A rhodamine-based colorimetric and reversible fluorescent chemosensor for selectively detection of Cu~(2+) and Hg~(2+) ions

摘要

A bifunctional colorimetric and fluorescent chemosensor RbCS has been successfully designed and synthesized by simple condensation of 3,5-dichlorosalicylaldehyde and rhodamine B hydrazide. In aqueous media, chemosensor RbCS exhibits remarkably enhanced absorbance intensity and color change from colorless to pink for Cu~(2+), and shows significant "off-on" fluorescence accompanied with color changes from colorless to red upon binding to Hg~(2+). The absorbance and fluorescence signals of RbCS can be restored with addition of EDTA disodium into solutions of RbCS-Cu~(2+) and RbCS-Hg~(2+), showing that the binding of chemosensor RbCS and Cu~(2+)/Hg~(2+) is chemically reversible.