A new N-substituted heteroacene can detect CN− and F− anions via anion–π interaction

Abstract

A novel heteroacene with an aroyleneimidazophenazine moiety (1) has been successfully synthesized and characterized. Compound 1 can selectively detect CN⁻ and F⁻ over another ten anions (Cl⁻, Br⁻, I⁻, Ac⁻, H₂PO₄⁻, NO₃⁻, SO₄²⁻, ClO₄⁻ and BF₄⁻, PF₆⁻) in mixed solvents with multiple responses including fluorescent “turn-off”, colorimetric and near-infrared absorption signaling. The interactions between 1 and CN⁻/F⁻ have been investigated through UV-vis and fluorescence experiments, and the results suggest that the anion–π interactions between 1 and CN⁻/F⁻ might be reversible processes upon the addition of Cu²⁺ and Fe³⁺ cations.