A Naphthalimide-Based Glyoxal Hydrazone for Selective Fluorescence Turn-On Sensing of Cys and Hcy

A fluorescent turn-on probe for Cys/Hcy based on inhibiting the C=N isomerization quenching process by an intramolecular hydrogen bond was reported. The probe exhibited higher selectivity toward Cys/Hcy over other amino acids as well as thiol-containing compounds.