A rhodamine B-based fluorescent sensor toward highly selective mercury (II) ions detection

•The X-ray crystal structure analyses exhibit the spirolactone of fluorescent sensor RA.•Chemosensor RA afford turn-on fluorescence enhancement and display high brightness for Hg2+.•The fluoresecent sensor RA can selectively recognize Hg2+ over other group 13 metals.

This work presented the design, syntheses and photophysical properties of a rhodamine B-based fluorescence probe, which exhibited a sensitive and selective recognition towards mercury (II). The chemosensor RA (Rhodamine- amide- derivative) contained a 5-aminoisophthalic acid diethyl ester and a rhodamine group, and the property of spirolactone of this chemosensor RA was detected by X-ray crystal structure analyses. Chemosensor RA afforded turn-on fluorescence enhancement and displayed high brightness for Hg2+, which leaded to the opening of the spirolactone ring and consequently caused the appearance of strong absorption at visible range, moreover, the obvious and characteristic color changed from colorless to pink was observed. We envisioned that the chemosensor RA exhibited a considerable specificity with two mercury (II) ions which was attributed to the open of spirolactone over other interference metal ions.

Graphical abstractFluorescence sensor RA can selectively recognize Hg2+ over other group 13 metals, most divalent first-row transition metals and millimolar concentrations of various alkali and alkaline earth metals.Figure optionsDownload full-size imageDownload as PowerPoint slide