Visualization of Zn2+ ions in live zebrafish using a luminescent iridium(III) chemosensor
A novel luminescent cyclometalated iridium(III) complex-based chemosensor (1) bearing a zinc-specific receptor, tris(2-pyridylmethyl)amine, and the 3-phenyl-1H-pyrazole ligand has been designed and synthesized. Upon the addition of Zn2+ ions to a solution of iridium(III) complex 1, a pronounced luminescence color change from blue to green can be observed, which may be attributed to the suppression of photoinduced electron transfer upon complexation of complex 1 with Zn2+ ions. The interaction of iridium(III) complex 1 with Zn2+ ions was investigated by UV-vis absorption titration, emission titration, and 1H NMR titration. Furthermore, the iridium(III) complex 1 exhibited good selectivity for Zn 2+ over 13 other common metal ions, including K+, Ag +, Na+, Ni2+, Fe3+, Hg2+, Cd2+, Mg2+, Ca2+, Cu2+, Mn 2+, Co2+, and Pb2+ ions. The practical application of the iridium(III) complex 1 in visualizing intracellular Zn 2+ distribution in live zebrafish was also demonstrated. © 2014 American Chemical Society.