Photographic elements containing aryloxy substituted photographic couplers

Abstract: Photographic elements comprising a support and a silver halide emulsion having associated therewith a dye-forming coupler of good reactivity with an aryloxy coupling-off group having in an ortho position a polarizable carbonyl, sulfonyl or phosphinyl moiety-containing group which is free of photo­ graphic dye groups and photographic reagent groups.

Description: This invention relates to photographic elements containing nondiffusible couplers. Images are commonly obtained in the photographic art by a coupling reaction between the development product of a silver halide color developing agent (e.g., oxidized aromatic primary amino developing agent) and a color-forming compound referred to as a coupler. The dyes produced by coupling are indoaniline, azomethine, indamine, or indophenol dyes, depending upon the chemical composition of the coupler and the color developing agent. The subtractive process of color formation is ordinarily employed in multicolored photographic elements and the resulting image dyes are usually cyan, magenta and yellow dyes which are formed in or adjacent silver halide layers sensitive to red, green and blue radiation, respectively. Since this is a mature art, the patent and technical literature is replete with references to compounds which can be used as couplers for the formation of photographic images. Preferred couplers which form cyan dyes upon reaction with oxidized color developing agents are phenols and naphthols. Representative couplers are described in the following patents and publications: U.S. Patents 2,772,162, 2,895,826, 3,002,836, 3,034,892, 2,474,293, 2,423,730, 2,367,531 and 3,041,236 and "Farbkuppler-eine Literaturübersicht," published in Agfa Mitteilungen, Band II, pp. 156-175 (1961). Preferred couplers which form magenta dyes upon reaction with oxidized color developing agent are pyrazolones, pyrazolotriazoles, pyrazolobenzimidazoles and indazolones. Representative couplers are described in such patents and publications as U.S. Patents 2,600,788, 2,369,489, 2,343,703, 2,311,082, 2,673,801, 3,152,896, 3,519,429, 3,061,432, 3,062,653, 3,725,067 and 2,908,573 and "Farbkuppler-eine Literaturübersicht," published in Agfa Mitteilungen, Band II, pp. 126-156 (1961). Couplers which form yellow dyes upon reaction with oxidized color developing agent are acylacetanilides such as benzoylacetanilides and pivalylacetanilides. Representative couplers are described in the following patents and publications: U.S. Patents 2,875,057, 2,407,210, 3,265,506, 2,298,443, 3,048,194 and 3,447,928 and "Farbkuppler-eine Literaturübersicht," published in Agfa Mitteilungen, Band II, pp. 112-126 (1961). Also known are couplers which form black or neutral dyes upon reaction with oxidized color developing agent. Representative couplers are resorcinols and m-aminophenols such as are described in U.S. Patents 1,939,231, 2,181,944, 2,333,106, 4,126,461, DE-A-2,644,194 and DE-A-2,650,764. Many of the color-forming couplers employed in photographic materials are four-equivalent couplers. In other words, they require two molecules of oxidized developing agent, and development of four molecules of silver halide, in order to ultimately produce one molecule of dye. Also known and used are two-equivalent couplers which require only one molecule of oxidized developing agent, and development of two molecules of silver halide, to produce one molecule of dye. Two-equivalent couplers contain a substiuent in the coupling position, known as a coupling-off group, which is eliminated from the coupler following reaction with oxidized developing agent without requiring the action of one additional molecule of oxidized developing agent, as is required by four equivalent couplers. Although numerous couplers are known in the art, there is a continuing search to improve upon existing couplers or optimize specific properties for a particular application. A particular property which frequently is of interest is reactivity. Reactivity relates to the rate at which the coupler reacts with oxidized color developing agent and it influences the dye density in the processed photographic image. While two-equivalent couplers are theoretically capable of yielding twice as much dye per unit of developed silver as four-equivalent couplers, they rarely, if ever, yield the amount of dye theoretically possible. The amount of dye obtained can be increased by increasing the reactivity of the coupler. It is thus a problem to increase the reactivity of couplers in photographic elements. The couplers used in the present