A water-soluble iridium complex: Highly sensitive to bisulfite and sequential recognition to Cu2Â + ions

A newly designed iridium complex [Ir(mepi)2bpy)]3 + (1) with indolium block was successfully used as a colorimetric probe for bisulfite in CH3CN-HEPES buffer system (v/v, 2:98). It is interesting that the in situ generated 1-SO3H system demonstrates sequential recognition to Cu2 +, along with the solution color recovering from colorless to light-yellow. The apparent solution color changes displayed that the complex 1 can be used to detect bisulfite and Cu2 + by naked eyes.77