US1374872A - Photosensitizing dye effective for infra-red radiation - Google Patents
Photosensitizing dye effective for infra-red radiation Download PDFInfo
- Publication number
- US1374872A US1374872A US397114A US39711420A US1374872A US 1374872 A US1374872 A US 1374872A US 397114 A US397114 A US 397114A US 39711420 A US39711420 A US 39711420A US 1374872 A US1374872 A US 1374872A
- Authority
- US
- United States
- Prior art keywords
- infra
- parts
- bases
- solution
- red radiation
- Prior art date
- Legal status (The legal status is an assumption and is not a legal conclusion. Google has not performed a legal analysis and makes no representation as to the accuracy of the status listed.)
- Expired - Lifetime
Links
- 230000005855 radiation Effects 0.000 title description 8
- 230000002165 photosensitisation Effects 0.000 title description 2
- 239000003504 photosensitizing agent Substances 0.000 title description 2
- LFQSCWFLJHTTHZ-UHFFFAOYSA-N Ethanol Chemical compound CCO LFQSCWFLJHTTHZ-UHFFFAOYSA-N 0.000 description 21
- RTZKZFJDLAIYFH-UHFFFAOYSA-N Diethyl ether Chemical compound CCOCC RTZKZFJDLAIYFH-UHFFFAOYSA-N 0.000 description 20
- 239000000975 dye Substances 0.000 description 19
- 239000000243 solution Substances 0.000 description 17
- OKKJLVBELUTLKV-UHFFFAOYSA-N Methanol Chemical compound OC OKKJLVBELUTLKV-UHFFFAOYSA-N 0.000 description 15
- SMWDFEZZVXVKRB-UHFFFAOYSA-N Quinoline Chemical compound N1=CC=CC2=CC=CC=C21 SMWDFEZZVXVKRB-UHFFFAOYSA-N 0.000 description 15
- WSFSSNUMVMOOMR-UHFFFAOYSA-N Formaldehyde Chemical compound O=C WSFSSNUMVMOOMR-UHFFFAOYSA-N 0.000 description 13
- 235000019441 ethanol Nutrition 0.000 description 11
- 239000000047 product Substances 0.000 description 10
- HEDRZPFGACZZDS-UHFFFAOYSA-N Chloroform Chemical compound ClC(Cl)Cl HEDRZPFGACZZDS-UHFFFAOYSA-N 0.000 description 8
- DGAQECJNVWCQMB-PUAWFVPOSA-M Ilexoside XXIX Chemical compound C[C@@H]1CC[C@@]2(CC[C@@]3(C(=CC[C@H]4[C@]3(CC[C@@H]5[C@@]4(CC[C@@H](C5(C)C)OS(=O)(=O)[O-])C)C)[C@@H]2[C@]1(C)O)C)C(=O)O[C@H]6[C@@H]([C@H]([C@@H]([C@H](O6)CO)O)O)O.[Na+] DGAQECJNVWCQMB-PUAWFVPOSA-M 0.000 description 8
- 238000009835 boiling Methods 0.000 description 8
- 229910052708 sodium Inorganic materials 0.000 description 8
- 239000011734 sodium Substances 0.000 description 8
- MUDSDYNRBDKLGK-UHFFFAOYSA-N 4-methylquinoline Chemical compound C1=CC=C2C(C)=CC=NC2=C1 MUDSDYNRBDKLGK-UHFFFAOYSA-N 0.000 description 7
- 206010070834 Sensitisation Diseases 0.000 description 6
- 125000000217 alkyl group Chemical group 0.000 description 6
- 239000000203 mixture Substances 0.000 description 6
- 230000008313 sensitization Effects 0.000 description 6
- IJGRMHOSHXDMSA-UHFFFAOYSA-N Atomic nitrogen Chemical compound N#N IJGRMHOSHXDMSA-UHFFFAOYSA-N 0.000 description 5
- 238000000034 method Methods 0.000 description 5
- 230000001235 sensitizing effect Effects 0.000 description 5
- XLYOFNOQVPJJNP-UHFFFAOYSA-N water Chemical compound O XLYOFNOQVPJJNP-UHFFFAOYSA-N 0.000 description 5
- QDRKDTQENPPHOJ-UHFFFAOYSA-N sodium ethoxide Chemical compound [Na+].CC[O-] QDRKDTQENPPHOJ-UHFFFAOYSA-N 0.000 description 4
- 125000000623 heterocyclic group Chemical group 0.000 description 3
- 229910052757 nitrogen Inorganic materials 0.000 description 3
- 239000000843 powder Substances 0.000 description 3
- 150000001875 compounds Chemical class 0.000 description 2
- 239000013078 crystal Substances 0.000 description 2
