A novel bifunctional chemosensor for bioimaging in living cells with highly sensitive colorimetric and fluorescence detection of CN− and Al3+

Abstract

A novel colorimetric/fluorescent chemosensor (1o) was designed and synthesized for the detection of CN⁻ and Al³⁺. 1o exhibited a selective dual channel response to CN⁻, while it showed fluorescence changes in response to Al³⁺, in acetonitrile solvent. In the presence of CN⁻, 1o underwent a significant color change through a deprotonation effect and nucleophilic addition mechanism. The chelation-induced enhanced fluorescence (CHEF) effect was demonstrated by the inhibition process of Al³⁺ binding-induced CN isomerization. We characterized the induction properties of 1o on CN⁻ and Al³⁺ using photophysical experiments and theoretical calculations. The chemosensor exhibited high sensitivity to CN⁻ and Al³⁺ with detection limits as low as 1.0 × 10⁻⁷ mol L⁻¹ and 3.0 × 10⁻⁹ mol L⁻¹, respectively. A simple test strip containing 1o was prepared for the rapid detection of CN⁻ by the naked eye. It is worth mentioning that 1o was successfully applied for the bioimaging of CN⁻ and Al³⁺ in living cells.