Abstract：
Heavy metal ions and antibiotic contamination have become a major environmental concern worldwide. The development of efficient recognition strategies of these pollutants at ultra-low concentrations in aqueous solutions as well as the elucidation of the intrinsic sensing mechanism are challenging tasks. In this work, unique luminescent Ln-MOF materials (NIIC-3-Ln) were assembled by rational ligand design. Among them, NIIC-3-Tb demonstrated highly selective luminescence quenching response toward Hg2+ and sulfadiazine (SDI) at subnanomolar concentrations in less than 7 s. In addition, a Hg2+ sensing mechanism through chelation was proposed on the basis of single-crystal X-ray diffraction analysis and Hg2+ adsorption study. The interaction mechanism of NIIC-3-Tb with SDI was revealed using a newly developed approach involving a (TD-)DFT based quantification of the charge transfer of a MOF-analyte supramolecular complex model in the ground and excited states. Effect of ultrasonic treatment on the surface morphology important for MOF sensing performance was revealed by gas adsorption experiments. The presented results indicate that NIIC-3-Ln is not only an advanced sensing material for the efficient detection of Hg2+ and SDI at ultra-low concentrations, but also opens up a new approach to study the sensing mechanism at the molecular level at ultra-low concentrations.
摘要：
重金属离子和抗生素污染已成为世界范围内的主要环境问题。在水溶液中超低浓度的这些污染物的有效识别策略的开发以及内在传感机制的阐明是具有挑战性的任务。在这项工作中,通过合理的配体设计组装了独特的发光Ln-MOF材料（NIIC-3-Ln）。其中,NIIC-3-Tb在小于7s的亚纳摩尔浓度下表现出对Hg2和磺胺嘧啶（SDI）的高度选择性发光猝灭响应。此外，在单晶X射线衍射分析和Hg2+吸附研究的基础上，提出了一种通过螯合的Hg2+传感机理。使用新开发的方法揭示了NIIC-3-Tb与SDI的相互作用机理，该方法涉及基于（TD-）DFT的MOF分析物超分子复合物模型在基态和激发态下的电荷转移定量。通过气体吸附实验揭示了超声处理对MOF传感性能重要的表面形态的影响。结果表明，NIIC-3-Ln不仅是在超低浓度下有效检测Hg2和SDI的先进传感材料，同时也为在超低浓度下研究分子水平的传感机理开辟了新的途径。
