A New 2,4-Bis(1H-benzoimidazol-2-yl)-phenol-cupric Complex System for the Detection of Glutathione

Based on the chelation-enhanced fluorescence quenching effect, a new benzimidazole derivative receptor (2,4-bis(1H-benzoimidazol-2-yl)-phenol) was synthesized from 4-hydroxybenzene-1,3-dicarbaldehyde and o-phenylenediamine in the presence of manganese(III) acetate via one-pot oxidative condensation. Exhibiting a large Stokes shift of 149 nm and showing excellent quenching properties for the recognition of copper ions by coordination, the fluorescence emission of the ensemble at 455 nm was switched on with a strong fluorescence recovery upon the addition of glutathione (GSH), with a detection limit of 8 × 10^–7 mol/L. The established method is sensitive and highly selective for GSH, presenting potential application as a fluorescent probe for label-free detection of glutathione in biological fluids.