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

Angew Chem Int Ed Engl. 2021 Mar 1;60(10):5168-5172. doi: 10.1002/anie.202012764. Epub 2021 Jan 21.

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.

Keywords: carbanions; fluorine; ion pairs; lipophilicity; luminescence.