Design and synthesis of a terbium(III) complex-based luminescence probe for time-gated luminescence detection of mercury(II) ions

摘要

Time-gated luminescence detection technique using lanthanide complexes as luminescent probes is a useful and highly sensitive method. However, the effective application of this technique is limited by the lack of the target-responsive luminescent lanthanide complexes that can specifically recognize various analytes in aqueous solutions. In this work, a dual-functional ligand that can form a stable complex with Tb ~(3+) and specifically recognize Hg ~(2+) ions in aqueous solutions, N,N,N1,N1-{[2,6- bis(3′-aminomethyl-1′-pyrazolyl)-4-[N,N-bis(3″, 6″-dithiaoctyl)-aminomethyl]- pyridine]} tetrakis(acetic acid) (BBAPTA), has been designed and synthesized. The luminescence of its Tb 3+ complex is weak, but can be effectively enhanced upon reaction with Hg ~(2+) ions in aqueous solutions. The luminescence response investigations of BBAPTA-Tb ~(3+) to various metal ions indicate that the complex has a good luminescence sensing selectivity for Hg ~(2+) ions, but not for other metal ions. Thus a highly sensitive time-gated luminescence detection method for Hg ~(2+) ions was developed by using BBAPTA-Tb ~(3+) as a luminescent probe. The dosedependent luminescence enhancement of the probe shows a good linearity with a detection limit of 17 nM for Hg ~(2+) ions. These results demonstrated the efficacy and advantages of the new Tb ~(3+) complex-based luminescence probe for the sensitive and selective detection of Hg ~(2+) ions.