Escola Universitària Salesiana de Sarrià (EUSS), Passeig Sant Joan Bosco 74, 08017 Barcelona, Spain.
Instituto de Nanociencia y Materiales de Aragón (INMA), CSIC-Universidad de Zaragoza, and Departamento de Física de la Materia Condensada, 50009 Zaragoza, Spain.
Dalton Trans. 2023 May 30;52(21):7258-7270. doi: 10.1039/d3dt00367a.
We present the synthesis, through a simple, microwave-assisted method, of lanthanoid-based 2D metal-organic frameworks (MOFs) of general formula [LnLn'(MeCOO)(PhCOO)], including homonuclear compounds ( = 1), LnEu, Tb, and heterometallic compounds, [TbEu]. The crystalline material is formed by neutral nanosheets held together by van der Waals interactions, which can be easily exfoliated by sonication. Photoluminescent emission in the visible range was observed for all of the synthesized 2D MOF compounds excitation of the ligand, showing benzoates are efficient antenna ligands. Efficient energy transfer from Tb → Eu was observed in the heterometallic [TbEu] compounds, which could potentially perform as luminescent thermometers. Inks containing nanosheets of 2D MOFs exfoliated in solution were prepared, and luminescent prints of Tb and Eu 2D MOFs on paper were made to show the possible application for anticounterfeiting. Frequency-dependent ac susceptibility results show the occurrence of slow magnetic relaxation in [TbEu] compounds through direct relaxation mechanisms, affected by bottleneck effect. A slowing down of the relaxation time is observed as the Eu/Tb ratio increases.
我们通过一种简单的微波辅助方法，合成了镧系元素二维金属有机骨架（MOF），通式为[LnLn'（MeCOO）（PhCOO）]，包括同核化合物（= 1）、LnEu、Tb 和异核化合物[TbEu]。这种晶态材料由中性纳米片通过范德华相互作用结合在一起，很容易通过超声处理进行剥离。所有合成的二维 MOF 化合物在可见光范围内都观察到了荧光发射，激发配体，表明苯甲酸酯是有效的天线配体。在异核[TbEu]化合物中观察到了从 Tb→Eu 的高效能量转移，这可能可以作为发光温度计。在溶液中剥离的二维 MOF 纳米片的墨水被制备，并且在纸上制作了 Tb 和 Eu 二维 MOF 的发光打印品，以展示可能的防伪应用。频率相关的交流磁化率结果表明，[TbEu]化合物中通过直接弛豫机制发生了缓慢的磁弛豫，受瓶颈效应的影响。随着 Eu/Tb 比的增加，弛豫时间减慢。
