A colorimetric F⁻ chemosensor with high selectivity: experimental and theoretical studies

Abstract: A new and simple colorimetric receptor 1, based on the combination of 2-amino-4-methylphenol moiety and julolidine moiety, has been designed and synthesized. 1 showed a selective colorimetric sensing ability toward F⁻ ion by changing color from yellow to orange, and could be utilized to monitor F⁻ without any inhibition by competitive anions such as CH₃COO⁻ and CN⁻. Based on Job plot, ESI-mass spectrometry and the ¹H NMR titration, the binding mode of 1 for F⁻ was proposed to be 1:1. Moreover, the sensing mechanism for F⁻ was theoretically supported by DFT and TD-DFT calculations. Graphical Abstract: [Figure not available: see fulltext.]