Patent GB-566684-A (GB)
Title: Improvements in or relating to the sensitizing of photographic emulsions with cyanine dyestuffs
IPC: G03C1/12
Filed: 1943-12-08
Abstract: A photographic silver halide emulsion contains as a sensitizing dye a cyanine dye which is a quaternary ammonium salt in which the anion is a sulphamic or N-substituted sulphamic acid radicle.  The cyanine dyes and intermediates therefor may be produced by treating with a metal sulphamate in a solvent a cyanine dye or an intermediate therefor which is a quaternary ammonium salt, of which the anion is one which forms with the metal a salt less soluble than the metal sulphamate in the solvent.  If the dye salt is a halide and the solvent an aqueous organic solvent, the metal sulphamate may be silver sulphamate. Other sulphamates and salts of N-alkyl and N-benzyl-sulphamic acids may be used, e.g. antimony, barium, iron, lead, mercury, and strontium sulphamates and the corresponding N-methyl, N-ethyl and N-benzyl sulphamates.  Other salts which may be used are silver N-methyl-sulphamate, silver N-ethylsulphamate, silver N - benzylsulphamate, and the compound AgSO3NH-C2H4NHSO3Ag.  With cyclammonium or cyanine chlorates in an alcohol medium, potassium sulphamate may be used and with cyanine nitrates in an alcoholic solution potassium or ammonium sulphamate.  The reaction may be effected at a range of temperatures.  The heterocyclic nuclei in the dyes may be from substituted or unsubstituted thiazoles, thiazolines, oxazoles, oxazolines, selenazoles, selenazolines, pyridines, quinolines and indolenines, and among the possible substituents are OH; alkoxy (e.g. methoxy, ethoxy, methylenedioxy); halogen (e.g. Cl and Br); alkyl or cycloalkyl (e.g. methyl, ethyl and cyclohexyl); aryl (e.g. phenyl and chlorophenyl); and amino and hydrocarbon-substituted amino.  The cyanine dye intermediates may be quaternary salts of heterocyclic nitrogen bases containing a reactive group in the a  or g  position to the heterocyclic nitrogen atom. The dyes may be cyanine dyes (including isocyanine, pseudocyanine, and neocyanine dyes) obtained by reacting a heterocyclic quaternary ammonium sulphamate containing a reactive methyl group with amyl nitrite, with an iodo heterocyclic quaternary salt, or with an alkylmercapto or arylmercapto heterocyclic ammonium salt; carbocyanine dyes made by reacting a heterocyclic ammonium sulphamate containing a reactive methyl group with an anilidovinyl heterocyclic ammonium salt, or with a 2-methylene-ketone or aldehyde heterocyclic N-alkyl base; dicarbocyanine dyes made by reacting a heterocyclic ammonium sulphamate containing a reactive alkyl group with b -anilinoacrolein anil or its derivatives; tricarbocyanine dyes made by reacting a heterocyclic ammonium sulphamate containing a reactive alkyl group with pentadiene dianil or its derivatives. Merocyanines may be prepared by reacting a heterocyclic compound containing a reactive methylene group with a heterocyclic ammonium sulphamate containing an active methyl group in the presence of an acid binding agent and/or acid anhydride, styryl dyes prepared by reacting a heterocyclic ammonium sulphamate containing a reactive alkyl group with a reactive aryl aldehyde; symmetrical carbocyanine dyes prepared by reacting a heterocyclic ammonium sulphamate containing a reactive methyl or methylene group in the a  or g  position to the heterocyclic N atom (e.g. a -methylbenzthiazole ethyl sulphamate or a -methylquinoline methyl sulphamate) with a carboxylic acid ortho ester (e.g. ethyl orthoformate), in the presence of an acid binding agent (e.g. pyridine, piperidine, or dimethylamine); erythro- and xanthro-isocyanine dyes prepared by heating a quinoline sulphamate having a reactive methyl group in the a -position to the heterocyclic N atom in an alcoholic ROH solution; isocyanine dyes prepared by condensing a heterocyclic ammonium sulphamate which contains a reactive NH2 group in the a -position to the heterocyclic N atom (e.g. a -aminobenzthiazole sulphamate), with an a -halogen substituted alkyl cycloammonium salt (e.g. a -iodoquinoline ethyl sulphamate) in the presence of sodium ethoxide; carbocyanine dyes prepared