A new Rhodamine B-based 'on-off' chemical sensor with high selectivity and sensitivity toward Fe3+ and its imaging in living cells

A new fluorescent chemosensor based on a Rhodamine B and pyrrole conjugate (RBPY) has been designed and synthesized. UV-vis absorption and fluorescence spectroscopic studies show that RBPY exhibits a high selectivity and sensitivity toward Fe3+ among many other metal cations in a MeOH/H2O solution (3:2, v/v, pH 7.10, HEPES buffer, 0.1 mM) by forming a 1:1 complex with Fe3+. Furthermore, results reveal that the formation of the RBPY-Fe3+ complex is fully reversible in the presence of sulfide anions and could also be used as an efficient sensor for S2-. Importantly, fluorescence microscopy experiments further demonstrated that RBPY can be utilized as a fluorescent probe for the detection of Fe3+ in human liver (L-02) cells. (C) 2014 Elsevier Ltd. All rights reserved.