A dinuclear iridium(III) complex as a visual specific phosphorescent probe for endogenous sulphite and bisulphite in living cells

A non-emissive dinuclear iridium(III) complex (SP-2) linked via an azo group has been adopted as a phosphorescent probe for sulphite and bisulphite. SP-2 exhibits a turn-on phosphorescent response toward sulphite and bisulphite with high selectivity and sensitivity. Furthermore, this probe can be used for living cell imaging to identify the presence of both external sulphite/ bisulphite supplemented into cell cultures and endogenous sulphite/ bisulphite biosynthesised in living cells.