The synthesis, characterisation and capability to selectively detect vapours of volatile organic compounds (VOCs) and nitroaromatic explosives of a new family of 2-dimensional rare earth (RE) MOFs based on a hexanuclear (RE³⁺)₆ secondary building unit (SBU) is reported. The reaction of RE(NO₃)₃ with 4,4′-sulfonyldibenzoic acid (H₂SDBA) in the presence of 2-fluorobenzoic acid (HFBA) in DMF/MeOH at 100 °C afforded compound [RE₆(μ₃-OH/F)₈(SDBA)₄(NO₃)₂(H₂O)₆]_n (UCY-15(RE); RE: Y, Eu, Gd, Tb, Dy, Ho, Er). The structure of UCY-15(RE) comprises a microporous 8-connected 2D network based on a (RE³⁺)₆ SBU and the angular dicarboxylate ligand SDBA²⁻ and contains rhombic channels along b and c axes. Gas sorption studies on activated UCY-15(Y) indicated a moderate BET surface area of 417 m² g⁻¹. Photoluminescence (PL) studies in the visible region of UCY-15(RE) (RE: Y, Eu, Gd, Tb) revealed that SDBA²⁻ is able to sensitize Eu³⁺ and Tb³⁺ ions. Thin films of UCY-15(RE) (RE: Y, Eu, Tb) embedded in polydimethylsiloxane (PDMS) were fabricated and evaluated for their sensing capability for vapours of selected VOCs and nitroaromatic compounds revealing different response to each analyte tested. A series of trimetallic analogues UCY-15(Y_100−x−yEu_xTb_y) (x, y = 5, 7.5, 10) were prepared aiming to superior sensing materials that combine the PL signals of UCY-15(Y), UCY-15(Eu) and UCY-15(Tb). The analogue UCY-15(Y_87.5Eu_7.5Tb₅) achieved the emission of white light whereas UCY-15(Y_87.5Eu₅Tb_7.5)@PDMS films were shown to selectively recognize the tested analytes. Overall, this work highlights the capability of microporous 2D MOFs containing highly accessible emissive centers to recognise vapours of selected analytes.

中文翻译：

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基于六核二次构建单元的二维稀土金属有机框架作为硝基芳烃和挥发性有机化合物蒸气的有效检测器

^{基于六核 (RE 3+} ) ₆二次建筑单元 (SBU)的新型二维稀土 (RE) MOF 家族的挥发性有机化合物 (VOC) 和硝基芳香族爆炸物的合成、表征和选择性检测能力被报道。RE(NO ₃ ) ₃与 4,4'-磺酰基二苯甲酸 (H ₂ SDBA) 在 2-氟苯甲酸 (HFBA) 的存在下在 DMF/MeOH 中于 100 °C 反应得到化合物 [RE ₆ (μ ₃ - OH/F) ₈ (SDBA) ₄ (NO ₃ ) ₂ (H ₂ O) ₆ ] _n ( UCY-15（回覆）; RE：Y、Eu、Gd、Tb、Dy、Ho、Er）。UCY-15 (RE)的结构包括一个基于 (RE ³⁺ ) ₆ SBU 和角二羧酸配体 SDBA ^2-的微孔 8 连接 2D 网络，并包含沿 b 和 c 轴的菱形通道。对活化的 UCY-15 (Y) 的气体吸附研究表明，中等 BET 表面积为 417 m ² g ^-1。UCY-15 (RE) (RE: Y, Eu, Gd, Tb)可见光区域的光致发光 (PL) 研究表明，SDBA ^2-能够敏化 Eu ³⁺和 Tb ³⁺离子。UCY-15薄膜(RE) (RE: Y、Eu、Tb) 嵌入聚二甲基硅氧烷 (PDMS) 中，并对其对选定 VOC 和硝基芳族化合物蒸气的传感能力进行了评估，揭示了对每种测试分析物的不同响应。一系列三金属类似物UCY-15 (Y _{100− x - y} Eu _x Tb _y ) ( x , y = 5, 7.5, 10) 旨在结合UCY-15 (Y)的 PL 信号的优质传感材料、UCY-15 (Eu) 和UCY-15 (Tb)。模拟UCY-15 (Y _87.5 Eu _7.5 Tb ₅) 实现了白光的发射，而UCY-15 (Y _87.5 Eu ₅ Tb _7.5 )@PDMS 薄膜被证明可以选择性地识别测试的分析物。总体而言，这项工作突出了包含高度可访问的发射中心的微孔 2D MOF 识别选定分析物蒸气的能力。