Detection of hydrazine via a highly selective fluorescent probe: A case study on the reactivity of cyano-substituted CC bond

Hydrazine plays wide roles in industrial fields but causes serious safety issues due to its high toxicity and strong activity; hence, it is important to develop reliable and convenient analytical tools for detection of hydrazine. In this work, two optical probes 1 and 2 were presented for detecting hydrazine incorporating malononitrile and 2-benzothiazoleacetonitrile, respectively. Probe 1 with dicyanovinyl was demonstrated to be more highly reactive to hydrazine, owing to the stronger electron-withdrawing ability of malononitrile. Moreover, probe 1 showed excellent selectivity toward hydrazine vapor over other amines in colorimetric and fluorescence turn-on modes. The hydrazone product between probe 1 and hydrazine was also confirmed by HRMS. In addition, probe 1-loaded TLC plates can discriminate hydrazine vapor from other volatile amines by naked eyes. Furthermore, probe 1 was successfully utilized for detection of hydrazine in living cells.