Design And Synthesis Of Tetradentate β-Diketonate-Europium(Ⅲ)Complex As Time-gated Luminescence Probe

Lanthanide probes, which have just appeared in recent two decades, stand out as valuable analytical tools among the prosperous optical chemical sensors, due to their unique luminescence properties, such as large Stokes shift, long luminescence lifetime and sharp emission profile. Based on those desirable photo-physical advantages, some lanthanide chelate-based luminescent probes have been developed for the biological targets. Here we would like to develop some new lanthanide complex luminescence probes for deploitation of their application fieldIn this work, we designed and synthetized the first Eu3+chelate-based luminescent probe specific for ascorbic acid, by incorporating a free radical,4-Amion-TEMPO,4-amion-2,2’,6,6’-tetramethyl-1-piperidinyloxyl to a new tetradentate beta-diketonate Eu3+complex, BHHBCB-Eu3+. It was found that the weak luminescence probe can react with ascorbic acid selectively and rapidly, accompanied by remarkable～14.5-fold luminescence enhancement with the increase of luminescence lifetime from0.18to0.38ms. The dose-dependent luminescence rise of the probe shows a good linearity with a detection limit of0.33nM for ascorbic acid. Moreover, the luminescence response of the probe is highly specific to ascorbic acid even in the presence of glutathione (Reduced)(GSH), dopamine (Dopa) and so on.A thorough investigation of the luminescence properties of the probe indicates that the new probe possesses the advantages of good specificity, sensitivity, kinetic and thermodynamic stabilities, wide pH available range, and the applicability for time-gated luminescence measurement, All the results showed that the new lanthanide complex TEMPO-BHHBCB-Eu(Ⅲ) can be a very useful tool for time-gated detection of ascorbic acid.Another luminescence probe, DNP-BHHBCB-Eu(Ⅲ), designed for detecting GHS, Cys, and Hcy, have been prepared, but unfortunately no luminescence responsive to target molecular have been obsearved.