Chhikara Aruna, Tomar Deepak, Bartwal Gaurav, Chaurasia Madhuri, Sharma Anuj, Gopal Swarita, Chandra Sulekh
Department of Chemistry, Dyal Singh College, University of Delhi, New Delhi, India.
Department of Chemistry, University of Delhi, New Delhi, India.
J Fluoresc. 2023 Jan;33(1):25-41. doi: 10.1007/s10895-022-02991-6. Epub 2022 Oct 8.
A novel thiadiazole functionalized schiff base chemoreceptor (E)-2,4-dichloro-6-(((5-mercapto-1,3,4-thiadiazol-2-yl)imino)methyl)phenol (SB-1) has been synthesized and characterized spectroscopically by using various techniques. Its photophysical behaviour was scanned towards a variety of metal ions in mixed aqueous media. The chemosensor (SB-1) displayed excellent selectivity towards Cu ion through fluorescent diminishment (turn-off phenomenon). Colorimetric analyses showed a rapid colour change from yellow to dark red under visible light upon addition of Cu ions. Interestingly, the original yellow colour reappeared back instantly after the addition of EDTA anions, thus confirming the reversible nature of SB-1. Competitive experiments validated no interference from the other co-existing metal ions in the recognition process of SB-1 towards Cu ion. Job's plot confirmed 1:1 binding stoichiometry between SB-1 and Cu ion with the binding constant value of 3.87 × 10 M. The limit of detection was determined to be 1.01 × 10 M suggesting good sensitivity of SB-1 towards Cu ions. Furthermore, pH-dependent UV-Vis spectral behaviour of SB-1 confirmed that it could act as an effective optical pH-sensor for highly acidic environment as well. Portable nature of probe SB-1 was explored by fabricating "easy-to-use" paper test strips, which allow robust and rapid detection of Cu ions. Based on the multi-responsive properties of SB-1, a 'NOR' logic gate was constructed by applying Cu and EDTA as chemical inputs (ln1: Cu, ln2: EDTA) while emission intensity observed at 560 nm was considered as output signal (O1). DFT optimized geometries confirmed that chemosensor SB-1 exists in Azo form (Enol form) in its ground state. Molecular docking of the SB-1 and its copper complex, into the binding site of TRK protein tyrosine kinase (PDB: 1t46) was also carried out to explore their biological activity and their potential use as TRK inhibitors.
一种新型的噻二唑官能化席夫碱化学传感器（E）-2,4-二氯-6-（（（5-巯基-1,3,4-噻二唑-2-基）亚氨基）甲基）苯酚（SB-1）已被合成，并通过各种技术进行了光谱表征。在混合水介质中研究了其对多种金属离子的光物理行为。化学传感器（SB-1）通过荧光减弱（关闭现象）对铜离子表现出优异的选择性。比色分析表明，加入铜离子后在可见光下颜色迅速从黄色变为深红色。有趣的是，加入EDTA阴离子后，原来的黄色立即重新出现，从而证实了SB-1的可逆性质。竞争实验证实，在SB-1对铜离子的识别过程中，其他共存金属离子没有干扰。Job曲线证实SB-1与铜离子的结合化学计量比为1:1，结合常数为3.87×10 M。检测限为1.01×10 M，表明SB-1对铜离子具有良好的灵敏度。此外，SB-1的pH依赖性紫外-可见光谱行为证实，它也可以作为高酸性环境的有效光学pH传感器。通过制作“易于使用”的纸质测试条探索了探针SB-1的便携性，该测试条能够可靠且快速地检测铜离子。基于SB-1的多响应特性，以铜和EDTA作为化学输入（输入1：铜，输入2：EDTA），同时将在560 nm处观察到的发射强度视为输出信号（输出1），构建了一个“或非”逻辑门。密度泛函理论（DFT）优化的几何结构证实，化学传感器SB-1在基态以偶氮形式（烯醇形式）存在。还对SB-1及其铜配合物与TRK蛋白酪氨酸激酶的结合位点（PDB：1t46）进行了分子对接，以探索它们的生物活性以及作为TRK抑制剂的潜在用途。
