds of the invention can be used with emulsions prepared, as indi cated above, 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 is emulsions which contain color formers.
• 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 poly(ethylene terephthalate), paper, baryta coated paper, polyolefin coated paper, e.g., polyethylene or polypropylene coated paper, which maybe 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 poly(ethylene terephthalate), paper, baryta coated paper, polyolefin coated paper, e.g., polyethylene or polypropylene coated paper, which maybe electron bombarded to promote emulsion adhesion, to produce the novel photographic elements of the invention.
• the above prepared dye containing the desensitizing 3- ethyl-6-nitrobenzothiazole nucleus is 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 (2.5 mole per cent of the halide being iodide) and having an average grain size of about 0.2 micron is prepared by adding an aqueous solution of potassium bromide and potassium iodide, and an aqueous solution of silver nitrate, simultaneously to a rapidly agitated aqueous gelatin solution at a temperature of 70 C., over a period of about 35 minutes.
• the emulsion is chill-set, shredded and Washed by leaching with cold water in the conventional manner.
• the emulsion is reduction-gold fogged by first adding 0.2 mg. of thiourea dioxide per mole of silver and heating for 60 minutes at 65 C. and then adding 4.0 mg.
• the dye of the above example 1,3 diethyl 6' nitro-3-pyrrolo[2,3-b]quinoxalinothiacarbocyanine p-toluenesulfonate, is then added to the above fogged emulsion in amount sufiicient to give a concentration of 0.08 gram of the dye per mole of silver.
• the resulting emulsion is 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 1.63 and a minimum density in exposed areas of 0.06, a maximum sensitivity of 550 nm. and a relative speed of 380. This result indicates that the dye compound of the above example is Well suited to function as both an electron acceptor and spectral sensitizer. It thus provides excellent quality direct positive photographic silver halide emulsions.
• the dye 1,3-diethyl-6'-nitro-3-pyrrolo- [2,3-b]quinoxalinoselenacarbocyanine salt e.g., the chloride, bromide, iodide, perchlorate, p-toluenesulfonate, etc. salts
• the like cyanine dyes e.g., the chloride, bromide, iodide, perchlorate, p-toluenesulfonate, etc. salts.
• EXAMPLE 3 1'-ethyl-'1, 3 3-trimethyl-3H-pyrrolo 2,3 -b] pyrido-3 pyrrolo[2,3-b]quinoxalinocarbocyanine iodide 1 ethyl 3-formylpyrrolo[2,3-b]quinoxaline (0.56 g., 1 mol.), 1,3,3-trimethyl-2-methylene-2,3-dihydropyrrolo- [2,3-b]pyridine (0.44 g., 1 mol.) and p-toluenesulfonic acid monohydrate (0.48 g., 1 mol.) in acetic anhydride (10 ml.) are heated at reflux for 1 minute.
• the mixture When cool, the mixture is diluted with excess ether and the product separated as an oil.
• the oil is dissolved in boiling methanol ml.) containing 47% aqueous HI (1.25 ml.). The solution is filtered, then chilled. The solid which crystallizes is collected and after a further recrystallization from methanol, the yield of purified dye is 0.38 g. (26% M.P. indistinct.
• This dye containing the desensitizing 1,3,3-trimethyl- 3H-pyrrolo[2,3-b]pyridine nucleus is tested in accordance 'with the test procedure of Example 1. The results of the test are recorded in Table 1 hereinafter. The densities are 1.65, and 0.03 for the unexposed and exposed areas, respectively, with maximum sensitivity at 530 nm. and a relative speed of 708. Accordingly, this dye is an excellent electron acceptor and spectral sensitizer for fogged direct positive photographic emulsions.
• EXAMPLE 4 6-chloro-1'-ethyl 1,3 diphenylimidazo[4,5-b]quinoxalino 3' pyrrolo[2,3-b]quinoxalinocarbocyanine ptoluenesulfonate
• This dye is prepared and purified in the same manner as that described for Example 2, except that 6-chl0ro-2 methyl-1,3 diphenylimidazo[4,5-b]quinoxalinium p-toluenesulfonate (1.36 g., 1 mol.) is used in place of 1,3- diallyl-Z-methylimid-azo[4,5-b]quinoxalinium p toluenesulfonate.
• the yield of purified dye is 0.21 .g. (11%), M.P. 300 C.
