A highly selective fluorescent sensor for Hg(ii) based on an NTe2 chelating motif and its application to living cell imaging

Abstract

A fluorescent probe (NBDTe) based on an NTe₂ chelating motif has been developed for the highly selective and sensitive detection of Hg²⁺. Significant fluorescence enhancement was observed with the chemosensor NBDTe in the presence of Hg²⁺. Moreover, the metal ions Ag⁺, Al³⁺, Ca²⁺, Cd²⁺, Co²⁺, Cu²⁺, Cr³⁺, Fe²⁺, Fe³⁺, Hg²⁺, Mg²⁺, Mn²⁺, Ni²⁺, Pb²⁺, and Zn²⁺ produced only minor changes in the fluorescence values of the system. The association constant (K_a) of Hg²⁺ binding to the chemosensor NBDTe was found to be 3.81 × 10³ M⁻¹, with a detection limit of 4.2 μM. The maximum fluorescence enhancement caused by Hg²⁺ binding to the chemosensor NBDTe was observed over the pH range of 4.0–10.0. In addition, fluorescence microscopy experiments showed that the chemosensor NBDTe can be used as a fluorescent probe for detecting Hg²⁺ in living cells.