A solvent-dependent chemosensor for fluorimetric detection of Hg(2+) and colorimetric detection of Cu(2+) based on a new diarylethene with a rhodamine B unit

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 Hg(2+) and Cu(2+) 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 Hg(2+). However, 1o showed a remarkable absorption band appeared with maximum absorption at 555 nm after the addition of Cu(2+) 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 Hg(2+) and Cu(2+) 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, Cu(2+) as the address input, and the absorbance at 555 nm and the absorbance ratio of (A(603)/A(274)) as the dual data outputs.