A fluorescent probe based on tetrahydro[5]helicene for highly selective recognition of hydrogen sulfide.

Endogenous hydrogen sulfide plays an important role in various physiological and pathological processes and the convenient and selective recognition of hydrogen sulfide has become a research hotspot. We designed and synthesized a tetrahydro[5]helicene and 2,4-dinitrobenzene conjugate (HD-DNP) as an effective fluorescent probe for selective detection of H2S. The selective deprotection of 2,4-dinitrophenyl ether group of HD-DNP by H2S led to a dramatic fluorescent enhancement (101-fold) at 500 nm and colorimetric change in DMSO-PBS solution. HD-DNP displays many advantages including low background without any self-fluorescence, as well as high selectivity towards common bio-thiols such as Cysteine, Homocysteine and Glutathione. The detection limit of this probe for H2S was found to be about 2.4 μM with a wide linear range (10-70 μM). The response mechanism of the probe with HS- is confirmed to be thiolysis of the dinitrophenyl ether induced by HS- through 1H NMR comparison investigations.