A novel synthetic route to thiacyanine dyes containing a perfluorinated polymethine chain

2-Iodobenzothiazole was reacted with tributyl(trifluorovinyl)tin and (2-chlorodifluorovinyl)tributyltin by the Stille reaction to yield 2-trifluorovinyl- and 2-(2-chlorodifluorovinyl)benzothiazole, respectively. The quaternary salt of 2-trifluorovinylbenzothiazole, when treated with fluoride ion, furnished the corresponding thiacarbocyanine dye containing a perfluorinated polymethine chain. The reaction involved nontrivial cleavage of the C–C bond to provide an energetically advantageous conjugated perfluoropolyenic system.