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

Abstract

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.