US2592515A - Photographic emulsions containing symmetrical tetranuclear dye salts - Google Patents

Description

April 8, 1952 Filed Oct. 31, 1950 Fig. I.

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L. PHOTOGRAPHIC EMULSIONS CONTAINING SYMMETRICAL c. HENSLEY 2,592,515

TETRANUCLEAR DYE SALTS' 2 SHEETS-SHEET l EMULSION OGITAINING DYE SALT OF EXAMPLE I EMULSION CONTAINING DYE SALT OF EXAMPLE II 4o 44 4a 52 56 so 64 ea EMULSION CONTAINING DYE SALT OF EXAMPLE Ill EMULSION CONTAINING DYE SALT OF EXAMPLE IV INVENTOR Lee C. Hensley A; iORNEYS April 8, 1952 Filed Oct. 31, 1950 Fig. 5.

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L. C. HENSLEY PHOTOGRAPHIC EMULSIONS CONTAINING SYMMETRICAL TETRANUCLEAR DYE SALTS 2 SHEETS SHEET 2 EMULSION CONTAINING DYE SALT OF EXAMPLE V EMULSION CONTAINING DYE SALT OF EXAMPLE VI EMULSION CONTAINING DYE SALT OF EXAMPLE VII EWLSION CONTAINING DYE SALT OF EXAMPLE VIII INVENTOR Lee C. Hensley BY) Lgw Patented Apr. 8, 1952 PHOTOGRAPHIC EMULSIONS CONTAINING SYMMETRICAL TETRANUCLE AR DYE SALTS Lee C. Hensley, BinghamtomN. Y., assignor to General Aniline & Film Corporation, New York, N. Y., a corporation of Delaware Application October 31, 1950, Serial No. 193,284

6 Claims. (01. 95-1) This invention relates to gelatino silver halide emulsions. and particularly to photographic emulsions sensitized by means of new symmetrical tetranuclear dye salts in which the central nucleus, 4,4'-bithiazole, is linked to two heterocyclic nitrogenous nuclei by a mono or polymethine chain.

The use of sensitizing dyes, particularly in multilayer color film, poses many problems. It is known that sensitizing dyes operate by dyeing the silver halide grain. To do this, they must be adsorbed to the silver halide. If they are displaced from the silver halide grains, they lose their effectiveness as sensitizers. It is also known that many color formers used in color photography have greater aflinity for silver halides than the sensitizers, and act to displace the same from the silver halide grains. One must, therefore, select a sensitizer which will not be so displaced.

Another problem arises as regards the migration ofthe sensitizers from one emulsion to another. Where this ensues, color distortion is the inevitable result. Many proposals have been made dealing with the anchoring of compounds in silver halide emulsions, the most noteworthy being the use oi a long alkyl chain (see Wilmanns et al. United States Patent 2,186,849).

It is, therefore, necessary, when providing sensitizers, particularly for color photography, to make certain that they have (1) the proper sensitizing power, (2) the ability to withstand displacement from silver halide grains by color formers, and (3) the ability to resist diffusion from one sensitized emulsion to another.

Efiorts which satisfy the last prerequisite, uniortunately; often lead to compounds which will not meet the first two tests. -Thus, it is known that the sensitizing power of cyanine dyes varies with the substituent on the cyanine N-atoms. Where this substituent is alkyl, the power decreases as the chain length increases. Hence, it a long alkyl chain be used to anchor the dye in the emulsion, we end up with aproduct of little or no sensitizing power- The use of other expedients to anchor the dye, on the other hand,

and

Y often gives products incapable oi withstanding on nc t t the displacement action of color formers insofar as the silver halide grains are concerned. It is thus manifest that the provision of sensitizers having the necessary prerequisite is a difficult problem, to say the least. It is known that many cyanine dyes sensitize photographic silver halide emulsions to high red sensitivity. Most of these dyes, however, are not suitable for sensitizing silver halide emulsions containing color coupling components. This is thought to be due to a physical displacement which the sensitizing dye undergoes when color coupling components are added. That is. the sensitizer is adsorbed to the surface of the silver halide grain, and then with addition of color coupling component, is displaced therefrom.