invention contain an aryloxy coupling off group. Couplers comprising a coupling moiety having an aryloxy substituent in the coupling position are known. Research Disclosure, August 1980, pages 339 and 340 describes polyfunctional couplers in which a ballasted coupler is blocked by being attached to the coupling position of a soluble coupler by means of an oxygen linking group. The couplers described are not two-equivalent dye-forming couplers since removal of the diffusible coupler first formed during photographic processing results in the consumption of at least six equivalents of silver to form a molecule of dye. Research Disclosure, July 1981, pages 268 and 269 describes blocked dye-forming couplers. The blocking group may be derived from a dye-forming soluble coupler. The soluble dye formed upon reaction with oxidised developing agent is removed during processing. Hence, the couplers described are not two-equivalent dye-forming couplers. US-A-4 248 962 describes couplers, including two-equivalent couplers, which release a photographic dye group or a photographic reagent group in a controlled manner as a function of silver halide development. In some instances the photographic dye or reagent group is joined to the ortho position of an aryloxy coupling off group and some intermediates shown in the preparative examples have ortho-substituted aryloxy coupling off groups. There is no suggestion that these intermediates would behave as couplers or that a particular type of substituent in a particular position of a coupling off group would have a significant effect on reactivity. UK-A-1 077 874 describes two-equivalent dye-forming couplers consisting of a ballasted dye-forming coupling group substituted in its coupling position with an aryloxy group. The couplers require the development of only two equivalents of silver halide for the formation of one molecule of image dye and are said to have good reactivity. The present invention provides a photographic element comprising a support bearing a photographic silver halide emulsion layer and, incorporated in the emulsion layer or a layer adjacent thereto, a two-equivalent dye-forming coupler consisting of a ballasted dye-forming coupling group substituted in its coupling position with an aryloxy group having ortho to the oxygen atom a group which contains a polarizable carbonyl, sulfonyl or phosphinyl moiety and which is free of photographic dye groups and photographic reagent groups. The dye-forming couplers used in the photographic elements of the invention have good reactivity and are capable of yielding high amounts of dye upon reaction with oxidized color developing agent. The dye-forming couplers in the photographic elements of the invention preferably have the structural formula: where: COUP represents a ballasted dye-forming coupling group substituted in its coupling position with the remainder of the structure; X represents the atoms to complete a phenyl or naphthyl nucleus; R is hydrogen or one or more substituents, preferably a substituent selected from halogen, alkyl, alkoxy, nitro, cyano, carboxy, alkoxycarbonyl, aryloxycarbonyl, akylsulfonyl, arylsulfonyl, amido (-NR¹COR²), carbamoyl (-CONR³R⁴), sulfonamido (-NR¹SO₂R²) and sulfamoyl (-SO₂NR³R⁴); each R¹ is hydrogen or alkyl of 1 to 4 carbon atoms; m is 0 to 4; A is a group containing a polarizable cabonyl, sulfonyl or phosphinyl moiety free of photographic dye groups and photographic reagent groups, preferably a group selected from -SO₂R², -SO₂NR³R⁴, -NR¹SO₂R², -NR¹SO₂NR³R⁴ and R² is hydrogen, alkyl or aryl; R³ and R⁴ are each, individually hydrogen, alkyl, aryl or heterocyclyl, or together R³ and R⁴ complete a heterocyclic ring with the nitrogen atom to which they are attached; and each R⁵ is, individually, alkyl, alkoxy, aryl or aryloxy. Unless otherwise specified, the alkyl and aryl portions of the above groups contain 1 to 20 and 6 to 20 carbon atoms, respectively. They can be unsubstituted or substituted with such groups as halogen (e.g., chloro, bromo and fluoro), hydroxy, cyano, carboxy and sulfamoyl. The heterocyclic portions of the above groups contain at least one 5- or 6-membered ring comprised of ring atoms selected from carbon, oxygen, nitrogen and sulfur. Especially preferred couplers of structural formula I, above, are those where: X completes a phenyl group; m is 0 or 1; R is hydrogen or is a para position substituent selected from carboxy, alkoxy, alkoxycarbonyl, hydroxyalkyl and hydroxyalkylsulfamoyl; R¹ is hydrogen; A is -NHCOR², CONR³R⁴, -SO₂R², -NHSO₂R² or -SO₂NR³R⁴; R² is alkyl or hydroxyalkyl of 1 to 4 carbon atoms; and one of R³ and