Williams cyanine

The first cyanine dye was made in 1856 by Greville Williams. Thus the blue charge-resonance system 6.216 was produced when oxidative coupling took place between N-... 

Yau CMS, Pascu SI, Odom SA, Warren JE, Klotz EJF, Frampton MJ, Williams CC, Coropceanu V, Kuimova MK, Phillips D, Barlow S, Bredas JL, Marder SR, Millar V, Anderson HL (2008) Stabilisation of a heptamethine cyanine dye by rotaxane encapsulation. Chem Commun 25 2897-2899... 

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. 

It is possible that the cyanines are constituted similarly to the phenylmethane dyestuffs, the methyl group of the lepidine furnishing the methane carbon atom. The cyanines belong to the earliest artificial dyestuffs, the first representative having been discovered by Greville Williams in 1856. 

Kieser, M. E., Pollard, A., and Williams, A. H. 1953. The occurrence of leuco-antho-cyanins in perry pears. Chemistry and Industry 1968, 1260. 

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