A rhodamine-based Hg2+ sensor with high selectivity and sensitivity in aqueous solution: a NS2-containing receptor.

A rhodamine-based sensor 1 was designed and synthesized by incorporation the rhodamine fluorophore and ionophore NS(2) with high affinity to Hg(2+). Sensor 1 exhibits a high selectivity and an excellent sensitivity and is a dual-responsive colorimetric and fluorescent Hg(2+)-specific sensor in aqueous buffer solution. In addition, the 1:1 binding mode was proposed based on the (1)H NMR and ES(+)MS studies.