Reversible Addition of Cyanide to Triphenylamine Attached Difluoroboron β-Diketonate Facilitated Selective Colorimetric and Fluorimetric Detection of Cyanide Ion

Abstract

Nucleophilic addition of cyanide on a new triphenylamine attached difluoroboron β-diketonate {4-[4-(diphenylamino) phenyl]-2,2-difluoro-6-methyl-2H-1,3,2-dioxaborinin-1-ium-2-uide (C4)} breaks the conjugation readily and thereby offers efficient and selective detection of cyanide. A rational mechanism based on UV/Vis, fluorescence, NMR (1H, 11B, and 19F) and HRMS analysis and DFT calculations has been proposed. The detection limit was found to be 0.36 µM. A test strip assay using the title compound has also been applied to detect CN– in aqueous solution for real-time applications.