School of Civil Engineering and Communication, North China University Of Water Resources and Electric Power, Zhengzhou 450045, Henan, China.
Spectrochim Acta A Mol Biomol Spectrosc. 2020 Jun 5;233:118172. doi: 10.1016/j.saa.2020.118172. Epub 2020 Feb 19.
In this paper, a series of Eu(III) complexes was designed using 2-thenoyltrifluoroacetone (TTA) as the first ligand, and phenanthroline derivatives as the second ligand. Their molecular structure was analyzed via their single crystals. Detailed photophysical analysis on these Eu(III) complexes suggested that ligand TTA was the major energy transfer antenna for emissive Eu(III). The phenanthroline-derived ligands showed low triplet levels (T), leading to a reverse energy transfer (triplet trap) from Eu(III) D to T of diamine ligands. This procedure actually compromised emission performance of these Eu(III) complexes. It was found that halogen anions, especially fluorine ion, interacted with these diamine ligands, which heightened triplet level of these diamine ligands. With the elimination of such triplet trap in these Eu(III) complexes, their Eu(III) emission was greatly improved, showing emission turn-on effect. Detailed sensing performance was discussed carefully. Eu(TTA)Phen showed a down-bending working curve following a two-site model Stern-Volmer equation. Eu(TTA)DPPZ and Eu(TTA)DPOX showed linear working curves with good selectivity. In addition to its emission turn-on sensing, Eu(TTA)DPOX still showed ratiometric sensing. Detailed sensing mechanism was discussed and confirmed.
在本文中，我们设计了一系列以 2-噻吩甲酰三氟丙酮（TTA）作为第一配体、并以菲咯啉衍生物作为第二配体的 Eu(III) 配合物。通过它们的单晶对其分子结构进行了分析。对这些 Eu(III) 配合物的详细光物理分析表明，配体 TTA 是发光 Eu(III) 的主要能量转移天线。源自菲咯啉的配体显示出较低的三重态能级（T），导致来自 Eu(III) D 到二胺配体 T 的反向能量转移（三重态陷阱）。这一过程实际上降低了这些 Eu(III) 配合物的发光性能。研究发现，卤阴离子，特别是氟离子，与这些二胺配体相互作用，提高了这些二胺配体的三重态能级。通过消除这些 Eu(III) 配合物中的三重态陷阱，它们的 Eu(III) 发光得到了显著改善，表现出发光开启效应。详细的传感性能进行了仔细讨论。Eu(TTA)Phen 遵循双位点 Stern-Volmer 方程呈现下弯工作曲线。Eu(TTA)DPPZ 和 Eu(TTA)DPOX 呈现线性工作曲线，具有良好的选择性。除了其发光开启感应外，Eu(TTA)DPOX 仍表现出比率感应。讨论并证实了详细的传感机制。
