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

A novel highly selective and sensitive bis-imidazole fluorescent chemical sensor, 2,6-bis(4,5-diphenyl-1H-imi-dazol-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.