Novel Long-Lifetime Iridium Complex as Lab-on-a-Molecule for Hg2+ and pH-Activatable Probes

Novel phosphorescent iridium complex (pq)(2)Ir(cys) (where pq = 2-phenylquinoline, cys = L-cysteine) was synthesized and characterized. Bearing a pH-activatable carboxyl group, the complex can act as lab-on-a molecule for determination of a trace amount of Hg2+, based on the fact that its phosphorescence can be sensitively and selectively quenched by Hg2+. Furthermore, its phosphorescence is reversibly responsive to pH changes in a wide pH range 7-13. Thus, the molecule was developed as highly selective orthogonal signaling protocol for Hg2+ and pH detection by one channel.