• the above prepared dye containing the desensitizing 1,3-diphenylimidazo]4,5-b]quinoxaline nucleus is tested by the producedure described in above Example 1.
• Reference thereto indicates that is dye is an outstanding electron acceptor and spectral sensitizer for fogged direct positive photographic emulsions.
• the densities are 1.64 and 0.02 for the unexposed and exposed areas, respectively, with maximum sensitivity at 550 nm. and a relative speed of 891.
• This dye containing the desensitizing 1,3,3-trimethyl- 5-nitro-3H-indole nucleus is tested in accordance with the test procedure of above Example 1. The results are recorded in Table 1 hereinafter. Referring to the table, it will be seen that the densities are 1.64 and 0.10 for the unexposed and exposed areas, respectively, with maximum sensitivity at 550 nm. and a relative speed of 661. This dye is accordingly, an excellent electron acceptor and spectral sensitizer for fogged direct positive photographic emulsions.
• the above prepared dye containing the desensitizing 1-ethyl-6-nitrobenzothiazole nucleus is an excellent electron acceptor and spectral sensitizer for fogged photographic reversal emulsions as indicated by the test procedure of above Example 1, the results of which are recorded in Table 1 hereinafter.
• the densities are 1.82 and 0.05 for the unexposed and exposed areas, respectively, with a maximum sensitivity at 535 nm. and a relative speed of 692.
• the dye is prepared in the same manner as Example 2, except that 1-butyl-7-chloro-3-formylpyrrolo[2,3-b]quin oxaline (1.09 g., 1 mol.) is used in place of 1-ethyl-3- for-mylpyrrolo[2,3-b]quinoxaline. After two recrystallizations from methanol containing HBr, the yield of purified dye is 0.72 g. (46%), MP. 2068 C., dec.
• the above prepared dye containing the desensitizing 1,3-diallylimidazo[4,5-b]quinoxaline nucleus is tested by the procedure of Example 1. The results are recorded in Table 1 hereinafter. Referring thereto, the densities are 1.90 and 0.03 for the unexposed and exposed areas, respectively, with maximum sensitivity at 530 nm. and a relative speed of 955.
• This dye is, accordingly, an excellent electron acceptor and spectral sensitizer for fogged direct positive photographic emulsions.
• This dye containing the desensitizing 1,3,3-trimethyl- 5-nitro-3H-indole nucleus is an excellent electron acceptor and spectral sensitizer for fogged direct positive photographic emulsions as indicated by the test procedure of above Example 1, the results of which are recorded in Table 1 hereinafter.
• the densities are 1.86 and 0.04 for the unexposed and exposed areas, respectively, with maximum sensitivity at 548 nm. and a relative speed of 661.
• EXAMPLE ll 6 chloro-l'-methyl-1,3-diphenyl-2-p-tolylimidazo [4,5-b] quinoxalino 3' pyrrolo[2,3 b]quinoxalinocarbocyanine p-toluenesulfonate
• This dye is prepared and purified in the same manner as that described in Example 9, except that 1,2,3,3-tetramethyl-S-nitro-3H-ind0lium p-toluenesulfonate (0.98 g., 1 mol.) is used in place of 3-ethyl-2-rnethyl-6-nitrobenzothiazolium
• EXAMPLE 14 1,1'-dimethyl-2,8-diphenyl-2'-p-tolyl-3-indolo-3 -pyrrolo- [2,3-b]quinoxalinocarbocyanine perchlorate 3 formyl-1-methyl-2-p-tolylpyrrolo[2,3-b]quinoxaline (0.75 g., 1 mol.) and 1-methyl-3-methylenebenzyl-2- phenylindole (0.77 g., 1 mol.) are added to a solution of 72% perchloric acid (0.28 g.) in acetic anhydride (10 ml.). The mixture is heated on a steam bath for 15 minutes, as green crystals separate. The mixture is allowed to cool, diluted with a little ether, and the solid collected. After recrystallization from acetic acid, the yield of purified dye is 1.04 g. (60%) M.P. 225 C. (dec.).
• Example 14 In place of the 1-methyl-3-methylenebenzyl-2-phenylindole in the above Example 14, there can be substituted an equivalent amount of, for example, 1-methyl-3-rnethylenebenzyl-Z-p-tolylpyrrolo[2,3-b]quinoxaline to give the corresponding dye having generally similar properties as an electron acceptor and spectral sensitizer for direct positive photographic silver halide emulsions.
