8-Hydroxyjulolidine-9-carboxaldehyde

8-Hydroxyjulolidine-9-carboxaldehyde (9-Formyl-8-hydroxyjulolidine) is a highly selective fluorescent probe for hydrogen sulfide (S2−) and silicate (SiO32−). 8-Hydroxyjulolidine-9-carboxaldehyde operates via a mechanism of blocking intramolecular charge transfer (ICT), exhibiting significant fluorescence enhancement in the presence of weak acid ions. 8-Hydroxyjulolidine-9-carboxaldehyde is promising for research of fluorescence imaging of hydrogen sulfide within living cells.