The functionalized ruthenium(II) polypyridine complexes for the highly selective sensing of mercury ions

A series of new ruthenium(II) polypyridine complexes appending with thioether groups were designed, synthesized and characterized. The sensing ability of the complexes toward mercury ions were studied by electronic absorption and emission spectra, and the reaction of the complexes with mercury ions were also confirmed by ESI mass spectroscopy and 1 HNMR spectroscopy. The thioether groups would react with mercury ion fast to form aldehyde group leading to the significant change in the spectra. The color of the complex changed from yellow to orange after addition of mercury ions, and the color of the emission changed from red orange to dark red with a large red shift (~80 nm). Importantly, these kinds of ruthenium(II) complexes show a unique recognition of mercury ions over other metal ions . The complexes with more thioether groups also showed a better sensitivity toward mercury ions, this is good strategy for the further design of the new phosphorescent probes for sensing of mercury ions.