- 125000002496 methyl group Chemical group [H]C([H])([H])* 0.000 description 2
- 239000002244 precipitate Substances 0.000 description 2
- 238000010992 reflux Methods 0.000 description 2
- SQGYOTSLMSWVJD-UHFFFAOYSA-N silver(1+) nitrate Chemical compound [Ag+].[O-]N(=O)=O SQGYOTSLMSWVJD-UHFFFAOYSA-N 0.000 description 2
- OKTJSMMVPCPJKN-UHFFFAOYSA-N Carbon Chemical compound [C] OKTJSMMVPCPJKN-UHFFFAOYSA-N 0.000 description 1
- RDFLLVCQYHQOBU-GPGGJFNDSA-O Cyanin Natural products O([C@H]1[C@H](O)[C@H](O)[C@H](O)[C@H](CO)O1)c1c(-c2cc(O)c(O)cc2)[o+]c2c(c(O[C@H]3[C@H](O)[C@@H](O)[C@H](O)[C@H](CO)O3)cc(O)c2)c1 RDFLLVCQYHQOBU-GPGGJFNDSA-O 0.000 description 1
- UFHFLCQGNIYNRP-UHFFFAOYSA-N Hydrogen Chemical compound [H][H] UFHFLCQGNIYNRP-UHFFFAOYSA-N 0.000 description 1
- ZLMJMSJWJFRBEC-UHFFFAOYSA-N Potassium Chemical compound [K] ZLMJMSJWJFRBEC-UHFFFAOYSA-N 0.000 description 1
- KWYUFKZDYYNOTN-UHFFFAOYSA-M Potassium hydroxide Chemical compound [OH-].[K+] KWYUFKZDYYNOTN-UHFFFAOYSA-M 0.000 description 1
- BQCADISMDOOEFD-UHFFFAOYSA-N Silver Chemical compound [Ag] BQCADISMDOOEFD-UHFFFAOYSA-N 0.000 description 1
- PMZURENOXWZQFD-UHFFFAOYSA-L Sodium Sulfate Chemical compound [Na+].[Na+].[O-]S([O-])(=O)=O PMZURENOXWZQFD-UHFFFAOYSA-L 0.000 description 1
- 238000010521 absorption reaction Methods 0.000 description 1
- 230000002411 adverse Effects 0.000 description 1
- 150000003863 ammonium salts Chemical class 0.000 description 1
- 239000007864 aqueous solution Substances 0.000 description 1
- 239000006227 byproduct Substances 0.000 description 1
- 229910052799 carbon Inorganic materials 0.000 description 1
- 239000003153 chemical reaction reagent Substances 0.000 description 1
- 238000009833 condensation Methods 0.000 description 1
- 230000005494 condensation Effects 0.000 description 1
- RDFLLVCQYHQOBU-ZOTFFYTFSA-O cyanin Chemical compound O[C@@H]1[C@@H](O)[C@H](O)[C@@H](CO)O[C@H]1OC(C(=[O+]C1=CC(O)=C2)C=3C=C(O)C(O)=CC=3)=CC1=C2O[C@H]1[C@H](O)[C@@H](O)[C@H](O)[C@@H](CO)O1 RDFLLVCQYHQOBU-ZOTFFYTFSA-O 0.000 description 1
- 230000002939 deleterious effect Effects 0.000 description 1
- 239000012153 distilled water Substances 0.000 description 1
- 238000001035 drying Methods 0.000 description 1
- 125000001495 ethyl group Chemical group [H]C([H])([H])C([H])([H])* 0.000 description 1
- 238000001704 evaporation Methods 0.000 description 1
- 230000008020 evaporation Effects 0.000 description 1
- 238000001914 filtration Methods 0.000 description 1
- 239000008098 formaldehyde solution Substances 0.000 description 1
- 229910052739 hydrogen Inorganic materials 0.000 description 1
- 239000001257 hydrogen Substances 0.000 description 1
- 239000002932 luster Substances 0.000 description 1
- QJGQUHMNIGDVPM-UHFFFAOYSA-N nitrogen group Chemical group [N] QJGQUHMNIGDVPM-UHFFFAOYSA-N 0.000 description 1
- OTCVAHKKMMUFAY-UHFFFAOYSA-N oxosilver Chemical compound [Ag]=O OTCVAHKKMMUFAY-UHFFFAOYSA-N 0.000 description 1
- 229910052700 potassium Inorganic materials 0.000 description 1
- 239000011591 potassium Substances 0.000 description 1
- 229910052709 silver Inorganic materials 0.000 description 1
- 239000004332 silver Substances 0.000 description 1
- 229910001961 silver nitrate Inorganic materials 0.000 description 1
- 239000002904 solvent Substances 0.000 description 1
- 238000003756 stirring Methods 0.000 description 1
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
