Rhodamine-labelled new architecture for dual sensing of Co2+ and Hg2+ ions

A new rhodamine-based chemosensor 1 selectively recognizes Co2+ and Hg2+ ions in CH3CN/water at pH 6.8 by showing different extents of change in emission. The disappearance of colour of mercury-ensemble of 1 followed by appearance of distinct bluish colour under UV illumination upon addition of l-cysteine distinguishes Hg2+ from Co2+ ions.