Synthesis And Application Of A Novel Europium(Ⅲ)Complex-based Luminescence Probe For Hypochlorous Acid

Time-resolved (or time-gated) luminescence bioassay based on long-lived lanthanide-complex probes is an ultrasensitive analytical method, since which enables the interferences from scattering lights and auto-fluorescence to be eliminated. On the basis of previous studies in our group, my work chose a Eu3+complex of (2.2’:6’,2’’-terpyridine-6,6"-diyl) bis(methylenenitrilo) tetrakis(acetate)(TTA-Eu3+) as a fluorophore owing to its high stability, luminescence quantum yield and water-solubility, and a Eu3+complex-based luminescence probe specific for time-resolved luminescence detection of hypochlorous acid was developed by conjugating a recognizer to TTA-Eu3+Using the photo-induced electron transfer (PeT) strategy, a novel europium(III) complex-based luminescent probe for hypochlorous acid,[4’-(ferrocene-carboxylate hydrazide) carbonyl-2.2’:6’.2"-terpyridine-6.6"-diyl] bis(methylenenitrilo) tetrakis(acetate)-Eu3+(FcTTA-Eu3+), was designed and synthesized by conjugating a hypochlorous acid-recognition and luminescence quenching moiety, ferrocene-carboxylate hydrazide. to the fluorophore TTA-Eu3+. The complex probe itself is almost non-luminescent, but can specifically react with hypochlorous acid to afford the europium(III) complex (4’-carboxyl-2,2’:6’.2"-terpyridine-6,6"-diyl) bis(methylenenitrilo) tetrakis(acetate)-Eu3(CTTA-Eu3+), accompanied by the remarkable dose-dependent luminescence enhancement, which allows hypochlorous acid to be quantitatively determined. The structure of FcTTA-Eu3+and CTTA-Eu3+were characterized by using1H and13C NMR, mass spectrum and elemental analysis methods. The new probe FcTTA-Eu3+is highly water-soluble and stable, and highly sensitive and selective with a wide pH available range for the time-resolved luminescence detection of hypochlorous acid. The detection limit for hypochlorous acid is as low as0.48nmol·L-In this thesis, the electrochemiluminescence (ECL) behavior of FcTTA-Eu3+and its ECL response to hypochlorous acid were also investigated. It was found that the ECL intensity of FcTTA-Eu3+was98-fold increased upon reaction with hypochlorous acid, which suggests that the probe could also be used for the luminescence and ECL dual-signaling detection of hypochlorous acid.