Chakraborty Gouri, Das Prasenjit, Mandal Sanjay K
Department of Chemical Sciences , Indian Institute of Science Education and Research Mohali , Sector 81, Manauli PO , S.A.S. Nagar, Mohali , Punjab 140306 , India.
ACS Appl Mater Interfaces. 2018 Dec 12;10(49):42406-42416. doi: 10.1021/acsami.8b15894. Epub 2018 Nov 27.
In this work, we have designed two new 3D metal-organic frameworks (MOFs), {Zn(TPOM)(1,4-NDC)} (1) and {Ni(TPOM)(1,4-NDC)(HO)} (2), utilizing both semi-rigid tetrapodal neutral linker, tetrakis(4-pyridyloxymethylene)methane (TPOM) and rigid ditopic anionic linker, 1,4-naphthalene dicarboxylic acid (H(1,4-NDC)). On the basis of the single-crystal X-ray diffraction, 1 has a 3D structure with star-shaped pores arising from four-fold symmetry due to the presence of a paddle-wheel core [Zn(OCCH)(CHN)] as a subunit, whereas 2 consists of a zig-zag 3D framework with strong hydrogen bonding between the coordinated water molecules and coordinated carboxylate groups. Their thermogravimetric analysis indicates an extraordinary thermal stability: 1 up to 400 °C and 2 up to 350 °C. In addition to elemental microanalysis and spectroscopic characterization (UV-vis and infra-red spectroscopy), the bulk phase purity of 1 and 2 as well as hydrolytic stability of 1 are established by powder X-ray diffraction. Exploiting the luminescence nature of 1, both solvent-dependent fluorescence properties and sensing of various amines in aqueous medium are demonstrated. It exhibits good sensing ability toward 4-nitroaniline (4-NA) and 2,6-dichloro-4-nitroaniline (2,6-DCNA; a broad spectrum pesticide belonging to toxicity class III) with the lowest detection limit of 88 ppb and 0.28 ppm, respectively. The mechanism of action has been established through Stern-Volmer plots, time-resolved fluorescence studies, spectral overlap, and density functional theory calculations. The recyclability and stability of 1 after sensing experiments also reveal no change in its crystallinity. Furthermore, selectivity test and time-dependent detection for 4-NA have been successfully demonstrated. For practical applications, naked eye detection of 4-NA using test paper strips is also displayed.
在本工作中，我们利用半刚性四齿中性连接体四（4 - 吡啶氧基甲基）甲烷（TPOM）和刚性双齿阴离子连接体1,4 - 萘二甲酸（H₂(1,4 - NDC)）设计了两种新型三维金属有机框架（MOF），即{Zn(TPOM)(1,4 - NDC)} （1）和{Ni(TPOM)(1,4 - NDC)(H₂O)} （2）。基于单晶X射线衍射，1具有三维结构，由于存在作为亚基的桨轮核心[Zn₂(μ - O₂CCH₃)₂(μ - CH₃CN)₂]，其具有由四重对称性产生的星形孔，而2由锯齿形三维框架组成，在配位水分子和配位羧酸根基团之间存在强氢键。它们的热重分析表明具有非凡的热稳定性：1高达400℃，2高达350℃。除了元素微量分析和光谱表征（紫外 - 可见光谱和红外光谱）外，通过粉末X射线衍射确定了1和2的体相纯度以及1的水解稳定性。利用1的发光性质，展示了其对溶剂依赖的荧光性质以及在水性介质中对各种胺的传感。它对4 - 硝基苯胺（4 - NA）和2,6 - 二氯 - 4 - 硝基苯胺（2,6 - DCNA；属于III类毒性的广谱农药）表现出良好的传感能力，最低检测限分别为88 ppb和0.28 ppm。通过Stern - Volmer图、时间分辨荧光研究、光谱重叠和密度泛函理论计算确定了作用机制。传感实验后1的可回收性和稳定性也表明其结晶度没有变化。此外，还成功展示了对4 - NA的选择性测试和随时间的检测。对于实际应用，还展示了使用试纸条对4 - NA进行肉眼检测。
