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.

The first rhodamine B based sensor 2 exhibits high selective colorimetric recognition of Cu2+ and fluorescent recognition of Hg2+ in MeOH:H2O (3:1) solution (HEPES 10 mM, pH 7.4).Figure optionsDownload as PowerPoint slideResearch highlights▶ A new rhodamine based sensor 2 has been developed. ▶ Sensor 2 can recognize Cu2+ and Hg2+ by UV–vis and fluorescence, respectively. ▶ The interactions of sensor 2 with Cu2+ and Hg2+ adopt 1:1 binding stoichiometry. ▶ Recognition of Cu2+ and Hg2+ is barely interfered by other metal ions.