Deprotonation and chelation synergically triggered near infrared fluorescence for selective detection of Hg(II)

A convenient strategy that does not need the tedious modification of the π-conjugation moiety to construct near infrared (NIR) sensors is in high demand. In this study, we present the design and synthesis of a NIR Hg(II) turn-on fluorescent sensor BODIPY-SAN, which shows several advantages including (1) simple to be synthesized by only a predictable modification of the core structure of 6-hydroxyindole-based BODIPY, (2) giving a turn-on NIR emission synergically triggered by chelation and deprotonation, (3) exhibiting Hg(II)-specific fluorescence response with the detection limit to be 5 × 10−7 M, (4) functioning as a novel cell-permeable NIR probe for intracellular Hg(II) in living HeLa cells.