Razavi Sayed Ali Akbar, Masoomi Mohammad Yaser, Morsali Ali
Department of Chemistry, Faculty of Science, Tarbiat Modares University, Tehran, Islamic Republic of Iran.
Chemistry. 2017 Sep 12;23(51):12559-12564. doi: 10.1002/chem.201702127. Epub 2017 Aug 10.
The ligands 3,6-di(pyridin-4-yl)-1,4-dihydro-1,2,4,5-tetrazine (H DPT), as a pillar spacer, and 4,4'-oxybis(benzoic acid) (H OBA), as a dicarboxylate linker, have been used to develop a dihydrotetrazine-functionalized pillared metal-organic framework (MOF), [Zn(OBA)(H DPT) ]⋅DMF (TMU-34), as a functionally convertible stimuli-responsive MOF-based sensor. Sonochemically synthesized TMU-34 powder has been employed in the sensing of volatile organic compounds (VOCs). The results show that TMU-34 can act as a solid-state, naked-eye visual chemosensor for the detection of chloroform in the liquid and gas phases. TMU-34, as a chemo-switchable MOF with rapid response, undergoes a significant color change from yellow to pink through reversible dynamic conversion of dihydrotetrazine into tetrazine upon exposure to chloroform in the presence of other VOCs. Whereas other colorimetric MOF-based sensors show a wide range of color changes in the presence of different analytes, TMU-34 undergoes a color change only in the presence of chloroform. A mechanism for the observed color change is proposed on the basis of UV/Vis and H NMR spectroscopic studies. These observations reveal that TMU-34 represents one of the most promising candidates for the highly selective and sensitive detection of chloroform.
配体3,6-二（吡啶-4-基）-1,4-二氢-1,2,4,5-四嗪（H DPT）作为支柱间隔物，4,4'-氧双（苯甲酸）（H OBA）作为二羧酸连接体，已被用于开发一种二氢四嗪功能化的柱撑金属有机框架（MOF），[Zn（OBA）（H DPT）]·DMF（TMU-34），作为一种功能可转换的刺激响应型基于MOF的传感器。超声化学合成的TMU-34粉末已用于挥发性有机化合物（VOCs）的传感。结果表明，TMU-34可作为一种固态、肉眼可视的化学传感器，用于检测液相和气相中的氯仿。TMU-34作为一种具有快速响应的化学可切换MOF，在其他VOCs存在下暴露于氯仿时，通过二氢四嗪向四嗪的可逆动态转化，会发生从黄色到粉红色的显著颜色变化。而其他基于比色MOF的传感器在存在不同分析物时会显示出广泛的颜色变化，TMU-34仅在存在氯仿时发生颜色变化。基于紫外可见光谱和核磁共振光谱研究，提出了观察到的颜色变化的机制。这些观察结果表明，TMU-34是氯仿高选择性和灵敏检测最有前景的候选物之一。
