Khan Sheeba, 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.
Inorg Chem. 2020 Apr 6;59(7):4588-4600. doi: 10.1021/acs.inorgchem.9b03709. Epub 2020 Mar 17.
A highly stable and luminescent 3D metal-organic framework (MOF), {[Zn(μ-OH)(BTC)(BBI4PY)]·10HO} (), with a rare [Zn(μ-OH)] core has been synthesized using a new rigid and functionalized pillar linker, 2,6-bis(pyridin-4-yl)-1,7-dihydrobenzo[1,2-:4,5-']diimidazole (BBI4PY) in combination with Zn(OAc)·2HO and 1,3,5-benzenetricarboxylic acid (HBTC) under solvothermal conditions. Unlike other MOFs with the [Zn(μ-OH)] core, was synthesized without using an external base, as the intrinsic basicity of BBI4PY served the purpose. Furthermore, it retains crystallinity and phase purity up to 350 °C on the basis of TGA and in situ variable temperature PXRD, correlating with its solid-state structure. Using the dehydrated water sorption studies show uptake of 220 cm g (corresponds to 10 water molecules). A large hysteresis in desorption isotherm signifies strong interactions between adsorbed water and Lewis basic sites present in the framework. The reversible nature of water sorption was further manifested by TGA and PXRD studies. As an example of its application, the highly fluorescent and electron-rich nature of has been utilized for the selective sensing of Fe and 2,4,6-trinitrophenol (TNP) in water with detection limits of 3.7 and 1.8 ppm, respectively. The mechanistic details for the turn-off quenching have been elucidated with the help of Stern-Volmer plots, spectral overlap, lifetime studies, and density functional theory calculations. This mechanistic evidence reveals that a combination of strong hydrogen bonding with resonance energy transfer and photoinduced electron transfer (PET) processes is synchronously responsible for the quenching of the fluorescence intensity of .
一种具有高稳定性和发光性的三维金属有机框架（MOF），{[Zn(μ-OH)(BTC)(BBI4PY)]·10H₂O} ()，其具有罕见的[Zn(μ-OH)]核心，是在溶剂热条件下，使用一种新型刚性功能化支柱连接体2,6-双（吡啶-4-基）-1,7-二氢苯并[1,2-:4,5-']二咪唑（BBI4PY）与Zn(OAc)₂·2H₂O和1,3,5-苯三甲酸（H₃BTC）合成的。与其他具有[Zn(μ-OH)]核心的MOF不同， 是在不使用外部碱的情况下合成的，因为BBI4PY的固有碱性起到了作用。此外，基于热重分析（TGA）和原位变温粉末X射线衍射（PXRD），它在高达350℃时仍保持结晶度和相纯度，这与其固态结构相关。使用脱水后的 进行水吸附研究表明，其吸附量为220 cm³ g⁻¹（相当于10个水分子）。解吸等温线中的大滞后现象表明吸附水与框架中存在的路易斯碱性位点之间存在强相互作用。水吸附的可逆性通过TGA和PXRD研究进一步得到证明。作为其应用的一个例子， 的高荧光性和富电子性质已被用于水中Fe³⁺和2,4,6-三硝基苯酚（TNP）的选择性传感，检测限分别为3.7和1.8 ppm。通过斯特恩-沃尔默图、光谱重叠、寿命研究和密度泛函理论计算，阐明了猝灭关闭的机理细节。这一机理证据表明，强氢键与共振能量转移和光致电子转移（PET）过程的结合共同导致了 的荧光强度猝灭。
