A fluorescent probe for the detection of Hg2+: Shift from “on-state A” to “on-state B”

A simple pyrene based receptor has been synthesised and shown to exist in the dimeric form in solution exhibiting an excimer band in the emission spectrum. The proposed dimeric form is supported by the DFT calculations. Further, the excimer fluorescence is bathochromically shifted with decreased emission intensity in the presence of Hg2+ suggestive of the formation of an aggregated complex. The sensing event also worked on the solid support; thus attesting the potential of the sensor for practical application in contact mode.