Rational design of a novel turn-on fluorescent probe for the detection and bioimaging of hydrazine with barbituric acid as a recognition group

A novel turn-on fluorescent probe with barbituric acid as a unique recognition group has been rationally designed and synthesized using a facile method for detecting hydrazine. The 5-((7-(dimethylamino)-4,5-dihydronaphtho [1,2-b] thiophen-2-yl)methylene)pyrimidine-2,4,6 (1H,3H,5H)-trione (DPT) probe displays a large emission signal ratio variation (more than a 40-fold enhancement) in the presence of hydrazine under neutral conditions. Interestingly, a novel recognition mechanism based on a hydrazine-triggered addition-cyclisation-retro aldol was proposed and confirmed. Additionally, the DPT probe exhibits a low detection limit (5 × 10 -8 M), applicable to the physiological pH range (3-12), a broad linear response range for hydrazine concentrations between 0 and 34 μM and a large Stokes shift (147 nm) for hydrazine detection in aqueous solution. Moreover, the DPT probe was successfully implemented for hydrazine imaging in vivo.