Single sensor for two metal ions: Colorimetric recognition of Cu2+ and fluorescent recognition of Hg2+

The first novel rhodamine B based sensor, rhodamine B hydrazide methyl 5-formyl-1H-pyrrole-2-carboxylate Schiff base (2) capable of detecting both Cu2+ and Hg2+ using two different detection modes has been designed and synthesized. The metal ion induced optical changes of 2 were investigated in MeOH:H2O (3:1) HEPES buffered solution at pH 7.4. Sensor 2 exhibits selective colorimetric recognition of Cu2+ and fluorogenic recognition of Hg2+ with UV-vis and fluorescence spectroscopy, respectively. Moreover, both of the Cu2+ and Hg2+ recognition processes are proven to be hardly influenced by other coexisting metal ions. (C) 2010 Elsevier B.V. All rights reserved.