Classifications

• • 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
  • G03C5/00—Photographic processes or agents therefor; Regeneration of such processing agents
  • G03C5/26—Processes using silver-salt-containing photosensitive materials or agents therefor
  • G03C5/38—Fixing; Developing-fixing; Hardening-fixing
• • 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
  • G03C1/42—Developers or their precursors

Definitions

• Photographic silver halide can be stabilized with certain organic sulfonium, organic sulfoxonium, organic ammonium, organic phosphonium, organic boronium, and/or organic siliconium halides of mixtures of these. These can be employed in a photographic element, processing solution or processing web. They are useful in combination with a nonaqueous, low-melting solvent, e.g. succinimide, sulfamide, urea, or acetamide.
• a nonaqueous, low-melting solvent e.g. succinimide, sulfamide, urea, or acetamide.
• This invention relates to silver halide complexing agents and in particular to the stabilization and fixing of silver halide sensitized photographic materials.
• the usual procedure employed in the processing of lightsensitive silver halide photographic elements is development of the latent silver image followed by fixing to remove residual light-sensitive silver salts. If rapid processing of films and papersis desired and'extreme permanence is not required, the unexposed silver halides may be left in the photograph and converted into compounds which are relatively inert to light, heat, and humidity.
• This type of rapid processing is known as stabilization and the criteria for judging its effectiveness are the stability of the resulting photographic image to moist incubation and light.
• Many of the known stabilization processes utilize complexing agents which have serious limitations. Often, opaque complexes are formed or the complexing agent bleaches the silver image.
• complexing agents are activated by water and thus, such agents cannot be incorporated into aqueous gelatin-silver halide emulsions without adversely affecting the sensitometric characteristics of the emulsion or the lightsensitive layer.
• These water-activated complexing agents are not suitable for dry-processing techniques.
• few silver halide stabilizers have been found which operate satisfactorily in diffusion transfer processes.
• silver halide complexing agents have been found which are free from these undesirable characteristics, and which can be used effectively to stabilize or fix a photographic element.
• photographic silver halide stabilization and fixing compositions which form stable, transparent silver halide complexes, and which can be in the form of either aqueous or nonaqueous solutions.
• Another object is to provide a process for the stabilization of photographic images.
• a further object is to provide a process for fixing photographic images which can employ aqueous or nonaqueous fixing baths.
• Still another object is to provide a simplified process for the stabilization of a photographic silver halide element which requires only heating of the element.
• a further object is to provide photographic silver halide stabilization compositions which can be employed in a photographic diffusion transfer process.
• Still another object is to provide photographic silver halide elements containing a heat-activated stabilization composition which will enable such elements to be stabilized by heating alone.
• a further object is to provide a class of silver salt complexing agents which have a slow rate of stabilization in cold aqueous solutions, but which will stabilize an exposed photographic element quite rapidly in hot aqueous solutions.
• Still another object is to provide a class of silver halide complexing agents which are odorless, unusually stable to adverse changes of heat, light, and humidity, which have little tendency to bleach silver images, and which do not cause tack or stickiness in processed elements.
• Another object is to provide a processing web containing silver halide complexing agents for processing photographic elements.
• a stabilizing amount of a complexing agent selected from the group consisting of organic sulfonium halides, organic sulfoxonium halides, organic ammonium halides, organic phosphonium halides, organic boronium halides, organic siliconium halides, or mixtures thereof.
• a complexing agent selected from the group consisting of organic sulfonium halides, organic sulfoxonium halides, organic ammonium halides, organic phosphonium halides, organic boronium halides, organic siliconium halides, or mixtures thereof.
• R1 R Q Rt 69 A x or m-lu-R, x
• A is S; A is N or P;
• X is a halide ion
• R R and R are lower alkyl; R, is lower alkyl or aryl, e.g. phenyl.
• R R' amino includes substituted amino groups, hydroxy includes ether linkages, alkyl includes substituted alkyl groups, and aryl includes substituted aryl groups.
• Especially preferred complexing agents falling within the above formula include tetraethylammonium bromide, 2- hydroxyethyltrimethylammonium bromide, tetraethylammonium chloride, ethyltrimethylammoniurn bromide, tetramethylammonium bromide,- tetrapropylammonium iodide, methylamine hydrobromide, trimethylamine hydrobromide, tetraethylphosphonium bromide, n-butyltriphenylphosphonium bromide, and trimethylsulfonium bromide.
