Cyanine Dyes as Sensitizers

The most common cyanine dyes used as green sensitizers are symmetrical benzimidazole and benzoxazole dyes 7-9. Dyes 7-9 also illustrate several common side-chain variations. The sulfobutyl and sulfopropyl groups are very common. The methylsulfopropyl side chain is used to improve solubility. 

Unsymmetrical benzothiazole-quinoline dye 10, benzothiazole-benzoxazole dye 11, and benzimidazole-benzoxazole dye 12 are also effective green sensitizers. It is important that these dyes J-aggregate and absorb between 500 and 600 nm with a peak absorbance at ca. 550 nm. 

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New sources of singlet oxygen continue to be developed. Near i.r. radiation ( > 900 nm), in the presence of a cyanine dye as sensitizer, has been used to generate 102.100 Thermal decomposition of the ozonide (52) produces 102 and the... 

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