Fast Intramolecular Thiol-Activated Arylselenoamides Provide Access to Triggered, Fluorogenic H₂Se Donors

H₂Se is the precursor for the biosynthesis of selenocompounds and is a potential gasotransmitter. Chemical tools for H₂Se delivery and detection are important for Se-related biology research. Key challenges in the field include developing compound platforms that are triggered to release H₂Se under various stimuli and developing fluorogenic donors that allow for real-time tracking of H₂Se delivery. Here we report a new general platform for triggered H₂Se donors based on controllable deprotection of a thiol, which can quickly activate an intramolecular arylselenoamide (<i>t</i>_1/2 < 1 min) to release H₂Se efficiently. Furthermore, we leverage this platform to develop the first examples of fluorogenic H₂Se donors, which can be used to monitor H₂Se release by fluorescence in real time. We anticipate that the well-defined donation chemistries will significantly advance the development of H₂Se donors and stimulate further in-depth studies of H₂Se biomedicine.