Kathirvelu Poomanirajeshwari, Kumar Surjith Muthu Krishna, Subburaj Ranjani, Murugan Gowripriya, Ariputhiran Muthulakshmi, Jeyasingh Vanthana, Lakshminarayanan Sudha, Narayanan Selvapalam, Piramuthu Lakshminarayanan
International Research Centre, Centre for Supramolecular Chemistry, Kalasalingam Academy of Research and Education (KARE), Anand Nagar, Krishnankoil, Srivilliputtur, Tamil Nadu 626 126, India.
Department of Chemistry, St. Mother Theresa Engineering College, Tuticorin, India.
Spectrochim Acta A Mol Biomol Spectrosc. 2025 Jan 5;324:124982. doi: 10.1016/j.saa.2024.124982. Epub 2024 Aug 18.
Imine based positional isomers (8E)-N-(4-((E)-(perfluorophenylimino)methyl)benzylidene)-2,3,4,5,6-pentafluorobenzenamine, L and (10E)-N-(3-(E-Perfluorophenylimino)methyl)benzylidene)-2,3,4,5,6-pentafluorobenzenamine, L have been designed, and synthesized by functionalizing two electron deficient aromatic moieties at the para-para'/ortho-ortho' positions in the phenyl core of the L and L respectively. The responses of L and L towards various anionic species are examined. The positional isomers L and L differs not only by showing distinguishable color change upon addition of anions but also differentiates themselves by the way of self-assembling together upon binding with cyanide anion. The naked-eye colorimetric experiments, UV-Vis, Nuclear Magnetic Resonance, and Infra-Red spectroscopic analyses reveal that the isomer L binds fluoride anion through 2:1 stoichiometry ratio. Unlike fluoride complex, the isomer L form aggregates while binding with cyanide ion. On the other hand, isomer L does not show any instant color change upon additions of any anion. Interestingly, after thirty minutes, only the color of the cyanide complex is turned into dark brown. While analyzing the spectroscopic results of cyanide complex of L, it is found that the cyanide complex begins to decompose and finally it is completely decomposed within 30 min. This unprecedented phenomenon about the colorimetric sensing of cyanide and destruction of cyanide complex with respect to time has not been reported in the literature yet. To the best of our knowledge this is the first example of study of sensing controlling the selectivity, mode of binding, self-aggregating and degradation properties of anionic complexes under the influence of positional isomeric effects. This present investigation provides simple and effective strategy to construct the sensor molecules with tunable binding properties in terms of easy to prepare as well as easy to use as a colorimetric sensor. _____________________________________________________________________________________________________.
基于亚胺的位置异构体（8E）-N-（4-（（E）-（全氟苯基亚氨基）甲基）亚苄基）-2,3,4,5,6-五氟苯胺，L和（10E）-N-（3-（E-全氟苯基亚氨基）甲基）亚苄基）-2,3,4,5,6-五氟苯胺，L已被设计，并通过分别在L和L的苯基核心的对-对'/邻-邻'位置官能化两个缺电子芳族部分来合成。研究了L和L对各种阴离子物种的响应。位置异构体L和L的不同之处不仅在于加入阴离子时显示出可区分的颜色变化，还在于与氰根阴离子结合时通过自组装方式彼此区分。肉眼比色实验、紫外-可见、核磁共振和红外光谱分析表明，异构体L以2:1的化学计量比结合氟离子。与氟化物配合物不同，异构体L在与氰离子结合时形成聚集体。另一方面，异构体L在加入任何阴离子后都没有显示出任何即时颜色变化。有趣的是，三十分钟后，只有氰化物配合物的颜色变成深棕色。在分析L的氰化物配合物的光谱结果时，发现氰化物配合物开始分解，最终在30分钟内完全分解。关于氰化物的比色传感以及氰化物配合物随时间破坏的这种前所未有的现象尚未在文献中报道。据我们所知，这是在位置异构效应影响下研究控制阴离子配合物的选择性、结合模式、自聚集和降解性质的传感的第一个例子。本研究提供了一种简单有效的策略，以构建具有可调结合性质的传感器分子，其易于制备且易于用作比色传感器。
