Cyanine dye

In cyanine dyes both charge-carrying terminal atoms of the methine chain are constituents of heterocyclic rings. Depending on the nature of the heterocycle, the methine chain can be coupled in the 2-, 3-, or 4-position to the charge-carry- 

Zeromethinecyanine Dyes. Naphtholactam and its TV-alkyl derivatives can be condensed with indoles in the presence of acid condensation agents such as phosphorus oxychloride to form red zeromethinecyanine dyes that dye polyacrylonitrile very lightfast shades [97], The indole may contain a methyl or phenyl group in the 2-position. If the 2-position is not substituted, the coloring strength increases because there is less steric hindrance [98], e.g., 41. 

Condensation of indoles with A-alkylquinolones or TV-alkylpyridones yields yellow and orange zeromethine dyes that dye polyacrylonitrile in lightfast shades [99], If the indole nitrogen atom is unsubstituted, intensely colored anhydro bases are formed from the zeromethinecyanine dyes. Dealkylation of the heterocyclic quaternary nitrogen atom also occurs [100], 

Monomethinecaynine Dyes The oldest dye of the this series is cyanine, a blue dye after which the whole class of dyes was named. Cyanine (42) was synthesized by Williams in 1856 from crude tar quinoline by quatemization with pentyl iodide, followed by treatment with alkali. The unsymmetrical monomethine dye coupled in the 2- and 4-positions of quinoline is termed isocyanine. 

Dimethinecyanine Dyes. In the most important dimethinecyanine dyes the methine chain links two indole moieties in the 2- and 3-positions. The dyes were initially used for dyeing and printing cellulose acetate [101], but became increas- 

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Kneipp K, Kneipp H, Deinum G, Itzkan I, Dasari R R and Feld M S 1998 Single-molecule detection of a cyanine dye in silver colloidal solution using near-infrared surface-enhanced Raman scattering App/. Spectrosc. 52 175-8... 

In the first chapter, devoted to thiazole itself, specific emphasis has been given to the structure and mechanistic aspects of the reactivity of the molecule most of the theoretical methods and physical techniques available to date have been applied in the study of thiazole and its derivatives, and the results are discussed in detail The chapter devoted to methods of synthesis is especially detailed and traces the way for the preparation of any monocyclic thiazole derivative. Three chapters concern the non-tautomeric functional derivatives, and two are devoted to amino-, hydroxy- and mercaptothiazoles these chapters constitute the core of the book. All discussion of chemical properties is complemented by tables in which all the known derivatives are inventoried and characterized by their usual physical properties. This information should be of particular value to organic chemists in identifying natural or Synthetic thiazoles. Two brief chapters concern mesoionic thiazoles and selenazoles. Finally, an important chapter is devoted to cyanine dyes derived from thiazolium salts, completing some classical reviews on the subject and discussing recent developments in the studies of the reaction mechanisms involved in their synthesis. 

IX. Cyanine Dyes Derived from Thiazolium Salts... 

Cyanine Dyes Derived from Thiazoliurn Saits... 

Even if the specific role attributed to benzothiazolium was not confirmed later (24), all these syntheses account for the significant and common behavior of quaternary salts, carbocations giving either symmetrical or asymmetrical reactive anhydrobases. They constitute the mam step in cyanine dye formation. 

Cyanine Dyes Derived from Thjazolium Salts 4. Tetranuciear Dyes... 

Cyanine Dyes Derived from Thiazoiium Salts 3. Modern Conception... 

F. M. Hamer, The Cyanine Dyes and Related Compounds. Wiley-Interscience, fvew York. 1964. 

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