An object of the present invention is to provide photographic silver halide emulsions with new symmetrical tetranuclear dyes containing a 4,4- bithiazole nucleus. I

A further object is to provide such dyes which are free from the disadvantages noted above.

Other objects and advantages of this invention will become apparent by reference to the following specification in which its preferred details and embodiments are described.

This invention is predicated upon the discovery that symmetrical tetranuclear dye salts, in which the central nucleus, 4,4'-bithiazole, is linked to two heterocyclic nitrogenous nuclei by a mono or polymethine chain, are not only sensitizers for orthochromatic and pancromatic film emulsions but are also compatible with color coupling components, being unaffected by the presence of color coupling components and exhibiting the property of non-migration from the layer in which they are incorporated. In the latter combination, the sensitizing action of the dye salts is not impaired or diminished. An additional advantage of these dye salts is their ability to remain fixed in the layer in which they are originally. deposited.

The symmetrical tetranuclear dyestuffs i'ulfilling the above advantages are characterized by the following general formulae:

whereinR is an alkyl or aralkyl group, e. g., methyl, ethyl, propyl, butyl, amyl, etc, benzyl, phenethyl and the like, R1 and R2 are either hydrogen or an alkyl group, e. g., methyl, ethyl.

propyl, butyl, and the like, R1 being'only hydrogen when n equals 1, X represents an anionic acid radical, e. g., Cl, Br, I, C104, SO iCHg, 804021-15, SO3C5H4CH3. and the like, Z represents the atoms necessary to complete a 5- or'fi-membered nitrogenous heterocyclic system of the type usual in cyanine dyes, such as pyridine, lepidine, quinoline, indoline, oxazole, thiazoline, thiazole, thiodiazole, pyrroline, selenazole, selenazoline, oxazoline, benzothiazole, benzoselenazole, benzoxazole, naphthothiazole, perinaphthiazole, naphthoselenazile, and the like, and n represents a positive integer ranging from I to 2.

The process of preparing the above tetranuclear cyanine dyes comprises condensing by gentle'heating or boiling, or by heating as on a steam bath or under reflux conditions, one mol of adiquaternary cyclammonium saltof 2,2'-dimethyl-4,4- bithiazole with two mols of a cyclammonium quaternary cyanine dye intermediate of the type used in the preparation of cyanine dyes. This condensation is carried out in the presence of an acid binding agent, such as nitrogenous heterocyclic base containing a small quantity of a tertiary base which may include a small quantity of acetic acid or acetic anhydried. The anions of the dye salts thus obtained are readily converted into different anions by methods well known in the art.

The diquaternary cyclammonium salts of 2,2- dimethyl-4,4'-bithiazole utilized in the condensation reaction are characterized by the following general formula:

HaC-C wherein R and X have the same values as above, and are obtained by vquaternizing 2,2'-dimethyl- 4,4-bithiazole characterized by the following formula': 4

The 2,2-dimethyl-4,4-bithiazole is prepared in the following manner:

Eight and six-tenths grams (0.1 mol) of butanedione-2,3 (diacetyl) in 35 cc. of carbon disulfide were treated dropwise with stirring, with a solution of 10.6 cc. of bromine in 20 cc. of carbon disulfide at the boiling point ofthe carbon disulfide. The addition was completed in 3 hours.

' water bath under increased pressure in the usual The stirring and heating were continued another 2 hours. After cooling,the carbon disulfide was decanted from the solid which had separated. The crystals were washed with petroleum ether (B. P. 60-75 C.). The melting point of the crude product was 109-111 C. After crystallizing from petroleum ether (B. P. Gil-75 C.), the melting point was 117 C. and the yield of the product was 13.6 grams.

