Thiophene Appended Dual Fluorescent Sensor for Detection of Hg2+ and Cysteamine.

An efficient and highly selective pyrene-thiophene conjugate has been reported as a dual sensor for Hg2+ and cysteamine (an important drug for genetic disorder). The sensor displays a turn-on fluorescence response towards Hg2+ in a 2:1 stoichiometric ratio via excimer formation with a detection limit as low as of 30.6 nM. The excimer emission upon binding with Hg2+ has been rationalized by experimental as well as theoritical studies. Moreover, the [probe-Hg2+] adduct functions as an efficient sensor for cysteamine. This sensing process happens via the extraction of Hg2+ from the adduct. In this paper, change in emission properties of the receptor with varying pH and water content has also been explained. The sensing abilities of the sensor were examined in real water sample analysis. Therefore, the sensor can be used as an efficient and reusable fluorescent sensor for recognition of Hg2+ in water.