Two birds with one stone: Multifunctional and highly selective fluorescent probe for distinguishing Zn2+ from Cd2+ and selective recognition of sulfide anion

A coumarin-based multifunctional fluorescent sensor containing a di-2-picolylamine (DPA) moiety (1) was presented. Interestingly, this probe could similarly act as ON-OFF type fluorescent sensor for Co2+ and Cu2+, then in situ generated 1-Co(II) and 1-Cu(II) ensembles could further serve as OFF-ON type fluorescent sensors to achieve the discrimination of Zn2+ from Cd2+ and selective recognition of sulfide anion in aqueous solution via displacement approach, respectively. Specially, 1-Cu(II) could permeate the cell membrane and could be used in fluorescence imaging of S2− in living biological samples. These ON-OFF-ON type fluorescent sensors exhibited high selectivity and sensitivity towards the targets.