A Fluorinated Carbanionic Substituent for Improving Water-solubility and Lipophilicity of Fluorescent Dyes.

Installation of a carbanionic substituent, that is strongly stabilised by two (trifluoromethyl)sulfonyl (Tf = SO 2 CF 3 ) groups, into several fluorescence dyes including boron-dipyrromethenes (BODIPYs), fluoresceins, and aminocoumarins has been achieved by the 2,2-bis(triflyl)ethylation reaction of the dye frameworks with highly electrophilic Tf 2 C=CH 2 , followed by neutralisation with NaHCO 3 . Despite the contradiction between water-solubility and lipophilicity, the carbanion-decorated dyes thus obtained showed significant enhancement of not only water-solubility but also lipophilicity. This work clearly demonstrates that the fluorinated, highly stabilised carbanionic substituent is a new option for controlling the macroscopic property of chemical materials.