Cyanide sensing has attracted increasing interest due to its toxicity and wide use in industrial activities. Herein, we developed three colorimetric cyanide sensors by the modification of the α-position of a dipyrrin chromophore with various carbonyl groups, namely, C6F5CO, C6H5CO and CHO for 1, 2 and 3, respectively. In dichloromethane, these sensors respond to both CN− and F− with distinct colour changes. UV-Vis, 1H NMR and HRMS measurements imply a two-process interaction between the sensors and CN−. Initially, CN− forms a hydrogen bond with the NH moiety, and then it attacks the carbonyl group of the sensors via a nucleophilic addition reaction. In contrast, in aqueous systems, only cyanide induced vivid solution colour changes from light yellow to pink via nucleophilic addition reactions. The CN− detection limits reach a micromolar level of 3.6 × 10−6 M, 4.2 × 10−6 M and 7.1 × 10−6 M for 1, 2 and 3, respectively. In view of the easy synthesis and the highly selective recognition of CN− with vivid colour changes, 1–3 may be developed as a novel and promising prototype of selective and sensitive colorimetric cyanide sensors.
由于
氰化物的毒性和在工业活动中的广泛应用,
氰化物传感引起了越来越多的关注。在此,我们通过对二
吡咯啉发色团的 α 位进行不同羰基的修饰,开发了三种
氰化物比色传感器,即 1、2 和 3 的羰基分别为 C6F5CO、C6H5CO 和 CHO。在
二氯甲烷中,这些传感器对 CN- 和 F- 都有明显的颜色变化。紫外-可见光、1H NMR 和 HRMS 测量结果表明,传感器与 CN- 之间存在两个过程的相互作用。首先,CN- 与 NH 分子形成氢键,然后通过亲核加成反应攻击传感器的羰基。相比之下,在
水性体系中,只有
氰化物通过亲核加成反应诱导溶液颜色从浅黄色变为粉红色。1、2 和 3 的 CN- 检测限分别达到 3.6 × 10-6 M、4.2 × 10-6 M 和 7.1 × 10-6 M 的微摩尔
水平。鉴于 1、2 和 3 易于合成,对 CN- 的识别选择性强,且颜色变化鲜明,因此可将其开发为一种新型的选择性灵敏比色
氰化物传感器原型。