A Probe for the Selective and Parts‐per‐Billion‐Level Detection of Copper(II) and Mercury(II) using a Micellar Medium and Its Utility in Cell Imaging

A novel colorimetric probe  1 based on the picolyl moiety has been designed and synthesized. Probe  1 is composed of a pyrene and a bispicolyl amine (BPA) unit, in which the BPA moiety acts as a binding unit and the binding phenomenon is sensed from the changes in the signaling subunit. The probe detects Cu 2+ specifically in water and both Cu 2+ and Hg 2+ efficiently in neutral Brij‐58 micellar media. The probe shows a color change visible to the naked eye upon addition of metal ions. Notably, in a micellar medium, probe  1 can detect both the Cu 2+ and Hg 2+ ions even at parts‐per‐billion levels. Furthermore, the probe shows ratiometric detection of both the metal ions making the sensing quantitative. The two metal ions could be discriminated both visibly under a UV lamp and with the use of fluorescence spectroscopy. The probe could be also used in biological cell lines for the detection of both Hg 2+ and Cu 2+ ions.