A new fluorescent pyrene-pyridine dithiocarbamate probe: A chemodosimeter to detect Hg2+ in pure aqueous medium and in live cells

A new pyrene-pyridine dithiocarbamate based fluorescent chemodosimeter, potassium (pyren-1-ylmethyl)(pyridin-2-ylmethyl)dithiocarbamate (L1) has been designed and synthesized. The chemodosimeter shows high selectivity and sensitivity (5.2 ppb) for Hg2+ in pure aqueous medium in which emission intensity was quenched by ≈80% due to the formation of new cyclized species, 1. The probe behaves as a chemodosimeter for Hg2+ ions and forms Hg2+ triggered cyclised imidazoline species with approximate detection time of 50 s and exhibits both colorimetric and fluorometric changes on detection of Hg2+ ion. Color of the probe (L1) changed from green to colorless visible to the naked eye and from green to dark blue upon the addition of Hg2+ ions under UV light. The Hg2+ triggered cyclization reaction was confirmed by spectral data analysis and a single crystal structure determination of the cyclised entity 2 obtained from the model compound potassium benzyl(pyridin-2-ylmethyl) dithiocarbamate (L2). L1 finds its application for detection of Hg2+ ions on paper strips, and in BSA (bovine serum albumin) medium. L1 is also applicable for the monitoring of Hg2+ ion in NIH3T3 live cells.