Screening mercury (II) with selective fluorescent chemosensor

A unique fluorescent chemosensor with simultaneous fluorescent enhancement and quenching (FEQ) for mercury (II) is reported. The chemosensor, which is composed of two perylene bisimide fluorophores and two nonmacrocycle receptors of 2,6-bis(aminoethyl)pyridine, was synthesized through the reaction of 2,6-pyridinedicarboxylic acid and N,N-biethylamine-perylene-3,4,9,10-tetracarboxylic bisimides under microwave irradiation. The chemosensor showed a high selectivity and sensitivity for Hg2+. One signal of 365 nm is obviously enhanced and another signal of 557 nm can be effectively quenched in the presence of Hg2+. In phosphate buffer of pH 7.0, the chemosensor has a linear range of (0.1–2.0) × 10−5 M of Hg2+ with a limit of detection of 1.0 × 10−8 M. In addition, The FEQ of chemosensor for Hg2+ is simply studied in the presence of human serum albumin. The above results show that it is an effective fluorescence probe for Hg2+.