Abstract：
Lanthanide metal-organic frameworks (Ln-MOFs) broaden the optical sensing applications of lanthanide ions due to the antenna effect between organic ligands and metals. However, the sensitization ability of the ligand to metal ions is limited, and maximizing the sensitization of the electrochemiluminescence behavior of Eu3+ is still a challenge for the application of Ln-MOFs. Therefore, under the guidance of the \"cascade sensitization mechanism\" based on the antenna effect sensitizing the electrochemiluminescence of bimetallic Ln-MOFs, we proposed Eu/Tb-MOFs with high luminescence intensity as a signal probe. According to the antenna effect, the conjugated structure and high extinction coefficient of the benzene ring of 2-amino terephthalic acid (NH2-BDC) can enhance the ECL luminescence intensity of Eu/Tb-MOFs. Tb3+ can act as an energy bridge between NH2-BDC and Eu3+, buffering the energy gap. The bimetallic sensitization is formed between Tb3+ and Eu3+, which can inhibit the reverse internal flow of energy and ensure the high luminous efficiency of Eu3+. In addition, the nanosphere mixed valence Fe3O4 as a co-reactant accelerator promotes the formation of transient free radical SO4•- through the valence change of Fe2+/Fe3+. The ECL immunosensor constructed by luminophores Eu/Tb-MOFs and nanosphere Fe3O4 provided a new explanation for the ECL self-luminous of Eu/Tb-MOFs.
摘要：
由于有机配体和金属之间的天线效应，镧系元素金属-有机骨架（Ln-MOF）拓宽了镧系元素离子的光学传感应用。然而,配体对金属离子的敏化能力有限，而使Eu3+的电化学发光行为的敏化最大化仍然是Ln-MOFs应用的挑战。因此,在“级联敏化机制”的指导下，基于天线效应敏化双金属Ln-MOFs的电化学发光，我们提出了具有高发光强度的Eu/Tb-MOFs作为信号探针。根据天线效应，2-氨基对苯二甲酸（NH2-BDC）苯环的共轭结构和高消光系数可以增强Eu/Tb-MOFs的ECL发光强度。Tb3+可以作为NH2-BDC和Eu3+之间的能量桥，缓冲能量间隙。双金属敏化是在Tb3+和Eu3+之间形成的，可以抑制能量的反向内部流动，保证Eu3+的高发光效率。此外,纳米球混合价Fe3O4作为共反应物促进剂，通过Fe2/Fe3的价态变化促进了瞬态自由基SO4•-的形成。由发光体Eu/Tb-MOFs和纳米球Fe3O4构建的ECL免疫传感器为Eu/Tb-MOFs的ECL自发光提供了新的解释。
