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.