A novel urea-linked dipodal naphthalene-based fluorescent sensor for Hg(II) and its application in live cell imaging

A novel cell-permeable urea-linked dipodal naphthalene-based fluorescent receptor 1 (1,1'-(1,5,5-trimethyl-3-oxocyclohexane-1,2-diyl)bis(3-(naphthalen-2-yl)urea) was designed and synthesized. The cation recognition ability of 1 was evaluated with a library of metal ions in DMSO/H₂O (9:1, v/v). The receptor showed a selective chromogenic and fluorescent turn-off response towards Hg(2+) among the surveyed metal ions. The developed sensor was successfully applied to image intracellular Hg(2+) in living cells and also for the determination of Hg(2+) content in real water samples. Moreover, the DFT calculations were performed to complement the experimental evidences.