Aggregation and deaggregation of rhodamine fluorescent probe for sequential recognition of Hg(II) and Cys with green emission

Many rhodamine B probes for metal ions and anions showing orange fluorescent have attracted a tremendous amount of attention. Herein a rhodamine B-based fluorescent probe 1 showing green fluorescence emission in the presence of Hg2+ was first reported. Self-assembled aggregation was proved to be the crucial factor for the green emitting fluorescence by means of resonance light scattering spectra, fluorescence spectra, ESI mass spectral analysis and SEM image. The probe 1 was developed as a excellent Hg(II)-selective green fluorescence agent in ethanol/HEPES buffer media (v/v = 3:7, pH 7.3) with a detection limit of 0.09 mu M. Meanwhile, the green fluorescence of 1-Hg2+ can be quenched severely by Cys but not for GSH, S2-, SO42-, SO32-, CN-, CO32- and HCY. The sequential switching effect for Hg2+ and then Cys has been achieved in aqueous media and bioimaging with satisfactory results. (C) 2016 Elsevier B.V. All rights reserved.