A novel dual-responsive fluorescent probe for the detection of copper(II) and nickel(II) based on BODIPY derivatives

A novel dual-responsive fluorescence probe 6 was constructed by introducing a dipicolyamine moiety on the BODIPY-based skeleton via Sonogashira coupling reaction and confirmed by 1H NMR, 13C NMR, elemental analysis and high-resolution mass spectroscopy (HRMS). The present probe 6 exhibited high selectivity and sensitivity toward Cu2+ and Ni2+ detection over other competitive metal ions by fluorescence quenching phenomena, respectively. In addition, the detection limits (DLs) for Cu2+ and Ni2+ were calculated to be as low as both 0.1 μM respectively, which were lower than the maximum allowable level of the World Health Organization (WHO) limit for the drinking water. The stoichiometric ratio of the probe 6 toward the Cu2+ or Ni2+ ions was determined to be 1:1 according to the result of the Job's plot and HRMS analysis. These results indicated that probe 6 can be used as a selective ‘‘turn-off’’ fluorescent sensor for the detection of Cu2+ and Ni2+.