Rhodamine-triazine based probes for Cu2+ in aqueous media and living cells

The performance of a number of rhodamine-triazine derivatives (probe R1–R4) which utilize rhodamine as the fluorophore with cyanuric chloride as the molecular platform have been evaluated. Spectroscopic analysis revealed that differing structural substitution patterns of the probe resulted in different sensitivity and selectivity for specific metal ions. The probes R1 and R2 were fluorescent/colorimetric probes for Cu2+, whilst R3 and R4 were probes for Al3+, Cr3+ and Fe3+. The probe R2 exhibited superior recognition for Cu2+ in neutral aqueous medium, and the optical switching behavior of R2 for Cu2+ and S2− could be used to construct a molecular logic gate. In addition, fluorescence imaging of probe R2 for Cu2+ in living cells was demonstrated.