One gram of 1,4-dibromobutanedione-2,3 and 0.63 gram of thioacetamide were dissolved in 20 cc. of absolute methanol and warmed for 10 minutes on the steam bath. The mixture (a solid had separated) was poured into 100 cc. of water. The

manner. The alkylating agent employed may be methyl or ethyl iodide, dimethyl sulfate, methyl p-toluenesulfonate, phenethyl iodide, and the like. The cyclammonium salts of the type used or proposed for the productionof cyanine dyes, and utilized in accordance with the present invention may be any one of those having an appropriate group in the reactive position to the nitrogen atom thereof. As examples of suitable cyclammonium quaternary cyanine dye salt intermediates having a reactive group in the 2-position to the nitrogen atom thereof so as to form a dirnonomethine dye, the following may be mentioned:

2-methylmercapto-6methylquinoline ethiodide 2-methylmercaptopyridine ethiodide 2-methylmercaptothiazoline ethiodide Z-phenylmercaptothiazoline ethiodide, and the like.

In preparing straight chain di-trimethine cyanine dye salts and branched chain di-trimethine dye salts, the following cyclammonium quaternary dye salt intermediates having a reactive group in the pi-position of the side chain in the 2-position of the nitrogen atom thereofmay be employed:

Z-(B-acetanilidovinyl) thiazoline ethiodide 2 (p-acetanilidovinyl) benzothiazole ethiodide 2- (B-acetanilidovinyl) benzoxazole ethiodide 2 (/3 ethyl-fl-methylmercaptophenyl) -5-methoxy-benzoselenazole ethiodide 2 (fl-methylmercapto-B-methylvinyl)benzothiazole ethiodide 2 (p-methylmercapto-;9-propylvinyl) benzothiazole ethiodide.

In preparing straight chain or branched dipentamethine and diheptamethine cyanine dye salts, the following cyclammonium, quaternary salts having a reactive group in delta and zetapositions of theside chain in 2 -position of the nitrogen atom thereof may be employed:

2 (4-acetanilido-1,3-butadienyl) pyridine ethiodide 2- (4 acetanilido 1,3 butadienyhbenzoxazole ethiodide 2-(4-ethoxy 1,3 butadienyDpyridine ethiodide 2 (4 anilino-3-methyl-1,3-butadienyl)pyridine ethiodide 2-(4-anilino-3-methyl-1,3-butadienyl) -/3 naphthoxazole ethiodide 5 2-(4-anilino-3-ethyl-l,3 butadienyl) a naphthothiazole ethiodide 2 (6-anilino-1,3,5 -hexatrienyl) thiazoline ethiodide 2-(6-anilino-1,3,5-hexatrieny1) -a naphthothiazole ethiodide 2-(6-anilino 1,3,5 hexatrienyl) 5 naphthothiazole ethiodide 2-( 6-anilino 1,3,5- hexatrienyl) a. naphthoselenazole ethiodide 2-(6 -anilino 1,3,5 hexatrienyl) B naphthaselenazole ethiodide '2-(6eanilino-4-methyl-l,3,5 -liexatrienyl)thiazoamount oi methanol and crystallized from pyriline ethiodide dine. 2-(6-ani1ino-4-methyl-1,3,5 -hexatrienyl) benzo- The purified product has a melting point of thiazole ethiodide 245-,-246 C. A methanol solution of the dye -2--(6-anilino-4-butyl 1,3,5 hexatrienyl) benzo- 5 showed an absorption maximum at 497 mi. The thiazole ethiodide. dye sensitized a silver bromoiodide emulsion The above cyclammomum (mammary dye salt from 450 m to 5'70 m, with a sensitivity maxiintermediates are well known to the art and mum 540 hence the methods for their preparation need Example II Se, CH s s C Se\ I i I 6 v. -0