• the complexing agents can be present in the solution in any amount which will effect stabilization and preferably comprise about 5 to about 40 percent by weight of the solution.
• Solution of the silver halide complexing agent may be made either in water or in a suitable nonaqueous, low-melting solvent.
• the complexing agents of the invention have a slow rate of stabilization in cold, aqueous solutions, but when a photographic element is treated'with a hot, aqueous solution of the complexing agent, rapid stabilization occurs.
• Nonaqueous solvents which are liquid and will promote stabilization at room temperature include formamide, N,'N-dimethylformamide, dimethylsulfoxide, and tetramethylene sulfone.
• Low-melting solvents such as succinimide, sulfamide, acetamide, and urea, which are solids at room temperature, are also quite useful. They can be coated onto the photographic element or a separate processing web along with the stabilizer, so that stabilization can be effected merely by heating the element, or bringing it into contact with the hot processing web.
• the silver halide complexing agents are incorporated in a low-melting, nonaqueous solvent, and a polymeric binder through which the melted solvent can diffuse.
• This mixture is coated as an image stabilization layer upon a light-sensitive photographic silver halide emulsion layer.
• the low-melting solvent is solid at room temperature, and the complexing agents contained therein are inactivev Upon heating, the solvent melts and allows diffusion of the complexing agent into the photographic emulsion layer where it reacts with unexposed silverhalide to cause stabilization.
• the combination of succinimide and tetraethylammonium bromide or tetraethylphosphonium bromide when used as a stabilizing composition has an exceptionally low tendency toward bleaching the silver image.
• Succinimide forms a clathrate which is extremely non deliquescent with tetraethylammonium bromide and with tetraethylphosphonium bromide, and thus fading is inhibited. Images stabilized with this composition do not fade as quickly as those fixed with alkali thiosulfates.
• Quaternary ammonium compounds have been used in photographic processes of the prior art.
• US Pat. No. 3,093,479 of Olivares et al. granted June 1 1, I963
• fixing of a photographic image is followed by treatment with a solution of a quaternary ammonium halide to prevent image fading and overall yellowing and to protect the image from microbacterial deterioration.
• the quaternary salt which is used in small concentrations ('1-2 percent), combines with any residual thiosulfate from the fixing process, apparently forming an insoluble, immobile molecule which cannot react with aerial or residual sulfide ion.
• quaternary ammonium compounds are used in larger amounts as silver halide complexing agents and react with the unexposed silver halide to form stable complexes, probably of the typeQeaAgx aThus, the quaternary salts act as stabilizers with the complexed silver halide either remaining in the element or being removed by washing.
• our compounds are used in larger amounts as complexing agents to prevent the printout of silver halide, an effect occurring after processing.
• Two kinds of stabilizing agents which form complexes with silver halides are known in the prior art-those which produce insoluble silver halide complexes and those which produce soluble complexes.
• Insoluble silver halide complexes which are usually opaque and, thus, generally not useful for stabilizing photographic film records, are formed from the reaction of thioglycolic acid, thiosalicylic acid, and similar mercapto compounds with silver halides.
• Alkali thiosulfates, alkali thiocyanates, thiourea, and certain thiourea derivatives convert silver halides into soluble complexes.
• the complexing agents of the invention constitute a new class of silver halide stabilizers quite unlike those of the prior art. They have a broad range of applications and avoid many of the limitations of the known stabilizers.
• the stabilizing agents of our invention can be incorporated into photographic silver halide emulsion layers, or coated in separate layers contiguous to the emulsion layer.
• the stabilizing agents of the invention can be conveniently coated from aqueous solutions at or below room temperature without prestabilization of the emulsion.
• solid, low-melting, nonaqueous solvents are used to provide a photographic element which may be stabilized merely by heating.
• the silver halide complexing agents of the invention may also be utilized in stabilizing or fixing baths, using either nonaqueous solvents or hot water.
• nonaqueous solvents such as alcohols, ketones, nitriles,
• the processing solutions of the invention can also be incorporated into a separate processing web. Stabilization can then be effected by contacting the web having the solution imbibed therein with the exposed photographic element.
