Multisignaling detection of Hg2+ based on a phosphorescent iridium(III) complex

A multisignaling chemosensor for Hg2+ based on the iridium(III) complex Ir(thq)(2)(acac) was realized through UV-Vis absorption, phosphorescent emission and electrochemical measurements. Upon addition of Hg2+, an obvious blue-shift in absorption spectra and a strong decrease of emission intensity were measured for Ir(thq)(2)(acac), which could be observed by the naked eye. Hg2+ is coordinated to Ir(thq)(2)(acac), forming a 1 : 1 complex. Because Hg2+ is a thiophilic metal ion, the interaction between Hg2+ and the sulfur atom of cyclometalated ligands is responsible for the significant variations in optical and electrochemical signals.