c-cn= z-.cn=o E H H g o-on=d-cn=o 0 crno- 0cm v v v. I I 11m 271B; (1335 v Ali H 21' not be discussed herein. While the above dye Fifty-five hundredths gram of 2,2-dime thylintermediates are disclosed'as being in the form 4,4'-bi.thiazole di-(ethyl ptoluenesulfonate) was of the preferred ethiodide, it is to be underdissolved in cc. of methanol with slight warmstoodthat they may also be employed in the ing. To this mixture 8 drops of triethylamine form of other quaternary salts previously menwere added. After 2 to 3 minutes, 1.1 grams of tioned. 2 (p-ethyl-p-methylmercaptovinyl) -5-methoxy,- In the preparation of these new symmetrical benzoselenazole'ethiodide were added and the tetranuclear dyestuffs, the '2,2'-dimethyl-4,4'-bimixture gently boiled for 10 minutes. After coolthiazole base is converted into the correspond- 25 ing the reaction mixture, 25 cc. of 10% aqueous ing alkyl or aralkyl quaternary cyclammonium potassium iodide solution were added with stirsalt in the manner usual with the conversion ring. After standing a short time, the solid was of other nitrogenous heterocyclic bases to the filtered oif and: washed with ether. The crude quaternary salt form. As previously pointed out, dye was digested in 50 cc. of an equal mixture of .this may be effected by fusion with alkyl or methanol and isopropanol'. After standing overaralkyl halide or by heating the base with an alkyl night, the dye was filtered off and recrystallize or aralkyl halide in a sealed tube in a water bath from the methanol; under increased pressure. A molecular equiva- Th yield of the dye Ob ained w .47 ram lent of the quaternary salt thus obtained is heatwith a meltingp 0 2 C- A m h nol ed with two molecular equivalents of the cyclarnsolution of the dye showed an absorption maxi-- rnonium cyanine dye salt intermediate in the mum at 5'71 mu. h y sensitized a lv r presence of a condensing agent, such as a heterobromoiodide emulsion from 500 m to 655 m cyclic nitrogenous base or an alcohol containing with a sensitivit maximum at 620 m/ a small quantity of a tertiary base at reflux temperature Example As condensing agents employed in the prep- 0 s s aration of the new dyes of the present invention, the following may be advantageously em- Hi0 C-CH=CH-CH=C ployedz. heterocyclic nitrogenous bases, such as pyridine, methylpyridine, dimethylpyridine, ethv 0 N N ylpyridine, ethylmethylpyridine, trimethylpyri- 12115 dim 21-. dine, quinoline and the like, or an alcohol, such as methyl, ethyl, propyl, isopropyl, butyl, iso- One gram. of z-(p-acetanilidovinyl)-5.6-

butyl, and the like, in the presence of a basic methylenedioxybenzothiazole ethiodide. .6 gram tertiary catalyst, such as trimethylamine, triof 2.2- m y '-b l Dr 1u ethylamine, and the like. .enesulfonate),j 25 cc. of pyridine. and 1 cc. of The following examples describe in detail the triethylaminewere gently boiled for 15.,minutes. methods for accomplishing the above objects, After cooling. two volumes of dilute aqueous but it is to be understood that they are inserted potassium iodide were added; The solid was merely for the purpose of illustration and are so filtered oil and washed with water and then not to be construed as limiting the scope of the ether. The product was purified by (1) digestinvention. ing with isopropanol, (2) digesting with an equal Example I mixture of methanol and isopropanol, (3) digest,-