• a dry web containing the complexing agent and a low-melting solvent such as succinimide, sulfamide, urea or acetamide, can be contacted with a photographic element and heated to mobilize the complexing agent.
• a developing agent may also be included in the photographic element or processing web which contains the stabilizing agent.
• the silver halide developing agents which may be used include those commonly known as silver halide reducing agents such as, for example 3-pyrazolidones, including 1- phenyl-3-pyrazolidone, l-phenyl-4,4-dimethyl-pyrazolidone, etc., ascorbates, including sodium isoascorbate, p-phenylenediamine, hydroquinones, N-methyl-p-aminophenol sulfate, catechol, etc.
• Especially preferred developing agents are l-phenyl-3-pyrazolidone and sodium isoascorbate.
• Another use of the silver halide complexing agents of the invention is in diffusion transfer processes.
• a photographic element is first exposed and developed.
• the unexposed silver halide in the nonimage areas of the element are then complexed or stabilized and diffused to a receiving sheet containing active nuclei.
• the silver complexes dissociate providing silver ions which can then be developed to a silver image on the receiving sheet.
• the complexing agents employed for this purpose must be capable of picking up and transferring all of the unexposed silver halide, and more importantly, the resulting complex must dissociate in contact with the nuclei in the receiving sheet.
• silver halide stabilizers and complexing agents form complexes which will not readily or sufficiently dissociate in contact with the receiving sheet.
• the silver complexes formed with the stabilizing compositions of this invention dissociate readily in contact with the receiving sheet nuclei and thus provide an extremely useful diffusion transfer System.
• the complexing agents of the invention When used to fix or stabilize a photographic image, the complexing agents of the invention need not be dissolved in only one solvent, but can also be dissolved in mixtures, complexes, or eutectics composed of several solvents. By a proper choice of solvents or mixtures of solvents, many variables in nonaqueous processing such as processing temperature, maximum density, fog level, and gamma can be adjusted as desired.
• the photographic silver halide emulsions of the photographic elements which can be stabilized in this invention can be sensitized using any of the well-known techniques in emulsion making, for example, by digesting with naturally active gelatin or various sulfur compounds and/or gold compounds.
• the emulsions can be sensitized with salts of noble metals of Group Vlll of the Periodic Table which have an atomic weight greater than
• the emulsions can be of the surface-sensitive or internally sensitive type.
• the emulsions can also contain speed-increasing addenda such as polyethylene glycols or thioether sensitizers.
• the emulsions of the photographic elements which can be stabilized according to our invention can also contain conventional addenda such as gelatin plasticizers, hardeners and coating aids. These emulsions are useful -in X-ray and other nonoptically sensitized emulsions, and can also be used in orthochromatic, panchromatic and infrared sensitive emulsions.
• the addenda can be added to the emulsion before or after sensitizing dyes, if any, are used.
• Various silver halides can be used as the sensitive salt, such as silver bromide, silver iodide, silver chloride, or mixed silver halides such as silver chlorobromide or silver bromoiodide.
• the emulsions can be used in photographic elements intended for color photography, and thus can contain color-forming couplers, or used as emulsions to be developed by solutions containing couplers or other color-generating materials, or emulsions of the mixedpacket type, as disclosed by Godowsky, U.S. Pat. No. 2,698,794, or emulsions of the mixed-grain type, such as disclosed by Carroll et al., U.S. Pat. No. 2,592,243.
• emulsion vehicles and dispersing agents for silver halide grains may be employed singly or in combination with each other, for example, gelatin, colloidal albumen, cellulose derivatives and synthetic resins, such as polyvinyl compounds.
• colloids examples include poly(vinyl alcohol), hydrolyzed poly( vinyl acetate), hydrolyzed cellulose ester, water-soluble ethanolamine cellulose acetate, polyacrylamide, copolymers having a combined acrylamide content of 3-60 percent, copolymers of alkyl acrylate and acrylic acid, a vinyl alcohol copolymer containing urethane carboxylic acid groups or containing cyano-acetyl groups, or polymeric material which results from polymerizing a protein or saturated acrylated protein with a monomer having a vinyl group such as disclosed by lllingsworth, U.S. Pat. No. 2,852,382
• Such polymeric addenda may be employed as latices or hydrosols in the preparation of the photographic emulsions of the photographic elements which may be stabilized'according to our invention.
