Department of Chemistry, Indrashil University, Kadi, Mehsana, Gujarat 382740, India.
Department of Basic Sciences, Institute of Infrastructure Technology Research and Management, Ahmedabad, 380026, India.
Soft Matter. 2021 Apr 28;17(16):4304-4316. doi: 10.1039/d1sm00038a.
We report, for the first time, the self-assembly of an acyl-thiourea based sensor, N-{(6-methoxy-pyridine-2-yl) carbamothioyl}benzamide (NG1), with panchromatic fluorescent fibres and its dual-sensing properties for the sequential detection of Cu2+ ions and lactic acid. The panchromatic fibres formed by NG1 were disrupted in the presence of Cu2+ ions and this was accompanied by a visible colour change in the solution from colourless to yellow. The addition of lactic acid to the NG1 + Cu2+ solution, on the other hand, induced re-aggregation to fibrillar structures and the colour of the solution again changed to colourless. Hence, it may be surmised that the disaggregation and re-aggregation impart unique dual-sensing properties to NG1 for the sequential detection of Cu2+ ions and lactic acid. The application of NG1 as a selective sensor for Cu2+ ions and lactic acid has been assessed in detail by UV-visible and fluorescence spectroscopy. Furthermore, two structural variants of NG1, namely, NG2 and NG3, were synthesized, which suggest the crucial role of pyridine in imparting panchromatic emission properties and of both pyridine and acyl-thiourea side chain in the binding of Cu2+ ions. The O-methoxy group plays an important part in making NG1 the most sensitive probe of its structural analogs. Finally, the utility of NG1 for the sequential and cellular detection of Cu2+ ions and lactic acid was studied in human RPE cells. The experimental results of the interaction of NG1 with Cu2+ ions and lactic acid have also been validated theoretically by using quantum chemical calculations based on density functional theory (DFT). To the best of our knowledge, this is the first report wherein a dual sensor for Cu2+ ions and lactate ions is synthesized. More importantly, the aggregation properties of the sensor have been studied extensively and an interesting correlation of the photophysical properties of the probe with its self-assembling behavior has been elucidated.
我们首次报道了酰基硫脲基传感器 N-{(6-甲氧基-吡啶-2-基)氨甲酰硫基}苯甲酰胺（NG1）的自组装，形成具有全色荧光纤维的传感器，并具有用于顺序检测 Cu2+离子和乳酸的双重传感性能。在存在 Cu2+离子的情况下，由 NG1 形成的全色纤维被破坏，并且溶液的颜色从无色变为黄色。另一方面，将乳酸加入到 NG1 + Cu2+溶液中，会诱导纤维状结构的再聚集，溶液的颜色再次变为无色。因此，可以推测出 NG1 的解聚和再聚集赋予了其独特的双重传感性能，用于顺序检测 Cu2+离子和乳酸。通过紫外可见光谱和荧光光谱详细评估了 NG1 作为 Cu2+离子和乳酸的选择性传感器的应用。此外，还合成了 NG1 的两种结构变体 NG2 和 NG3，这表明吡啶在赋予全色发射性能以及吡啶和酰基硫脲侧链在结合 Cu2+离子方面起着关键作用。O-甲氧基在使 NG1 成为其结构类似物中最敏感探针方面起着重要作用。最后，在人 RPE 细胞中研究了 NG1 用于顺序和细胞检测 Cu2+离子和乳酸的用途。还通过基于密度泛函理论（DFT）的量子化学计算对 NG1 与 Cu2+离子和乳酸相互作用的实验结果进行了理论验证。据我们所知，这是首次报道合成用于 Cu2+离子和乳酸离子的双重传感器。更重要的是，广泛研究了传感器的聚集性质，并阐明了探针的光物理性质与其自组装行为之间的有趣相关性。