R⁴ is hydrogen and the other is alkyl or hydroxyalkyl of 1 to 4 carbon atoms. The coupling group represented by COUP can be any ballasted coupling group known or used in the art to form a colored product with oxidized color developing agent. As indicated above, common yellow dye-forming couplers are acylacetanilides such as acetoacetanilides and benzoylacetanilides, common magenta dye-forming couplers are pyrazolones, pyrazolotriazoles, pyrazolobenzimidazoles and indazolones. Common cyan dye-forming couplers are phenols and naphthols, and common neutral dye-forming couplers are resorcinols and m-aminophenols. These couplers can form the coupling group, COUP in Formula I above. Structures of preferred coupling groups are shown below. In these structures the unsatisfied bond indicates the position where the aryloxy coupling-off group used for this invention is joined (i.e., the "coupling position"). Yellow dye-forming acylacetanilide coupling groups: where: R⁶ is a ballast group and R⁷ is hydrogen or one or more halogen, alkyl or alkoxy groups. Cyan dye-forming phenol and naphthol coupling groups: where: R⁶ is a ballast group, and R⁸ is one or more halogen (e.g., chloro, fluoro), lower alkyl (e.g., methyl, ethyl, butyl) or lower alkoxy (e.g., methoxy, ethoxy, butoxy) groups. Magenta dye-forming pyrazolone and pyrazolotriozole coupling groups: where: R⁶ is a ballast group R⁹ is halogen, lower alkyl, lower alkoxy, phenyl or substituted phenyl (e.g., 2,4,6-trihalophenyl), and R¹⁰ is a blocking group which is removable during processing, such as an acyl group. Representative couplers that can be used in the photographic elements of this invention are shown below: Couplers that can be used in the photographic elements of this invention can be prepared by condensing a coupler having a halogen (e.g., chloro) coupling-off substituent with a appropriately ortho substituted phenol or naphthol in the presence of an acid acceptor. Alternatively, a halogen derivative of the phenol or naphthol can be condensed with coupler, or precursor thereof, which has a hydroxy group in the coupling position, other reactive positions on the coupler being blocked until after attachment of the coupling-off group. Representative preparations of couplers are shown in the preparative examples, infra. The couplers in the photographic elements of the invention are incorporated either in the silver halide emulsion layers (normally being incorporated in the emulsions coated to produce them) or in layers adjacent the silver halide emulsion layers so that during development, the coupler can react with development products such as oxidized color developing agent. The couplers may thus be said to be "associated" with the appropriate silver halide emulsion layers or to be in "reactive association" with them. The photographic elements of the invention can be single color elements or multicolor elements. Multicolor elements contain dye image-forming units sensitive to each of the three primary regions of the spectrum. Each unit can be comprised of a single emulsion layer or of multiple emulsion layers sensitive to a given region of the spectrum. The layers of the element, including the layers of the image-forming units, can be arranged in various orders as known in the art. In an alternative format, the emulsions sensitive to each of the three primary regions of the spectrum can be disposed as a single segmented layer, e.g., as by the use of microvessels as described in Belgian patent 881,513. A typical multicolor photographic element of the invention comprises a support bearing a cyan dye image-forming unit comprised of at least one red-sensitive silver halide emulsion layer having associated therewith at least one cyan dye-forming coupler, a magenta dye image-forming unit comprising at least one green sensitive silver halide emulsion layer having associated therewith at least one magenta dye-forming coupler and a yellow dye image-forming unit comprising at least one blue-sensitive silver halide emulsion layer having associated therewith at least one yellow dye-forming coupler, at least one of the couplers in the photographic element being a coupler with an aryloxy coupling-off group as described above. The element can contain additional layers, such as filter layers, interlayers, overcoat layers, subbing layers, and the like. In the following discussion of suitable materials for use in the photographic elements of this invention, reference is made to Research Disclosure, December 1978, Item 17643, published by Industrial Opportunities Ltd., Homewell Havant, Hampshire, PO9 1EF, U.K. This publication is identified