Mitochondria-targeted phosphorescent cyclometalated iridium(III) complex for bioimaging of H2S

The selective visualization of H2S in mitochondria is still a challenge, but it correlates closely with mitochondrial damage and some related diseases. In this work, a cyclometalated iridium complex Ir-DNB, [Ir(ppy)2(N<^>N)](PF6) (ppy = 2-phenylpyridine, N<^>N = (4'-methyl-[2,2'-bipyridin]-4-yl)methyl 2-((2,4-dinitrophenyl) thio)benzoate) has been explored for the detection of mitochondrial H2S. Adding H2S to a solution of complex Ir-DNB results in a clearly luminescence enhancement, and displays high selectivity and sensitivity. Moreover, this complex displays negligible toxicity and good mitochondrial localization to HeLa cells, and has also been successfully used for endogenous and exogenous H2S imaging in vitro and in vivo.