3-(Pyridine-4-thione)BODIPY as a chemodosimeter for detection of Hg(II) ions

A new chemodosimeter for detection of Hg(II) ions based on boron-dipyrromethene (BODIPY) is developed. The 3-(pyridine-4-thione)BODIPY was synthesized in high yield by treating 3-(pyridine-4-one)BODIPY with Lawesson's reagent. The 3-(pyridine-4-thione) BODIPY was confirmed by HR-MS mass, H-1, H-1-H-1 COSY, F-19 and B-11 NMR techniques. In H-1 NMR, the protons which are adjacent to sulfur in 3-(pyridine-4-thione)BODIPY showed similar to 1 ppm downfield shift compared to equivalent protons in 3-(pyridine-4-one)BODIPY. The absorption and electrochemical properties experienced slight changes in 3-(pyridine-4-thione)BODIPY compared to 3-(pyridine-4-one)BODIPY. The compound 3-(pyridine-4-thione)BODIPY is very weakly fluorescent compared to 3-(pyridine-4-one)BODIPY. Furthermore, 3(pyridine-4-thione)BODIPY can be used as an exclusive chemodosimeter for Hg2+ ion as it shows significant enhancement in the fluorescence intensity and a dramatic visible color change from pink to fluorescent green in the presence of Hg(II) ions. (C) 2012 Elsevier Ltd. All rights reserved.