A turn-off fluorescent chemical sensor based on Bis-imidazole structure for highly selective and accurate detection of Cu2+ in living cells

Abstract

A novel highly selective and sensitive bis-imidazole fluorescent chemical sensor, 2,6-bis(4,5-diphenyl-1H-imidazol-2-yl)-4-methylphenol (BMP) was synthesized and utilized for spectral sensing of Cu²⁺. After the addition of Cu²⁺, the green fluorescence of BMP solution quickly quenched, and in the presence of multiple metal ions showed good anti-interference to Cu²⁺, the detection limit was 1.59 nM. Job's plot and ¹H NMR analysis confirm that there is a 2:1 cooperative pattern between BMP and Cu²⁺. DFT calculations at the B3LYP/LANL2DZ/6-311 g level of theory were conducted to explore possible theoretical explanations. The detection of Cu²⁺ by this probe has good repeatability under the alternating action of Cu²⁺ and EDTA. Test strips made of BMP were used for rapid “naked-eye”detection of Cu²⁺ in aqueous medium. The probe was successfully used to monitor Cu²⁺ in living cells and real water samples.