by condensing a cyclammonium sulphamate containing a reactive methylene group in the a -position with compounds of formula W-CH=NH (wherein W is a group such as amino alkoxy, or acyl or a halogen atom) in the presence of an organic acid anhydride (e.g. acetic anhydride) and reacting the product with a salt of a N-hydrocarbon cyclammonium base containing a reactive methyl group in the a - or g -position; carbocyanine dyes including meso-substituted carbocyanine dyes obtained by reacting cyclammonium sulphamate containing a reactive methyl group in the a - or g -position with a diacylformamidine or a C-alkyl-substituted diacylformamidine in the presence of an acid anhydride (e.g. acetic or propionic) and reacting the product with a cyclammonium salt containing a reactive group, e.g. methylene, methyl, or alkylmercapto, or a halogen atom; or dyes formed by reacting cyclammonium sulphamates having a reactive group in the a - or g -position (e.g. a -methylbenzthiazole N-ethyl sulphamate) with compounds of the formula <FORM:0566684/IV/1> (wherein W is a reactive group, A is O, S, or Se, and Z either the residue of a 5-membered heterocyclic nucleus containing 2 nuclear non-metallic atoms other than carbon, of which at least one is trivalent N and another of which is divalent when other than N (e.g. a thiazolone, oxazolone, imidazolone, rhodanine, 2-thio-2 : 4 (3 : 5)-oxazoledione, hydantoin an N-substituted derivative, pyrazolone, or thiopyrazolone), or the residue of a 6-membered heterocyclic nucleus containing 2 nuclear trivalent N atoms (e.g. a barbituric acid).  Mono- and polymethine-dyes particularly useful have the formula <FORM:0566684/IV/2> wherein X is a sulphamate radical, Y and Z the same or different residues of heterocyclic nuclei, R1 and R11 the same or different monovalent hydrocarbon radicals connected to N through acyclic carbon, and n is O or a small positive integer. R1 and R11 may be alkyl (e.g. methyl, ethyl or isopropyl), aralkyl (e.g. benzyl or chlorobenzyl), or alkenyl (e.g. allyl).  3 : 31 - Diethyl - 9 - methylthiacarbocyanine sulphamate is prepared by refluxing a mixture of silver sulphamate with an aqueous ethyl alcohol solution of 3 : 31-diethyl-9-methylthiacarbocyanine iodide.  31 31 - Diethylselenacarbocyanine sulphamate, 3 : 31 - diethyl - 5 : 51 : 9 - trimethylthiacarbo - cyanine sulphamate, 3 : 31 : 9 - triethyl - 5 : 51 - dimethylselenacarbocyanine sulphamate, 3 : 1-diethyl-5-methylselenapseudocyanine sulphamate, and 3 : 31 - diethyl - 5- methyl benzselenapseudocyanine sulphamate are similarly prepared.  The dyes may be added to gelatino silver halide emulsions. a -Methylbenzthiazole N-ethyl sulphamate is prepared by refluxing together a -methylbenzthiazole ethiodide and silver sulphamate dissolved in 95 per cent ethyl alcohol.  3 : 31-Diethyl - 9 - methylthiacarbocyanine sulphamate is prepared by refluxing together 2-methylbenzthiazole N-ethyl sulphamate, ethyl orthoacetate and dry pyridine.  The sulphamates may be dispersed in the silver salt emulsions before coating or the coated layers may be bathed in the sulphamate solutions.  Details of suitable procedure and quantities are given.  The emulsions may also contain colour couplers (for colour development or azo coupling processes), e.g. phenols, naphthols, naphthylamines, aminonaphthols, acetoacetic acid esters, cyanacetic acid esters, pyrazolones, and coumaranones containing high molecular weight groups.  The sensitized emulsions have a good blue-light sensitivity.  Specifications 458,400, 465,823 and 489,161 are referred to.  The Specification as open to inspection under Sect. 91 refers also to dyes formed by reacting cyclammonium sulphamates having a reactive group in the a - or g -position with a compound of formula <FORM:0566684/IV/3> , where W is a reactive group, A is tellurium, and Z is either the residue of a 5-membered heterocyclic nucleus containing 2 nuclear non-metallic atoms other than carbon, of which at least one is trivalent and the other divalent where other than N, or the residue of a 6-membered heterocyclic nucleus containing two nuclear trivalent N atoms.  This subject-matter does not appear in the Specification as accepted.