Polymethine and other Dyes

Sulphur-containing polymethine dyes, including those incorporating thiazolidine and benzothiazole residues, exhibit certain anomalous chromophoric properties (e.g. abnormal vinylene shifts), which have been traced to an interannular non-bonded S-S interaction in the monomethine ion. The conclusion is supported both by a detailed examination of the 

Korotkaya and V. Y. Pochinok, Khim. geterotsikl. Soedinenii, 1972, 786 (Chem. Abs., 

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