Fluorescence “on–off–on” chemosensor for selective detection of Hg2+ and S2−: application to bioimaging in living cells

Abstract

A phenothiazine based diamino-malenonitrile-linked chromogenic and fluorogenic probe (P-1) was synthesized and characterized for the specific detection of Hg²⁺ and S²⁻. In the presence of Hg²⁺, the probe produces “switch-off” along with a color change from yellow to brown, allowing colorimetric detection of Hg²⁺ by the naked eye. The sensitivity of probe P-1 towards Hg²⁺ and S²⁻ was demonstrated in living cells, and cell toxicity assay also reveals that the probe P-1 can be used for selective imaging of Hg²⁺ and S²⁻ in living cells.