• the first three examples illustrate the effectiveness of the complexing agents of this invention as fixing agents.
• EXAMPLE 1 A percent solution of 2-hydroxyethyltrimethylammoniurn bromide was made up in formamide.
• a sample of photographic paper which was made up of a gelatino-silver chloride emulsion (containing 77 mg. silver per square foot) was immersed in this bath for 1 minute at room temperature. This sample was washed in water for 5 minutes and analyzed for silver. The silver content was 1.6 mg. per square foot, indicating that with only 1' minute of treatment and 5 minutes washing, practically all of the silver had been removed by this fixing composition.
• EXAMPLE 2 A 20 percent solution of 2-hydroxyethyltrimethylammonium bromide was made up in water. A sample of the silver chloride paper used in example I was immersed for 4 minutes at room temperature, washed in water for 5 minutes, and analyzed for silver. The silver content was 63 mg. per square foot. This demonstrates that the quaternary salt was a poor fixing agent in water at room temperature.
• EXAMPLE 3 The procedure of example 2 was repeated but with the quaternary salt solution at 90 C. and with an immersion time of 1 minute. The washed sample was analyzed for silver. The silver content was 2.5 mg. per square foot, indicating the 2- hydroxyethyltrimethylammonium bromide to be a good fixing agent in hot water.
• EXAMPLE 4 The following example illustrates the preparation and use of a photographic element containing a complexing agent of our invention.
• This solution was dispersed in 186 g. of 7 percent ethyl cellulose in toluene.
• Solution B was dispersed in 186 g. of 7 percent ethyl cellulose in toluene.
• the two dispersions, A and B were mixed together in equal parts and then coated on paper having a gelatino-silver chloride emulsion using a 0.0'l0-inch knife and dried.
• the coating was exposed to a line copy negative for 10 seconds (40 watt bulb) and heated on a 155C. mandrel for 5 seconds.
• the print showed a good image (D 0.4) and the background was pale yellow.
• the print was exposed to a fluorescent desk lamp for one week with no deterioration of the image and no darkening ,of the background.
• the dispersion was coated (using a 0.008-inch knife) on paper having a gelatino-silver chloride emulsion.
• the coating was exposed to a line copy negative for 10 seconds (40 watt bulb) and heated on a C. mandrel for 10 seconds. An image appeared during the first few seconds of heating.
• the sample was exposed to a fluorescent desk lamp (20 watt) at a distance of 6 inches for 24 hours with no deterioration of the image and no increase in fog level.
• EXAMPLE 6 The following solution was prepared: Succinirnide If) g l-PhenyH-pyrazolidone 1.5 g. Sodium lsoarcorbate 2.5 g. Tetraethylammonium bromide 6.5 g Water I! g This solution was dispersed in 93 g. of 7 percent ethyl cellulose in toluene.
• The'dispersion was coated (0.008-inch knife) on paper having a gelatino-silver chloride emulsion and dried.
• the coating was exposed to a line copy negative for ID seconds (40 watt bulb) and then heated on a 155 C. mandrel for 3 seconds.
• the developed image was exposed to a fluorescent desk lamp (20 watt) at a distance of 6 inches for 24 hours with no deterioration of the image and no increase in fog level.
• EXAMPLE 7 A sample from example 6 was stored at 50 percent relative humidity and 73 C. for 6 weeks. it was then exposed and heated at 155 C. for 3 seconds. The resulting developed and stabilized image showed approximately the 'same quality as that in example 6, indicating good shelf life of the coated paper.
• EXAMPLE 8 The following solution was prepared: Succiniinide 15.0 g. Water 20.0 g. l-Phenyl-J-pyrazolidone L5 g. Sodium lsoascorbate 2.5 g. 2-llydroxyethyltrimethylammonium chloride 4.0 g.
• the dispersion was coated (0.008 inch knife) on paper having a gelatino-silver chloride emulsion and dried.
• the coating was exposed to a line copy negative for 10 seconds (40 watt bulb) and heated on a 155 C. mandrel for 3 seconds.
• a gray, black image resulted with a yellow background.
• the print was stable to fluorescent light with no change in the image. or background.