- C09B23/02—Methine or polymethine dyes, e.g. cyanine dyes the polymethine chain containing an odd number of >CH- or >C[alkyl]- groups
- C09B23/04—Methine or polymethine dyes, e.g. cyanine dyes the polymethine chain containing an odd number of >CH- or >C[alkyl]- groups one >CH- group, e.g. cyanines, isocyanines, pseudocyanines
Definitions
- Dyes of this type are known to be substituted ammonium salts, the sensitizing action being due to the positive ammonium radical.
- the nature of the negative radical will be of influence only in so far as it affects adversely the solubility of the compound or possesses deleterious action of its own. It will therefore be possible to use any quaternary compounds satisfactory in these respects.
- oz-methylated quinolin bases are meant de rivatives of quinolin, or related bases, having a methyl group adjacent to the nitrogen of the heterocyclic ring, and by -unsubstituted quinolin bases andy-methylated quinolin bases are ,meant derivatives of quinolin, and related bases, having, respectlvely, a
- Example 1 1.5 parts of epidin ethiodid are dissolved in 320 parts of absolute methyl alcohol, and a solution of sodium mthylate prepared by dissolving 0.058 part of metallic sodium in 80 parts of absolute methyl alcohol is added. After standing 100 hours the solution is poured into 1000 parts of distilled water, the solution extracted with carbon 'tetrachlorid to remove by-products, the dye extracted from v the solution with chloroform, and the extract washed with water, dried over anhydrous sodium sulfate and evaporated to a small volume. The concentrated solution is poured into1'20 parts of anhydrous ethyl ether and the bluish black yield is small.
- Example 2 1.57 parts of lepidin isoproyl iodid are dissolved in 16Iparts of absoute methyl alcohol and heated to-boiling.-
- a solution of sodium methylajte prepared by dissolving 0.058 part of metallicsodium in 4 parts of absolute methyl alcohol is;
- Example 3 6 parts of lepidin ethiodid are dissolved in 80 parts of 95 .per cent. ethyl alcohol and heated to boiling under a reflux condenser. After the air in the flask has been expelled a mixture of 1 part pf 40 per cent. formaldehyde solution and a solution of sodium ethylate, prepared by dissolving 0.23 part of metallic'sddium in 16 parts of absolute ethyl alcohol, is added gradually. The boiling is continued ten minutes, the flask stoppered and allowed to cool slowly. After 24 hours the dye is filtered off, washed with ice-cold ethyl alcohol and finally ether. The yield is approximately 0.4 part'of a purplish-black powder with a few crystals large enough to'give distinct reflections.
- Example 4 1.5 parts of lepidin methiodid are dissolved in 28 parts of 95 per cent. ethyl alcohol, the solution heated to boiling under a reflux condenser to expel air, and 22.5 parts of chloroform added. A solution of sodium ethylate, prepared by dissolving 0.115 part of metallic sodium in 8 parts of absolute ethyl alcohol, is then run gradually directly into the boiling solution, and the boiling'continued ten minutes after the addition is complete. The flask is stoppered while hot and allowed to cool slowly. After 24 hours the dye is filtered off, washed successively with ice-cold 95 per cent. ethyl alcohol, absolute ether, water, mixtures of alcohol and ether, and finally absolute ether. The yield is approximately 0.05 part of microscopic crystals showing both green and copper-colored metallic reflection.
