In this work, the 2D Eu(III) coordination polymer {[Eu(HPDC)(PDC)]}_n (PDC = 2,6-pyridinedicarboxylate) (1) was prepared in a fast manner via microwave-assisted hydrothermal synthesis. The same compound was obtained by a conventional hydrothermal route and had its structure determined through single crystal X-ray diffraction. In 1, the HPDC and PDC ligands exhibit terminal and chelating bridging modes, respectively, forming a coordination polymer through interconnected europium–carboxylate chains, leading to a highly ordered two-dimensional layer. The nanosheets in 1 self-organize in the solid-state by intermolecular interactions, producing a 3D supramolecular network. Solid-state photoluminescence studies have shown that the antenna effect is responsible for the red emission of the compound under ultraviolet excitation. In alcoholic solutions, it was possible to exfoliate the material by ultrasonication in a top-down approach, leading to single nanosheets of 1. In the chemical stability studies, there was observed a water-induced transformation of 1, leading to the compound {[Eu(PDC)(HPDC)(H₂O)₂]·4H₂O}_n (2). The aqueous suspension of this material shows strong red luminescence with the naked-eye. 2 demonstrates reversible behavior induced by heating under reduced pressure. Our work highlights the properties related to solvent-induced exfoliation and water-induced transformation.

中文翻译：

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发光二维Eu（III）配位聚合物在水相中的化学转化

在这项工作中，通过微波辅助水热合成快速制备了二维Eu（III）配位聚合物{[Eu（HPDC）（PDC）]} _n（PDC = 2,6-吡啶二羧酸酯）（1）。通过常规的水热途径获得相同的化合物，并通过单晶X射线衍射确定其结构。在图1中，HPDC和PDC配体分别表现出末端和螯合桥接模式，通过相互连接的euro-羧酸盐链形成配位聚合物，从而形成高度有序的二维层。1中的纳米片通过分子间相互作用在固态中自组织，产生3D超分子网络。固态光致发光研究表明，天线效应是紫外线激发下化合物红色发射的原因。在酒精溶液中，有可能通过自上而下的方法通过超声剥离材料，从而形成1个纳米片。在化学稳定性研究中，观察到水诱导的1转化，从而生成化合物{[Eu（PDC）（HPDC）（H ₂ O）₂ ]·4H ₂ O} _n（2）。该材料的水悬浮液用肉眼显示出强烈的红色发光。2证明了在减压下加热引起的可逆行为。我们的工作重点介绍了与溶剂引起的剥落和水引起的转化有关的特性。