Department of Chemistry, Jadavpur University, Kolkata-700032, India.
Department of Chemistry, Durham University, Durham, DH1 3LE, UK.
Phys Chem Chem Phys. 2022 Sep 14;24(35):20941-20952. doi: 10.1039/d2cp02482a.
A new ratiometric fluorescent probe ()-2-(benzo[]thiazol-2-yl)-3-(8-methoxyquinolin-2-yl)acrylonitrile (HQCN) was synthesised by the perfect blending of quinoline and a 2-benzothiazoleacetonitrile unit. In a mixed aqueous solution, HQCN reacts with hydrazine (NH) to give a new product 2-(hydrazonomethyl)-8-methoxyquinoline along with the liberation of the 2-benzothiazoleacetonitrile moiety. In contrast, the reaction of hypochlorite ions (OCl) with the probe gives 8-methoxyquinoline-2-carbaldehyde. In both cases, the chemodosimetric approaches of hydrazine and hypochlorite selectively occur at the olefinic carbon but give two different products with two different outputs, as observed from the fluorescence study exhibiting signals at 455 nm and 500 nm for hydrazine and hypochlorite, respectively. A UV-vis spectroscopy study also depicts a distinct change in the spectrum of HQCN in the presence of hydrazine and hypochlorite. The hydrazinolysis of HQCN exhibits a prominent chromogenic as well as ratiometric fluorescence change with a 165 nm left-shift in the fluorescence spectrum. Similarly, the probe in hand (HQCN) can selectively detect hypochlorite in a ratiometric manner with a shift of 120 nm, as observed from the fluorescence emission spectra. HQCN can detect hydrazine and OCl as low as 2.25 × 10 M and 3.46 × 10 M, respectively, as evaluated from the fluorescence experiments again. The excited state behaviour of the probe HQCN and the chemodosimetric products with hydrazine and hypochlorite are studied by the nanosecond time-resolved fluorescence technique. Computational studies (DFT and TDDFT) with the probe and the hydrazine and hypochlorite products were also performed. The observations made in the fluorescence imaging studies with human blood cells manifest that HQCN can be employed to monitor hydrazine and OCl in human peripheral blood mononuclear cells (PBMCs). It is indeed a rare case that the single probe HQCN is found to be successfully able to detect hydrazine and hypochlorite in PBMCs, with two different outputs.
一种新的比率荧光探针 ()-2-(苯并噻唑-2-基)-3-(8-甲氧基喹啉-2-基)丙烯腈 (HQCN) 通过喹啉和 2-苯并噻唑乙腈单元的完美混合合成。在混合水溶液中，HQCN 与肼 (NH) 反应生成新产物 2-(肼基甲基)-8-甲氧基喹啉，同时释放 2-苯并噻唑乙腈部分。相比之下，次氯酸根离子 (OCl) 与探针反应生成 8-甲氧基喹啉-2-醛。在这两种情况下，肼和次氯酸根的化学计量比方法都选择性地发生在烯烃碳上，但给出了两个不同的产物，荧光研究观察到的信号分别为 455nm 和 500nm。紫外可见光谱研究也表明，HQCN 存在时，肼和次氯酸根的光谱有明显变化。HQCN 的肼解反应表现出明显的显色和比率荧光变化，荧光光谱向左移动 165nm。同样，手中的探针 (HQCN) 可以以比率方式选择性地检测次氯酸根，荧光发射光谱观察到 120nm 的位移。从荧光实验再次评估，HQCN 可以分别检测低至 2.25×10-6 M 和 3.46×10-6 M 的肼和 OCl。通过纳秒时间分辨荧光技术研究了探针 HQCN 以及与肼和次氯酸根的化学计量产物的激发态行为。还对探针和肼和次氯酸根产物进行了计算研究 (DFT 和 TDDFT)。在与人类外周血单核细胞 (PBMCs) 的荧光成像研究中观察到的情况表明，HQCN 可用于监测 PBMCs 中的肼和 OCl。实际上，很少有情况是单个探针 HQCN 能够成功地在 PBMCs 中检测到肼和次氯酸根，并且有两种不同的输出。
