Coumarin 1,4-enedione for selective detection of hydrazine in aqueous solution and fluorescence imaging in living cells

Hydrazine is a widely used but highly toxic chemical reagent, and the development of a fluorescent probe for hydrazine detection is very meaningful. In this study, a novel coumarin-derived fluorescent probe containing a 1,4-enedione moiety for hydrazine detection was developed. The recognition of hydrazine with the probe brings about obvious fluorescence enhancement over other environmentally relevant ions and amine-containing species. The limit of detection for hydrazine is 2.7×10^-8 M in aqueous solution. The fluorescence enhancement was ascribed to the cyclization reaction of the 1,4-enedione moiety of the probe and hydrazine which form a six-membered pyridazine ring and intramolecular charge transfer (ICT) mechanism. The mass spectrometry (MS), nuclear magnetic resonance (NMR) analysis and theoretical calculations confirmed the recognition produced. The probe can be used to determine trace hydrazine in real water samples. More importantly, the probe also showed good potential in detecting hydrazine by imaging of living HeLa cells.