• EXAMPLE 9 The dispersion used in example 8 was coated (0.006-inch knife) on a substrate consisting of AgBr (30 mg. per square foot) which had been vacuum-deposited on paper support. The coating was exposed to a line copy negative for 20 seconds (40 watt bulb) and heated on a 155- C. mandrel for 3 seconds. A gray, black image appeared on a tan background. The print was stable to fluorescent light with no change in the image quality and no increase in fog.
• EXAMPLE 10 This example illustrates the use of quaternary ammonium halides in nonaqueous solvents as the silver halide complexing agent for a diffusion transfer process.
• a piece of paper having a gelatino-silver chloride emulsion was exposed to a line copy negative for 30 seconds in a printing box (40 watt lamp).
• the solution was wiped over the surface of the photographic paper with a camel's hair brush and then a ditfusion transfer receiving sheet was placed in face-toface contact with the dampened paper.
• the sandwich was heated on a 140 C. mandrel for 2 seconds and the papers separated. A positive, brown-black image of that on the exposed paper was on the receiving sheet.
• the dispersion was coated (0.004-inch knife) over a sheet of paper having a fogged, direct positive, silver chloride emulsion of the type in US. Pat. No. 2,541,472 and dried. It was then exposed for 45 seconds to a line copy negative using a number 2 Photoflood with a piece of yellow sheeting interspersed between the lamp and the negative. The coated paper was then heated on a 155 C. mandrel for 3 seconds and a positive reproduction of the positive image resulted. The print was stable to fluorescent light with no deterioration of the image and no increase in background.
• EXAMPLE 12 The following solution was prepared: Succinimide 10.0 g. Methane sulfonamide 5.0 g. Water 20.0 ml.
• the dispersion was coated (0.006-inch knife) over a sheet of paper having a gelatino-silver chloride emulsion and dried. It was then exposed to a line copy negative (10 seconds, 40 watt bulb) and heated on a 155 C. mandrel for three seconds. A brown image resulted with an off-white background. The paper was incubated at 100 percent relative humidity, 75 C., for 24 hours with no deterioration of the image and no increase in the background.
• EXAMPLE l3 The following solution was prepared: Succinirnide 6.0 g. Sulflmide 2.0 g. Water 3.0 g. Tetnpropylammonium iodide 8.0 g.
• the dispersion was coated (0.004-inch knife) on a photographic paper which contained AgCl, gelatin, succinimide, lphenyl-4-methyl-3-pyrazolidone and sodium isoascorbate.
• the paper was then exposed to a line copy negative (30 seconds, 40 watt bulb) and heated on a 155 C. mandrel for 4 seconds. A black image resulted with a yellow background.
• the paper was exposed to fluorescent light for 24 hours with no deterioration of the image and no increase in background. This paper, when not coated with the dispersion, will give an excellent image after exposure and heating, but the background will darken on exposure to visible light.
• EXAMPLE 14 A silver halide emulsion was prepared as follows: (a) 14 g. of a silver chloride coagulum, which contains 15 g. of gelatin and one mole of silver in each 370 g. of emulsion, was dispersed in g. of gelatin which also contained 7 g. of succinimide; (b) a solution was made as follows:
• the dispersion was coated over paper having a gelatinosilver chloride emulsion using an 0.008-inch knife.
• the dried coating was exposed to a line image and heated for 5 seconds at C. A developed and stabilized image resulted.
• the dispersion was coated over paper having a gelatinosilver chloride emulsion using a 0.008-inch knife.
• the dried coating was exposed to a line image and heated at l55 C. for 5 seconds. A developed and stabilized image resulted.
• EXAMPLE 18 The following solution was prepared: Succinimide l5.0 g. Sodium lsoascorbate 2.5 g l-Phenyl-Iipyrazolidone L5 3 'l'rimethylsult'onium bromide 5.0 g. Water 20.0 ml
• the dispersion was coated over paper having a gelatinosilver chloride emulsion using a 0.006inch knife.
• the dried coating was exposed to a line image and heated at l40 C. for
• Succinimide [5.0 g. Sodium lsoascorbate 2.5 g. l-Phenyl-3- yrazolidone 1.5 g. Ethyl dimethylsulfoxonium bromide 8.3 g. Water 20.0 ml.
• This solution was dispersed in 45 g. of a 15 percent toluene solution of cellulose acetate-butyrate.