• Examples 15 to 20 illustrate the preparation of cyanine dyes of the invention containing the l-aryl- 3-pyrrolo[2,3-b]pyrazine nucleus, i.e., wherein R and R of Formula I each represent hydrogen, alkyl, or aryl.
• R and R of Formula I each represent hydrogen, alkyl, or aryl.
• EXAMPLE 15 A mixture of 1.12 g. (1 mol.) of 3-formyl-1-phenylpyrrolo[2,3-b]pyrazine, 1.98 g. (1 mol.) of 3-ethyl-2- methyl-6-nitrobenzothiazoliurn p-toluenesulfonate, and 10 ml. of acetic anhydride are heated at reflux for 2 minutes. After chilling, the crude dye is collected on a filter and washed first with acetic anhydride, then with ether. After two recrystallizations from acetic acid, 2.47 g. (87%) of pure dye is obtained as shiny orange plates, M.P. 200- 202 C., (dec.).
• EXAMPLE 16 3-methyl-5-nitro-1'-phenyloxa-3 '-pyrrolo [2,3-b] pyrazinocarbocyanine ptoluenesulfonate
• a mixture of 1.12 g. (1 mol.) of 3-formy1-1-phenylpyrrolo[2,3-b]pyrazine, 1.82 g. (1 mol.) of 2,3-dimethy1- -nitrobenzoxazolium p-toluenesulfonate, and ml. of acetic anhydride are heated at reflux for 2 minutes. The solution is chilled and diluted with 50 ml. of ether. The crude dye is collected on a filter and washed with ether. After recrystallization from acetic acid, 1.16 g. (54%) of pure dye is obtained as bright yellow crystals, M.P. 232-235 C. (dec.).
• EXAMPLE 17 1,3-dimethyl- 1'-phenylimidazo [4,5 -b] quinoxalino-3 pyrrolo 2,3-b] pyrazinocarbocyanine p-toluenesulfonate
• EXAMPLE 18 6-chloro-1,1',3 -triphenylirnidazo [4,5 -b] quinoxalino-3 pyrrolo [2,3 -b] pyrazinocarbocyanine bromide
• EXAMPLE 21 To 9.0 pounds of a silver chloride gelatin emulsion containing an equivalent of 100 grams of silver nitrate is added 0.017 gram of 6-chloro-1'-ethy11,3-diphenylimidazo [4,5-b]quinoxalino 3' pyrrolo[2,3-b]quinoxalinocarbocyanine p-toluenesulfonate (Example 4). 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:
• the light fogged material can be exposed to an image with light modulated by a Wratten No. 15 filter to give a direct positive image.
• a Wratten No. 15 filter to give a direct positive image.
• EXAMPLE 22 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 10 minutes. At the end of the holding period, the pH is adjusted to 6.0 and 0.125 g. of 1,3-diallyl-1'-butyl 7'-chloroimidazo[4,5-b]quinoxalino- 3'-pyrrolo[2,3-b]quinoxalinocarbocyanine bromide (Example 7). The emulsion is coated on a support, and provides good direct positive images. Similar results are obtained when the dyes of Examples 5, 6, 8 and 11 are substituted for the above dye.
• the mixture is heated on a steam-bath for 3 hours, then poured into water (200 ml.), 5 N NaOH (125 m1.) is added and the mixture stirred for 15 minutes.
• the product is extracted with chloroform, the extract dried over MgSO and the chloroform evaporated.
• the oily residue, which becomes partially crystalline on standing, is stirred with ligroin (50 ml.) and the solid collected and washed with ligroin.
• the yield of light grey solid is 1.6 g. (30% M.P. 154155 C. This material is used without further purification.
• the mixture is diluted with ice and water, and the solid collected and 'well washed with water. After recrystallization from aqueous acetic acid, the yield is 7.45 g. (57%) M.P. 145-6 C.
• Phosphoryl chloride (0.46 g., 1 mol.+50%) is added to dimethyl form'amide ml.) and the solution cooled below C.
• 1-methyl-2-p-tolylpyrrolo[2,3-b]quinoxaline (0.55 g., 1 mol.) is added.
• the mixture is heated on a steam-bath for minutes, cooled, and diluted with water ml).
