A Fluorinated Carbanionic Substituent for Improving Water Solubility and Lipophilicity of Fluorescent Dyes

Abstract

Installation of a carbanionic substituent, that is strongly stabilized by two (trifluoromethyl)sulfonyl (Tf=SO₂ CF₃ ) 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 Tf₂ C=CH₂ , followed by neutralization with NaHCO₃ . 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 stabilized carbanionic substituent is a new option for controlling the macroscopic property of chemical materials.