Synthesis and Properties of Rhodamine B Derivative for Recognition of Cu2+and Hg2+

A novel rhodamine B derivative L was synthesized facilely by the condensation reaction of rhodamine B hydrazide and 2-hydroxyquinoline-3-carbaldehyde, and its structure was characterized by H-1 NMR, MS techniques and elemental analysis. The recognition properties of the target compound L with metal ions had been investigated in CH3CN-H2O (V : V=1 : 1) solution by the ultraviolet spectrophotometry and the fluorescence spectrophotometry. The results showed that the probe L exhibited the selective colorimetric recognition of Cu2+ and the fluorogenic recognition of Hg2+. Upon the addition of Cu2+ or Hg2+, the spirolactam ring of probe L was opened and 1 : 1 ligand-copper complex or 1 : 2 ligand-mercury complex was formed, and both of the Cu2+ and Hg2+ recognition processes were proven to be a revisible process.