A solvent-dependent chemosensor for fluorimetric detection of Hg2+ and colorimetric detection of Cu2+ based on a new diarylethene with a rhodamine B unit

Abstract

A novel solvent-dependent chemosensor 1o based on a diarylethene containing a rhodamine B unit has been designed. It could be used as a dual-functional chemosensor for selective detection of Hg²⁺ and Cu²⁺ by monitoring the changes in the fluorescence and UV-vis spectral in different solvents. A striking fluorescence enhancement at 617 nm was observed in DMSO upon the addition of Hg²⁺. However, 1o showed a remarkable absorption band appeared with maximum absorption at 555 nm after the addition of Cu²⁺ in THF. The results of ESI-MS spectra and Job's plot confirmed a 1 : 1 binding stoichiometry between 1o and the two ions. The limits of detection of Hg²⁺ and Cu²⁺ were determined to be 0.14 μM and 0.51 μM, respectively. A 1 : 2 demultiplexer circuit was constructed by using UV light as data input, Cu²⁺ as the address input, and the absorbance at 555 nm and the absorbance ratio of (A₆₀₃/A₂₇₄) as the dual data outputs.