Imine bond transformation of a dynamic Sm(III) macrocycle-based chemosensor: The indirect approach for detecting...

Herein, we report our strategy to develop the efficient chemosensor and real-time monitoring technique for cyanuric chloride (TCT) detection. A luminescent macrocyclic mononuclear Sm(III) complex Sm-2_k bearing with two dynamic imine bonds has been constructed via the template synthesis between dialdehyde H₂Q_k and matched diamine 1,2-bis(2-aminoethoxy)ethane. Sensing experiments reveal that complex Sm-2_k exhibits the turn-off fluorescent and colorimetric response for TCT in CH₃OH. It is especially encouraging that this optical sensing process is not only rapid within 60 s but also high-efficient in the presence of TCT analogues as well as sensitive with the low limit of detection (LOD, 1.74 μM) and wide linear sensing range. Mechanism studies demonstrate that TCT sensing is mainly based on the imine bond transformation of probe Sm-2_k, which is due to the increased acidity induced by TCT. Meanwhile, a smartphone-based analytical method was developed to make complex Sm-2_k accessible for the real-time TCT detection by RGB value outputs. It is believed that this work can shed some constructive lights on design of chemosensors and convenient detection technique for highly reactive analytes.