Thermal Truncation of Heptamethine Cyanine Dyes.

Cyanine dyes are a class of organic, usually cationic molecules containing two nitrogen centers linked through conjugated polymethine chains. The synthesis and reactivity of cyanine derivatives have been extensively investigated for decades. Unlike the recently described phototruncation process, the thermal truncation (chain shortening) reaction is a phenomenon that has rarely been reported for these important fluorophores.

Sulfonothioated -Methyl BODIPY Shows Enhanced Uncaging Efficiency and Releases HS.

-Methyl BODIPY photocages stand out for their absorption properties and easy chromophore derivatization. However, their low uncaging efficiencies often hinder applications requiring release of protected substrates in high amounts. In this study, we demonstrate that the sulfonothioated BODIPY group photocleaves a sulfonylthio group from the -methyl position with a 10-fold higher quantum yield than the most efficient leaving groups studied to date.