• Tropolone boron bromide is soluble in water, forrnamide and molten succinimide. A 5 percent solution in water showed no tendency to dissolve silver chloride or silver bromide. A 5 percent solution in formamide (or molten succinimide) dissolved silver chloride and silver bromide very readily.
• EXAMPLE 22 This example makes use of tropolone silicon chloride as a silver halide complexing agent.
• a 10 percentsolution in water showed no tendency to dissolve silver chloride or silver bromide.
• a 10 percent solution in formamide (or molten succinimide) dissolved silver chloride.
• EXAMPLE 23 This example illustrates a quaternary halide-succinimide mixture for silver halide stabilizing processing at room temperature. A large amount of water was used to lower the crystallization point of the mixture.
• the following solution can be used as a bath or as a surface application using a hopper or roller.
• a photographic silver halide stabilizing composition consisting essentially of a solution of an organic silver halide complexing agent in a silver halide stabilizing concentration of about 5 percent to about 40 percent by weight of said solution in a solvent which comprises formamide, dimethylsulfoxide, dimethylformamide, succinimide, sulfamide. urea or acetamide, said complexing agent being an organic sulfonium halide, an organic ammonium halide, an organic phosphonium halide, tropolone boronium halide, tropolone siliconium halide, or mixtures thereof.
• composition of claim 1 wherein said complexing agent is tetraethylammonium bromide, 2-hydroxy-ethyltrimethlammonium bromide, tetrapropylammonium iodide, tetra-ethylphosphonium bromide, or trimethylsulfonium bromide.
• composition of claim 1 wherein said complexing agent is tetraethylammonium bromide.
• composition of claim 1 which also contains a polymeric binder.
• a process comprising developing a latent image in an exposed photographic silver halide element and stabilizing the undeveloped photographic silver halide, in said element with a solution consisting essentially of an organic silver halide complexing agent in a silver halide stabilizing concentration of about 5 to about 40 percent by weight of the solution; said complexing agent being an organic sulfonium halide, an organic ammonium halide, an organic phosphonium halide, a tropolone boronium halide, a tropolone siliconium halide, or mixtures thereof in water or a low-melting, nonaqueous solvent.
• a photographic silver halide stabilizing composition consisting essentially of a solution of an organic silver halide complexing agent, in a silver halide stabilizing concentration of about 5 percent to about 40 percent by weight of said solution, in a solvent which comprises a formamide, dimethylsulfoxide, dimethylformamide, Lmethylformamide, succinimide, Lsulfamide, urea or acetamide, said complexing agent being (a) a compound of the formula:
• A is S; A is N or P; R R and R are lower alkyl; R is lower alkyl or phenyl; X is a halide ion;
• composition of claim 1 comprising a photographic silver halide developing agent.
• a process comprising developing a latent image in an exposed photographic silver halide element and stabilizing the underdeveloped photographic silver halide in said element, with a solution consisting essentially of an organic silver halide complexing agent, in a silver halide stabilizing concentration of about 5 percent to about 40 percent by weight of said solution, said complexing agent being (a) a compound of the formula:
• A is S; A is P or N; R,, R and R are lower alkyl; R, is lower alkyl or phenyl; X is a halide ion;
• tropolone boronium halide b. tropolone boronium halide; or c. tropolone siliconium halide, or mixtures thereof, in water or a low-melting, nonaqueous solvent.

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• Chemical & Material Sciences (AREA)
• General Physics & Mathematics (AREA)
• Spectroscopy & Molecular Physics (AREA)
• Chemical Kinetics & Catalysis (AREA)
• Engineering & Computer Science (AREA)
• Materials Engineering (AREA)
• Non-Silver Salt Photosensitive Materials And Non-Silver Salt Photography (AREA)
• Organic Low-Molecular-Weight Compounds And Preparation Thereof (AREA)
• Pharmaceuticals Containing Other Organic And Inorganic Compounds (AREA)
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Cited By (7)

• 1966
  • 1966-08-29 US US575548A patent/US3615510A/en not_active Expired - Lifetime
• 1967
  • 1967-08-23 BE BE703006D patent/BE703006A/xx unknown
  • 1967-08-25 GB GB39264/67A patent/GB1175106A/en not_active Expired
  • 1967-08-28 DE DE19671597540 patent/DE1597540A1/de active Pending

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