hereafter by the term "Research Disclosure." The silver halide emulsions employed in the photographic elements of this invention can be either negative-working or positive-working. Suitable emulsions and their preparation are described in Research Disclosure Sections I and II and the publications cited therein.. Suitable vehicles for the emulsion layers and other layers of elements of this invention are described in Research Disclosure Section IX and the publications cited therein. In addition the photographic elements of the invention can include other couplers as described in Research Disclosure Section VII, paragraphs D, E, F and G and the publications cited therein. These couplers can be incorporated in the elements and emulsions as described in Research Disclosure Section VII, paragraph C, and the publications cited therein. The photographic elements of this invention can contain brighteners (see Research Disclosure Section V), antifoggants and stabilizers (see Research Disclosure Section VI), antistain agents and image dye stabilizers (see Research Disclosure Section VII, paragraphs I and J), light absorbing and scattering materials (see Research Disclosure Section VIII), hardeners (see Research Disclosure Section XI), plasticizers and lubricants (see Research Disclosure Section XII), antistatic agents (see Research Disclosure Section XIII), matting agents (see Research Disclosure Section XVI) and development modifiers (see Research Disclosure Section XXI). The photographic elements of the invention can be coated on a variety of supports as described in Research Disclosure Section XVII and the references described therein. Photographic elements of the invention can be exposed to actinic radiation, typically in the visible region of the spectrum, to form a latent image as described in Research Disclosure Section XVIII and then processed to form a visible dye image as described in Research Disclosure XIX. Processing to form a visible dye image includes the step of contacting the photographic element with a color developing agent to reduce developable silver halide and oxidize the color developing agent. Oxidized color developing agent in turn reacts with the coupler to yield a dye. Preferred color developing agents that can be used in processing the photographic elements of the invention are p -phenylene diamines. Especially preferred are 4-amino-N,N-diethyl-aniline hydrochioride, 4-amino-3-methyl-N,N-diethylaniline hydrochloride, 4-amino-3-methyl-N-ethyl-N-β-(methane-sulfonamido) ethylaniline sulfate hydrate, 4-amino-3-methyl-N-ethyl-N-β-hydroxyethylaniline sulfate, 4-amino-3-β-(methanesulfonamido)ethyl-N,N-diethylaniline hydrochloride and 4-amino-N-ethyl-N(2-methoxyethyl)- m -toluidine di- p -toluene sulfonic acid. With negative-working silver halide this processing step leads to a negative image. To obtain a positive (or reversal) image, this step can be preceded by development with a non-chromogenic developing agent to develop exposed silver halide, but not form dye, then uniformly fogging the element to render unexposed silver halide developable, followed by development in with a chromogenic developer. Alternatively, a direct-positive emulsion can be employed to obtain a positive image. Development is followed by the conventional steps of bleaching, fixing, or bleach-fixing, to remove silver and silver halide, washing and drying. The following examples further illustrate this invention. Preparative Example 1 Preparation of Coupler No. 12 Coupler No. 12 To a slurry of 18.2 g (0.03 mol) of a and 5.1 g (0.03 mol) of 2-acetamidomethylphenol b in 50 ml acetonitrile, 7.0 g (0.06 mol) of tetramethylguanidine (TMG) was added with stirring. The reaction mixture was stirred at 20°C. for 15 hours. The precipitated salt was collected, washed with cold ethyl acetate and then taken to 200 ml with methanol. The solution was poured slowly into an ice-water hydrochloric acid mixture to decompose the salt to the coupler. Recrystallization from ethyl acetate gave 10.0 g (45%) of white solid product; m.p. 177-181°C. Preparative Example 2 Preparation of Coupler No. 24 Coupler No. 24 To a solution of 19.5 g (0.033 mol) of a and 6.7 g (0.064 mol) of triethylamine in 150 ml acetonitrile was added with stirring 8.1 g (0.033 mol) of methyl-3-methanesulfonamido-4-hydroxy benzoate b. The mixture was heated with stirring on a steam bath for 3 hours. After cooling, the mixture was poured into ice-water containing 5 ml concentrated hydrochloric acid. The gummy solid was collected, triturated with water and dried. The crude product was chromatographed through a silica gel column eluting