Selenophene-containing silicon-rhodamine: A novel near-infrared fluorescent probe for Hg2+ detection and its application in cell imaging.

Monitoring of mercury ion (Hg2+) pollution is one of the eternal themes due to its notorious toxicity. Herein, we elaborately designed a novel fluorescent probe N'-((selenophen-2-yl)methylene)Si-rhodamine B hydrazide (Se-SiRH) by integrating 2-formylselenophene with Si-rhodamine B hydrazide. Se-SiRH exhibited an excellent near-infrared response towards Hg2+ in MeOH/PBS solution (1:1, v/v, pH = 7.0) and superior specificity towards Hg2+ than other metal ions. Meanwhile, striking sensitivity towards Hg2+ was found and the limit of detection in fluorescence measurement was calculated to be 2.1 × 10-9 mol·L-1. What's more, Hg2+-binding mechanism was confirmed with Job-plot measurement, HR-MS and theoretical calculation. Importantly, the success in detecting Hg2+ in real water samples and visualizing Hg2+ in HepG2 cells validated its eye-catching application capability in environmental and biological research.