A selective phosphorescent chemodosimeter for mercury ion

The synthesis and crystal structure of an anionic phosphorescent iridium complex TBA[Ir(dfppy)2(NCS)2] (1) were reported. 1 can selectively detect Hg2+ with the help of UV–Vis absorption and emission spectra titration. In the presence of Hg2+, the obvious decrease of the luminescence intensity at 475 nm was investigated, which could be observed by the naked eyes. The phosphorescence quantum efficiency in CH3CN solution changed from 0.07 to 0.00085. No obvious spectra changes were observed upon addition of a large excess of other transition metals. Due to its strong thiophilic affinity, the special chemical reaction induced by Hg2+ is responsible for the significant change of absorption and luminescence spectra, which is confirmed by ESI-MS.