Rhodamine-based bis-sulfonamide as a sensing probe for Cu2+ and Hg2+ ions

A new rhodamine-based bis-sulfonamide 1 has been designed and synthesized. The receptor selectively recognizes Cu2+ and Hg2+ ions in CH3CN-water (4/1, v/v; 10 mu M tris HCl buffer, pH 6.8) by showing different emission characteristics and color changes. While Cu2+ is sensed through increase in emission, Hg2+ is detected by a weak ratiometric change in emission of 1. The receptor shows in vitro detection of both the ions in human cervical cancer (HeLa) cells.