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, 1H, 1H–1H COSY, 19F and 11B NMR techniques. In 1H NMR, the protons which are adjacent to sulfur in 3-(pyridine-4-thione)BODIPY showed ∼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.

Graphical abstractThe 3-(pyridine-4-thione)BODIPY was synthesized and showed it as a selective chemodosimeter for Hg2+ ions detection.Figure optionsDownload full-size imageDownload as PowerPoint slideHighlights► 3-(Pyridine-4-thione)BODIPY has been synthesized using 3-(pyridine-4-one)BODIPY. ► 3-(Pyridine-4-thione)BODIPY show different electronic properties. ► 3-(Pyridine-4-thione)BODIPY is non-fluorescent. ► 3-(Pyridine-4-thione)BODIPY can be used as chemodosimeter for Hg(II) ion detection. ► Non-fluorescent thione BODIPY changes to fluorescent upon addition of Hg(II) ion.