with dichloromethane. The fractions containing the pure product were combined and the solvent removed under reduced pressure to give a white residue. Recrystallization from isopropyl alcohol gave 16 g (61%) of white solid; m.p. 96-97°C. Preparative Example 3 Preparation of Coupler Nos. 28 and 29 Coupler No. 28 To a stirred solution of 17 g (0.03 mol) of a in 100 ml dimethylformamide was added an equivalent amount of 50% sodium hydroxide solution and 7.2 g (0.03 mol) of b. After stirrina 2 hours at 20°C., the mixture was poured into ice-water containing 15 ml concentrated hydrochloric acid. The crude product c was collected, washed and dried, then dissolved in 150 ml tetrahydrofuran and reduced with 275.8 kPa (40 psi) hydrogen over a palladium on charcoal catalyst. To the solution of product d , after removal of the catalyst by filtration, was added with stirring 8 ml acetyl chloride and 8 ml quinoline. After stirring 1 hour this mixture was poured into ice-water containing 15 ml concentrated hydrochloric acid and the resultant solid was purified on a silica gel column to obtain 4.5, Coupler No. 28, mp. 194-5°C. A portion of Coupler No. 28 was hydrolyzed in alcoholic aqueous sodium hydroxide solution to yield the corresponding p -COOH compound, Coupler No. 29, mp. 234-235°C, after recrystallization from acetonitrile. Examples 1-45 To demonstrate the unexpected results obtained with photographic elements of the invention, a series of photographic elements was prepared to compare photographic elements containing couplers with ortho-substituted aryloxy groups in their coupling position as described above with analogous couplers containing para-substituted aryloxy groups. Additional photographic elements were prepared in this series to demonstrate that not all ortho-substituents provide improved sensitometric results when compared to their para-substituted analogs. The elements were prepared by coating a poly(ethyleneterephthalate) film support with (1) a photosensitive layer containing a silver bromoiodide emulsion at 0.75 g Ag/m², gelatin at 3.78 g/m², and one of the couplers identified below dispersed in one-half its weight of di-n-butylphthalate and coated at 2.7 × 10⁻³ moles/m² and (2) an overcoat layer containing gelatin at 1.08 g/m² and bis-vinylsulfonylmethyl ether hardener at 1.0 weight percent based on total gelatin. Samples of each of the photographic elements were imagewise exposed through a graduated density test object and developed for 2¾ minutes at 40°C in the following developing solution. After development, each photographic element was stopped, washed, bleached, washed, fixed, washed and dried by conventional means. After processing, each photographic element was sensitometrically evaluated by plotting color density vs. log exposure sensitometric curves and recording maximum density (D max ) and gamma (γ). Gamma is the slope of the straight line portion of the sensitometric curve. The higher the density and gamma, the more reactive the coupler. In Tables I and II results are reported for couplers of the type used in the photographic elements of this invention compared with control couplers ("C") which either omit the ortho position substituent or place it in the para position of the coupling-off group. It will be observed that the couplers used in the photographic elements of the invention are significantly more reactive. In Tables III and IV results are reported for couplers used in the photographic elements of the invention compared with couplers with the same polarizable group in the para position of the coupling-off group. In Table V results are reported for couplers not used in the invention having the same non-polarizable group in each of the ortho and para positions of the coupling-off group. From Tables III and IV it will be observed that couplers used in the invention are significantly more reactive than control ("C") couplers which contain a polarizable group in the para position, whereas from Table V it will be observed that there is no significant difference in reactivity between couplers in which the same non-polarizable substituent is in either the ortho or para position. Further, it will be observed from a comparison of Tables III and IV with Table V that couplers used in the invention are more reactive than couplers with non-polarizable groups in the ortho position of the coupling-off group. The couplers employed in Tables III and V have the basic structure: The couplers employed in Table IV have the basic structure: Results obtained with additional couplers used in the photographic elements of the invention are reported in Table VI.