• 5 N NaOH (4.4 ml.) is added.
• a viscous mass separated which became crystalline on stirring. The solid is collected and washed with Water. After recrystallization from ethanol, the yield is 0.40 g. (67%), M.P. 182.5- 183.0 C.
• 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. 1,055,155 and 1,102,028, issued Mar. 4, 1913, and
• a direct positive emulsion in accordance with claim 1 containing a photographic color coupler dispersed in coupler solvent.
• a direct positive, photographic emulsion in accordance with claim 1 which comprises fogged silver halide grains, said grains being such that a test portion thereof, when coated as a photographic silver halide emulsion on a support to give a maximum density of at least about 1 upon processing for 6 minutes at about 68 F. in Kodak DK-SO developer has a maximum density which is at least about 30% greater than the maximum density of an identical coated test portion which is processed for 6 minutes at about 68 F. in Kodak DK-SO developer after being bleached for about minutes at about 68 F. in a bleach composition of:
• n represents a positive integer of from 1 to 2;
• L represents a methine linkage;
• R represents a member selected from the group consisting of an alkyl group, an alkenyl group and an aryl group;
• R represents a member selected from the group consisting of an alkyl group and an aryl group;
• R and R each taken individually represents a member selected from the group consisting of a hydrogen atom, an alkyl group, and an aryl group;
• R and R taken together represent the non-metallic atoms necessary to complete a pyrrolo[2,3-b]quinoxaline nucleus;
• R represents a member selected from the group consisting of a hydrogen atom and an aryl group;
• R represents a member selected from the group consisting of an alkyl group, an aryl group and a heterocyclic radical containing from 5 to 6 atoms in the heterocyclic ring and having a hetero nitrogen, oxygen or sulfur atom;
• X represents an
• a densitizing nucleus selected from the group consisting of a nitrobenzothiazole nu cleus, a nitrobenzoxazole nucleus, a nitrobenzoselenazole nucleus, a nitroindole nucleus, an imidaZo[4,5-b]quinoxaline nucleus, and a l,3,3,trialkyl-3H-pyr
• a direct positive emulsion in accordance with claim 12 which comprises fogged silver halide grains, said grains being such that a test portion thereof, when coated as a photographic silver halide emulsion on a support to give a maximum density of at least about 1 upon processing for 6 minutes at about 68 F. in Kodak DK-SO developer, has a maximum density which is at least about 30% greater than the maximum density of an identical coated test portion which is processed for 6 minutes at about 68 F. in Kodak DK-SO developer after being bleached for about 10 minutes at about 68 F. in a bleach composition of:
• a photographic element comprising a support having thereon at least one layer containing an emulsion of claim 1.
• a photographic element comprising a support having thereon at least one layer containing an emulsion of claim 11.
• a photographic element comprising a support having thereon at least one layer containing an emulsion of claim 3.
• a photographic element comprising a support having thereon at least one layer containing an emulsion of claim 12.
• a photographic element comprising a support having thereon at least one layer containing an emulsion of claim 20.
• a light-sensitive emulsion as defined by claim 28 wherein said cyanine dye is selected from those represented by the following general formulas:
• n represents a positive integer of from 1 to 2;
• L represents a methine linkage;
• R represents a member selected from the group consisting of an alkyl group, an alkenyl group and an aryl group;
• R represents a member selected from the group consisting of an alkyl group and an aryl group;
• R and R taken together represent the non-metallic atoms necessary to complete a pyrrolo[2,3-b]quinoxaline nucleus;
• R represents a member selected from the group consisting of a hydrogen atom and an aryl group;
• R represents a member selected from the group consisting of an alkyl group, an aryl group and a heterocyclic radical containing from 5 to 6 atoms in the heterocyclic ring and having a hetero nitrogen, oxygen or sulfur atom;
• X represents an acid ani

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• 1968
  • 1968-02-15 US US705595A patent/US3598595A/en not_active Expired - Lifetime
• 1969
  • 1969-02-14 DE DE19691907618 patent/DE1907618A1/de not_active Withdrawn
  • 1969-02-14 BE BE728462D patent/BE728462A/xx unknown
  • 1969-02-14 GB GB8205/69A patent/GB1254596A/en not_active Expired
  • 1969-02-14 FR FR6903552A patent/FR2001951A1/fr not_active Withdrawn

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