A novel imidazo[1,5-α]pyridine-based fluorescent probe with a large Stokes shift for imaging hydrogen sulfide.

An imidazo[1,5-α]pyridine-based fluorescence probe NIPY-DNP with a large Stokes shift (193 nm) has been successfully developed for highly selective, sensitive and rapid detection of H 2 S. The selective deprotection of 2,4-dinitrophenyl ether group of NIPY-DNP by H 2 S led to a dramatic fluorescent enhancement (273-fold) at 505 nm within 5 min in PBS buffer solution. The sensing mechanism is proposed on the basis of the thiolysis reaction by H 2 S, which has been confirmed by HPLC and HRMS. The detection limit is 0.36 μM, which is superior to the other reported H 2 S probes. Additionally, cell imaging studies demonstrated that NIPY-DNP could be used to visualize H 2 S in living cells. [ABSTRACT FROM AUTHOR]