Claims: A photographic element comprising a support bearing a photographic silver halide emulsion layer and, incorporated in the emulsion layer or a layer adjacent thereto, a two-equivalent dye-forming coupler consisting of a ballasted dye-forming coupling group substituted in its coupling position with an aryloxy group having ortho to the oxygen atom a group which contains a polarizable carbonyl, sulfonyl or phosphinyl moiety and which is free of photographic dye groups and photographic reagent groups. A photographic element as in Claim 1 wherein the dye-forming coupler has the structure: where: COUP represents a ballasted dye-forming coupling group substituted in its coupling position with the remainder of the structure; X represents the atoms to complete a phenyl or naphthyl nucleus; R is hydrogen or one or more substituents; each R¹ is hydrogen or alkyl of 1 to 4 carbon atoms; m is 0 to 4; and A is a group containing a polarizable carbonyl, sulfonyl or phosphinyl moiety free of photographic dye groups and photographic reagent groups. A photographic element according to Claim 2 wherein: R is hydrogen or one or more substituents selected from halogen, alkyl, alkoxy, nitro, cyano, carboxy, alkoxycarbonyl, aryloxycarbonyl, alkylsulfonyl, arylsulfonyl, amido (-NR¹COR²), carbamoyl (-CONR³R⁴), sulfonamido (-NR¹SO₂R²) and sulfamoyl (-SO₂NR³R⁴); A is a group containing a polarizable carbonyl, sulfonyl or phosphinyl moiety selected from -SO₂R², -SO₂NR³R⁴, -NR¹SO₂R², -NR¹SO₂NR³R⁴ and each R¹ is hydrogen or alkyl of 1 to 4 carbon atoms; R² is hydrogen, alkyl or aryl; R³ and R⁴ are each, individually hydrogen, alkyl, aryl or heterocyclyl, or together R³ and R⁴ complete a heterocyclic ring with the nitrogen atom to which they are attached; and each R⁵ is, individually, alkyl, alkoxy, aryl or aryloxy, the alkyl or aryl portion of any substituent R¹ to R⁵ possibly being substituted. A photographic element according to Claim 3 wherein: X completes a phenyl group; m is 0 or 1; R is hydrogen or is a para position substituent selected from carboxy, alkoxy, alkoxycarbonyl, hydroxyalkyl and hydroxyalkylsulfamoyl. R¹ is hydrogen; A is -NHCOR², -CONR³R⁴, -SO₂R², -NHSO₂R² or -SO₂NR³R⁴; R² is alkyl or hydroxyalkyl of 1 to 4 carbon atoms; and one of R³ and R⁴ is hydrogen and the other is alkyl or hydroxyalkyl of 1 to 4 carbon atoms. A photographic element according to any of Claims 2, 3 or 4 wherein COUP is an acetoacetanilide yellow dye-forming coupling group. A photographic element according to any of Claims 2, 3 or 4 wherein COUP is a phenol or naphthol cyan dye-forming coupling group. A photographic element according to any of Claims 2, 3 or 4 wherein COUP is a pyrazolone or pyrazolotriazole magenta dye-forming coupling group.

Inventors: LAU PHILIP THIAM SHIN, LAU, PHILIP THIAM SHIN
Applicants: EASTMAN KODAK CO, EASTMAN KODAK COMPANY (A NEW JERSEY CORPORATION)
Application year: 1982
Main classification: G03C7
IPC codes: G03C7, C09B55