MANGO‐“Fruitcage”: A Conditional Photocage Utilizing a Fluorescence Light‐Up Aptamer

Photolabile protecting groups (PPGs) offer light‐controlled molecular activation, but improving their photolysis quantum yield (QY) remains a challenge. Here, we present a proof of concept for an approach that we call “fruitcaging” which pertains to new conditionally activatable photocages. We show that a photocleavable thiazole orange 1 derivative (TO1‐cage) alone has a QY below 0.1%, rendering it nearly inactive. However, in the presence of the fluorescence light‐up aptamer (FLAP) Mango, the fluorescence emission increased 180‐fold, and the photocleavage reaction 14‐fold. Femtosecond time resolved experiments revealed a drastically prolonged excited state lifetime of the TO1‐cage upon binding to the Mango‐aptamer, which facilitates the cleavage reaction and turned an inactive photocage to an active aptamer‐photocage system—the “fruitcage”. This strategy offers detailed insights in the engineering of the excited state dynamics of a TO1‐based PPG and therefore presents a new tool for efficient conditionally activated PPG for a variety of applications in the field of photochemistry.