- Example 5 4.5 parts of p-tolulepidin are dissolved in 32 arts of 95 per cent. ethyl alcohol, and a so ution of 2.5 parts of silver nitrate in 48 parts of 95 per cent. ethyl alcohol added, with stirring. The precipitated silver iodid is filtered off, the solution concentrated to three-fifths of its original volume and heated under arefiux condenser to expel air. A solution of sodium ethylate prepared by dissolving 0.23 part of metallic sodium in 16 parts of absolute ethyl alcohol and 0.75 part of a 40 per cent. aqueous solution of formaldehyde are mixed and slowly added to the boiling solution.
- Dyes effective for infrared photographic sensitization produced by the action of strong bases upon the higher alkyl halids of lepidin.
- Dyes effective for infra red photographic sensitization produced by the action of strong bases on the higher quaternary addition products of Y-methylated quinolin bases.
- Dyes effective for infra-red photographic sensitization produced by the action of strong bases in the presence of formaldehyde on the quaternary addition products of y-methylated uinolin bases.
Description
i STT'ES PATENT OFFICE.
ELLIOT Q. ADAMS, 0F BERKELEY, CALIFORNIA, AND HERBERT L. HALLER, 0F
CINCINNATI, OHIO.
PEOTUSEN'SITIZING DYE EFFECTIVE FOR INFRA-RED RADIATION.
No Drawing.
Specification of Letters Patent.
Patented Apr. 12, 1921.
Application filed July 17, 1920. Serial No. 307,114.
To all whom it may concern:
Be it known that we, ELLIOT Q. ADAMS and HERBERT L. HALLER, citizens of the United States of America, and employees of the. Department of Agriculture, residing in the city of Berkeley, county of Alameda, State of California, and in the city of Cincinnati, county of Hamilton, State of Ohio, respectively, whose post office address. is Department of Agriculture, Washington, D Q, have invented new and useful Photosensitizing Dyes Effective for Infra-Red Radiation, of which the following is a specification.
Dyes of this type are known to be substituted ammonium salts, the sensitizing action being due to the positive ammonium radical. Hence, the nature of the negative radical will be of influence only in so far as it affects adversely the solubility of the compound or possesses deleterious action of its own. It will therefore be possible to use any quaternary compounds satisfactory in these respects.
This application is made under the act of. March 3, 1883, chapter 143 (22 Stat. L., 625), and the invention herein descrlbed and claimed may be used by the Government of the United States or any of its officers or employees in the prosecution of work for the Government, and any person in the United States, without payment to; us of any royalty thereon.
It is known that a mixture of the quaternary halids (or other addition products) of quinolin and quinaldin,'or', more generally, of an oz-methylated and a y-unsubstituted quinolin base,yields with strong-bases in alcohol solution a 'dye of the iso-cyanin type; while a mixture of the quaternary halids (or other addition products) of quinolin and lepidin,.or, more generally, of a y-methylated and a y -unsubstituted quinolin base,-yields with strong bases in alcohol solution a dye of the cyanin type. By
oz-methylated quinolin bases are meant de rivatives of quinolin, or related bases, having a methyl group adjacent to the nitrogen of the heterocyclic ring, and by -unsubstituted quinolin bases andy-methylated quinolin bases are ,meant derivatives of quinolin, and related bases, having, respectlvely, a
' hydrogen and a methyl group diametrically opposite the nitrogen of 1 the heterocyclic ring. By strong bases are meant sodium and potassium hydroxid, silver oxid, and the methylates and ethylates of sodium and potassium. I
We have found that the quaternary halids or other addition products of su'iiiciently pure lepidin, or other -methylated quinolin bases, yield when treated with strong bases under suitable conditions dyes effective for infrared radiation, whose sensitization maximum lies farther into the infra-red than that of the dicyanins. Low concentration of reagents, high radical weight of the alkyl group attached to the nitrogen of the heterocyclic ring, and the presence of formaldehyde or chloroform favor this type of condensation. By higher alkyl roup is meant an alkyl group heavier than t e ethyl group; by higher quaternary addition prodnets-quaternary addition products 0011- taming such higher alkyl groups.
The characteristic absorption maximum of this class of dyes is in the neighborhood of 70005, their sensitization maximum at approximately 7400A The following examples will serve to illustrate the preferred procedure. The invention, however, is not confined to these exam ples. The parts are by weight.
