A highly selective chemosensor for mercury(II) cations based on cyclometalated iridium(III) complex

A cyclometalated iridium(III) complex, Ir(dpci)2(dtc) (Ir1, dpci = 3,4-diphenylcinnoline, dtcH = diethyl dithiocarbamic acid), was synthesized from the reaction of the iridium complex [Ir(dpci)2(Cl)]2 and dtcNa in methanol/CH2Cl2, and characterized by FT-IR, 1H NMR and mass spectroscopies. The photoluminescence spectrum of Ir1 shows emission maximum at 686 nm with a lifetime of 0.77 μs and PL quantum yields is ca. 0.021. Moreover, [Ir(dpci)2(dtc)], containing a dithiocarbamate ancillary ligand, can serve as a highly selective turn-on chemodosimeter for Hg2+, which is associated with the dissociation of the dithiocarbamate ancillary ligand from the complex.