A dual thiourea-appended perylenebisimide "turn-on" fluorescent chemosensor with high selectivity and sensitivity for Hg in living cells.

Sensing heavy metal ions particularly for the most toxic Hg is a long-term pursuit for chemists because of its obvious and extreme harmfulness to both the environment and human health. Herein, a novel 'turn-on' perylenebisimide-thiourea fluorescent probe PBI-BTB is achieved for rapid detection of Hg in a DMSO/HO (5/1, v/v) solution through a typical Hg-promoting desulfurization reaction, which has been investigated through Job's plot titration, FT-IR, H NMR and HRMS analysis. A remarkable fluorescence emission enhancement at 540 and 580 nm is observed in the presence of Hg, which is visible to the naked eye with high selectivity and sensitivity. Moreover, probe PBI-BTB combined strong anti-interference recognition with short response time (< 1 min). The rapid fluorescence response with low limit of detection (0.35 μM) in a wide pH range of 3.0-11.0 makes PBI-BTB a promising candidate for detection of Hg without any buffer system. Furthermore, the practicability of probe PBI-BTB upon the Hg recognition in human liver cancer cells (HepG-2) has been studied through fluorescent live cell imaging which reveals the probe's low toxicity to organism as well as the favorable cell permeability of PBI-BTB for detecting Hg in biological systems.