Highly emissive triphenylamine based fluorophores for detection of picric acid

Triphenylamine based, dumbbell shaped, highly fluorescent compound 1 was designed and synthesized. Compound 1 showed blue emission with quantum efficiency as high as 0.78 in benzene solution. Compound 1 showed turn-off sensitivity to picric acid, which is a common constituent of many powerful explosives and unavoidable environmental threats. The turn-off sensitivity to picric acid is attributed to the excited state charge transfer from compound 1 to picric acid. Compound 1 selectively senses picric acid with a detection limit of ∼400 ppb.