Synthesis of a di(2-picolyl)amino-b-diketone dual-functional ligand that can coordinate to europium(Ⅲ) for responding to copper(Ⅱ) and sulfide ions

摘要

Lanthanide complex-based luminescent probes/chemosensors have shown great utilities in various biological and environmental assays with time-resolved detection mode to eliminate background noises.In this work,by conjugating di(2-picolyl)amine(DPA)with a tetradentateβ-diketone 1,2-bis[4'-(1",1",1",2",2"-pentafluoro-3",5"-pentanedion-5"-yl)benzyl]-4-chlorosulfo-benzene(BPPBCB),a novel dual-functional ligand that can coordinate to Eu^(3+)for responding to Cu^(2+)and S^2 ions in aqueous media,DPA-BPPBCB,has been designed and synthesized.Theβ-diketone moiety of DPA-BPPBCB can form a strongly luminescent complex with Eu^(3+).Upon reaction with Cu^(2+),accompanied by the formation of heterobimetallic complex Cu^(2+)-DPA-BPPBCB-Eu^(3+),the Eu^(3+)luminescence was quenched.While in the presence of S^2,owing to the high affinity of S^2 to Cu^(2+),stable CuS was formed,which resulted in the release of Cu^(2+)from Cu^(2+)-DPA-BPPBCB-Eu^(3+),to restore the luminescence of the Eu^(3+)complex.This unique"on-off-on"luminescence response of the Eu3+complex enabled Cu^(2+)and S^2 ions in aqueous media to be detected with time-resolved luminescence detection mode.