Synthesis, photophysical properties and fluorescent application of novel [1,2,4]triazolo[1,5-a]pyrimidin-7(4H)-one derivatives

To extend the application of our theoretical screening method for exploring novel fluorescent fragments, we identified [1,2,4]triazolo[1,5-a]pyrimidin-7(4H)-one as a potential fluorophore, whose optical properties are rarely investigated. In this work, nineteen of novel [1,2,4]triazolo[1,5-a]pyrimidin-7(4H)-one derivatives were designed, synthesized and the relationship between the structure and fluorescence property of [1,2,4]triazolo [1,5-a]pyrimidin-7(4H)-one derivatives was systematically elucidated. The representative compound 5b exhibited notable fluorescence intensity with good fluorescence quantum yield (Phi = 0.285) in PBS. More importantly, compound 5b selectively detected the Fe3+ ions through fluorescent quenching effect with rapid response, good anti-interference and low detection limit (LOD = 1.82 mu M), and could be applied for encryption ink. This work provides an efficient way to explore novel fluorescent molecules.