Institute of Chemical Sciences, Bahauddin Zakariya University, Multan, Pakistan.
Department of Chemistry, Khwaja Fareed University of Engineering and Information Technology, Rahim Yar Khan, 64200, Pakistan.
Sci Rep. 2021 Sep 28;11(1):19242. doi: 10.1038/s41598-021-98400-2.
Highly selective and sensitive 2,7-naphthyridine based colorimetric and fluorescence "Turn Off" chemosensors (L1-L4) for detection of Ni in aqueous media are reported. The receptors (L1-L4) showed a distinct color change from yellow to red by addition of Ni with spectral changes in bands at 535-550 nm. The changes are reversible and pH independent. The detection limits for Ni by (L1-L4) are in the range of 0.2-0.5 µM by UV-Visible data and 0.040-0.47 µM by fluorescence data, which is lower than the permissible value of Ni (1.2 µM) in drinking water defined by EPA. The binding stoichiometries of L1-L4 for Ni were found to be 2:1 through Job's plot and ESI-MS analysis. Moreover the receptors can be used to quantify Ni in real water samples. Formation of test strips by the dip-stick method increases the practical applicability of the Ni test for "in-the-field" measurements. DFT calculations and AIM analyses supported the experimentally determined 2:1 stoichiometries of complexation. TD-DFT calculations were performed which showed slightly decreased FMO energy gaps due to ligand-metal charge transfer (LMCT).
报道了一种基于 2,7-萘啶的高选择性和高灵敏度的比色和荧光“关闭”化学传感器（L1-L4），可用于检测水相中的 Ni。受体（L1-L4）在加入 Ni 后会发生明显的颜色变化，从黄色变为红色，同时在 535-550nm 处的光谱带发生变化。这种变化是可逆的，与 pH 无关。通过紫外可见数据，（L1-L4）对 Ni 的检测限在 0.2-0.5µM 范围内，通过荧光数据，检测限在 0.040-0.47µM 范围内，低于 EPA 规定的饮用水中 Ni 的允许值（1.2µM）。通过 Job 图和 ESI-MS 分析发现，L1-L4 与 Ni 的结合比为 2:1。此外，这些受体可用于定量测定实际水样中的 Ni。通过浸渍棒法形成试条增加了 Ni 测试的实际适用性，可用于现场测量。DFT 计算和 AIM 分析支持实验确定的络合 2:1 计量比。进行了 TD-DFT 计算，结果表明由于配体-金属电荷转移（LMCT），FMO 能隙略有减小。