OHP s s cm \CH H0/ cn=c g g 0-41-02! N N |H| N I I N afil IHI xHl 21' Seven tenths gram of 2-methylmercapto-6- ing with methanol. The mixture was allowedto methylquinoline ethiodide and 0.6 gram of 2,2'- cool each time before the product was filtered o'if. dimethyl-4,4'-bithiazole di-(ethyl p-toluenesul- The weight of the final product was 0.45, gram fonate) in 8 cc. of methanol containing 0.5 cc. of 1 with a melting point of 249-259 C. A methanol triethylamine were gently heated until methylsolution of the dye showed an absorption maximercaptan ceased to be evolved. After standing mum at 600 mi. The dye sensitized a silver several hours, the solid was filtered by suction. bromoiodide emulsion from 520 my to 670 mi, The dye was purified by boiling with a small 7; with a sensitivity at 640 m ape-again Example IV Fifty-six hundredths gram of 2,3-dihydro-3- ethyl-5,6-methylenedioxy 2 thioacetonylidenebenzothiazole, v1 gram of methyl p-toluenesulf onate, and 0.3 gramof 2,2-dimethyl-'4,4-bithiazole di-(ethyl p-toluenesulfonate) were warmed gently in a. free flame with stirring for 4-5 minutes. Five cc. of methanol were added and themixture boiled until about half of the methanol had boiled. off. Twenty-five cc. of pyridine and 15. drops of triethylamine were added and the mixture boiled for 5 minutes. After cooling, 100 cc. of a potassium iodide solution were added to the reaction solution with stirring. The mixturewas allowed to'stand 3 hours, the product filtered off and air dried. The dye was digested with 70 cc. of isopropanol. After cooling, the solid wasfiltered off, dissolved in 150 cc. of hot methanol, filtered while hot, and the filtrate evaporated to about 70 cc. The addition of about one-half volume of ether caused the dye to separate as a powder. The yield of the finalv dye'was 0.13 gram having amelting point of '267-263" C. A methanol solution of the dye showed an absorption maximum at 5'13 m t- The dye sensitized a silver bromoiodide emulsion irom 500 m to 645 m with a sensitivity-maximum at 620 m l.

Example V Five tenths gram of 2-(,8-acetanilidovinyl)- 4,5-benzobenzothiazole methiodide and 0.3 gram of 2,2-dimethyl-4,4'-bithiazole di-(ethyl p-toluenesulfonate) in 10.cc. of pyridine containing 10 drops of triethylamine were stirred at room temperature for 5 minutes and then. gently boiled for 5 minutes; After tooling,v the reaction mixture was diluted with 25 cc. of a 10% aqueous solution of potassium iodide. After an hour, the product was filtered off and washed with water and then ether. .15 minutes with 40 cc. of isopropanol. After cooling;v the product was filtered off and redigested twice with 40 cc. portions of methanol.

The yield of the purified dye was 0.3 gram with a melting point of 236-237" C. A methanol solu- Example VI S C 'rn him that A 21- Forty-five hundredths gram of 2,2f-dimethyl- 1 4,4'-bithiazole di-(ethyl p-toluenesulfonate) and The product was digested for ity maximum'at 610 mp.

Example -v11 Eighty-seven hundredths gram of 2-(fi-a'cet anilidovinyllbenzoxazole ethiodide and 0.6 gram of 2,2-'dimethyl-4,4" bithiazol'e di ethiodide were dissolved in 30 cc. of methanol and warmed on a steam bath for 15 minutes'in the presence of 10 drops of triethylamine. Five drops of a 40% aqueous solution of sodium perchlorate" were added and the mixture warmed another 15 minutes. After cooling, the crystals were filtereciofi and recrystallized from methanol.

' The crystallized dye has a melting point of 273- 274 C. A methanolsolution'of. the dyeshowed an absorption maximum at 532mu. The dye sensitized a silver bromoiodide emulsion from 460 m l to 605m with a sensitivity maximum at Example VIII One andiifteen-hundredthsgram of Z-(t-acetanilidobutadienyllbenzoxazole ethiodide', 0.98 gram of 2,2-dimethyl-4,4-bithiazole di-(phenoxyethyl p-toluenesulfonate), and 8 drops of triethylamine were stirred for 5 minutes at room temperature in 6 cc. of pyridine. The solution was then gently boiled for 4 minutes. After cooling, the dye was precipitated by adding- 2 volumes of a- 20% aqueous potassium iodide solution. The

' productwas dissolved in methanol and precipitated by the addition of a small amount of water. The dye after being crystallized twice from methanol melted at 193-195 C.