Example 1: 1.5 parts of epidin ethiodid are dissolved in 320 parts of absolute methyl alcohol, and a solution of sodium mthylate prepared by dissolving 0.058 part of metallic sodium in 80 parts of absolute methyl alcohol is added. After standing 100 hours the solution is poured into 1000 parts of distilled water, the solution extracted with carbon 'tetrachlorid to remove by-products, the dye extracted from v the solution with chloroform, and the extract washed with water, dried over anhydrous sodium sulfate and evaporated to a small volume. The concentrated solution is poured into1'20 parts of anhydrous ethyl ether and the bluish black yield is small.
Example 2: 1.57 parts of lepidin isoproyl iodid are dissolved in 16Iparts of absoute methyl alcohol and heated to-boiling.-
A solution of sodium methylajte prepared by dissolving 0.058 part of metallicsodium in 4 parts of absolute methyl alcohol is;
added. After standing for some time the precipitate filtered ofi. The
solution is concentrated to one-fourth of its original volume and poured into 150' parts of absolute ether. The precipitate is removed by filtration, washed successively with absolute ether, water, and absolute ether, and, after drying, dissolved in absolute methyl alcohol, and the solvent removed by evaporation at room temperature. The yield is approximately 0.35 part of a purplish-black powder.
Example 3: 6 parts of lepidin ethiodid are dissolved in 80 parts of 95 .per cent. ethyl alcohol and heated to boiling under a reflux condenser. After the air in the flask has been expelled a mixture of 1 part pf 40 per cent. formaldehyde solution and a solution of sodium ethylate, prepared by dissolving 0.23 part of metallic'sddium in 16 parts of absolute ethyl alcohol, is added gradually. The boiling is continued ten minutes, the flask stoppered and allowed to cool slowly. After 24 hours the dye is filtered off, washed with ice-cold ethyl alcohol and finally ether. The yield is approximately 0.4 part'of a purplish-black powder with a few crystals large enough to'give distinct reflections.
Example 4: 1.5 parts of lepidin methiodid are dissolved in 28 parts of 95 per cent. ethyl alcohol, the solution heated to boiling under a reflux condenser to expel air, and 22.5 parts of chloroform added. A solution of sodium ethylate, prepared by dissolving 0.115 part of metallic sodium in 8 parts of absolute ethyl alcohol, is then run gradually directly into the boiling solution, and the boiling'continued ten minutes after the addition is complete. The flask is stoppered while hot and allowed to cool slowly. After 24 hours the dye is filtered off, washed successively with ice-cold 95 per cent. ethyl alcohol, absolute ether, water, mixtures of alcohol and ether, and finally absolute ether. The yield is approximately 0.05 part of microscopic crystals showing both green and copper-colored metallic reflection.
Example 5 4.5 parts of p-tolulepidin are dissolved in 32 arts of 95 per cent. ethyl alcohol, and a so ution of 2.5 parts of silver nitrate in 48 parts of 95 per cent. ethyl alcohol added, with stirring. The precipitated silver iodid is filtered off, the solution concentrated to three-fifths of its original volume and heated under arefiux condenser to expel air. A solution of sodium ethylate prepared by dissolving 0.23 part of metallic sodium in 16 parts of absolute ethyl alcohol and 0.75 part of a 40 per cent. aqueous solution of formaldehyde are mixed and slowly added to the boiling solution. The boiling is continued ten minutes after the complete addition of the sodium ethylateformaldehyde mixture, the flask stoppered while hot and allowed to cool very slowly. After 24 hours the dye is filtered off, washedsucoessivel with ice-cold 90 per cent. ethyl alcohol, et er, water, a mixture of absolute ether and alcohol, and finally absolute ether. The yield is approximately 0.25 part of a crystalline powder with a yellow green metallic luster.
Having now fully described our invention, what we claim and desire to protect by Letters Patent is:
1. Dyes effective for infrared photographic sensitization produced by the action of strong bases uponthe higher alkyl halids of lepidin.
2. Dyes effective for infra red photographic sensitization produced by the action of strong bases on the higher quaternary addition products of Y-methylated quinolin bases.
3. Dyes effective for infra-red photographic sensitization produced by the action of strong bases in the presence of formaldehyde on the quaternary addition products of y-methylated uinolin bases.
