Detection of thiophenol in buffer, in serum, on filter paper strip, and in living cells using a red-emitting amino phenothiazine boranil based fluorescent probe with a large Stokes shift

A novel red-emitting dye, PB-NH2, was synthesized by incorporation of an electron rich phenothiazine moiety to classical boranil dye. PB-NH2 displayed excellent photophysical properties, such as long emission wavelength, large Stokes shift, strong emission both in solution and in solid state. Based on this attractive platform, Probe 1, was constructed for selective detection of thiophenol. Notably, Probe 1 was ultrasensitive in response to thiophenol, and the corresponding detection limits for thiophenol in theoretical and in experimental were determined to be 1.4 and 10 nM, respectively. Significantly, Probe 1 showed great potential for practical applications, and the applications in real water samples, in serum, on filter paper strips and in living cells were successfully demonstrated.