Unfolding with mercury: anthracene-oxyquinoline dyad as a fluorescent indicator for Hg(II)

An anthracene-oxyquinoline dyad (HQ-AN) is synthesized which acts as a selective fluorescent reporter for Hg(II) with a detection limit of 3.2 × 10−6 M in acetonitrile–water system. The phenomenon of unfolding of HQ-AN from its initial folded conformation in acetonitrile–water system, selectively in the presence of Hg(II) is indicated from spectrofluorometric studies. The sensing event is monitored by the marked change in fluorescence emission occurring due to quenching of the excimer and retaining of the monomer emission of the two anthracene units in HQ-AN.