4. Dyes effective for infra-red photographic sensitization produced by the action of strong bases in the presence ofchloroform on the quaternary addition products of r-methylated quinolin bases.
5. The process of producing photographic sensitizing dyes e'fiective for infra-red radiation by the action of sodium ethylate and formaldeh de in alcohol solution on the alkyl halids o lepidin.
6. The process of producing photographic sensitizing dyes effective for infra-red radiation by the action of strong bases and formaldehyde on the quaternary addition products of -methylated quinolin bases.
7. The process of producing photographic sensitizing dyes effective for infra-red radiation by the action of strong bases and chloroform on the quaternary addition products of y-methylated quinolin bases.
8. The process of producing photographic sensitizing dyes effective for infra-red radiation by the action of strong bases on the higher quaternary addition products of ymethylated quinolin bases.
In testimony whereof, we afiix our signaturesin the presence of two subscribing witnesses."
ELLIOT Q. ADAMS. HERBERT L. HALLER.
Priority Applications (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US397114A US1374872A (en) | 1920-07-17 | 1920-07-17 | Photosensitizing dye effective for infra-red radiation |
Applications Claiming Priority (1)
| Application Number | Priority Date | Filing Date | Title |
|---|---|---|---|
| US397114A US1374872A (en) | 1920-07-17 | 1920-07-17 | Photosensitizing dye effective for infra-red radiation |
Publications (1)
| Publication Number | Publication Date |
|---|---|
| US1374872A true US1374872A (en) | 1921-04-12 |
Family
ID=23569882
Family Applications (1)
| Application Number | Title | Priority Date | Filing Date |
|---|---|---|---|
| US397114A Expired - Lifetime US1374872A (en) | 1920-07-17 | 1920-07-17 | Photosensitizing dye effective for infra-red radiation |
Country Status (1)
| Country | Link |
|---|---|
| US (1) | US1374872A (en) |
-
1920
- 1920-07-17 US US397114A patent/US1374872A/en not_active Expired - Lifetime
Similar Documents
| Publication | Publication Date | Title |
|---|---|---|
| US1374872A (en) | Photosensitizing dye effective for infra-red radiation | |
| Rapoport et al. | The preparation of some tetrasubstituted amidrazones | |
| US1374871A (en) | Photosensitizing dye of the isocyanin type | |
| US2829149A (en) | New fuchsine cyanide | |
| Solomons et al. | The Diazapentalene System. IV. The Parent Pyrazolo [1, 2-α] pyrazole and Derivatives1 | |
| US2350804A (en) | Derivatives of hesperidin and process for preparing the same | |
| US3449335A (en) | Merocyanine dyes containing the carbostyril nucleus | |
| Landau | The Molar Refraction of Sulfonyl Chlorides | |
| US2111183A (en) | Dyes of the polymethine series and preparation of the same | |
| US2481953A (en) | Cyanine dyestuffs and process of making same | |
| OHTSUKA et al. | Studies of Heterocyclic Compounds. VII. The Reactions of 5, 6-Dihydrothiazolo [2, 3-b] thiazolium Salts with Carbanions | |
| GB782311A (en) | Merocyanine dyes, methods of making them and photographic emulsions containing them | |
| US3005015A (en) | Polycyanoheptatrienes and a process for their preparation | |
| US1437674A (en) | Process of making photographic sensitizing dyes of the dicyanine type | |
| SU293023A1 (en) | METHOD FOR OBTAINING TRICARBOCYANINOUS DYES | |
| deStevens et al. | Investigations in heterocycles. VIII. Quinazolines and pyrimidines | |
| DE857886C (en) | Methods for sensitizing and oversensitizing photographic emulsions | |
| US1338349A (en) | Process of making photosensitizing-dyes effective for infra-red radiation | |
| SU423291A3 (en) | ||
| US2705234A (en) | Polymethine dyes | |
| US2464537A (en) | Unsymmetrical cyanines | |
| Grandberg et al. | A study of pyrazoles: LVIII. Reactivity of pyrazolo [2, 3-a] pyridine | |
| Haley | Reactions of methylpyrylium, thiapyrylium, and flavylium salts with tetracyanoethylene | |
| SU126206A1 (en) | The method of obtaining tiatricarbocyanine dyes | |
| DE923868C (en) | Process for the preparation of thiazolone cyanine dyes |