An ICT based highly selective and sensitive sulfur-free sensor for naked eye as well as fluorogenic detection of Hg2+ in mixed aqueous media

A new internal charge transfer (ICT) based colorimetric as well as fluorogenic sulfur-free probe for highly selective and sensitive monitoring of Hg2+ has been developed and reported in this Letter. It gives a colorimetric and fluorometric response upon addition of Hg2+ in acetonitrile:water (1:1) solution at a physiological pH, with no significant interference of other competitive metal ions. Receptor (TPM) shows a distinct color change from light yellow to orange upon progressive addition of Hg2+, so that it can serve as a naked-eye sensor for Hg2+ ion. It exhibits excellent reproducibility, reversibility, and selectivity with the detection limit at micro-molar level.