A 2,5-diaryl-1,3,4-oxadiazole-based fluorescent probe for rapid and highly selective recognition of hydrogen sulfide with a large Stokes shift through switching on ESIPT

A new 2,5-diaryl-1,3,4-oxadiazole-based ratiometric fluorescent probe (OXDNP) for rapid and highly selective recognition of hydrogen sulfide has been developed. [Display omitted] A new 2,5-diaryl-1,3,4-oxadiazole derived ratiometric fluorescent probe (OXDNP) for hydrogen sulfide recognition has been developed. Probe OXDNP displays highly selective and sensitive detection to HS− over other anions and thiol-containing amino acids in DMSO solution with fast response and a large Stokes shift. Through HS− induced thiolysis of the dinitrophenyl ether, the excited state intramolecular proton transfer (ESIPT) featured precursor was released, which led to dual fluorescence emission ‘turn on’ and ratiometric emission behavior of the sensing system. The pseudo-first-order reaction rate constant was calculated to be 1.234s−1. The HS− recognition mechanism was proved by HPLC–MS and 1H NMR comparison investigations.