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Alkanediyl bridged benzimidazolo monomethine cyanine dyes, processes for their preparation, and photographic emulsions and elements containing such dyes |
| T104601 |
Alkanediyl bridged benzimidazolo monomethine cyanine dyes, processes for their preparation, and photographic emulsions and elements containing such dyes
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| Patent Drawings: | |
| Inventor: |
Gilbert |
| Date Issued: |
September 4, 1984 |
| Application: |
06/570,147 |
| Filed: |
January 12, 1984 |
| Inventors: |
Gilbert; David P. (Rochester, NY)
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| U.S. Class: |
540/603; 544/245; 548/305.7 |
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| Abstract: |
Alkanediyl bridged benzimidazolo monomethine cyanine dyes are disclosed wherein at least one benzimidazolo nucleus is provided with an electron-withdrawing group. A disclosed preparation of the dyes includes producing an electron-withdrawing group substituted bis(2-nitrophenyl)-2-R.sup.1 -propanediamide, where R.sup.1 is hydrogen or alkyl; converting the nitro groups to primary amine substituents; removing the elements of water to effect ring closure; and thereafter providing the --CR.sup.1 -- linked benzimidazole nuclei so formed with an N,N.sup.1 -alkanediyl bridging group and quaternizing substituents. Dye synthesis is completed by reducing the --CR.sup.1 -- linking group to the corresponding methine. The dyes are useful as sensitizers in silver halide emulsions and photographic elements. |
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