. The absorption maximum. in methanol is 613 m The sensitization maximum in a silver iodobromide-emulsion is at 665 me with the sensitivity range extending from'540 my to 700m In the'preparation of emulsions containing these-tetranuclear cyanine dyes, the dye may be dissolved inmethyl or ethyl alcohol and the a1- coholic; solution containing from 5 to 50 milligrams of the dye added to a liter oi emulsion.

, I l9 10 While in general practicer it may not be nees- I'erred procedures, materials, and uses; it is v to'ibe sary to add the dye iii-amounts larger than'tho'se understood that the new classes of tetranuclear above given, generally, for satisfactory results, cyan ne dyes and th ir us as s sit z n yes is amounts ranging from to 25 milligrams are notlimited thereto and numerous variations and sufficient to obtain the maximum sensitizing e'fmodifications may be made, as r ple. his feet. However, I do. not-wish 'to limit my invencondensing the diquaternary; ammonium salt of tion to thequantities just indicatedxas the most 2,2-dimeth yl-4,4'-bithiazole with a dialkylamisuitable amount will in each case befourid by: a nobenzene in the presence of a basicrcondensirig few comparative experiments. The dyes may be agents 8- p p y y dye a e obadded to theemulsion in the form of solutions. tained. Accordingly, it is intended'that the iri- Suitable solvents'y as indicated in the examples, vention be defined only by the accompanying are the alcohols, for instance, methyl or ethyl alclaims. cohol. which may be anhydrous" or diluted with a I claim: small volume of water. In actual practice, the l. A photographic gelatino silver halide emuldyes are applied to the emulsion during any stage sion which contains a dyestuff characterized by of its production. However, they are preferably the formula selected from the class consisting of added to the finished emulsion before coating. the following formulae:

and

Th r ic spectrogram o s i u i g wherein R represents a member selected from the the accompanying. drawing illustrate the regions class consisting of alkyl and aralkyl groups. R1 of th p tr m o which some f t r and R2 represent members selected from the class nuclear cyanine dyes will sensitize a gelatino consisting of hydrogen and alky1groups,R1 being silver halide emulsion containing about 4-5% of only hydrogen when n equals 1. n represents a silver halide and the extent of the sensitization positive integer ranging from 1 to 2, X represents at various wavelengths. Figures 1 to 8 of this an anionic radical, and Z represents the atoms drawing illustrate the sensitizing properties of necessary to complete a member of the group the dyes prepared in accordance with Examples consisting of 5- and G-membered nitrogenous 1 to 8, respectively. heterocyclic ring system.

This application is a continuation-in-part of my 2. A photographic gelatino silver halide emulapplication Serial No. 92,584, filed May 11, 1949, sion which contains a dyestuff of the following now abandoned, which was a division of applica- 5 structure:

3. A photographic gelatino silver halide emultion Serial No. 67, 075, filed Decembei 23, 1948. now abandoned. The sensitizing dyestuffs per se 3123 3 22 contains dyestufi of the following s s 89 o-on=i on=o FF E o-on=i on=c cmo- \N N/ V \N 0011,

recl'mdina l' g z Eamon serial No 193 283 filed 4. A photographic gelatino silver halide emul- While the present invention has been described sion which contains dyestufi of the following in considerable detail with respect to certain prestructure:

P5; A phot ogl-aphic elitinosilver halide=-emuI-.- '36. .A photographic gelatinp silvqnhalldp @1911]- :s ipn which contains ;a 'dyestufl of the following s1onwhich gontains "a dye'atufl 0! the vfollowing structure: 7 structure: I

LEE C. No references .cited.

Claims (1)

1. A PHOTOGRAPHIC GELATION SILVER HALIDE EMULSION WHICH CONTAINS A DYESTUFF CHARACTERIZED BY

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